Heat treatment of Mg-Zn-Gd and Mg-Zn-Dy alloys for enhanced wear and corrosion properties

Heat treatment of Mg-Zn-Gd and Mg-Zn-Dy alloys for enhanced wear and corrosion properties | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Heat treatment of Mg-Zn-Gd and Mg-Zn-Dy alloys for enhanced wear and corrosion properties Rakesh K.R, Pratyush Mohanty, Srikanth Bontha, Ramesh M. R, Vamsi Krishna Balla This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8065387/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 7 You are reading this latest preprint version Abstract In this study, the effect of heat-treatment on the microstructure, wear, and corrosion behavior of Mg-1Zn-2Gd-0.4Zr (wt. %) and Mg-1Zn-2Dy-0.4Zr (wt. %) alloys were studied. The alloys were solution treated at 500 ℃ for 12 h, followed by ageing for 12 h at 225 ℃ (T6). The microstructural analysis revealed significant amount of secondary phase precipitation after heat treatment in both alloys, which resulted in 20 to 25% increase in the hardness. Wear tests performed between 200 and 400 ℃, at different loading conditions (10 N, 20 N), revealed improved wear resistance in Mg-Zn-Gd alloy samples compared to Mg-Zn-Dy alloy. Further improvement in the wear resistance was also observed after heat treatment. Delamination, abrasion, and oxidation were found to be dominant wear mechanisms in these alloys. Immersion corrosion tests carried out in 3.5 wt. % NaCl solution demonstrated that the heat treatment can significantly improves the corrosion resistance. This is primarily due to the changes in microstructure, i.e., uniform distribution of secondary phases after heat treatment. Among the two alloys, Mg-Zn-Gd alloy in heat-treated condition was found to exhibit relatively lower corrosion rate than the Mg-Zn-Dy alloy in both as-cast and heat-treated conditions. Mg-Zn-Gd alloy Mg-Zn-Dy alloy Microstructure Heat-treatment Wear Corrosion Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 1. INTRODUCTION Magnesium (Mg) is, possesses many unique properties such as high specific strength, excellent castability, and better noise and vibration damping capability [ 1 ]. Recent developments also showed that Mg is a potential replacement for other engineering materials in structural, automotive, and aerospace applications [ 2 ][ 3 ][ 4 ]. Traditionally, aluminium is a lightweight material and that has replaced the steel and then cast iron in the automotive industry. Lighter than Aluminum, using Mg for automotive components (steering wheel, gearboxes, cylinder blocks etc.,) is further expected to reduce the weight of the automobile and thereby result in more fuel-efficient vehicles [ 5 ]. Despite having many desirable characteristics, certain limitations such as low workability, poor corrosion resistance, and low mechanical strength at elevated temperatures have limited the wide-spread applicability of Mg. Alloying Mg with one or more elements such as aluminium (Al), zinc (Zn), manganese (Mn), zirconium (Zr) and rare earth elements (REE) etc. in varying concentrations can improve specific properties of Mg for desired applications. Among the various binary alloy system studied, the Mg-Zn alloy system is found to be second strongest ductile alloy system in Mg-based alloys [ 6 ]. Other alloying element zirconium (Zr) is added as a grain refiner to the Mg or its alloys containing Zn, yttrium (Y). The degree of grain refinement attained by Zr addition is better than other grain refinement methods [ 7 ]. The addition of bismuth (Bi) also studied and concluded that heat resistance of Mg alloy is improved at elevated temperature. However addition of Bi to Mg-Nd alloy results in a decrease in strength at room temperature [ 2 ]. Although the binary alloy systems developed were observed to be higher corrosion rate and lower yield strength [ 8 ]. Based on the combinative requirement of strength and lower corrosion rate, third alloying elements are added to make the alloy suitable for various industrial applications. Leading commercial Mg alloys include Mg-Al-Mn (AM Series), Mg-Al-Zn (AZ Series), and Mg-Zn-REE (AE Series) Mg-Zn-Zr (ZK series) [ 2 ]. Recently, new class of materials, rare earth elements (REE) got an attention such as gadolinium (Gd), dysprosium (Dy), yttrium (Y), neodymium (Nd), etc. have proven to be effective alloying elements for improving the strength, ductility, corrosion and creep strength of magnesium alloys [ 3 ], [ 4 ]. This lead to the design of many Mg-REE based series alloys. Irrespective of its cost and complexity in casting it is irreplaceable with its applications in aerospace and defence field.[ 11 ]. The strengthening of Mg alloys by the adding of REE is because of solid solution strengthening and precipitation hardening mechanism. Rare earth elements such as gadolinium (Gd) and dysprosium (Dy) have very high solubility of 23.49 wt. % and 25.8 wt. % respectively in Mg at eutectic temperature, which makes these elements appropriate for precipitation hardening compared to other elements from the lanthanide series [ 10 ]. Mg alloys with little amount of REE addition exhibit good elongation and better strength [ 12 ]. The tensile strength and ductility notably enhanced by the formation of long period stacking ordered phases (LPSO) when REE elements are added as the third alloying element [ 13 ]. WE43 (4 wt.% Y, 3 wt.% (Nd, Ce, Dy)], Mg-Y (4 wt.%) are extensively investigated REE alloy with improved mechanical properties (~ 195 MPa) and corrosion resistance [ 14 ]. In order to tailor the wear, and corrosion properties heat treatment and secondary deformation techniques were adopted for Mg-REE alloys [ 15 ] [ 16 ]. Various kinds of heat-treatments have been performed on Mg alloys to improve their strength by forming hard eutectic phases [ 17 ]. Among the heat treatment, precipitation strengthening through age hardening in Mg alloys is the exploited phenomena to achieve desired mechanical and microstructure properties [ 18 ]. The AZ91alloy showed a lower wear resistance due to the distribution of Mg 17 Al 12 eutectic phase. This problem was tackled by dissolving the Mg 17 Al 12 phase completely through T6 heat treatment, thereby improving improved the mechanical properties [ 19 ]. In the case of ZK (Magnesium-Zinc-Zirconium) alloys T6 age hardening process leads to an addition to its strength but it is less compared to the Al-based alloys. This low age hardening response is mainly due to the Zn 2 Zr intermetallic formation [ 18 ]. Gao et al. [ 20 ] performed heat-treatment on Mg-15Gd-5Y-0.5Zr alloy and reported the formation of a cuboid-shaped compound (Mg 2 Y 3 Gd 2 ), which improved the strength of the alloy at elevated temperatures. Li et al. [ 21 ] reported the formation of cuboid-shaped phases and block-shaped 14H LPSO phases, which will enhance the mechanical and corrosion properties of Mg–10Gd–3Y–1.2Zn–0.4Zr after post solution treatment at 500 ℃ for varying time period (i.e.12, 30, 48, and 72 hrs). In another study, Zheng et al. [ 22 ] reported an increase in the hardness of Mg–10Gd–6Y–2Zn–0.6Zr alloy after solution treatment followed by ageing. Similar studies have also been carried out with Mg-Zn-Dy alloys, where heat-treatment has resulted in improved in their strength, hardness, and corrosion properties [ 23 ][ 24 ]. In this work, solution heat-treatment of Mg-1Zn-2Gd-0.4Zr (wt. %) and Mg-1Zn-2Dy-0.4Zr (wt. %) followed by aging (T6) were performed and their effect on the microstructure, hardness, wear, and corrosion behaviour have been investigated. 2. MATERIALS AND METHODS 2.1 Alloy preparation and heat treatment Mg-Zn-Gd and Mg-Zn-Dy alloys with specified composition were prepared through conventional casting route. The alloys Mg-Zn-Dy and Mg-Zn-Gd were prepared in a furnace under an Ar + 2% SF 6 protective environment. Primarily, Mg-Zn parent melt was prepared, and at a temperature of 750℃, other alloying elements such as Gd, Dy, and Zr were added carefully. After 20 minutes of holding, the molten melt was stirred for 20 minutes, followed by pouring into the cast iron mold. The prepared alloy compositions are Mg-1% Zn-2%Gd-0.4%Zr and Mg-1%Zn-2% Dy-0.4%Zr respectively. Heat treatment (T6) was performed on as-cast Mg-Zn-Gd-Zr and as-cast Mg-Zn-Dy-Zr alloys. The specimens were placed in a tubular furnace and were solution treated at 500 ℃ for 12 hours and then quenched in cold water. Then the samples were aged at 225℃ for different time durations (12, 18, and 24 hours) and subsequently quenched in cold water. T6-12, convention indicates heat treatment of alloy followed by 12 hours of ageing. Similarly for the different ageing time the conventions T6-18 and T6-24 are used in the following discussion. 2.2 Microstructural analysis The as-cast and heat-treated (T6) specimens were prepared from the bulk material into cube samples of dimensions of 5 mm × 5 mm × 5 mm cube samples. All the specimens were polished with different grades of SiC sheets ranging from 200 to 2000 grit. Later these specimens were cloth polished with diamond paste of size 0.25 µm till mirror finish was achieved on the surface. All the samples were then etched with a solution of picric acid (2.5 g), ethanol (100 ml), acetic acid (25 ml) and distilled water (25 ml). After etching the specimens were rinsed with running water and dried with a blower. Optical microscope images were taken to understand the distribution of different phases. SEM images were taken at various magnifications using JSM-6380LA, JEOL USA Ltd to identify the type of phases. X-ray Diffractometer (DX-GE-2P, JEOL, Japan) was used in the 2θ range of 20–100 degree and at a scanning rate of 2 ֯/min on the as-cast and heat-treated samples for phase analysis. 2.3 Hardness and wear studies Hardness testing of all the specimens (as-cast and heat-treated alloys) was carried out using Brinell hardness tester for (Instron, USA) with a steel ball indenter of diameter 10 mm. A load of 250 kg was applied with a dwell period of 30 sec. At least five measurements were performed on each sample, and the mean value is reported. Dry sliding wear tests were performed using a Pin on Disc apparatus with EN-24 steel disc as the counter material on both as-cast and heat-treated alloys. The specimens were prepared according to the ASTM G-99 standard. Loads of 10 and 20 N with a temperature range of 200 ℃-400 ℃ were considered for the wear study. The sliding velocity and sliding distance were fixed at 1.25 m/s and 1500 m, respectively. Before starting the experiment, the disc was cleaned with ethanol to remove the debris on the surface. Further it was cleaned with alcohol. The weight of each sample was measured before and after the wear test for calculating mass loss. The worn pin surfaces and wear debris were collected and analysed using a scanning electron microscope (SEM) and X-ray diffraction (XRD) techniques. Table 1 presents the input parameters used in the wear study. Table 1 Input parameters for wear study Alloy Condition Load (N) Temperature (°C) Mg-Zn-Dy As-cast 10, 20 200, 300, 400 Heat treated 10, 20 200, 300, 400 Mg-Zn-Gd As-cast 10, 20 200, 300, 400 Heat treated 10, 20 200, 300, 400 2.4 Corrosion studies An immersion corrosion study was carried out, and a setup similar to the one used in the study of song et al. [ 25 ] was used. The set up consists of 500 ml beaker and 75 ml funnel. A solution of 150 ml was poured into each beaker, and the specimens were immersed in it. The funnel was placed just above the sample in an inverted position to collect the hydrogen evolved during the corrosion process (30 ± 2 ℃). All the specimens were cut into samples of dimensions 10mm × 10 mm × 5 mm (length × Width × Thickness) from a larger block and then ground with polishing paper (of grade ranging from 200–2000). The specimens were then subjected to cloth polishing with diamond paste till mirror finish was obtained. Next, the weights of the specimens were measured in a 0.001 mg precision weight measuring machine. Then these specimens were mounted to a PVC cylindrical pipe of 20 mm height and 15 mm dia, such that only one surface was exposed to solution. For the study, a solution of 3.5 wt. % NaCl was prepared. The samples were immersed in the 3.5 wt. % NaCl solution for 72 hours. Following this, the samples were thoroughly cleaned with a solution (chromic acid (200 ml/l) and silver nitrate (10 ml/l)) to remove all the corrosion products from the samples. Then the samples were rinsed in water and dried with the help of a blower. The cleaned samples were then taken for weight measurement. The corrosion rate was calculated as: (C.R) w = \(\:\frac{8.76\times\:{10}^{4}\times\:W}{A\times\:t}\) (1) Where (C.R.) w is the corrosion rate in (mm/year), W is the weight loss in g, A is the exposed surface area in (mm 2 ), and t is the immersion time in hours. 3. RESULTS AND DISCUSSION 3.1 Hardness studies Table 2 presents the results of Brinell hardness study results on both as-cast and heat-treated Mg-Zn- Gd and Mg-Zn-Dy alloys. Table 2 Hardness results of as-cast and heat-treated Mg-Zn-Gd and Mg-Zn-Dy alloys Alloy Brinell Hardness Number (BHN) As-Cast Heat treatment condition-(Time (h)) T6-(12) T6-(18) T6-(24) Mg-Zn-Gd 37 ± 1.5 47 ± 1.5 47 ± 1.6 48± 1.7 Mg-Zn-Dy 39 ± 1.6 46 ± 1.8 47 ± 1.3 47± 1.5 In Table 2, T6-(12) represents the T6 sample with an aging time of 12 hours; similarly, T6-(18) and T6-(24) represent the T6 sample with aging times of 18 hours and 24 hours respectively. It is reported that the hardness of Mg alloys increases after heat treatment due to the uniform re-distribution of secondary phases [17]. In this study, it was observed that after heat treatment, the BHN of both the alloys increased by 20–25%. The BHN of Mg-Zn-Gd alloy in as-cast condition was found to be 37 ± 1.5. After solution treatment followed by 12 hours of aging its hardness increased to 47 ± 1.5 BHN. For Mg-Zn-Dy alloy, the hardness increased from 39 ± 1.6 BHN in the as-cast condition to 46 ± 1.8 BHN for the (T6-12) condition. The T6 heat-treatment with an aging period of 18 and 24 hours did not significantly increase the hardness. Therefore, the heat-treated sample with 12 hours of aging was found to be the optimum among the ones considered in this work. Hence for all further studies, the heat-treatment (T6) followed by ageing at 12 hours i.e., (T6-(12)) is considered for the comparison with as-cast Mg-Zn-Gd and Mg-Zn-Dy alloys. Precipitation hardening was the primary reason for the increase in hardness in both the alloys, which causes co-segregation of secondary element atoms. The secondary phases containing rare earth and zinc elements are harder when compared to the α-Mg matrix. When these secondary phases dissolve into the α-Mg matrix, the hardness of the matrix phase increases. Nie et al. [26] concluded that co-segregation in the form of Gd–Zn dimers could provide more effective pinning of gliding dislocations, and therefore contribute to an increase in the hardness. Guangli et al. [27] reported a similar result, which reported an increase in hardness of the Mg-Dy-Zn alloy after solution treatment followed by cooling for 20 minutes at a rate of 2 ℃/min. 3.2 Microstructural and phase analysis The optical microscope (OM) and scanning electron microscope (SEM) images of as-cast and heat-treated (T6-(12)) Mg-Zn-Gd alloy are represented in Fig. 1. Among the different aging conditions, heat treatment followed by 12 hours of ageing is considered to be effective in improving the properties of these alloys. This conclusion is drawn based on the hardness results presented in section 3.2.. In this paper, the heat treatment followed by 12 hours of aging is referred to as (T6 – (12). Figures 1 (a) and (b) show dendritic grains and secondary phases distributed along the grain boundaries of as-cast Mg-Zn-Gd alloy. The microstructure of the as cast Mg-Zn-Gd primarily composed of α-Mg, Mg 5 Gd phases, and few eutectic phases, which could be a combination of α-Mg, MgZn 2, and Mg 5 Gd phase. In the as-cast alloy (Fig. 1 (a), the secondary eutectic phases (dark regions), that are present along the grain boundary, and are non- homogeneously distributed. The micrographs of the heat-treated (T6-(12)) alloy, (Figs. 1 (c) and (d)) reveal that the formation of secondary phases is significantly lower. The secondary phases have been dissolved into the α-Mg matrix, and fine lamellar precipitates have formed inside the grains. The grains of the heat-treated alloy were found to be more homogeneous with uniform distribution of secondary precipitates. There were some globular type phases identified from SEM images, which are shown in Figs. 1 (c) and (d). The morphology of these phases matched with the morphology of Mg 5 Gd reported in the work of Peng et al. [28]. There were some new block-shaped precipitates, and their morphology matched that of f MgGd 3 , as reported in [29] and [30]. These phases were also confirmed by the XRD results shown in Fig. 3 (b). Yamasaki et al. [31] identified the hard lamellar phase, to be 2H and 14H type LPSO phases. A similar kind of fine lamellar precipitate analogous to LPSO in nature was also observed in smaller quantities in this study, and are shown in Fig. 1 (d ). XRD results of Mg-Zn-Gd alloy sample are shown in Figs. 3 (a) and (b). The peaks of Mg 5 Gd and α-Mg in as-cast and heat-treated Mg-Zn-Gd alloy are shown in Fig. 3(a). A new MgGd 3 peak was observed in heat-treated (T6-(12)) Mg-Zn-Gd alloy (Fig. 3 (b) ) at angles of ~ 33° and 57°. The presence of these new Mg-REE compounds validates the presence of different morphologies, that have been identified from the micrographs (Figs. 1 (c ) and (d)). Figure 2 shows the optical microscope and scanning electron microscope (SEM) images of as-cast and heat-treated (T6-(12)) Mg-Zn-Dy alloy. In the as-cast Mg-Zn-Dy (Figs. 2 (a) and (b)) , the grains have a dendritic structure with a large fraction of secondary phases distributed primarily at the grain boundaries. There were many large and small regions of intermetallic phases that were also present inside the grain (black colour inside the grain as shown in Figs. 2 (c) and (d) ). The SEM image of the as-cast alloy shown in Fig. 2 (d) , reveals few rectangular-shaped particles along with some irregular shaped precipitates. The morphology of the rectangular-shaped precipitates was found to be matching with the morphology of Mg 2 Dy precipitates. While the irregularly shaped precipitates observed were found to have similar morphology as that of (Mg, Zn) x Dy precipitates reported in the study of Bi et al. [32]. Mg 24 Dy 5 , with different morphology, was also formed at the grain boundary. Numerous small black spots were observed, which were primarily situated at the grain boundary. Lamellar phases were also observed inside the grain (Fig. 2 (c)). Similar kinds of fine lamellar phases were reported in [33]. This phase was reported to be the 14H LPSO phase. The distribution of the small precipitates in the heat-treated Mg-Zn-Dy was non-homogenous, and many clusters of these intermetallic phases were observed. Figures 3 (c) and (d) show the XRD results of as-cast and heat-treated (T6-(12)) Mg-Zn-Dy alloy. The peaks observed in the as-cast alloy were α-Mg, Mg 24 Dy 5, and Mg 2 Dy ( Fig. 3 (c)). These results confirm their findings from the microstructural analysis. However, in the case of the heat-treated (T6-(12)) Mg-Zn-Dy alloy, the peak of Mg 24 Dy 5 ( Fig. 3 (d)) , phase were not present, which supports the idea of the slight dissolution of eutectic phases after heat-treatment. 3.3 Wear studies The effect of heat treatment on wear rate is represented in Figs. 4, 5. The wear behaviour of as-cast and heat-treated (T6-(12)) Mg-Zn-Gd and Mg-Zn-Dy alloys are shown in Fig. 4. It is known that the wear rate of a material depends on the load, velocity, coefficient of friction, and surface temperature [34] [35] [36]. From Fig. 4 it can be observed that the wear rate of the as-cast alloy is higher than that of the heat-treated samples at different loading conditions. The lower wear rate heat-treated alloys is primarily due to the high hardness of these samples as a result of precipitation of secondary phases along the grain boundaries during heat treatment. Mehta et al. [37] studied the wear behaviour of Mg-Al alloy and reported that higher the hardness of the material lower would be the wear rate under dry sliding wear conditions. It was also observed from Archard’s law, [38] that the wear rate is inversely proportional to the hardness. It is clearly observed from the hardness measurements (Table 2 ) that the hardness of the alloy is increased after heat treatment and therefore the wear resistance. The formation/precipitation of the LPSO phase after heat treatment is the ideal strengthening secondary phase in both Mg-Zn-Gd and Mg-Zn-Dy alloys. The LPSO phase has higher hardness, better thermal stability, and coherent interface with the Mg matrix [32]. This infers that the thermally stable Mg 24 Dy 5 and LPSO (14-H) resist the material flow during friction and wear [39] thereby improving the wear resistance. This is evident from Fig. 4, where the wear rate decreased as the heat treatment temperature increased from 200 to 400°C for both the alloys. This could be due to changes in microstructure of both the alloys at high temperature condition and changes in the strength or hardness with temperature and consequent changes in the deformation behaviour of the samples at these test temperatures [40]. Similarly, during dry sliding wear testing of Mg-11Y-5Gd-2Zn, the wear resistance of the heat-treated samples was found to be higher than the as-cast samples, which was attributed to the precipitation of Mg 12 Y 1 Zn 1 phase [41] [42]. Further , the wear rate of the alloys increased with increasing load from 10 N to 20 N for both the alloys tested. This is due to increased contact pressure. Figure 4 (a) shows the wear rate of Mg-Zn-Gd in as-cast and T6-(12) conditions with respect to the temperature. As it can be observed from Fig. 4 (a) , for a load of 10 N, the wear rate is decreasing from 1.6x10 − 3 mm 3 /mm to 1.2x10 − 3 mm 3 /mm with an increase in temperature (200°C to 400°C )for both as-cast and T6 - (12) Mg-Zn-Gd alloy. But the heat-treated alloy exhibit a lower wear rate when compared to as-cast alloy. The same trend was observed for the Mg-Zn-Dy alloy, when loaded at 20 N. However, the wear rate exhibited a drastic increase when compared to 10 N load in the Mg-Zn-Gd alloys in both as-cast and heat-treated conditions. At 20 N loading also the heat-treated Mg-Zn-Gd alloy shows a lower wear rate when compared to as-cast alloy. Figure 4 (b) shows the wear rate of Mg-Zn-Dy alloy in both as-cast and heat-treated conditions. At an applied load of 10 N, the wear rate of both as-cast and heat-treated alloy sample decreases with an increase in temperature. In the as-cast and heat treated condition, minimum wear rate was observed at 400°C temperature. When compared to as cast and heat-treated samples, heat-treated samples exhibit lower wear rate. The heat-treated sample exhibits minimum wear rate at 400°C. The secondary phases (MgGd3, Mg 5 Gd) in the heat treated alloy has higher strength and thermal stability than α-Mg (dominated in as-cast sample) which is saturated with Gd and Zn. The secondary hard phases effectively give resistance to the material flow in the course of wear. These phases also could effectively pin the grain boundary sliding.[41]. Figs .5 (a) and (b) show the variation in coefficient of friction with respect to temperature in both Mg-Zn-Gd and Mg-Zn-Dy alloys in as-cast and heat-treated conditions, respectively. The general trend, which can be observed for the two alloys is that the coefficient of friction decreases with increased temperatures. Higher temperature during the surface contact between the sample and disc could lead to oxidation of alloy. This surface oxidation act as a protective layer against wear damage and this leads to decrease in wear rate [41]. Similar dry sliding behavior trends have reported for Mg-10Gd-3Y-0.4Zr and Mg-11Y-5Gd-2Zn magnesium alloys [34]. This study reported that the wear debris generated at the surface gets oxidized and fills in the valleys of the worn surface at high surface temperatures. This study reported that at the high surface temperatures, the wear debris generated at the surface gets oxidized and fills in the valleys of the worn surface. This oxidized debris layer acts as a protective layer and prevents metal to metal contact between the surfaces, which reduces the friction between them and subsequently decreases the wear rates. A similar observation was also reported by Arora et al. [43], who reported the formation of a mechanically mixed oxide glaze layer (MML), which protects the material from severe wear. With an increase in load from 10 to 20 N, the co-efficient of friction also increased. This is because at higher loads, the surface in contact gets closer to the nominal area of the sample, which increases the friction between them. Figures 6 (a) and 6 (b) show the SEM micrographs of the worn surfaces of as-cast and heat-treated (T6-(12)) Mg-Zn-Gd alloy tested at 20 N load and 400℃ surface temperature. From these images, it can be observed that both the as-cast and heat-treated alloy surfaces have a large number of parallel ridges and grooves lying in the direction of sliding. These features can be attributed to abrasive wear mechanism. Further, the hard asperities between the pin and the counter disc plough the pin. Ploughing leads to removal of small fragments from the pin. When the load increases from 10 to 20 N, the wear behavior changes into a delamination mode of wear (Figs. 6 (a), (b) ). In the delamination mode wear, the debris are formed as the outcome of detachment of subsurface layer from the bulk material. The subs-surface cracks may either exist or nucleate due to the stresses during the course of wear test. Once the subsurface crack joins the wear surface, the dominant wear mechanism is delamination [44]. Figures 6 (a) , (b) , shows that the layers are peeled off from the surface, and short cracks are perpendicular to the sliding direction. The detached wear particles form a sheet-like morphology having shallow craters behind. The thin wear sheet formation on the surface is generally fatigue assisted. The repeated sliding between the surfaces creates a crack on the pins and that shears the surface and leads to the formation of thin sheets [35]. It was observed that the wear rate increased with increasing applied load. Essentially this is due to the increase in penetration of hard asperities from the counter disc to the softer pin thereby leading to the increase in the fracture of softer pin surface. It is also reported that micro-cracking and sub-surface deformation tendency also increase with an increase in the load [45] but it is not observed in these worn surface micrographs (Figs. 6 (a),(b)) . Figures 6 (c ) and (d) show the SEM images of the worn surfaces of as-cast and heat-treated (T6-(12)) Mg-Zn-Dy alloy that was tested at 20 N load and 400 ℃ temperature. The wear rate showing decrease in trend at this higher load and temperature condition. These SEM images reveal features of abrasive wear on the worn surfaces of both as-cast and heat-treated Mg-Zn-Dy alloy. These are primarily caused when the hard asperities present in between the pin and disc, plough into the pin under the application of load, forming grooves by the removing small pieces of material, which results in wearing of the surface by abrasion. Further, delamination wear is also observed on both as-cast and heat-treated (T6-(12)) Mg-Zn-Dy alloy. Several wear debris with a plate-like shape and having a shiny metallic appearance were observed on this worn surface. The debris that form as the subsurface layers detach from the parent material. Many cracks form during wear, which develops perpendicular to the direction of sliding. When these cracks intersect with, it results in the detachment of sheet-like wear particles [40]. This was also reported as a fatigue-related wear mechanism, which is caused due to repeated sliding. The subsurface cracks, might have been present during the course of wear test. Further, as these cracks meet the wear surface it results in delamination wear. In Fig. 6 (c) , the surface of the worn pin appeared to be black in color, revealing the presence of an oxide layer. The formation of oxide wear debris covers the valleys on the surface of the pin, and this type of wear mechanism is known as oxidation wear [42]. Sliding due to frictional heating at higher temperatures results in the contact surface getting oxidized, and this will making a compact oxide layer over the surface. This layer prevents the metallic contact between the pin and counter disc, thereby leading to minimum wear rate [45]. The formation of these oxide layers was identified by XRD analysis and are shown in Fig. 7. XRD analysis results of the worn surface at a load of 20 N for both Mg-Zn-Gd and Mg-Zn-Dy alloys are shown in Fig. 7. The spectra shown in Figs. 7 (a) and (b) , reveal that the worn surface of both the alloys contain ZnO phase. This could be due to the high surface temperature during wear test that causes zinc to oxidize in an open atmosphere. Abrasion is the dominant wear mechanism evident from the surface micrographs of worn surface and associated with fragmented chips (Fig. 6). The surface of the as cast Mg-Zn-Gd pin appears dark and it is covered by thin layer, which could be mainly due to the oxidation of surface. The strong peak of oxygen is observed in the alloy (Fig. 7) and is reported in previous studies as well [40]. The frictional heating during sliding causes oxidation of the surfaces. Initially, the wear occurs through the removal of these oxide layers. But later, the oxide debris fills the grooves on the surface of the pin, and that further restricts the direct metallic contact, leading to a reduction in the wear. However, the heat-treated Mg-Zn-Dy surface primarily showed abrasion and delamination wear, as was the case in the Mg-Zn-Gd alloy. Figure 7 (b) shows the XRD results of the worn surface of Mg-Zn-Dy alloy. Peaks of MgO and ZnO phases hint at the presence of an oxide layer on the surface of the worn Mg-Zn-Dy alloy. Compared to ZnO, the peaks of MgO are more pronounced in the XRD spectra. The presence of oxides on the surface of the sample clearly suggest that this is oxidation mode of wear [42]. The oxidized debris aid in the formation of a protective layer which makes it difficult to create further abrasion between alloy samples and counter face. Hence the wear rate starts to decrease. At high surface temperature, the repeated sliding on the oxidized surface leads to a lower wear rate. 3.1 Corrosion analysis The corrosion rate of as-cast and heat-treated (T6-(12)) Mg-Zn-Gd and Mg-Zn-Dy alloys are presented in Table 3. A significant reduction in corrosion rate was observed in both Mg-Zn-Gd and Mg-Zn-Dy alloys after T6-(12) heat treatment. The corrosion rate of as-cast Mg-Zn-Gd alloy was found to be 3.86 mm/year, whereas the heat-treated Mg-Zn-Gd alloy showed a corrosion rate of 1.48 mm/year, resulting in a reduction of about 61% with heat treatment. Similarly, the corrosion rate of Mg-Zn-Dy alloy reduced to 2.62 mm/year from 3.92 mm/year after heat-treatment. The microstructure analysis of the heat-treated alloys, (Figs. 1 and 2 ) , showed that the cathodic eutectic phases in as-cast alloy have dissolved into the α-Mg matrix. Further, a large number of fine lamellar precipitates have formed in the matrix which has, inhibited the corrosion and improved the corrosion resistance of the alloys. The large secondary phases present in as-cast Mg-Zn-Gd and Mg-Zn-Dy alloys, adjacent to α-Mg matrix acts as a cathode to the anodic α-Mg. This can initiate galvanic corrosion on the surface [6].The formation of secondary phases influences the galvanic corrosion behaviour. It is reported in the AZ alloy studies that a significant number of finely and continuously distributed secondary phases could more effectively prevent the growth of corrosion in an AZ alloys. But on the other hand, if the amount of secondary phase is low and distributed non-homogenously, it would act as a galvanic cathode and that accelerated the corrosion [10][32]. In the present study, it was observed that secondary phases that are present in the heat treated (T6-12) Mg-Zn-Gd (Mg 5 Gd, MgGd 3, and fine lamellar LPSO phase) alloy are distributed along the grain boundaries. These phases are more homogenous and uniformly distributed and could act as a corrosion barrier [46]. The improved fraction of anode to cathode ratio after heat treatment can reduce the gravity of the galvanic effect, leading to the increased corrosion resistance [47]. In Mg-Zn-Dy alloy, as seen in the micrograph (Fig. 2 (c), (d)) , the distribution of secondary phases such as Mg 24 Dy 5 , Mg 2 Dy are quite discontinuous and they behave as a galvanic cathode to increase the corrosion rate. After T6-12 heat treatment, a large number of secondary phases are dissolved into the matrix, which leads to a reduction in the galvanic corrosion of the alloy [39]. The presence of the LPSO phase also plays an essential role in improving the corrosion resistance in Mg-Zn-Dy and Mg-Zn-Gd alloys [46] [47] of The corrosion rate of heat-treated Mg-Zn-Dy alloy is higher when compared to the heat-treated Mg-Zn-Gd alloy.. Unlike the Mg-Zn-Gd alloy, the microstructure of heat-treated Mg-Zn-Dy alloys consists of intermetallic precipitates, which are seen in cluster (Fig. 2 (d)) form accelerate the corrosion rate. However, the more prominent cathodic eutectic phases have dissolved into the matrix. As a result, the outcome was a reduction in the corrosion rate in heat treated Mg-Zn-Dy sample when compared to its as-cast counterpart. Table 3 Corrosion rate of the alloys in as-cast and heat-treated conditions Alloys Corrosion rate (mm/year) As-cast T6-(12) Mg-Zn-Gd 3.86 \(\:\pm\:\)1 1.48\(\:\pm\:\) 0.1 Mg-Zn-Dy 3.92\(\:\pm\:\)0.8 2.62\(\:\pm\:\)0.2 The SEM images of the corroded surfaces of as-cast and heat-treated (T6-(12)) Mg-Zn-Gd alloy are presented in Figs. 8 (a ) and (b) respectively. It can be observed that in the case of as-cast Mg-Zn-Gd alloy, the attack on the surface due to corrosion is severe, and that corrosion has penetrated to the subsurface level, which is a case of galvanic corrosion. Many corrosion pits were also observed on the surface. However, in the case of heat-treated (T6-(12)) Mg-Zn-Gd alloy, the attack on the surface due to corrosion is relatively less, and besides, many areas on the surface were not attacked by corrosion at all. Filiform type of corrosion was observed in heat-treated Mg-Zn-Gd alloy, and is shown in Fig. 8 (b) . Filiform corrosion of Mg alloys in NaCl was reported and detailed in various studies [48]. In addition to the filiform corrosion tendency, the Mg alloys containing REE’s are oxidised and attached to the corrosion film. This film with REE improves the corrosion resistance. This could be the reason for the improved corrosion resistance in the heat-treated sample. Figures 8 (c) and (d) show the SEM images of the corroded surface of as-cast and heat-treated (T6-(12)) Mg-Zn-Dy alloy respectively. Many corrosion pits were observed on the as-cast Mg-Zn-Dy surface. Pitting corrosion is generally observed in Mg alloys and is caused by the galvanic couple effect between matrix and secondary phases [25]. Corrosion has propagated through the surface to the subsurface level, and a larger portion of the surface has been attacked. Pitting corrosion is also observed in heat-treated Mg-Zn-Dy alloy. However, a large portion of the surface was still unaffected from corrosion, which showed that heat-treatment had improved the corrosion resistance of the Mg-Zn-Dy alloy. 3 CONCLUSIONS In this study, characterization of as-cast and heat-treated Mg-Zn-Gd and Mg-Zn-Dy alloys in terms of microstructure, wear properties, and corrosion behaviour was carried out, and the following conclusions were drawn. After heat treatment, the eutectic secondary phases dissolved into the α-Mg matrix, and new precipitates were formed in both the alloys. However, compared to Mg-Zn-Gd alloy the microstructure of Mg-Zn-Dy alloy showed cluster of intermetallic phases or precipitates distributed were more non-uniformly. Heat-treated alloys showed 20 to 25% higher hardness when compared to as-cast alloys due to precipitation hardening, which also resulted in relatively lower wear rate. Wear studies on these alloys, conducted at different temperatures, revealed a significant amount of surface, and wear debris oxidation that was adhered to the counter surface. These oxidized debris form a protective layer and act as solid lubricants leading to reduction in both friction and wear rate. Corrosion studies showed that the heat-treatment could improve the corrosion resistance of both Mg-Zn-Gd and Mg-Zn-Dy alloys significantly. For Mg-Zn-Gd and Mg-Zn-Dy alloys, a reduction of 60% and 30% respectively in the corrosion rate was achieved after heat-treatment. This improvement in the corrosion resistance of these alloys can be attributed to the dissolution of large eutectic phases and homogeneous distribution of a large number of fine precipitates throughout the alloy matrix. Declarations Conflicts of interest or competing interests There is no conflict of interest for the submitted journal. Supplementary information: There is no supplementary information attached along with the submitted paper Ethical approval Not applicable for the submitted paper Author Contribution Dr. Rakesh K.R. first and the corresponding author has designed the alloys, casted them and carried out all the microstructure, mechanical and corrosion studies on the alloys. Mr. Pratyush Mohanty assisted to carry out the experimentation and consolidating the results of the study. Dr. Srikanth Bontha, Dr. Ramesh M.R. and Dr. Vamsi Krishna Balla are the research mentors and they have guided him in the course of this work. Acknowledgement The authors would like to thank the Metallurgical and Materials Engineering Department, National Institute of Technology, Karnataka for providing access to various experimental facilities. Data and code availability No datasets were generated or analysed during the current study References M.K. Kulekci, Magnesium and its alloys applications in automotive industry, Int. J. Adv. Manuf. Technol. 39 (2008) 851–865. doi: 10.1007/s00170-007-1279-2 . Z. Yang, J.P. Li, J.X. Zhang, G.W. Lorimer, J. Robson, Review on Research and Development of Magnesium Alloys, Acta Metall. Sin. (English Lett. 21 (2008) 313–328. doi: 10.1016/S1006-7191(08)60054-X . J. Hirsch, T. Al-Samman, Superior light metals by texture engineering: Optimized aluminum and magnesium alloys for automotive applications, Acta Mater. 61 (2013) 818–843. doi: 10.1016/j.actamat.2012.10.044 . J. Song, J. She, D. Chen, F. Pan, Latest research advances on magnesium and magnesium alloys worldwide, J. Magnes. Alloy. 8 (2020) 1–41. doi: 10.1016/j.jma.2020.02.003 . C. Author, ORIGINAL ARTICLES Magnesium and Aluminum Alloys in Automotive Industry, J. Appl. Sci. Res. 8 (2012) 4865–4875. G.-L. Song, A. Atrens, Corrosion Mechanisms of Magnesium Alloys, Adv. Eng. Mater. 1 (1999) 11–33. doi: 10.1002/(SICI)1527-2648(199909)1 . Y.C. Lee, A.K. Dahle, D.H. Stjohn, The role of solute in grain refinement of magnesium, Metall. Mater. Trans. A Phys. Metall. Mater. Sci. 31 (2000) 2895–2906. doi: 10.1007/BF02830349 . Q. Peng, Y. Huang, L. Zhou, N. Hort, K.U. Kainer, Preparation and properties of high purity Mg-Y biomaterials, Biomaterials. 31 (2010) 398–403. doi: 10.1016/j.biomaterials.2009.09.065 . S.J. Liu, G.Y. Yang, S.F. Luo, W.Q. Jie, Microstructure and mechanical properties of sand mold cast Mg-4.58Zn-2.6Gd-0.18Zr magnesium alloy after different heat treatments, J. Alloys Compd. 644 (2015) 846–853. doi: 10.1016/j.jallcom.2015.05.062 . S. Tekumalla, S. Seetharaman, A. Almajid, M. Gupta, Mechanical Properties of Magnesium-Rare Earth Alloy Systems: A Review, 2015. doi: 10.3390/met5010001 . G. Wu, C. Wang, M. Sun, W. Ding, Recent developments and applications on high-performance cast magnesium rare-earth alloys, J. Magnes. Alloy. (2020). doi: 10.1016/j.jma.2020.06.021 . Y. Chen, Z. Xu, C. Smith, J. Sankar, Recent advances on the development of magnesium alloys for biodegradable implants, Acta Biomater. 10 (2014) 4561–4573. doi: 10.1016/j.actbio.2014.07.005 . Z. Leng, J. Zhang, M. Zhang, X. Liu, H. Zhan, R. Wu, Microstructure and high mechanical properties of Mg-9RY-4Zn (RY: Y-rich misch metal) alloy with long period stacking ordered phase, Mater. Sci. Eng. A. 540 (2012) 38–45. doi: 10.1016/j.msea.2012.01.057 . F. Witte, V. Kaese, H. Haferkamp, E. Switzer, A. Meyer-Lindenberg, C.J. Wirth, H. Windhagen, In vivo corrosion of four magnesium alloys and the associated bone response, Biomaterials. 26 (2005) 3557–3563. doi: 10.1016/j.biomaterials.2004.09.049 . K.R. Gopi, H.S. Nayaka, S. Sahu, Investigation of Microstructure and Mechanical Properties of ECAP-Processed AM Series Magnesium Alloy, J. Mater. Eng. Perform. 25 (2016) 3737–3745. doi: 10.1007/s11665-016-2229-7 . A. Jana, M. Das, V.K. Balla, Effect of heat treatment on microstructure, mechanical, corrosion and biocompatibility of Mg-Zn-Zr-Gd-Nd alloy, J. Alloys Compd. 821 (2020) 153462. doi: 10.1016/j.jallcom.2019.153462 . P.J. Apps, H. Karimzadeh, J.F. King, G.W. Lorimer, Phase compositions in magnesium-rare earth alloys containing yttrium, gadolinium or dysprosium, Scr. Mater. 48 (2003) 475–481. doi: 10.1016/S1359-6462(02)00509-2 . J.D. Robson, C. Paa-Rai, The interaction of grain refinement and ageing in magnesium-zinc-zirconium (ZK) alloys, Acta Mater. 95 (2015) 10–19. doi: 10.1016/j.actamat.2015.05.012 . H. Yan, Z. Wang, Effect of heat treatment on wear properties of extruded AZ91 alloy treated with yttrium, J. Rare Earths. 34 (2016) 308–314. doi: 10.1016/S1002-0721(16)60030-3 . Y. Gao, Q. Wang, J. Gu, Y. Zhao, Y. Tong, Behavior of Mg-15Gd-5Y-0.5Zr alloy during solution heat treatment from 500 to 540 ??C, Mater. Sci. Eng. A. 459 (2007) 117–123. doi: 10.1016/j.msea.2007.01.057 . D.J. Li, X.Q. Zeng, J. Dong, C.Q. Zhai, W.J. Ding, Microstructure evolution of Mg-10Gd-3Y-1.2Zn-0.4Zr alloy during heat-treatment at 773 K, J. Alloys Compd. 468 (2009) 164–169. doi: 10.1016/j.jallcom.2008.01.078 . L. Zheng, C. Liu, Y. Wan, P. Yang, X. Shu, Microstructures and mechanical properties of Mg-10Gd-6Y-2Zn-0.6Zr(wt.%) alloy, J. Alloys Compd. 509 (2011) 8832–8839. doi: 10.1016/j.jallcom.2011.06.090 . X.M. Luo, G.L. Bi, J. Jiang, M. Li, R.G. Li, Y.D. Li, Y. Ma, Y. Hao, Compressive anisotropy of extruded Mg-Dy-Zn alloy sheet, Trans. Nonferrous Met. Soc. China (English Ed. 26 (2016) 390–397. doi: 10.1016/S1003-6326(16)64127-4 . G. Bi, Y. Li, S. Zang, J. Zhang, Y. Ma, Y. Hao, Microstructure, mechanical and corrosion properties of Mg-2Dy-xZn (x = 0, 0.1, 0.5 and 1 at.%) alloys, J. Magnes. Alloy. 2 (2014) 64–71. doi: 10.1016/j.jma.2014.03.002 . G. Song, a. Atrens, Understanding Magnesium Corrosion—A Framework for Improved Alloy Performance, Adv. Eng. Mater. 5 (2003) 837–858. doi: 10.1002/adem.200310405 . J.F. Nie, K. Oh-ishi, X. Gao, K. Hono, Solute segregation and precipitation in a creep-resistant Mg-Gd-Zn alloy, Acta Mater. 56 (2008) 6061–6076. doi: 10.1016/j.actamat.2008.08.025 . B.I. Guangli, J. Jing, Z. Fan, F. Daqing, Microstructure evolution and corrosion properties of Mg-Dy-Zn alloy during cooling after solution treatment, 34 (2016) 931–937. doi: 10.1016/S1002-0721(16)60117-5 . Q. Peng, N. Ma, H. Li, Gadolinium solubility and precipitate identification in Mg-Gd binary alloy, J. Rare Earths. 30 (2012) 1064–1068. doi: 10.1016/S1002-0721(12)60179-3 . M. Saadati, R.A. Khosroshahi, G. Ebrahimi, M. Jahazi, Formation of precipitates in parallel arrays on LPSO structures during hot deformation of GZ41K magnesium alloy, Mater. Charact. 131 (2017) 234–243. doi: 10.1016/j.matchar.2017.07.007 . A. Kielbus, T. Rzychon, R. Przeliorz, DSC and Microstructural Investigations of the Elektron 21 Magnesium Alloy, Mater. Sci. Forum. 638–642 (2010) 1447–1452. doi: 10.4028/www.scientific.net/MSF.638-642.1447 . M. Yamasaki, Mechanical properties of warm-extruded Mg – Zn – Gd alloy with coherent 14H long periodic stacking ordered structure precipitate, 53 (2005) 799–803. doi: 10.1016/j.scriptamat.2005.06.006 . G. Bi, D. Fang, L. Zhao, Q. Zhang, J. Lian, Q. Jiang, Z. Jiang, Double-peak ageing behavior of Mg-2Dy-0.5Zn alloy, J. Alloys Compd. 509 (2011) 8268–8275. doi: 10.1016/j.jallcom.2011.05.117 . L. tao YUAN, G. li BI, Y. dong LI, J. JIANG, Y. xiang HAN, D. qing FANG, Y. MA, Effects of solid solution treatment and cooling on morphology of LPSO phase and precipitation hardening behavior of Mg–Dy–Ni alloy, Trans. Nonferrous Met. Soc. China (English Ed. 27 (2017) 2381–2389. doi: 10.1016/S1003-6326(17)60264-4 . M. Hu, Q. Wang, C. Chen, D. Yin, W. Ding, Z. Ji, Dry sliding wear behaviour of Mg – 10Gd – 3Y – 0. 4Zr alloy, J. Mater. 42 (2012) 223–229. doi: 10.1016/j.matdes.2012.05.051 . C.Y.H. Lim, S.C. Lim, M. Gupta, Wear behaviour of SiCp-reinforced magnesium matrix composites, Wear. 255 (2003) 629–637. doi: 10.1016/S0043-1648(03)00121-2 . G. Bi, Y. Li, X. Huang, T. Chen, Y. Ma, Y. Hao, Dry sliding wear behavior of an extruded Mg-Dy-Zn alloy with long period stacking ordered phase, J. Magnes. Alloy. 3 (2015) 63–69. doi: 10.1016/j.jma.2014.12.006 . D.S. Mehta, S.H. Masood, W.Q. Song, Investigation of wear properties of magnesium and aluminum alloys for automotive applications, J. Mater. Process. Technol. 155–156 (2004) 1526–1531. doi: 10.1016/j.jmatprotec.2004.04.247 . J.F. Archard, Contact and rubbing of flat surfaces, J. Appl. Phys. 24 (1953) 981–988. doi: 10.1063/1.1721448 . G. Bi, Y. Li, S. Zang, J. Zhang, Y. Ma, Y. Hao, Microstructure, mechanical and corrosion properties of Mg-2Dy-xZn (x = 0, 0.1, 0.5 and 1 at.%) alloys, J. Magnes. Alloy. 2 (2014) 64–71. doi: 10.1016/j.jma.2014.03.002 . S. Anbu, S. Ramanathan, Dry sliding wear behavior of hot extruded ZE41A magnesium alloy, Mater. Sci. Eng. A. 527 (2010) 1815–1820. doi: 10.1016/j.msea.2009.11.017 . M.L. Hu, Q.D. Wang, C. Li, W.J. Ding, Dry sliding wear behavior of cast Mg-11Y-5Gd-2Zn magnesium alloy, Trans. Nonferrous Met. Soc. China (English Ed. 22 (2012) 1918–1923. doi: 10.1016/S1003-6326(11)61408-8 . J. An, R.G. Li, Y. Lu, C.M. Chen, Y. Xu, X. Chen, L.M. Wang, Dry sliding wear behavior of magnesium alloys, Wear. 265 (2008) 97–104. doi: 10.1016/j.wear.2007.08.021 . R. Arora, S. Kumar, G. Singh, O. Pandey, Influence of particle size and temperature on the wear properties of rutile-reinforced aluminium metal matrix composite, J. Compos. Mater. 49 (2015) 843–852. doi: 10.1177/0021998314526079 . S. Das, S. V Prasad, T.R. Ramachandran, – 187 173 Microstructure Composites*, 33 (1989) 173–187. S. Anbu, S. Ramanathan, Dry sliding wear behavior of as-cast ZE41A magnesium alloy, Mater. Des. 31 (2010) 1930–1936. doi: 10.1016/j.matdes.2009.10.054 . A. Srinivasan, Y. Huang, C.L. Mendis, C. Blawert, K.U. Kainer, N. Hort, Investigations on microstructures, mechanical and corrosion properties of Mg-Gd-Zn alloys, Mater. Sci. Eng. A. 595 (2014) 224–234. doi: 10.1016/j.msea.2013.12.016 . R.R. Kottuparambil, S. Bontha, R.M. Rangarasaiah, S.B. Arya, A. Jana, M. Das, V.K. Balla, S. Amrithalingam, T.R. Prabhu, Effect of zinc and rare-earth element addition on mechanical, corrosion, and biological properties of magnesium, J. Mater. Res. 33 (2018) 3466–3478. doi: 10.1557/jmr.2018.311 . L. Yang, Y. Huang, Q. Peng, F. Feyerabend, K.U. Kainer, R. Willumeit, N. Hort, Mechanical and corrosion properties of binary Mg – Dy alloys for medical applications, Mater. Sci. Eng. B. 176 (2011) 1827–1834. doi: 10.1016/j.mseb.2011.02.025 . Additional Declarations No competing interests reported. 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10:02:10","extension":"png","order_by":18,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":429260,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-8065387/v1/748efb3be049b126b61422e6.png"},{"id":96454433,"identity":"0f15074b-4b0c-4e15-bbe6-f8340ad701f7","added_by":"auto","created_at":"2025-11-21 10:02:44","extension":"xml","order_by":19,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":131344,"visible":true,"origin":"","legend":"","description":"","filename":"c847fc2d968447789cb712d527a0dd2c1structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-8065387/v1/5458251c750d2b7067fb2bc0.xml"},{"id":96411915,"identity":"28c12033-cf8d-4b41-821f-fa84b65c6ad9","added_by":"auto","created_at":"2025-11-20 18:58:34","extension":"html","order_by":20,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":141930,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8065387/v1/b793cd158bc2a28f1ca906ed.html"},{"id":96454863,"identity":"c59e0ebe-9458-4cdf-96d5-06beb2580921","added_by":"auto","created_at":"2025-11-21 10:03:13","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":688375,"visible":true,"origin":"","legend":"\u003cp\u003eOptical micrographs of (a) as-cast and (b) heat treated Mg-Zn-Gd alloy. \u0026nbsp;SEM micrographs of (c) as cast, and (d) heat-treated Mg-Zn-Gd alloy\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8065387/v1/75b3a1935384fc0d8c26122f.jpeg"},{"id":96454266,"identity":"224baac9-c825-4ef7-b3a2-aeacfc4c465f","added_by":"auto","created_at":"2025-11-21 10:02:31","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":672553,"visible":true,"origin":"","legend":"\u003cp\u003eOptical micrographs of (a) as-cast and (b) heat treated Mg-Zn-Dy alloy. SEM micrographs of (c) as-cast and (d) heat-treated Mg-Zn-Dy alloy\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8065387/v1/33df41218e714f0ca7f4b6d5.jpeg"},{"id":96411898,"identity":"caaaa6d8-4147-4248-8f29-10b9a1735cbc","added_by":"auto","created_at":"2025-11-20 18:58:34","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":195600,"visible":true,"origin":"","legend":"\u003cp\u003eXRD spectra of as-cast and heat treated alloys (a), (b) Mg-Zn-Gd alloy and (c), (d) Mg-Zn-Dy alloy\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8065387/v1/c8ff6fe98c3cc3f3a77e9d6e.jpeg"},{"id":96454406,"identity":"28c1f596-e689-4120-806e-3d09202c7f44","added_by":"auto","created_at":"2025-11-21 10:02:42","extension":"jpeg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":223749,"visible":true,"origin":"","legend":"\u003cp\u003eWear rate as function of temperature at different loads for (a) Mg-Zn-Gd and (b) Mg-Zn-Dy alloys\u003c/p\u003e","description":"","filename":"floatimage4.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8065387/v1/dad5253928e3679c1984dd0e.jpeg"},{"id":96411907,"identity":"81af98fd-70cd-404b-9dda-97aaedef6383","added_by":"auto","created_at":"2025-11-20 18:58:34","extension":"jpeg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":241688,"visible":true,"origin":"","legend":"\u003cp\u003eCoefficient of friction as a function of temperature at different loads for (a) Mg-Zn-Gd and (b) Mg-Zn-Dy alloys\u003c/p\u003e","description":"","filename":"floatimage5.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8065387/v1/be2ad6902ce65de530a564d7.jpeg"},{"id":96411900,"identity":"f9c94ac0-647b-4f4f-8dd7-d8de5d9c4d20","added_by":"auto","created_at":"2025-11-20 18:58:34","extension":"jpeg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":544790,"visible":true,"origin":"","legend":"\u003cp\u003eSEM Micrographs of worn Surface at 20 N load and 400°C (a) As-cast Mg-Zn-Gd Alloy, (b) T6-(12) Mg-Zn-Gd Alloy, (c) As-cast Mg-Zn-Dy Alloy, (d) T6-(12) Mg-Zn-Dy \u0026nbsp;Alloy\u003c/p\u003e","description":"","filename":"floatimage6.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8065387/v1/0139080eb005b1e449390290.jpeg"},{"id":96453577,"identity":"986a3faf-9a0d-4794-9aaf-a903f8d3fbba","added_by":"auto","created_at":"2025-11-21 10:00:51","extension":"jpeg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":152097,"visible":true,"origin":"","legend":"\u003cp\u003eXRD spectra of worn (20 N load at 400°C) (a) Mg-Zn-Gd (b) Mg-Zn-Dy alloy surface at as-cast and heat treated (T-6(12) condition\u003c/p\u003e","description":"","filename":"floatimage7.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8065387/v1/d153d015842847bbbdc73353.jpeg"},{"id":96411904,"identity":"615b1056-7888-4a9a-87e4-1f9bdd72c215","added_by":"auto","created_at":"2025-11-20 18:58:34","extension":"jpeg","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":704465,"visible":true,"origin":"","legend":"\u003cp\u003eSEM morphology of corroded surface after the immersion in NaCl solution (a) As-cast Mg-Zn-Gd alloy (b) T6-(12) Mg-Zn-Gd alloy(c) As-cast Mg-Zn-Dy alloy (d) T6-12 Mg-Zn-Dy alloy\u003c/p\u003e","description":"","filename":"floatimage8.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8065387/v1/2c36549fd48737e8fe9b482f.jpeg"},{"id":96708107,"identity":"86681131-cd29-4c96-a65a-12e8dd77f790","added_by":"auto","created_at":"2025-11-25 09:56:51","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4236521,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8065387/v1/25a60d1e-02c4-489a-88b5-31b3c6336b43.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Heat treatment of Mg-Zn-Gd and Mg-Zn-Dy alloys for enhanced wear and corrosion properties","fulltext":[{"header":"1. INTRODUCTION","content":"\u003cp\u003eMagnesium (Mg) is, possesses many unique properties such as high specific strength, excellent castability, and better noise and vibration damping capability [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Recent developments also showed that Mg is a potential replacement for other engineering materials in structural, automotive, and aerospace applications [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e][\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e][\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Traditionally, aluminium is a lightweight material and that has replaced the steel and then cast iron in the automotive industry. Lighter than Aluminum, using Mg for automotive components (steering wheel, gearboxes, cylinder blocks etc.,) is further expected to reduce the weight of the automobile and thereby result in more fuel-efficient vehicles [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eDespite having many desirable characteristics, certain limitations such as low workability, poor corrosion resistance, and low mechanical strength at elevated temperatures have limited the wide-spread applicability of Mg. Alloying Mg with one or more elements such as aluminium (Al), zinc (Zn), manganese (Mn), zirconium (Zr) and rare earth elements (REE) etc. in varying concentrations can improve specific properties of Mg for desired applications. Among the various binary alloy system studied, the Mg-Zn alloy system is found to be second strongest ductile alloy system in Mg-based alloys [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Other alloying element zirconium (Zr) is added as a grain refiner to the Mg or its alloys containing Zn, yttrium (Y). The degree of grain refinement attained by Zr addition is better than other grain refinement methods [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. The addition of bismuth (Bi) also studied and concluded that heat resistance of Mg alloy is improved at elevated temperature. However addition of Bi to Mg-Nd alloy results in a decrease in strength at room temperature [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Although the binary alloy systems developed were observed to be higher corrosion rate and lower yield strength [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Based on the combinative requirement of strength and lower corrosion rate, third alloying elements are added to make the alloy suitable for various industrial applications. Leading commercial Mg alloys include Mg-Al-Mn (AM Series), Mg-Al-Zn (AZ Series), and Mg-Zn-REE (AE Series) Mg-Zn-Zr (ZK series) [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Recently, new class of materials, rare earth elements (REE) got an attention such as gadolinium (Gd), dysprosium (Dy), yttrium (Y), neodymium (Nd), etc. have proven to be effective alloying elements for improving the strength, ductility, corrosion and creep strength of magnesium alloys [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. This lead to the design of many Mg-REE based series alloys. Irrespective of its cost and complexity in casting it is irreplaceable with its applications in aerospace and defence field.[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. The strengthening of Mg alloys by the adding of REE is because of solid solution strengthening and precipitation hardening mechanism. Rare earth elements such as gadolinium (Gd) and dysprosium (Dy) have very high solubility of 23.49 wt. % and 25.8 wt. % respectively in Mg at eutectic temperature, which makes these elements appropriate for precipitation hardening compared to other elements from the lanthanide series [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Mg alloys with little amount of REE addition exhibit good elongation and better strength [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. The tensile strength and ductility notably enhanced by the formation of long period stacking ordered phases (LPSO) when REE elements are added as the third alloying element [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. WE43 (4 wt.% Y, 3 wt.% (Nd, Ce, Dy)], Mg-Y (4 wt.%) are extensively investigated REE alloy with improved mechanical properties (~\u0026thinsp;195 MPa) and corrosion resistance [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn order to tailor the wear, and corrosion properties heat treatment and secondary deformation techniques were adopted for Mg-REE alloys [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Various kinds of heat-treatments have been performed on Mg alloys to improve their strength by forming hard eutectic phases [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Among the heat treatment, precipitation strengthening through age hardening in Mg alloys is the exploited phenomena to achieve desired mechanical and microstructure properties [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. The AZ91alloy showed a lower wear resistance due to the distribution of Mg\u003csub\u003e17\u003c/sub\u003eAl\u003csub\u003e12\u003c/sub\u003e eutectic phase. This problem was tackled by dissolving the Mg\u003csub\u003e17\u003c/sub\u003eAl\u003csub\u003e12\u003c/sub\u003e phase completely through T6 heat treatment, thereby improving improved the mechanical properties [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. In the case of ZK (Magnesium-Zinc-Zirconium) alloys T6 age hardening process leads to an addition to its strength but it is less compared to the Al-based alloys. This low age hardening response is mainly due to the Zn\u003csub\u003e2\u003c/sub\u003eZr intermetallic formation [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Gao et al. [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e] performed heat-treatment on Mg-15Gd-5Y-0.5Zr alloy and reported the formation of a cuboid-shaped compound (Mg\u003csub\u003e2\u003c/sub\u003eY\u003csub\u003e3\u003c/sub\u003eGd\u003csub\u003e2\u003c/sub\u003e), which improved the strength of the alloy at elevated temperatures. Li et al. [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e] reported the formation of cuboid-shaped phases and block-shaped 14H LPSO phases, which will enhance the mechanical and corrosion properties of Mg\u0026ndash;10Gd\u0026ndash;3Y\u0026ndash;1.2Zn\u0026ndash;0.4Zr after post solution treatment at 500 ℃ for varying time period (i.e.12, 30, 48, and 72 hrs). In another study, Zheng et al. [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e] reported an increase in the hardness of Mg\u0026ndash;10Gd\u0026ndash;6Y\u0026ndash;2Zn\u0026ndash;0.6Zr alloy after solution treatment followed by ageing. Similar studies have also been carried out with Mg-Zn-Dy alloys, where heat-treatment has resulted in improved in their strength, hardness, and corrosion properties [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e][\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn this work, solution heat-treatment of Mg-1Zn-2Gd-0.4Zr (wt. %) and Mg-1Zn-2Dy-0.4Zr (wt. %) followed by aging (T6) were performed and their effect on the microstructure, hardness, wear, and corrosion behaviour have been investigated.\u003c/p\u003e"},{"header":"2. MATERIALS AND METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Alloy preparation and heat treatment\u003c/h2\u003e\u003cp\u003eMg-Zn-Gd and Mg-Zn-Dy alloys with specified composition were prepared through conventional casting route. The alloys Mg-Zn-Dy and Mg-Zn-Gd were prepared in a furnace under an Ar\u0026thinsp;+\u0026thinsp;2% SF\u003csub\u003e6\u003c/sub\u003e protective environment. Primarily, Mg-Zn parent melt was prepared, and at a temperature of 750℃, other alloying elements such as Gd, Dy, and Zr were added carefully. After 20 minutes of holding, the molten melt was stirred for 20 minutes, followed by pouring into the cast iron mold. The prepared alloy compositions are Mg-1% Zn-2%Gd-0.4%Zr and Mg-1%Zn-2% Dy-0.4%Zr respectively.\u003c/p\u003e\u003cp\u003eHeat treatment (T6) was performed on as-cast Mg-Zn-Gd-Zr and as-cast Mg-Zn-Dy-Zr alloys. The specimens were placed in a tubular furnace and were solution treated at 500 ℃ for 12 hours and then quenched in cold water. Then the samples were aged at 225℃ for different time durations (12, 18, and 24 hours) and subsequently quenched in cold water. T6-12, convention indicates heat treatment of alloy followed by 12 hours of ageing. Similarly for the different ageing time the conventions T6-18 and T6-24 are used in the following discussion.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Microstructural analysis\u003c/h2\u003e\u003cp\u003eThe as-cast and heat-treated (T6) specimens were prepared from the bulk material into cube samples of dimensions of 5 mm \u0026times; 5 mm \u0026times; 5 mm cube samples. All the specimens were polished with different grades of SiC sheets ranging from 200 to 2000 grit. Later these specimens were cloth polished with diamond paste of size 0.25 \u0026micro;m till mirror finish was achieved on the surface. All the samples were then etched with a solution of picric acid (2.5 g), ethanol (100 ml), acetic acid (25 ml) and distilled water (25 ml). After etching the specimens were rinsed with running water and dried with a blower. Optical microscope images were taken to understand the distribution of different phases. SEM images were taken at various magnifications using JSM-6380LA, JEOL USA Ltd to identify the type of phases. X-ray Diffractometer (DX-GE-2P, JEOL, Japan) was used in the 2θ range of 20\u0026ndash;100 degree and at a scanning rate of 2 ֯/min on the as-cast and heat-treated samples for phase analysis.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Hardness and wear studies\u003c/h2\u003e\u003cp\u003eHardness testing of all the specimens (as-cast and heat-treated alloys) was carried out using Brinell hardness tester for (Instron, USA) with a steel ball indenter of diameter 10 mm. A load of 250 kg was applied with a dwell period of 30 sec. At least five measurements were performed on each sample, and the mean value is reported.\u003c/p\u003e\u003cp\u003eDry sliding wear tests were performed using a Pin on Disc apparatus with EN-24 steel disc as the counter material on both as-cast and heat-treated alloys. The specimens were prepared according to the ASTM G-99 standard. Loads of 10 and 20 N with a temperature range of 200 ℃-400 ℃ were considered for the wear study. The sliding velocity and sliding distance were fixed at 1.25 m/s and 1500 m, respectively. Before starting the experiment, the disc was cleaned with ethanol to remove the debris on the surface. Further it was cleaned with alcohol. The weight of each sample was measured before and after the wear test for calculating mass loss. The worn pin surfaces and wear debris were collected and analysed using a scanning electron microscope (SEM) and X-ray diffraction (XRD) techniques. Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e presents the input parameters used in the wear study.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eInput parameters for wear study\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAlloy\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCondition\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eLoad\u003c/p\u003e\u003cp\u003e(N)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTemperature\u003c/p\u003e\u003cp\u003e(\u0026deg;C)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eMg-Zn-Dy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAs-cast\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e10, 20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e200, 300, 400\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHeat treated\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e10, 20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e200, 300, 400\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eMg-Zn-Gd\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAs-cast\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e10, 20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e200, 300, 400\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eHeat treated\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e10, 20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e200, 300, 400\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e2.4 Corrosion studies\u003c/h2\u003e\u003cp\u003eAn immersion corrosion study was carried out, and a setup similar to the one used in the study of song et al. [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e] was used. The set up consists of 500 ml beaker and 75 ml funnel. A solution of 150 ml was poured into each beaker, and the specimens were immersed in it. The funnel was placed just above the sample in an inverted position to collect the hydrogen evolved during the corrosion process (30\u0026thinsp;\u0026plusmn;\u0026thinsp;2 ℃). All the specimens were cut into samples of dimensions 10mm \u0026times; 10 mm \u0026times; 5 mm (length \u0026times; Width \u0026times; Thickness) from a larger block and then ground with polishing paper (of grade ranging from 200\u0026ndash;2000). The specimens were then subjected to cloth polishing with diamond paste till mirror finish was obtained. Next, the weights of the specimens were measured in a 0.001 mg precision weight measuring machine. Then these specimens were mounted to a PVC cylindrical pipe of 20 mm height and 15 mm dia, such that only one surface was exposed to solution. For the study, a solution of 3.5 wt. % NaCl was prepared. The samples were immersed in the 3.5 wt. % NaCl solution for 72 hours. Following this, the samples were thoroughly cleaned with a solution (chromic acid (200 ml/l) and silver nitrate (10 ml/l)) to remove all the corrosion products from the samples. Then the samples were rinsed in water and dried with the help of a blower. The cleaned samples were then taken for weight measurement. The corrosion rate was calculated as:\u003c/p\u003e\u003cp\u003e(C.R)\u003csub\u003ew\u003c/sub\u003e = \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\frac{8.76\\times\\:{10}^{4}\\times\\:W}{A\\times\\:t}\\)\u003c/span\u003e\u003c/span\u003e (1)\u003c/p\u003e\u003cp\u003eWhere (C.R.)\u003csub\u003ew\u003c/sub\u003e is the corrosion rate in (mm/year), \u003cem\u003eW\u003c/em\u003e is the weight loss in g, \u003cem\u003eA\u003c/em\u003e is the exposed surface area in (mm\u003csup\u003e2\u003c/sup\u003e), and \u003cem\u003et\u003c/em\u003e is the immersion time in hours.\u003c/p\u003e\u003c/div\u003e"},{"header":"3. RESULTS AND DISCUSSION","content":"\u003cdiv id=\"Sec8\"\u003e\n \u003ch2\u003e3.1 Hardness studies\u003c/h2\u003e\n \u003cp\u003eTable\u0026nbsp;2 presents the results of Brinell hardness study results on both as-cast and heat-treated Mg-Zn- Gd and Mg-Zn-Dy alloys.\u003c/p\u003e\n \u003cdiv\u003e\n \u003cp\u003e\u003cstrong\u003eTable 2\u003c/strong\u003e Hardness results of as-cast and heat-treated Mg-Zn-Gd and Mg-Zn-Dy alloys\u003c/p\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAlloy\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"4\" valign=\"top\" style=\"width: 481px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eBrinell Hardness Number (BHN)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eAs-Cast\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 361px;\"\u003e\n \u003cp\u003eHeat treatment condition-(Time (h))\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003eT6-(12)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003eT6-(18)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003eT6-(24)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMg-Zn-Gd\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e37 \u0026plusmn; 1.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e47 \u0026plusmn; 1.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e47 \u0026plusmn; 1.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e48\u0026plusmn; 1.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMg-Zn-Dy\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e39 \u0026plusmn; 1.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e46 \u0026plusmn; 1.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e47 \u0026plusmn; 1.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e47\u0026plusmn; 1.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003eIn Table\u0026nbsp;2, T6-(12) represents the T6 sample with an aging time of 12 hours; similarly, T6-(18) and T6-(24) represent the T6 sample with aging times of 18 hours and 24 hours respectively. It is reported that the hardness of Mg alloys increases after heat treatment due to the uniform re-distribution of secondary phases [17]. In this study, it was observed that after heat treatment, the BHN of both the alloys increased by 20\u0026ndash;25%. The BHN of Mg-Zn-Gd alloy in as-cast condition was found to be 37\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5. After solution treatment followed by 12 hours of aging its hardness increased to 47\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5 BHN. For Mg-Zn-Dy alloy, the hardness increased from 39\u0026thinsp;\u0026plusmn;\u0026thinsp;1.6 BHN in the as-cast condition to 46\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8 BHN for the (T6-12) condition.\u003c/p\u003e\n \u003cp\u003eThe T6 heat-treatment with an aging period of 18 and 24 hours did not significantly increase the hardness. Therefore, the heat-treated sample with 12 hours of aging was found to be the optimum among the ones considered in this work. Hence for all further studies, the heat-treatment (T6) followed by ageing at 12 hours i.e., (T6-(12)) is considered for the comparison with as-cast Mg-Zn-Gd and Mg-Zn-Dy alloys.\u003c/p\u003e\n \u003cp\u003ePrecipitation hardening was the primary reason for the increase in hardness in both the alloys, which causes co-segregation of secondary element atoms. The secondary phases containing rare earth and zinc elements are harder when compared to the \u0026alpha;-Mg matrix. When these secondary phases dissolve into the \u0026alpha;-Mg matrix, the hardness of the matrix phase increases. Nie et al. [26] concluded that co-segregation in the form of Gd\u0026ndash;Zn dimers could provide more effective pinning of gliding dislocations, and therefore contribute to an increase in the hardness. Guangli et al. [27] reported a similar result, which reported an increase in hardness of the Mg-Dy-Zn alloy after solution treatment followed by cooling for 20 minutes at a rate of 2 ℃/min.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec9\"\u003e\n \u003ch2\u003e3.2 Microstructural and phase analysis\u003c/h2\u003e\n \u003cp\u003eThe optical microscope (OM) and scanning electron microscope (SEM) images of as-cast and heat-treated (T6-(12)) Mg-Zn-Gd alloy are represented in Fig.\u0026nbsp;1. Among the different aging conditions, heat treatment followed by 12 hours of ageing is considered to be effective in improving the properties of these alloys. This conclusion is drawn based on the hardness results presented in section 3.2.. In this paper, the heat treatment followed by 12 hours of aging is referred to as (T6 \u0026ndash; (12).\u003c/p\u003e\n \u003cp\u003eFigures 1 \u003cstrong\u003e(a)\u003c/strong\u003e and \u003cstrong\u003e(b)\u003c/strong\u003e show dendritic grains and secondary phases distributed along the grain boundaries of as-cast Mg-Zn-Gd alloy. The microstructure of the as cast Mg-Zn-Gd primarily composed of \u0026alpha;-Mg, Mg\u003csub\u003e5\u003c/sub\u003eGd phases, and few eutectic phases, which could be a combination of \u0026alpha;-Mg, MgZn\u003csub\u003e2,\u003c/sub\u003e and Mg\u003csub\u003e5\u003c/sub\u003eGd phase. In the as-cast alloy (Fig. 1 (a), the secondary eutectic phases (dark regions), that are present along the grain boundary, and are non- homogeneously distributed. The micrographs of the heat-treated (T6-(12)) alloy, (Figs. 1 \u003cstrong\u003e(c) and (d))\u003c/strong\u003e reveal that the formation of secondary phases is significantly lower. The secondary phases have been dissolved into the \u0026alpha;-Mg matrix, and fine lamellar precipitates have formed inside the grains. The grains of the heat-treated alloy were found to be more homogeneous with uniform distribution of secondary precipitates. There were some globular type phases identified from SEM images, which are shown in Figs. 1 \u003cstrong\u003e(c)\u003c/strong\u003e and \u003cstrong\u003e(d).\u003c/strong\u003e The morphology of these phases matched with the morphology of Mg\u003csub\u003e5\u003c/sub\u003eGd reported in the work of Peng et al. [28]. There were some new block-shaped precipitates, and their morphology matched that of f MgGd\u003csub\u003e3 ,\u003c/sub\u003e as reported in [29] and [30]. These phases were also confirmed by the XRD results shown in Fig. 3\u003cstrong\u003e(b).\u003c/strong\u003e Yamasaki et al. [31] identified the hard lamellar phase, to be 2H and 14H type LPSO phases. A similar kind of fine lamellar precipitate analogous to LPSO in nature was also observed in smaller quantities in this study, and are shown in Fig. 1 \u003cstrong\u003e(d\u003c/strong\u003e).\u003c/p\u003e\n \u003cp\u003eXRD results of Mg-Zn-Gd alloy sample are shown in Figs.\u0026nbsp;3 (a) and (b). The peaks of Mg\u003csub\u003e5\u003c/sub\u003eGd and \u0026alpha;-Mg in as-cast and heat-treated Mg-Zn-Gd alloy are shown in Fig.\u0026nbsp;3(a). A new MgGd\u003csub\u003e3\u003c/sub\u003e peak was observed in heat-treated (T6-(12)) Mg-Zn-Gd alloy (Fig. 3 \u003cstrong\u003e(b)\u003c/strong\u003e) at angles of ~\u0026thinsp;33\u0026deg; and 57\u0026deg;. The presence of these new Mg-REE compounds validates the presence of different morphologies, that have been identified from the micrographs (Figs. 1 \u003cstrong\u003e(c\u003c/strong\u003e) and \u003cstrong\u003e(d)).\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eFigure 2 shows the optical microscope and scanning electron microscope (SEM) images of as-cast and heat-treated (T6-(12)) Mg-Zn-Dy alloy. In the as-cast Mg-Zn-Dy (Figs. 2 \u003cstrong\u003e(a)\u003c/strong\u003e and \u003cstrong\u003e(b))\u003c/strong\u003e, the grains have a dendritic structure with a large fraction of secondary phases distributed primarily at the grain boundaries. There were many large and small regions of intermetallic phases that were also present inside the grain (black colour inside the grain as shown in Figs. 2 \u003cstrong\u003e(c)\u003c/strong\u003e and \u003cstrong\u003e(d)\u003c/strong\u003e). The SEM image of the as-cast alloy shown in Fig. 2 \u003cstrong\u003e(d)\u003c/strong\u003e, reveals few rectangular-shaped particles along with some irregular shaped precipitates. The morphology of the rectangular-shaped precipitates was found to be matching with the morphology of Mg\u003csub\u003e2\u003c/sub\u003eDy precipitates. While the irregularly shaped precipitates observed were found to have similar morphology as that of (Mg, Zn)\u003csub\u003ex\u003c/sub\u003eDy precipitates reported in the study of Bi et al. [32]. Mg\u003csub\u003e24\u003c/sub\u003eDy\u003csub\u003e5\u003c/sub\u003e, with different morphology, was also formed at the grain boundary. Numerous small black spots were observed, which were primarily situated at the grain boundary. Lamellar phases were also observed inside the grain (Fig. 2 \u003cstrong\u003e(c)).\u003c/strong\u003e Similar kinds of fine lamellar phases were reported in [33]. This phase was reported to be the 14H LPSO phase. The distribution of the small precipitates in the heat-treated Mg-Zn-Dy was non-homogenous, and many clusters of these intermetallic phases were observed.\u003c/p\u003e\n \u003cp\u003eFigures 3 \u003cstrong\u003e(c)\u003c/strong\u003e and \u003cstrong\u003e(d)\u003c/strong\u003e show the XRD results of as-cast and heat-treated (T6-(12)) Mg-Zn-Dy alloy. The peaks observed in the as-cast alloy were \u0026alpha;-Mg, Mg\u003csub\u003e24\u003c/sub\u003eDy\u003csub\u003e5,\u003c/sub\u003e and Mg\u003csub\u003e2\u003c/sub\u003eDy \u003cstrong\u003e(\u003c/strong\u003eFig. 3 \u003cstrong\u003e(c)).\u003c/strong\u003e These results confirm their findings from the microstructural analysis. However, in the case of the heat-treated (T6-(12)) Mg-Zn-Dy alloy, the peak of Mg\u003csub\u003e24\u003c/sub\u003eDy\u003csub\u003e5\u003c/sub\u003e \u003cstrong\u003e(\u003c/strong\u003eFig. 3 \u003cstrong\u003e(d))\u003c/strong\u003e, phase were not present, which supports the idea of the slight dissolution of eutectic phases after heat-treatment.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec10\"\u003e\n \u003ch2\u003e3.3 Wear studies\u003c/h2\u003e\n \u003cp\u003eThe effect of heat treatment on wear rate is represented in Figs.\u0026nbsp;4, 5. The wear behaviour of as-cast and heat-treated (T6-(12)) Mg-Zn-Gd and Mg-Zn-Dy alloys are shown in Fig.\u0026nbsp;4. It is known that the wear rate of a material depends on the load, velocity, coefficient of friction, and surface temperature [34] [35] [36]. From Fig.\u0026nbsp;4 it can be observed that the wear rate of the as-cast alloy is higher than that of the heat-treated samples at different loading conditions. The lower wear rate heat-treated alloys is primarily due to the high hardness of these samples as a result of precipitation of secondary phases along the grain boundaries during heat treatment. Mehta et al. [37] studied the wear behaviour of Mg-Al alloy and reported that higher the hardness of the material lower would be the wear rate under dry sliding wear conditions. It was also observed from Archard\u0026rsquo;s law, [38] that the wear rate is inversely proportional to the hardness. It is clearly observed from the hardness measurements (Table\u0026nbsp;2\u003cstrong\u003e)\u003c/strong\u003e that the hardness of the alloy is increased after heat treatment and therefore the wear resistance. The formation/precipitation of the LPSO phase after heat treatment is the ideal strengthening secondary phase in both Mg-Zn-Gd and Mg-Zn-Dy alloys. The LPSO phase has higher hardness, better thermal stability, and coherent interface with the Mg matrix [32]. This infers that the thermally stable Mg\u003csub\u003e24\u003c/sub\u003eDy\u003csub\u003e5\u003c/sub\u003e and LPSO (14-H) resist the material flow during friction and wear [39] thereby improving the wear resistance. This is evident from Fig.\u0026nbsp;4, where the wear rate decreased as the heat treatment temperature increased from 200 to 400\u0026deg;C for both the alloys. This could be due to changes in microstructure of both the alloys at high temperature condition and changes in the strength or hardness with temperature and consequent changes in the deformation behaviour of the samples at these test temperatures [40].\u003c/p\u003e\n \u003cp\u003eSimilarly, during dry sliding wear testing of Mg-11Y-5Gd-2Zn, the wear resistance of the heat-treated samples was found to be higher than the as-cast samples, which was attributed to the precipitation of Mg\u003csub\u003e12\u003c/sub\u003eY\u003csub\u003e1\u003c/sub\u003eZn\u003csub\u003e1\u003c/sub\u003e phase [41] [42]. \u003cstrong\u003eFurther\u003c/strong\u003e, the wear rate of the alloys increased with increasing load from 10 N to 20 N for both the alloys tested. This is due to increased contact pressure. Figure 4 \u003cstrong\u003e(a)\u003c/strong\u003e shows the wear rate of Mg-Zn-Gd in as-cast and T6-(12) conditions with respect to the temperature. As it can be observed from Fig. 4 \u003cstrong\u003e(a)\u003c/strong\u003e, for a load of 10 N, the wear rate is decreasing from 1.6x10\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e mm\u003csup\u003e3\u003c/sup\u003e/mm to 1.2x10\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e mm\u003csup\u003e3\u003c/sup\u003e/mm with an increase in temperature (200\u0026deg;C to 400\u0026deg;C )for both as-cast and T6 - (12) Mg-Zn-Gd alloy. But the heat-treated alloy exhibit a lower wear rate when compared to as-cast alloy. The same trend was observed for the Mg-Zn-Dy alloy, when loaded at 20 N. However, the wear rate exhibited a drastic increase when compared to 10 N load in the Mg-Zn-Gd alloys in both as-cast and heat-treated conditions. At 20 N loading also the heat-treated Mg-Zn-Gd alloy shows a lower wear rate when compared to as-cast alloy. Figure\u0026nbsp;4\u003cstrong\u003e(b)\u003c/strong\u003e shows the wear rate of Mg-Zn-Dy alloy in both as-cast and heat-treated conditions. At an applied load of 10 N, the wear rate of both as-cast and heat-treated alloy sample decreases with an increase in temperature. In the as-cast and heat treated condition, minimum wear rate was observed at 400\u0026deg;C temperature. When compared to as cast and heat-treated samples, heat-treated samples exhibit lower wear rate. The heat-treated sample exhibits minimum wear rate at 400\u0026deg;C. The secondary phases (MgGd3, Mg\u003csub\u003e5\u003c/sub\u003eGd) in the heat treated alloy has higher strength and thermal stability than \u0026alpha;-Mg (dominated in as-cast sample) which is saturated with Gd and Zn. The secondary hard phases effectively give resistance to the material flow in the course of wear. These phases also could effectively pin the grain boundary sliding.[41].\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eFigs .5 (a)\u003c/strong\u003e and \u003cstrong\u003e(b)\u003c/strong\u003e show the variation in coefficient of friction with respect to temperature in both Mg-Zn-Gd and Mg-Zn-Dy alloys in as-cast and heat-treated conditions, respectively. The general trend, which can be observed for the two alloys is that the coefficient of friction decreases with increased temperatures. Higher temperature during the surface contact between the sample and disc could lead to oxidation of alloy. This surface oxidation act as a protective layer against wear damage and this leads to decrease in wear rate [41]. Similar dry sliding behavior trends have reported for Mg-10Gd-3Y-0.4Zr and Mg-11Y-5Gd-2Zn magnesium alloys [34]. This study reported that the wear debris generated at the surface gets oxidized and fills in the valleys of the worn surface at high surface temperatures. This study reported that at the high surface temperatures, the wear debris generated at the surface gets oxidized and fills in the valleys of the worn surface. This oxidized debris layer acts as a protective layer and prevents metal to metal contact between the surfaces, which reduces the friction between them and subsequently decreases the wear rates. A similar observation was also reported by Arora et al. [43], who reported the formation of a mechanically mixed oxide glaze layer (MML), which protects the material from severe wear. With an increase in load from 10 to 20 N, the co-efficient of friction also increased. This is because at higher loads, the surface in contact gets closer to the nominal area of the sample, which increases the friction between them.\u003c/p\u003e\n \u003cp\u003eFigures 6 \u003cstrong\u003e(a)\u003c/strong\u003e and \u003cstrong\u003e6 (b)\u003c/strong\u003e show the SEM micrographs of the worn surfaces of as-cast and heat-treated (T6-(12)) Mg-Zn-Gd alloy tested at 20 N load and 400℃ surface temperature. From these images, it can be observed that both the as-cast and heat-treated alloy surfaces have a large number of parallel ridges and grooves lying in the direction of sliding. These features can be attributed to abrasive wear mechanism. Further, the hard asperities between the pin and the counter disc plough the pin. Ploughing leads to removal of small fragments from the pin. When the load increases from 10 to 20 N, the wear behavior changes into a delamination mode of wear (Figs. 6\u003cstrong\u003e(a), (b)\u003c/strong\u003e). In the delamination mode wear, the debris are formed as the outcome of detachment of subsurface layer from the bulk material. The subs-surface cracks may either exist or nucleate due to the stresses during the course of wear test. Once the subsurface crack joins the wear surface, the dominant wear mechanism is delamination [44]. Figures\u0026nbsp;6\u003cstrong\u003e(a)\u003c/strong\u003e, \u003cstrong\u003e(b)\u003c/strong\u003e, shows that the layers are peeled off from the surface, and short cracks are perpendicular to the sliding direction. The detached wear particles form a sheet-like morphology having shallow craters behind. The thin wear sheet formation on the surface is generally fatigue assisted. The repeated sliding between the surfaces creates a crack on the pins and that shears the surface and leads to the formation of thin sheets [35]. It was observed that the wear rate increased with increasing applied load. Essentially this is due to the increase in penetration of hard asperities from the counter disc to the softer pin thereby leading to the increase in the fracture of softer pin surface. It is also reported that micro-cracking and sub-surface deformation tendency also increase with an increase in the load [45] but it is not observed in these worn surface micrographs (Figs.\u0026nbsp;6\u003cstrong\u003e(a),(b))\u003c/strong\u003e .\u003c/p\u003e\n \u003cp\u003eFigures 6 \u003cstrong\u003e(c\u003c/strong\u003e) and \u003cstrong\u003e(d)\u003c/strong\u003e show the SEM images of the worn surfaces of as-cast and heat-treated (T6-(12)) Mg-Zn-Dy alloy that was tested at 20 N load and 400 ℃ temperature. The wear rate showing decrease in trend at this higher load and temperature condition. These SEM images reveal features of abrasive wear on the worn surfaces of both as-cast and heat-treated Mg-Zn-Dy alloy. These are primarily caused when the hard asperities present in between the pin and disc, plough into the pin under the application of load, forming grooves by the removing small pieces of material, which results in wearing of the surface by abrasion. Further, delamination wear is also observed on both as-cast and heat-treated (T6-(12)) Mg-Zn-Dy alloy. Several wear debris with a plate-like shape and having a shiny metallic appearance were observed on this worn surface. The debris that form as the subsurface layers detach from the parent material. Many cracks form during wear, which develops perpendicular to the direction of sliding. When these cracks intersect with, it results in the detachment of sheet-like wear particles [40]. This was also reported as a fatigue-related wear mechanism, which is caused due to repeated sliding. The subsurface cracks, might have been present during the course of wear test. Further, as these cracks meet the wear surface it results in delamination wear. In Fig. 6 \u003cstrong\u003e(c)\u003c/strong\u003e, the surface of the worn pin appeared to be black in color, revealing the presence of an oxide layer. The formation of oxide wear debris covers the valleys on the surface of the pin, and this type of wear mechanism is known as oxidation wear [42]. Sliding due to frictional heating at higher temperatures results in the contact surface getting oxidized, and this will making a compact oxide layer over the surface. This layer prevents the metallic contact between the pin and counter disc, thereby leading to minimum wear rate [45]. The formation of these oxide layers was identified by XRD analysis and are shown in Fig. 7.\u003c/p\u003e\n \u003cp\u003eXRD analysis results of the worn surface at a load of 20 N for both Mg-Zn-Gd and Mg-Zn-Dy alloys are shown in Fig. 7. The spectra shown in Figs. 7 \u003cstrong\u003e(a)\u003c/strong\u003e and \u003cstrong\u003e(b)\u003c/strong\u003e, reveal that the worn surface of both the alloys contain ZnO phase. This could be due to the high surface temperature during wear test that causes zinc to oxidize in an open atmosphere. Abrasion is the dominant wear mechanism evident from the surface micrographs of worn surface and associated with fragmented chips (Fig. 6). The surface of the as cast Mg-Zn-Gd pin appears dark and it is covered by thin layer, which could be mainly due to the oxidation of surface. The strong peak of oxygen is observed in the alloy (Fig. 7) and is reported in previous studies as well [40]. The frictional heating during sliding causes oxidation of the surfaces. Initially, the wear occurs through the removal of these oxide layers. But later, the oxide debris fills the grooves on the surface of the pin, and that further restricts the direct metallic contact, leading to a reduction in the wear. However, the heat-treated Mg-Zn-Dy surface primarily showed abrasion and delamination wear, as was the case in the Mg-Zn-Gd alloy. Figure 7 \u003cstrong\u003e(b)\u003c/strong\u003e shows the XRD results of the worn surface of Mg-Zn-Dy alloy. Peaks of MgO and ZnO phases hint at the presence of an oxide layer on the surface of the worn Mg-Zn-Dy alloy. Compared to ZnO, the peaks of MgO are more pronounced in the XRD spectra. The presence of oxides on the surface of the sample clearly suggest that this is oxidation mode of wear [42]. The oxidized debris aid in the formation of a protective layer which makes it difficult to create further abrasion between alloy samples and counter face. Hence the wear rate starts to decrease. At high surface temperature, the repeated sliding on the oxidized surface leads to a lower wear rate.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec11\"\u003e\n \u003ch2\u003e3.1 Corrosion analysis\u003c/h2\u003e\n \u003cp\u003eThe corrosion rate of as-cast and heat-treated (T6-(12)) Mg-Zn-Gd and Mg-Zn-Dy alloys are presented in Table\u0026nbsp;3. A significant reduction in corrosion rate was observed in both Mg-Zn-Gd and Mg-Zn-Dy alloys after T6-(12) heat treatment. The corrosion rate of as-cast Mg-Zn-Gd alloy was found to be 3.86 mm/year, whereas the heat-treated Mg-Zn-Gd alloy showed a corrosion rate of 1.48 mm/year, resulting in a reduction of about 61% with heat treatment. Similarly, the corrosion rate of Mg-Zn-Dy alloy reduced to 2.62 mm/year from 3.92 mm/year after heat-treatment. The microstructure analysis of the heat-treated alloys, (Figs.\u0026nbsp;1 and 2\u003cstrong\u003e)\u003c/strong\u003e, showed that the cathodic eutectic phases in as-cast alloy have dissolved into the \u0026alpha;-Mg matrix. Further, a large number of fine lamellar precipitates have formed in the matrix which has, inhibited the corrosion and improved the corrosion resistance of the alloys. The large secondary phases present in as-cast Mg-Zn-Gd and Mg-Zn-Dy alloys, adjacent to \u0026alpha;-Mg matrix acts as a cathode to the anodic \u0026alpha;-Mg. This can initiate galvanic corrosion on the surface [6].The formation of secondary phases influences the galvanic corrosion behaviour. It is reported in the AZ alloy studies that a significant number of finely and continuously distributed secondary phases could more effectively prevent the growth of corrosion in an AZ alloys. But on the other hand, if the amount of secondary phase is low and distributed non-homogenously, it would act as a galvanic cathode and that accelerated the corrosion [10][32].\u003c/p\u003e\n \u003cp\u003eIn the present study, it was observed that secondary phases that are present in the heat treated (T6-12) Mg-Zn-Gd (Mg\u003csub\u003e5\u003c/sub\u003eGd, MgGd\u003csub\u003e3,\u003c/sub\u003e and fine lamellar LPSO phase) alloy are distributed along the grain boundaries. These phases are more homogenous and uniformly distributed and could act as a corrosion barrier [46]. The improved fraction of anode to cathode ratio after heat treatment can reduce the gravity of the galvanic effect, leading to the increased corrosion resistance [47]. In Mg-Zn-Dy alloy, as seen in the micrograph (Fig. 2\u003cstrong\u003e(c), (d))\u003c/strong\u003e, the distribution of secondary phases such as Mg\u003csub\u003e24\u003c/sub\u003eDy\u003csub\u003e5\u003c/sub\u003e, Mg\u003csub\u003e2\u003c/sub\u003eDy are quite discontinuous and they behave as a galvanic cathode to increase the corrosion rate. After T6-12 heat treatment, a large number of secondary phases are dissolved into the matrix, which leads to a reduction in the galvanic corrosion of the alloy [39]. The presence of the LPSO phase also plays an essential role in improving the corrosion resistance in Mg-Zn-Dy and Mg-Zn-Gd alloys [46] [47] of\u003c/p\u003e\n \u003cp\u003eThe corrosion rate of heat-treated Mg-Zn-Dy alloy is higher when compared to the heat-treated Mg-Zn-Gd alloy.. Unlike the Mg-Zn-Gd alloy, the microstructure of heat-treated Mg-Zn-Dy alloys consists of intermetallic precipitates, which are seen in cluster (Fig.\u0026nbsp;2\u003cstrong\u003e(d))\u003c/strong\u003e form accelerate the corrosion rate. However, the more prominent cathodic eutectic phases have dissolved into the matrix. As a result, the outcome was a reduction in the corrosion rate in heat treated Mg-Zn-Dy sample when compared to its as-cast counterpart.\u003c/p\u003e\n \u003cdiv\u003e\n \u003ctable id=\"Tab3\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 3\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eCorrosion rate of the alloys in as-cast and heat-treated conditions\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eAlloys\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eCorrosion rate (mm/year)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAs-cast\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eT6-(12)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMg-Zn-Gd\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.86 \\(\\:\\pm\\:\\)1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.48\\(\\:\\pm\\:\\) 0.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMg-Zn-Dy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.92\\(\\:\\pm\\:\\)0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.62\\(\\:\\pm\\:\\)0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003eThe SEM images of the corroded surfaces of as-cast and heat-treated (T6-(12)) Mg-Zn-Gd alloy are presented in Figs. 8 \u003cstrong\u003e(a\u003c/strong\u003e) and \u003cstrong\u003e(b)\u003c/strong\u003e respectively. It can be observed that in the case of as-cast Mg-Zn-Gd alloy, the attack on the surface due to corrosion is severe, and that corrosion has penetrated to the subsurface level, which is a case of galvanic corrosion. Many corrosion pits were also observed on the surface. However, in the case of heat-treated (T6-(12)) Mg-Zn-Gd alloy, the attack on the surface due to corrosion is relatively less, and besides, many areas on the surface were not attacked by corrosion at all. Filiform type of corrosion was observed in heat-treated Mg-Zn-Gd alloy, and is shown in Fig. 8 \u003cstrong\u003e(b)\u003c/strong\u003e. Filiform corrosion of Mg alloys in NaCl was reported and detailed in various studies [48]. In addition to the filiform corrosion tendency, the Mg alloys containing REE\u0026rsquo;s are oxidised and attached to the corrosion film. This film with REE improves the corrosion resistance. This could be the reason for the improved corrosion resistance in the heat-treated sample. Figures 8 \u003cstrong\u003e(c)\u003c/strong\u003e and \u003cstrong\u003e(d)\u003c/strong\u003e show the SEM images of the corroded surface of as-cast and heat-treated (T6-(12)) Mg-Zn-Dy alloy respectively. Many corrosion pits were observed on the as-cast Mg-Zn-Dy surface. Pitting corrosion is generally observed in Mg alloys and is caused by the galvanic couple effect between matrix and secondary phases [25]. Corrosion has propagated through the surface to the subsurface level, and a larger portion of the surface has been attacked. Pitting corrosion is also observed in heat-treated Mg-Zn-Dy alloy. However, a large portion of the surface was still unaffected from corrosion, which showed that heat-treatment had improved the corrosion resistance of the Mg-Zn-Dy alloy.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"3 CONCLUSIONS","content":"\u003cp\u003eIn this study, characterization of as-cast and heat-treated Mg-Zn-Gd and Mg-Zn-Dy alloys in terms of microstructure, wear properties, and corrosion behaviour was carried out, and the following conclusions were drawn.\u003c/p\u003e\u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003eAfter heat treatment, the eutectic secondary phases dissolved into the α-Mg matrix, and new precipitates were formed in both the alloys. However, compared to Mg-Zn-Gd alloy the microstructure of Mg-Zn-Dy alloy showed cluster of intermetallic phases or precipitates distributed were more non-uniformly.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eHeat-treated alloys showed 20 to 25% higher hardness when compared to as-cast alloys due to precipitation hardening, which also resulted in relatively lower wear rate.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eWear studies on these alloys, conducted at different temperatures, revealed a significant amount of surface, and wear debris oxidation that was adhered to the counter surface. These oxidized debris form a protective layer and act as solid lubricants leading to reduction in both friction and wear rate.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eCorrosion studies showed that the heat-treatment could improve the corrosion resistance of both Mg-Zn-Gd and Mg-Zn-Dy alloys significantly. For Mg-Zn-Gd and Mg-Zn-Dy alloys, a reduction of 60% and 30% respectively in the corrosion rate was achieved after heat-treatment. This improvement in the corrosion resistance of these alloys can be attributed to the dissolution of large eutectic phases and homogeneous distribution of a large number of fine precipitates throughout the alloy matrix.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eConflicts of interest or competing interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThere is no conflict of interest for the submitted journal.\u003c/p\u003e\u003cp\u003e\u003ch2\u003eSupplementary information:\u003c/h2\u003e\u003cp\u003eThere is no supplementary information attached along with the submitted paper\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003ch2\u003eEthical approval\u003c/h2\u003e\u003cp\u003eNot applicable for the submitted paper\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eDr. Rakesh K.R. first and the corresponding author has designed the alloys, casted them and carried out all the microstructure, mechanical and corrosion studies on the alloys. Mr. Pratyush Mohanty assisted to carry out the experimentation and consolidating the results of the study. Dr. Srikanth Bontha, Dr. Ramesh M.R. and Dr. Vamsi Krishna Balla are the research mentors and they have guided him in the course of this work.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThe authors would like to thank the Metallurgical and Materials Engineering Department, National Institute of Technology, Karnataka for providing access to various experimental facilities.\u003c/p\u003e\u003ch2\u003eData and code availability\u003c/h2\u003e\u003cp\u003eNo datasets were generated or analysed during the current study\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eM.K. Kulekci, Magnesium and its alloys applications in automotive industry, Int. J. Adv. Manuf. Technol. 39 (2008) 851\u0026ndash;865. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00170-007-1279-2\u003c/span\u003e\u003cspan address=\"10.1007/s00170-007-1279-2\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZ. Yang, J.P. Li, J.X. Zhang, G.W. Lorimer, J. Robson, Review on Research and Development of Magnesium Alloys, Acta Metall. Sin. (English Lett. 21 (2008) 313\u0026ndash;328. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/S1006-7191(08)60054-X\u003c/span\u003e\u003cspan address=\"10.1016/S1006-7191(08)60054-X\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eJ. Hirsch, T. Al-Samman, Superior light metals by texture engineering: Optimized aluminum and magnesium alloys for automotive applications, Acta Mater. 61 (2013) 818\u0026ndash;843. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.actamat.2012.10.044\u003c/span\u003e\u003cspan address=\"10.1016/j.actamat.2012.10.044\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eJ. Song, J. She, D. Chen, F. Pan, Latest research advances on magnesium and magnesium alloys worldwide, J. Magnes. Alloy. 8 (2020) 1\u0026ndash;41. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jma.2020.02.003\u003c/span\u003e\u003cspan address=\"10.1016/j.jma.2020.02.003\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eC. Author, ORIGINAL ARTICLES Magnesium and Aluminum Alloys in Automotive Industry, J. Appl. Sci. Res. 8 (2012) 4865\u0026ndash;4875.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eG.-L. Song, A. Atrens, Corrosion Mechanisms of Magnesium Alloys, Adv. Eng. Mater. 1 (1999) 11\u0026ndash;33. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1002/(SICI)1527-2648(199909)1\u003c/span\u003e\u003cspan address=\"10.1002/(SICI)1527-2648(199909)1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eY.C. Lee, A.K. Dahle, D.H. Stjohn, The role of solute in grain refinement of magnesium, Metall. Mater. Trans. A Phys. Metall. Mater. Sci. 31 (2000) 2895\u0026ndash;2906. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/BF02830349\u003c/span\u003e\u003cspan address=\"10.1007/BF02830349\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eQ. Peng, Y. Huang, L. Zhou, N. Hort, K.U. Kainer, Preparation and properties of high purity Mg-Y biomaterials, Biomaterials. 31 (2010) 398\u0026ndash;403. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.biomaterials.2009.09.065\u003c/span\u003e\u003cspan address=\"10.1016/j.biomaterials.2009.09.065\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eS.J. Liu, G.Y. Yang, S.F. Luo, W.Q. Jie, Microstructure and mechanical properties of sand mold cast Mg-4.58Zn-2.6Gd-0.18Zr magnesium alloy after different heat treatments, J. Alloys Compd. 644 (2015) 846\u0026ndash;853. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jallcom.2015.05.062\u003c/span\u003e\u003cspan address=\"10.1016/j.jallcom.2015.05.062\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eS. Tekumalla, S. Seetharaman, A. Almajid, M. Gupta, Mechanical Properties of Magnesium-Rare Earth Alloy Systems: A Review, 2015. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3390/met5010001\u003c/span\u003e\u003cspan address=\"10.3390/met5010001\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eG. Wu, C. Wang, M. Sun, W. Ding, Recent developments and applications on high-performance cast magnesium rare-earth alloys, J. Magnes. Alloy. (2020). doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jma.2020.06.021\u003c/span\u003e\u003cspan address=\"10.1016/j.jma.2020.06.021\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eY. Chen, Z. Xu, C. Smith, J. Sankar, Recent advances on the development of magnesium alloys for biodegradable implants, Acta Biomater. 10 (2014) 4561\u0026ndash;4573. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.actbio.2014.07.005\u003c/span\u003e\u003cspan address=\"10.1016/j.actbio.2014.07.005\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZ. Leng, J. Zhang, M. Zhang, X. Liu, H. Zhan, R. Wu, Microstructure and high mechanical properties of Mg-9RY-4Zn (RY: Y-rich misch metal) alloy with long period stacking ordered phase, Mater. Sci. Eng. A. 540 (2012) 38\u0026ndash;45. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.msea.2012.01.057\u003c/span\u003e\u003cspan address=\"10.1016/j.msea.2012.01.057\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eF. Witte, V. Kaese, H. Haferkamp, E. Switzer, A. Meyer-Lindenberg, C.J. Wirth, H. Windhagen, In vivo corrosion of four magnesium alloys and the associated bone response, Biomaterials. 26 (2005) 3557\u0026ndash;3563. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.biomaterials.2004.09.049\u003c/span\u003e\u003cspan address=\"10.1016/j.biomaterials.2004.09.049\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eK.R. Gopi, H.S. Nayaka, S. Sahu, Investigation of Microstructure and Mechanical Properties of ECAP-Processed AM Series Magnesium Alloy, J. Mater. Eng. Perform. 25 (2016) 3737\u0026ndash;3745. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s11665-016-2229-7\u003c/span\u003e\u003cspan address=\"10.1007/s11665-016-2229-7\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eA. Jana, M. Das, V.K. Balla, Effect of heat treatment on microstructure, mechanical, corrosion and biocompatibility of Mg-Zn-Zr-Gd-Nd alloy, J. Alloys Compd. 821 (2020) 153462. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jallcom.2019.153462\u003c/span\u003e\u003cspan address=\"10.1016/j.jallcom.2019.153462\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eP.J. Apps, H. Karimzadeh, J.F. King, G.W. Lorimer, Phase compositions in magnesium-rare earth alloys containing yttrium, gadolinium or dysprosium, Scr. Mater. 48 (2003) 475\u0026ndash;481. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/S1359-6462(02)00509-2\u003c/span\u003e\u003cspan address=\"10.1016/S1359-6462(02)00509-2\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eJ.D. Robson, C. Paa-Rai, The interaction of grain refinement and ageing in magnesium-zinc-zirconium (ZK) alloys, Acta Mater. 95 (2015) 10\u0026ndash;19. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.actamat.2015.05.012\u003c/span\u003e\u003cspan address=\"10.1016/j.actamat.2015.05.012\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eH. Yan, Z. Wang, Effect of heat treatment on wear properties of extruded AZ91 alloy treated with yttrium, J. Rare Earths. 34 (2016) 308\u0026ndash;314. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/S1002-0721(16)60030-3\u003c/span\u003e\u003cspan address=\"10.1016/S1002-0721(16)60030-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eY. Gao, Q. Wang, J. Gu, Y. Zhao, Y. Tong, Behavior of Mg-15Gd-5Y-0.5Zr alloy during solution heat treatment from 500 to 540 ??C, Mater. Sci. Eng. A. 459 (2007) 117\u0026ndash;123. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.msea.2007.01.057\u003c/span\u003e\u003cspan address=\"10.1016/j.msea.2007.01.057\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eD.J. Li, X.Q. Zeng, J. Dong, C.Q. Zhai, W.J. Ding, Microstructure evolution of Mg-10Gd-3Y-1.2Zn-0.4Zr alloy during heat-treatment at 773 K, J. Alloys Compd. 468 (2009) 164\u0026ndash;169. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jallcom.2008.01.078\u003c/span\u003e\u003cspan address=\"10.1016/j.jallcom.2008.01.078\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eL. Zheng, C. Liu, Y. Wan, P. Yang, X. Shu, Microstructures and mechanical properties of Mg-10Gd-6Y-2Zn-0.6Zr(wt.%) alloy, J. Alloys Compd. 509 (2011) 8832\u0026ndash;8839. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jallcom.2011.06.090\u003c/span\u003e\u003cspan address=\"10.1016/j.jallcom.2011.06.090\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eX.M. Luo, G.L. Bi, J. Jiang, M. Li, R.G. Li, Y.D. Li, Y. Ma, Y. Hao, Compressive anisotropy of extruded Mg-Dy-Zn alloy sheet, Trans. Nonferrous Met. Soc. China (English Ed. 26 (2016) 390\u0026ndash;397. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/S1003-6326(16)64127-4\u003c/span\u003e\u003cspan address=\"10.1016/S1003-6326(16)64127-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eG. Bi, Y. Li, S. Zang, J. Zhang, Y. Ma, Y. Hao, Microstructure, mechanical and corrosion properties of Mg-2Dy-xZn (x = 0, 0.1, 0.5 and 1 at.%) alloys, J. Magnes. Alloy. 2 (2014) 64\u0026ndash;71. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jma.2014.03.002\u003c/span\u003e\u003cspan address=\"10.1016/j.jma.2014.03.002\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eG. Song, a. Atrens, Understanding Magnesium Corrosion\u0026mdash;A Framework for Improved Alloy Performance, Adv. Eng. Mater. 5 (2003) 837\u0026ndash;858. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1002/adem.200310405\u003c/span\u003e\u003cspan address=\"10.1002/adem.200310405\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eJ.F. Nie, K. Oh-ishi, X. Gao, K. Hono, Solute segregation and precipitation in a creep-resistant Mg-Gd-Zn alloy, Acta Mater. 56 (2008) 6061\u0026ndash;6076. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.actamat.2008.08.025\u003c/span\u003e\u003cspan address=\"10.1016/j.actamat.2008.08.025\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eB.I. Guangli, J. Jing, Z. Fan, F. Daqing, Microstructure evolution and corrosion properties of Mg-Dy-Zn alloy during cooling after solution treatment, 34 (2016) 931\u0026ndash;937. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/S1002-0721(16)60117-5\u003c/span\u003e\u003cspan address=\"10.1016/S1002-0721(16)60117-5\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eQ. Peng, N. Ma, H. Li, Gadolinium solubility and precipitate identification in Mg-Gd binary alloy, J. Rare Earths. 30 (2012) 1064\u0026ndash;1068. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/S1002-0721(12)60179-3\u003c/span\u003e\u003cspan address=\"10.1016/S1002-0721(12)60179-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eM. Saadati, R.A. Khosroshahi, G. Ebrahimi, M. Jahazi, Formation of precipitates in parallel arrays on LPSO structures during hot deformation of GZ41K magnesium alloy, Mater. Charact. 131 (2017) 234\u0026ndash;243. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.matchar.2017.07.007\u003c/span\u003e\u003cspan address=\"10.1016/j.matchar.2017.07.007\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eA. Kielbus, T. Rzychon, R. Przeliorz, DSC and Microstructural Investigations of the Elektron 21 Magnesium Alloy, Mater. Sci. Forum. 638\u0026ndash;642 (2010) 1447\u0026ndash;1452. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.4028/www.scientific.net/MSF.638-642.1447\u003c/span\u003e\u003cspan address=\"10.4028/www.scientific.net/MSF.638-642.1447\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eM. Yamasaki, Mechanical properties of warm-extruded Mg \u0026ndash; Zn \u0026ndash; Gd alloy with coherent 14H long periodic stacking ordered structure precipitate, 53 (2005) 799\u0026ndash;803. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.scriptamat.2005.06.006\u003c/span\u003e\u003cspan address=\"10.1016/j.scriptamat.2005.06.006\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eG. Bi, D. Fang, L. Zhao, Q. Zhang, J. Lian, Q. Jiang, Z. Jiang, Double-peak ageing behavior of Mg-2Dy-0.5Zn alloy, J. Alloys Compd. 509 (2011) 8268\u0026ndash;8275. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jallcom.2011.05.117\u003c/span\u003e\u003cspan address=\"10.1016/j.jallcom.2011.05.117\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eL. tao YUAN, G. li BI, Y. dong LI, J. JIANG, Y. xiang HAN, D. qing FANG, Y. MA, Effects of solid solution treatment and cooling on morphology of LPSO phase and precipitation hardening behavior of Mg\u0026ndash;Dy\u0026ndash;Ni alloy, Trans. Nonferrous Met. Soc. China (English Ed. 27 (2017) 2381\u0026ndash;2389. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/S1003-6326(17)60264-4\u003c/span\u003e\u003cspan address=\"10.1016/S1003-6326(17)60264-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eM. Hu, Q. Wang, C. Chen, D. Yin, W. Ding, Z. Ji, Dry sliding wear behaviour of Mg \u0026ndash; 10Gd \u0026ndash; 3Y \u0026ndash; 0. 4Zr alloy, J. Mater. 42 (2012) 223\u0026ndash;229. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.matdes.2012.05.051\u003c/span\u003e\u003cspan address=\"10.1016/j.matdes.2012.05.051\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eC.Y.H. Lim, S.C. Lim, M. Gupta, Wear behaviour of SiCp-reinforced magnesium matrix composites, Wear. 255 (2003) 629\u0026ndash;637. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/S0043-1648(03)00121-2\u003c/span\u003e\u003cspan address=\"10.1016/S0043-1648(03)00121-2\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eG. Bi, Y. Li, X. Huang, T. Chen, Y. Ma, Y. Hao, Dry sliding wear behavior of an extruded Mg-Dy-Zn alloy with long period stacking ordered phase, J. Magnes. Alloy. 3 (2015) 63\u0026ndash;69. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jma.2014.12.006\u003c/span\u003e\u003cspan address=\"10.1016/j.jma.2014.12.006\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eD.S. Mehta, S.H. Masood, W.Q. Song, Investigation of wear properties of magnesium and aluminum alloys for automotive applications, J. Mater. Process. Technol. 155\u0026ndash;156 (2004) 1526\u0026ndash;1531. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jmatprotec.2004.04.247\u003c/span\u003e\u003cspan address=\"10.1016/j.jmatprotec.2004.04.247\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eJ.F. Archard, Contact and rubbing of flat surfaces, J. Appl. Phys. 24 (1953) 981\u0026ndash;988. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1063/1.1721448\u003c/span\u003e\u003cspan address=\"10.1063/1.1721448\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eG. Bi, Y. Li, S. Zang, J. Zhang, Y. Ma, Y. Hao, Microstructure, mechanical and corrosion properties of Mg-2Dy-xZn (x = 0, 0.1, 0.5 and 1 at.%) alloys, J. Magnes. Alloy. 2 (2014) 64\u0026ndash;71. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jma.2014.03.002\u003c/span\u003e\u003cspan address=\"10.1016/j.jma.2014.03.002\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eS. Anbu, S. Ramanathan, Dry sliding wear behavior of hot extruded ZE41A magnesium alloy, Mater. Sci. Eng. A. 527 (2010) 1815\u0026ndash;1820. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.msea.2009.11.017\u003c/span\u003e\u003cspan address=\"10.1016/j.msea.2009.11.017\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eM.L. Hu, Q.D. Wang, C. Li, W.J. Ding, Dry sliding wear behavior of cast Mg-11Y-5Gd-2Zn magnesium alloy, Trans. Nonferrous Met. Soc. China (English Ed. 22 (2012) 1918\u0026ndash;1923. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/S1003-6326(11)61408-8\u003c/span\u003e\u003cspan address=\"10.1016/S1003-6326(11)61408-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eJ. An, R.G. Li, Y. Lu, C.M. Chen, Y. Xu, X. Chen, L.M. Wang, Dry sliding wear behavior of magnesium alloys, Wear. 265 (2008) 97\u0026ndash;104. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.wear.2007.08.021\u003c/span\u003e\u003cspan address=\"10.1016/j.wear.2007.08.021\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eR. Arora, S. Kumar, G. Singh, O. Pandey, Influence of particle size and temperature on the wear properties of rutile-reinforced aluminium metal matrix composite, J. Compos. Mater. 49 (2015) 843\u0026ndash;852. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1177/0021998314526079\u003c/span\u003e\u003cspan address=\"10.1177/0021998314526079\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eS. Das, S. V Prasad, T.R. Ramachandran, \u0026ndash; 187 173 Microstructure Composites*, 33 (1989) 173\u0026ndash;187.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eS. Anbu, S. Ramanathan, Dry sliding wear behavior of as-cast ZE41A magnesium alloy, Mater. Des. 31 (2010) 1930\u0026ndash;1936. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.matdes.2009.10.054\u003c/span\u003e\u003cspan address=\"10.1016/j.matdes.2009.10.054\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eA. Srinivasan, Y. Huang, C.L. Mendis, C. Blawert, K.U. Kainer, N. Hort, Investigations on microstructures, mechanical and corrosion properties of Mg-Gd-Zn alloys, Mater. Sci. Eng. A. 595 (2014) 224\u0026ndash;234. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.msea.2013.12.016\u003c/span\u003e\u003cspan address=\"10.1016/j.msea.2013.12.016\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eR.R. Kottuparambil, S. Bontha, R.M. Rangarasaiah, S.B. Arya, A. Jana, M. Das, V.K. Balla, S. Amrithalingam, T.R. Prabhu, Effect of zinc and rare-earth element addition on mechanical, corrosion, and biological properties of magnesium, J. Mater. Res. 33 (2018) 3466\u0026ndash;3478. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1557/jmr.2018.311\u003c/span\u003e\u003cspan address=\"10.1557/jmr.2018.311\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eL. Yang, Y. Huang, Q. Peng, F. Feyerabend, K.U. Kainer, R. Willumeit, N. Hort, Mechanical and corrosion properties of binary Mg \u0026ndash; Dy alloys for medical applications, Mater. Sci. Eng. B. 176 (2011) 1827\u0026ndash;1834. doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.mseb.2011.02.025\u003c/span\u003e\u003cspan address=\"10.1016/j.mseb.2011.02.025\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-materials-science-metallurgy","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [ Journal of Materials Science: Metallurgy](https://link.springer.com/journal/44492)","snPcode":"44492","submissionUrl":"https://submission.springernature.com/new-submission/44492/3?","title":"Journal of Materials Science: Metallurgy","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Open","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Mg-Zn-Gd alloy, Mg-Zn-Dy alloy, Microstructure, Heat-treatment, Wear, Corrosion","lastPublishedDoi":"10.21203/rs.3.rs-8065387/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8065387/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn this study, the effect of heat-treatment on the microstructure, wear, and corrosion behavior of Mg-1Zn-2Gd-0.4Zr (wt. %) and Mg-1Zn-2Dy-0.4Zr (wt. %) alloys were studied. The alloys were solution treated at 500 ℃ for 12 h, followed by ageing for 12 h at 225 ℃ (T6). The microstructural analysis revealed significant amount of secondary phase precipitation after heat treatment in both alloys, which resulted in 20 to 25% increase in the hardness. Wear tests performed between 200 and 400 ℃, at different loading conditions (10 N, 20 N), revealed improved wear resistance in Mg-Zn-Gd alloy samples compared to Mg-Zn-Dy alloy. Further improvement in the wear resistance was also observed after heat treatment. Delamination, abrasion, and oxidation were found to be dominant wear mechanisms in these alloys. Immersion corrosion tests carried out in 3.5 wt. % NaCl solution demonstrated that the heat treatment can significantly improves the corrosion resistance. This is primarily due to the changes in microstructure, i.e., uniform distribution of secondary phases after heat treatment.\u003c/p\u003e\u003cp\u003eAmong the two alloys, Mg-Zn-Gd alloy in heat-treated condition was found to exhibit relatively lower corrosion rate than the Mg-Zn-Dy alloy in both as-cast and heat-treated conditions.\u003c/p\u003e","manuscriptTitle":"Heat treatment of Mg-Zn-Gd and Mg-Zn-Dy alloys for enhanced wear and corrosion properties","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-20 18:58:29","doi":"10.21203/rs.3.rs-8065387/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-02-24T15:08:41+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-18T08:17:34+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"2988190844578679657260322589824219676","date":"2025-12-15T05:29:54+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-11-10T17:27:28+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-11-10T11:25:32+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-11-10T11:24:38+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Materials Science: Metallurgy","date":"2025-11-08T17:02:58+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-materials-science-metallurgy","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [ Journal of Materials Science: Metallurgy](https://link.springer.com/journal/44492)","snPcode":"44492","submissionUrl":"https://submission.springernature.com/new-submission/44492/3?","title":"Journal of Materials Science: Metallurgy","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Open","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"045439fd-39ac-409c-a84d-d638aee1853c","owner":[],"postedDate":"November 20th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-21T17:10:14+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-20 18:58:29","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8065387","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8065387","identity":"rs-8065387","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}