Ti-Ni-Cu Shape Memory Alloy Preparation by Powder Metallurgy and Hot Forging

Ti-Ni-Cu Shape Memory Alloy Preparation by Powder Metallurgy and Hot Forging | 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 Ti-Ni-Cu Shape Memory Alloy Preparation by Powder Metallurgy and Hot Forging Samah Elkhatib, Ayman Elsayed, Junko Umeda, Katsuyoshi Kondoh This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7603587/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 26 Mar, 2026 Read the published version in Discover Materials → Version 1 posted 12 You are reading this latest preprint version Abstract Ti-Ni-Cu shape memory alloys (SMAs), produced through an optimized preparation route including thermo-mechanical deformation, present a promising alternative to traditional Ti-Ni alloys, offering certain advantages. In this study, two Ti-Ni-Cu SMAs were fabricated using powder metallurgy. Fine micron-sized powders were mixed elementally, followed by spark plasma sintering, hot forging, and heat treatment comprising homogenization, solution treatment, aging, and low-temperature quenching. Microstructural evolution across processing stages was examined, and the transformation behavior of heat-treated alloys was characterized by differential scanning calorimetry. Corrosion resistance and hardness were also evaluated. Results revealed relatively high transformation temperatures (60–75°C) with reduced hysteresis. Hot forging significantly enhanced alloy performance by refining microstructure and improving elemental bonding and diffusion. Corrosion resistance improved notably compared to Ti-Ni alloys, while Ti50-Ni30-Cu20 exhibited a 28% hardness increase. Overall, Ti-Ni-Cu SMAs demonstrate improved functional and structural properties, making them strong candidates for advanced shape memory applications. Shape Memory Alloy Powder Metallurgy Hot Forging Spark plasma sintering Microstructure Corrosion Resistance Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 1. Introduction Shape memory alloys (SMAs) are an important group of alloys that show a distinctive shape memory effect due to the thermo-elastic transformation, which enables them to be applied in various areas. The alloys are usually in the cubic austenite phase at high temperatures, while they transform into the monoclinic martensite phase upon cooling [ 1 ]. Alloying elements are sometimes added to the alloy to incorporate other benefits, like increasing the corrosion resistance or altering the transformation temperatures [ 2 , 3 ]. Additionally, SMAs can be employed in a system to offer actuation, sensing, energy dissipation, monitoring, and structural healing. They have many essential applications in technology [ 4 ]. Due to their many intriguing mechanical and physical qualities, including their long fatigue life, good flexibility, and ability to be used as solid-state refrigeration materials, SMAs are still gaining more attention [ 5 , 6 ]. These characteristics have led to the widespread usage of SMAs in applications including automotive, aerospace, structural, industrial, and biomedical products [ 7 – 11 ]. Generally, shape memory alloys were manufactured using various manufacturing techniques, as powder metallurgy (PM) and additive manufacturing (AM) [ 12 ]. Processes such as spark plasma sintering, hot isostatic pressing, conventional sintering, and self-propagating high-temperature synthesis were used, where powder metallurgy has provided the possibility of fine adjustment of the chemical compositions [ 13 , 14 ]. It also enabled the realization of better distribution of fine precipitates that can enhance the overall performance of the alloys [ 14 ]. In contrast, some AM processes, such as selective laser sintering, laser powder bed fusion, laser-engineered net shaping, arc-melting, and selective laser melting, are used to fabricate parts with complex shapes [ 16 – 19 ]. The Ti-Ni alloy's high-temperature deformation is usually applied as a hot activation process based on energy redistribution and dissipation governed by the flow stress, which is affected by the process parameters: temperature, strain rate, and degree of deformation [ 20 – 22 ]. Post-sintering thermo-mechanical deformation was used to improve the performance of Ti-Ni alloys through altering the transformation temperatures and increasing the ductility of the alloys by grain refinement [ 23 , 24 ]. As a novel sintering technique, microwave sintering exhibits some advantages, such as increasing heating rates and reducing sintering times and energy consumption [ 11 ]. Consequently, it has been successfully applied to prepare Ni-Ti alloys with enhanced properties [ 8 , 25 ]. Hot Isostatic pressing was also one of the promising processes for manufacturing Ti-Ni shape memory alloys. The use of high pressure during consolidation enabled the use of higher temperatures, which eventually enhanced the diffusion [ 26 ]. Equi-atomic and near equi-atomic Ti-Ni concentrations are widely used in many application fields. While higher Ti is usually used to stabilize the alloy at higher temperatures and to increase the transformation temperatures, Ni has an extraordinary reduction effect on the transformation temperatures [ 27 , 28 ]. In recent years, various investigations have demonstrated how the third element addition influences the transformation temperature and shape recovery of NiTi alloys [ 29 , 30 ]. Cu addition is known to enhance the characteristics of Ti-Ni alloys [ 31 ], and adding more copper to Ni-Ti-based alloys may improve their capacity to repassivate, which would boost their resistance to corrosion [ 32 ]. By lowering the temperature hysteresis of TiNiCu and caused the alloy's phase transformation to shift from a one-step (B2→B19′) to a two-step (B2→B19→B19′) thermoelastic phase transformation [ 33 ], and consequently, it is determined that the strengthening of the parent phase with increasing Cu content is the cause of the Cu-content dependency of the transition hysteresis of the B2 B19 in Ti-Ni-Cu alloys [ 34 ], Cu can increase the fatigue life and the shape memory effect [ 35 , 36 ]. Copper addition can also improve the corrosion resistance of the alloy [ 37 ]. Processing parameters such as the type of consolidation process or heat treatment conditions also affect the performance of the alloys considerably [ 38 – 41 ]. Moreover, the aging heat treatment parameters and the subsequent quenching medium type and temperature also decide many characteristics of the alloy performance, like the transformation temperatures and the mechanical properties [ 42 – 44 ]. Because of its strong and great biocompatibility, Ti-Ni-Cu SMA is classified as a biomedical material and has a wide range of medicinal applications. Compared to the other varieties of Ti-Ni SMAs, the Ti-Ni-Cu SMAs have the greatest damping capacity and the narrowest temperature hysteresis [45]. Cu addition enhances many of the mechanical characteristics of Ti-Ni alloys. Furthermore, Cu exhibits remarkable antitrust and exceptional temperature stability, inhibiting Ti 3 Ni 4 dissolution. Numerous academics have thoroughly examined the mechanical characteristics and microstructure of the Ti-Ni-Cu alloy in detail. Goryczka T., and Humbeeck J. manufactured the porous Ni–Ti–Cu shape memory alloys using powder technology [ 46 , 47 ]. The use of a proper combination of sintering temperature and time led to a homogenous Ti-Ni-Cu alloy. In their respective discussions, Bingfei Liu and Yangjie Hao validated a constitutive model that predicted how various copper contents affected the mechanical characteristics of Ti-Ni-Cu SMA and its tensile and compressive asymmetric properties [ 48 ]. Yingying Z. et al used coaxial powder-feeding laser additive manufacturing technology to prepare large-size thin-walled Ni50Ti40Cu10 and Ni45Ti40Cu15 alloys with TiB 2 and TiC as inoculants coated on a titanium substrate. They studied the mechanical properties and the microstructure of Ni-Ti-Cu alloys to select appropriate inoculants for wider application. Mohammed S. [ 49 ] reviewed the studies conducted on Ni-Ti-Cu SMAs and suggested that NiTi-based SMAs have greater technical applicability than the other SMA families [ 50 ]. The aim of the current study is basically to investigate the effect of processing parameters like forging, spark plasma sintering, homogenization, aging, and the subsequent quenching temperatures on the thermoelastic transformation of the Ti-Ni-Cu shape memory alloy. 2. Experimental Procedures Ti50-Ni40-Cu10 and Ti50-Ni30-Cu20 alloys were prepared using powder metallurgy processes. Pure elemental powders were employed. The average particle size of the powder was determined following ASTM B822, and the chemical purity of the powder was analyzed using ASTM E1479, having the characteristics shown in Table 1 . Mechanical alloying was then performed in a planetary ball mill for 8 hours after placing the powder mixtures in the zirconia jar and flowing Ar gas for 5 minutes. Alloy concentrations of atomic percentages Ti50-Ni40-Cu10 and Ti50-Ni30-Cu20 were prepared in this study. A ball-to-powder ratio of 2 to 1 and a speed of 100 rpm were used. Table 1 Elemental powder characteristics. Powder Manufacturer Morphology Purity [%] Average particle size [µm] Ti Tohtec Inc. Spongy 99.8 < 45 Ni Vale Canada Limited Spiky 99.8 3–5 Cu Nippon Atomized Inc. spherical 99.9 5 The powder mixtures were then consolidated using spark plasma sintering (Syntax SPS 1030S) at a temperature of 900°C for 30 minutes in a vacuum atmosphere to consolidate 30 mm diameter and 25 mm height billets. The heating rate was 25°C/min. After that, the forging of the sintered billets was performed at a temperature of 900°C after preheating in Ar atmosphere for 10 minutes using a heating rate of 5°C/min. Open die forging was employed using a hydraulic press at a ram speed of 4 mm/s. Homogenization of the forged billets was then done at 900°C for 12 hrs., followed by aging at 500°C for 1 hr. in an Ar gas atmosphere. The samples were then quenched from the aging temperature into a mixture of liquid nitrogen and oil at a temperature of -50°C. Originally, it was intended to quench the samples after aging at the cryogenic liquid nitrogen “LN” temperature of -196°C. That was to enhance the shape memory characteristics of the alloys by getting a fully martensitic structure after quenching. However, the practice has proven to be challenging as the LN tends to instantly form a bubble around the quenched sample, which eventually reduces the cooling rate. Hence, a low-freezing-temperature oil was used to mix with the LN to form a low-temperature quenching medium while minimizing its temperature, such that the oil does not solidify, which turned out to be at about − 50°C. The elemental and mixture powders, as well as the manufactured samples, were then characterized using a scanning electron microscope coupled with EDS analysis (JEOL, JEM-6500F). X-ray diffraction analysis (Shimadzu, XRD-6100) was also used to characterize the phases existing in both the powders and the manufactured samples. Differential scanning calorimetry (DSC-60, Shimadzu) was also used to investigate the pattern and the temperatures of transformation between the austenite and martensite phases in the alloys. The TiNiCu alloys have been tested for their corrosion behavior in a simulated body fluid solution, while for comparison, the TiNi alloy was also tested. A typical three-electrode electrochemical cell and an IVUMStat (Potentiostat/Galvanostat) were used to conduct the electrochemical tests. The working electrode was Ti-Ni, while a platinum electrode and a silver-silver electrode were used as counter and reference electrodes, respectively. A simulated body fluid solution was used for electrochemical evaluations to simulate the corrosive environment encountered in the human body. To conduct the electrochemical impedance spectroscopy (EIS) test, a sinusoidal potential excitation amplitude of 5 mV was applied across the frequency range of 100 kHz to 10 mHz. For every specimen, the electrochemical tests were conducted at least three times, and the outcomes demonstrated excellent repeatability. Before each test, the electrodes were immersed in the solution for 30 minutes, or until the OCP was reached. Tafel polarization curves were obtained by automatically changing the electrode potential from − 1000 to + 2500 mV at open-circuit potential (OCP) at a scan rate of 1 mV/s. Starting in the cathodic direction, polarization moved towards the anodic direction. Through the Vickers hardness test, five hardness measurement readings were obtained for each sample. It was assessed using a 10 kgf load, and it took 10 seconds for all specimens to make an indentation. The outcomes of the reported Vickers hardness test values of the specimens are compiled. 3. Results and Discussion The scanning electron microscope images of elemental powders, as well as the Ti50-Ni30-Cu20 alloy powder mixture in Fig. 1 , show that the starting powders had quite varying particle sizes. The Ni powder had an average particle size of about 4 µm Fig. 1 (b) , and the Cu powder had an average particle size of 5 µm Fig. 1 (c) , while the Ti powder had a slightly coarser particle size of 45 µm Fig. 1 (a). The Ti50-Ni30-Cu20 alloy mixture powder image in Fig. 1 (d) shows that the mixing process resulted in a homogeneous blending of powder types without signs of agglomeration. The difference in particle sizes between Ni, Cu, and Ti powders allows for better powder filling than when powders have similar particle sizes. The XRD patterns of the consolidated alloys’ elemental constituents, after mixing and SPS sintering, and after shape memory heat treatment, are shown in Fig. 2 . The patterns show that TiNi B2 austenite is the dominant phase in the structure of both alloys, along with Ti2Ni second-phase particles, which are usually present after processing of the alloy at temperatures above 800˚C. It can be shown from the figure that all the elemental constituent XRD peaks of Ti, Ni and Cu powders disappeared from the alloys after SPS processing. This indicates that enough diffusion could be realized during SPS, eventually forming the target alloys. In the case of the current study, the Ti2Ni particles were present after the SPS process performed at 900 ˚C, which may be due to either the effect of some minor localized composition inhomogeneity (sites where the Ti content exceeds 50% atomic percentage) or the high temperature and relatively slow cooling in SPS processing. The non-transforming Ti2NiCu phase is also detectable in both alloys, which was previously reported to exist in the alloy, reducing the heat input (or output) required for the direct transformations between the austenite and martensite phases [ 51 ]. The amount of the Ti2NiCu phase increased as the Cu content increased from 10% to 20%. Figure 3 shows that spark plasma sintering resulted in the formation of a network microstructure of TiNi B2 austenite phase (appearing as the lighter areas in Fig. 3 (a) , along with less volume fraction of the second-phase regions of Ti2Ni (appearing as darker areas). The above-mentioned phase identification agrees well with the XRD results shown in Fig. 2 and is also supported by the EDS analysis shown in Fig. 4 . In this EDS analysis, it can be seen that points 4, 5, and 6 show higher Ti concentrations, revealing that they relate to the Ti2Ni second phase. On the other hand, the forging of the alloy resulted in the austenite phase encapsulating the Ti2Ni second phase into tiny distributed areas, as shown in Fig. 3 (b). Furthermore, precipitates of the Ti2NiCu phase can also be observed in the structure of the forged sample. However, homogenization heat treatment, which was performed at a temperature of 900 ˚C for 12 hrs., and the subsequent aging heat treatment resulted in that phase being dissolved in the structure of the alloy while the martensite platelets started to be observable, as shown in Fig. 3 (c). On the other hand, Ti50-Ni30-Cu20 alloy has shown quite different characteristics, as the fine martensite platelets can be observed even after SPS processing, as shown in Fig. 5 (a) . The observation of the martensite phase in this alloy, rather than the alloy containing 10% Cu, can be due to the difference in transformation temperatures, as Cu is known to shift the transformation temperatures to higher values. Forging in the case of this alloy has resulted in the formation of finer precipitates of the Ti2NiCu phase, as shown in Fig. 5 (b) , which are more distributed than in the case of the Ti50-Ni40-Cu10 alloy. The SEM image of the water-quenched alloy, shown in Fig. 5 (c) , shows that the volume fraction of the martensite phase has considerably increased. Furthermore, quenching of alloys at the temperature of -50°C has resulted in the formation of a near-fully martensite (about 90%) structure in both alloys, as shown in Fig. 6 . Moreover, the lower temperature of the quenching medium has also resulted in the precipitates almost disappearing from both alloys, apparently as a result of the higher cooling rates that do not allow them to form, Fig. 6 (a, b) . The alloy containing 20% Cu has shown more areas full of martensite phase, as it was previously shown to be due to the difference in transformation temperatures, as shown in Fig. 6 (b) . The DSC patterns of the consolidated alloys, which were obtained after the samples underwent the SPS, forging, homogenization, aging heat treatments and the subsequent − 50°C oil quenching, are shown in Fig. 7 . Both alloys showed clear single-step transformations from austenite to martensite and vice versa [typical single-stage B2↔ B19′]. The alloy containing 20% Cu has shown higher transformation temperatures than the alloy containing 10% Cu. Moreover, the 20% Cu alloy has also shown narrower transformation temperature hysteresis than that of the 10% Cu alloy, which was previously shown to be related to the presence of Cu in TiNi-based shape memory alloys. Furthermore, the martensite transition (Ms) of Ti-Ni-Cu alloys showed a tendency of gradual increase as the Cu concentration increased. The phases of Cu4Ti3 and NiTi martensite (B19′ phase) change as the amount of Cu alloying element increases. It was found that adding Cu increased the initiation temperature for the martensite transition (Ms) of 10% Cu alloys, indicating that Cu most likely replaced Ni in Ni-rich alloys. Figure 8 depicts the Potentiodynamic Polarization Curve (PPC) for the three samples. All three samples exhibit a relatively weak passivation behavior. The Ti50-Ni50 sample shows an active passivation transition. At the low potential level, it shows a clear active response. Then, while the potential increases, a transpassive region with a sharp increase in the current density appears, suggesting a less stable passive film. The transpassive region starts at about 0.5 V. The addition of 10% Cu shows a more stable passive film, even lowering the passive current density and reducing the metal dissolution. It also shifts the onset of the transpassive region to 0.6 V, which also recommends the more pronounced passive film stability. The 20% Cu-containing sample showed further enhanced corrosion resistance, notably in terms of a reduced passive current density. The broad passive region indicates that the transpassive breakdown potential increased significantly. This also reveals the more stable passive layer, even at a wider potential range. Moreover, the copper-containing alloys presented more positive Ecorr values, suggesting better corrosion resistance. This could be due to the synergistic effect of copper with titanium and nickel by forming a more stable oxide (or hydroxide) layer. Figure 9 reveals the Nyquist plots of electrochemical impedance spectroscopy of the alloys. All the plots show a single depressed semi-circular arc indicating a protective film formation. The TiNi alloy exhibits the smallest semi-circular arc, indicating the relatively lowest corrosion resistance. The addition of 10% Cu leads to an increase in the arc, which is indicative of better corrosion resistance. A further increase in Cu-content to 20% shows the highest charge transfer resistance. Those findings are consistent with the potentiodynamic polarization results in suggesting the strong positive influence of Cu addition in enhancing the corrosion resistance of the TiNi alloy. The Vickers macro hardness test was carried out to measure the apparent hardness of specimens of Ti50-Ni50 alloy and for TiNiCu alloys containing 10% and 20% Cu. Figure 10 establishes the Vickers hardness of different types of investigated alloys, averaged from 5 readings per sample. It can be noticed that the hardness of Ti50-Ni30-Cu20 alloy increased with increasing the addition of copper and has a high value compared to Ti50-Ni50 and Ti50-Ni40-Cu10, which showed a net progressive increased in macro-hardness of (17.9%) and (28.12%), respectively. Still, the Ti50-Ni40-Cu10 decreased with increasing the Cu mass fraction, with a decrease (7.9%) concerning the Ti50-Ni50. The hardness of the Cu-containing Ti-Ni alloys are usually affected by multiple factors simultaneously, which often results in the above mentioned seemingly complex behavior. The decrease in hardness for Ti50-Ni40-Cu10 alloy is mostly due to the solid solution formation, compared with the case of Ti50-Ni30-Cu20 in which a harder Ti 2 NiCu intermetallic compound was formed, as shown in Fig. 2 . Other reasons for that softening are both the retention of austenite, as shown in Fig. 6 and the coarsening of the microstructure, clearly observable in Fig. 3 compared with that of Fig. 4 , which is a result of the lack of obstacles to dislocation movement. This softening in the Ti50-Ni40-Cu10 alloy was also previously reported in alloy ribbons [ 52 ]. On the other hand, the increase in hardness for Ti50-Ni30-Cu20 is mainly due to the hard intermetallic compound formation and the vast increase in the martensite phase, evident in Fig. 6 . 4. Conclusions TiNiCu alloys containing 10% and 20% Cu were synthesized using the powder metallurgy technique. Spark plasma sintering was employed to consolidate the alloys, followed by hot forging, homogenization, and aging heat treatment, and subsequent quenching in various media (water and − 50°C oil). The results show that the conclusions of this study may be as follows; Spark plasma sintering is a process that can be used to consolidate TiNiCu shape memory alloys, as the alloys were formed without any residual elemental constituent powders. Hot forging can be employed to refine the microstructures of the alloys and to improve the diffusion of the alloying elements. The use of rapid quenching at lower temperatures results in the formation of higher volume fractions of martensite and less possibility of forming precipitates. The processing route used in this study could yield alloys with a clear single-step reversible transformation between the austenite and martensite phases. The Cu addition to the Ti-Ni shape memory alloy increased the transformation temperature with narrower hysteresis. Increased Cu-content to 20% results in the highest charge transfer resistance, indicating Cu-addition's strong positive influence on TiNi alloy corrosion resistance. The Vickers macro hardness test revealed that copper addition enhances the hardness of Ti50-Ni30-Cu20 alloy, while Ti50-Ni40-Cu10 decreases with Cu mass fraction. Declarations Funding: No financial support for this study was provided Conflicts of interest: "On behalf of all authors, the corresponding author states that there is no conflict of interest.". The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Availability of data and material: The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request. Code availability : No code was used to support this study. Ethics approval and consent to participate: Not applicable. Consent to publish declaration: Not applicable. Consent to Participate declaration: not applicable. Authors' contributions : Conceptualization, S.E.-k, A. E.-S., J.U wrote the main manuscript, S.E.-k, A. E.-S., J.U prepared all the figures. All authors conducted experiments, analysed the data and reviewed the manuscript. All authors have read and agreed to the published version of the manuscript. References S. Jiang, D. Sun, Y. Zhang, L. Hu, Metals (Basel). 7 8 (2017). doi: 10.3390/met7080294. C. Xiong, Y. Li, J. Zhang, Y. Wang, W. Qu, Y. Ji, J. Alloys Compd. 853 157090(2021). doi: 10.1016/j.jallcom.2020.157090. S. Jasjeevan, G. Simranpreet, D. Manu, S.Shubham, S.Mandeep, D., Shashi, L. Chang, S.Sunpreet & M. Shoaib, S. Bashir, M. Shamseldin, Materials. 15, 5681 (2022), doi:10.3390/ma15165681. B. Mohammed Ibrahim, S. S. Mohammed, and E. Balci, Funct. Mater. 6 2 40–50(2023). doi: 10.54565/jphcfum.1357636. S. Iyer, P. Hubert, Eng. Res. Express. 4 1 (2022). doi: 10.1088/2631-8695/ac2bf1. Y. Cao, X. Zhou, D. Cong, H. Zheng, Y. Cao, Z. Nie, Acta Mater. 194 178–189 (2020), doi:10.1016/j.actamat.2020.04.007. Y. Gao, X. Xue, H. Gao, W. Luo, K. Wang, S. Li, Metals (Basel). 12 10 (2022). doi: 10.3390/met12101562. S. Wen, J. Gan, F. Li, Y. Zhou, C. Yan, Y. Shi, Materials (Basel). 14 16 (2021). doi: 10.3390/ma14164496. J. Su, O. Mahmoud, J. Su, O. Mahmoud, H. A. Nasr-el-din, Futur. Eng. J. 4 1 (2023). doi:10.54623/fue.fej.4.1.2. S. Santosh, R. Praveen, V. Sampath, Trans. Indian Inst. Met. 72 6 1465–1468 (2019). doi: 10.1007/s12666-019-01591-6. Z. He, Z. Wang, D. Wang, X. Liu, B. Duan, Materials (Basel) 15 20 (2022). doi:10.3390/ma15207331. E. Farber, J. N. Zhu, A. Popovich, V. Popovich, Mater. Today Proc. 30 761–767 (2019). doi: 10.1016/j.matpr.2020.01.563. D. F. Abbas, K. K. Resan, A. M. Takhakh, IOP Conf. Ser. Mater. Sci. Eng.671 1 (2020). doi:10.1088/1757899X/671/1/012142. S. L. Zhu, X. J. Yang, F. Hu, S. H. Deng, Z. D. Cui, Mater. Lett. 58 19 2369–2373 (2004). doi:10.1016/j.matlet.2004.02.017. A. Bahador, E. Hamzah, K. Kondoh,T. Asma Abubakar, F. Yusof, J. Umeda, Trans. Nonferrous Met. Soc. China. 28 3 502–514 (2018). doi:10.1016/S1003-6326(18)64683-7. Z. Wang, J. Chen, C. Besnard, L. Kunčická, R. Kocich, A. M. Korsunsky, Acta Mater., 202 135–148 (2021). doi:10.1016/j.actamat.2020.10.049. C. Tatar, R. Acar, and I. N. Qader, Eur. Phys. J. Plus. 135 1–11 (2020). doi:10.1140/epjp/s13360-020-00288-w. Z. Xiong, Z. Li, Z. Sun, S. Hao, Y. Yang, M. Li, J. Mater. Sci. Technol. 35 10 2238–2242 (2019). doi: 10.1016/j.jmst.2019.05.015. X. Wang, J. Yu, J. Liu, L. Chen, Q. Yang, H. Wei, . Addit. Manuf. 36 (2020). doi:10.1016/j.addma.2020.101545. W. Li, C. Zhao, Crystals. 8 9 (2018). doi:10.3390/cryst8090345. C. Tao, H. Huang, G. Zhou, B. Zheng, X. Zuo, L. Chen Materials (Basel). .14 20 (2021). doi: 10.3390/ma14206173. K. D. Salman, J. Phys. Conf. Ser. 1973 1 (2021). doi:10.1088/17426596/1973/1/012108. A. Shuytcev, G. Markova, A. Kasimtcev, and S. Volod’Ko, Mater. Today Proc. 4 3 4685–4689 (2017). doi: 10.1016/j.matpr.2017.04.052. A. Radi, J. Khalil-Allafi, M. R. Etminanfar, S. Pourbabak, D. Schryvers, and B. Amin-Ahmadi, Mater. Des. 142 93–100 (2017). doi:10.1016/j.matdes.2018.01.024. Q. Zhang, S. Hao, Y. Liu, Z. Xiong, W. Guo, Y. Yang, Appl. Mater. Today. 19 1–25 (2020). doi: 10.1016/j.apmt.2019.100547. M. D. McNeese, D. C. Lagoudas, T. C. Pollock, Mater. Sci. Eng. A. 280 2 334–348 (2000). doi:10.1016/S0921-5093(99)00550-X. C. Machio, M. N. Mathabathe, A. S. Bolokang, J. Alloys Compd. 848:156494 (2020). doi: 10.1016/j.jallcom.2020.156494. F. Dagdelen, M. Aldalawi, M. Kok, I. N. Qader, Eur. Phys. J. Plus. 134 2 1–6 (2019). doi:10.1140/epjp/i2019-12479-3. N. Sharma, K. K. Jangra, T. Raj, Proc. Inst. Mech. Eng. Part L J. Mater. Des. Appl. 232 3 250–269 (2018). doi:10.1177/1464420715622494. O. Karakoc, K. C Atli, A. Evirgen, J. Pons, R. Santamarta, O. Benafan, Mater. Sci. Eng. A. 794 (2020) 139857. doi:10.1016/j.msea.2020.139857. S. H. Mohammed, M. A. Mohammed, A. A. Aljubouri, S. H. Shahatha, J. Phys. Conf. Ser. 1963 1 (2021). doi: 10.1088/1742-6596/1963/1/012017. C. Craciunescu, A. S. Hamdy, 8 8, 10320-10334 (2013) . https://doi.org/10.1016/S1452-3981(23)13113-0. F. J. Gil, J. A. Planell, J. Biomed. Mater. Res.. 48 5 682–688 (1999). doi: 10.1002/(SICI)10974636. Nam, Tae-Hyun & Saburi, Toshio & Nakata, Yoshiyuki & Shimizu, Ken'ichi, Materials Transactions, JIM.31. 1050-1056 (1990). doi:10.2320/matertrans1989.31.1050 K. Nargatti, S. Ahankari, A Review. J. Intell. Mater. Syst. Struct. 2022; 33 4 503–531(2022). doi:10.1177/1045389X211023582. K. Tsuji, Y. Takegawa, K. Kojima, Mater. Sci. Eng. A. 136 C 1–4 (1991). doi:10.1016/09215093(91)90435-P. C. Velmurugan, J. Kesavan, V. Senthilkumar, and K. Ramya, Mater. Today Proc. 43 520–523 (2020). doi:10.1016/j.matpr.2020.12.027. J. Mentz, J. Frenzel, M. F X Wagner, K. Neuking, G. Eggeler, H. Buchkremer, Mater. Sci. Eng. A. 491 1–2 270–278 (2008). doi: 10.1016/j.msea.2008.01.084. Y. Q. Fu, Y. W. Gu, C. Shearwood, J. K. Luo, A. J. Flewitt, and W. I. Milne, Nanotechnology. 17 21 5293–5298 (2006). doi:10.1088/0957-4484/17/21/002. Y. Q. Zhang, S. Y. Jiang, Y. N. Zhao, M. Tang, Nonferrous Met. Soc. China (English Ed.) 22 11 2685–2690 (2012). doi:10.1016/S1003-6326(11)61518-5. M. Morakabati, S. Kheirandish, M. Aboutalebi, A. K. Taheri, S. M. Abbasi, J. Alloys Compd. 499 1 57–62 (2010). doi:10.1016/j.jallcom.2010.01.124. A. Sinha, B. Mondal, B. C. Maji, P. P. Chattopadhyay, Mater. Sci. Eng. A. 580 273–278 (2013). doi: 10.1016/j.msea.2013.05.036. A. Elsayed, J. Umeda,K. Kondoh, J. Alloys Compd. 842 (2020) . doi: 10.1016/j.jallcom.2020.155931. B. Fu, K. Feng, and Z. Li, Mater. Lett.. 220 148–151 (2018). doi: 10.1016/j.matlet.2018.03.030. F. Villa, A. Nespoli, F. Passaretti, and E. Villa, Materials (Basel). 14 14 107084 (2020). doi: 10.3390/ma14143770. N. Nayan, G. Singh, S. Murty, P. Narayan, M. Mohan,P. Venkitakrishnan, Intermetallics, 131 107084(2021). doi: 10.1016/j.intermet.2021.107084. T. Goryczka, J. Van Humbeeck, J. Alloys Compd. 456(1–2) 94–200(2008). doi: 10.1016/j.jallcom.2007.02.094. B. Liu, Y. Hao, C. - Comput. Model. Eng. Sci. 131 3 1601–1613(2022). doi: 10.32604/cmes.2022.019226. Z. Yingying, L. Hao, H. Man, C. Xia, T. Jian, W. jingmin, Eng. Res. Express 5, 025064(2023). https://doi.org/10.1088/2631-8695/acdce1 R. Qadir, S. Mohammed, M. Kök, I. Qader, J. Phys. Chem. Funct. Mater. 4 2 49–56(2021). doi: 10.54565/jphcfum.1018817. M. Valeanu, M. Lucaci, A. D. Crisan, M. Sofronie, L. Leonat, V. Kuncser, J. Alloys Compd. 509 13 4495–4498 (2011). doi:10.1016/j.jallcom.2011.01.154. K. X. Hau, N. H. Yen, N. H. Ngoc, T. V. Anh, P. T. Thanh, N. V. Toan, N. H. Dan, Mater. Trans. 64 4 849-854 (2023). doi:10.2320/matertrans.MT-M2022161. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 26 Mar, 2026 Read the published version in Discover Materials → Version 1 posted Editorial decision: Revision requested 15 Oct, 2025 Reviews received at journal 12 Oct, 2025 Reviews received at journal 08 Oct, 2025 Reviews received at journal 28 Sep, 2025 Reviewers agreed at journal 28 Sep, 2025 Reviewers agreed at journal 28 Sep, 2025 Reviewers agreed at journal 28 Sep, 2025 Reviewers invited by journal 28 Sep, 2025 Editor invited by journal 26 Sep, 2025 Editor assigned by journal 14 Sep, 2025 Submission checks completed at journal 14 Sep, 2025 First submitted to journal 12 Sep, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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13:00:30","extension":"xml","order_by":52,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":104826,"visible":true,"origin":"","legend":"","description":"","filename":"7a9675d89f1341329e403f550f1d96e91structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7603587/v1/713ca0eb52da9b2f88a7238d.xml"},{"id":93141478,"identity":"2263309f-e8d2-46a6-8648-089edb66b516","added_by":"auto","created_at":"2025-10-09 13:08:30","extension":"html","order_by":53,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":117023,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7603587/v1/25a013fd047a90a600d758b2.html"},{"id":93142861,"identity":"8aed6aa3-8764-4a51-8354-8d6809441cf0","added_by":"auto","created_at":"2025-10-09 13:16:29","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1382925,"visible":true,"origin":"","legend":"\u003cp\u003eSEM images of the elemental powders of Ti (a), Ni (b), Cu (c), and alloy mixture (d)\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-7603587/v1/e359a11184d6e1ba5001df4f.png"},{"id":93141456,"identity":"06a2811b-d643-41b1-bd12-51243775f04e","added_by":"auto","created_at":"2025-10-09 13:08:29","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":4421098,"visible":true,"origin":"","legend":"\u003cp\u003eXRD patterns of Ti-Ni-Cu alloy powder constituents, after SPS, and after shape memory heat treatment.\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-7603587/v1/5597308b14f8d5614614ede7.png"},{"id":93140662,"identity":"9597f37f-6a99-4ff7-803e-4bce70b142f9","added_by":"auto","created_at":"2025-10-09 13:00:28","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":1253376,"visible":true,"origin":"","legend":"\u003cp\u003eSEM images of consolidated Ti50-Ni40-Cu10 alloy after SPS (a), after forging (b), and after homogenization, aging and water quenching (c).\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-7603587/v1/100bc1195689bd3d63fc9272.png"},{"id":93140664,"identity":"e8c5e133-7820-4b6c-91ce-a8e9d86e5992","added_by":"auto","created_at":"2025-10-09 13:00:28","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":669128,"visible":true,"origin":"","legend":"\u003cp\u003eEDS analysis of Ti50-Ni40-Cu10 alloy after homogenization heat treatment.\u003c/p\u003e","description":"","filename":"Figure4.png","url":"https://assets-eu.researchsquare.com/files/rs-7603587/v1/c619a95118ba35aa2b4b1f13.png"},{"id":93140665,"identity":"96a311fc-8abb-4042-9a16-abe3507bac69","added_by":"auto","created_at":"2025-10-09 13:00:29","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":1056163,"visible":true,"origin":"","legend":"\u003cp\u003eSEM images of consolidated Ti50-Ni30-Cu20 alloy after SPS (a), after forging (b), and after homogenization and aging and water quenching (c).\u003c/p\u003e","description":"","filename":"Figure5.png","url":"https://assets-eu.researchsquare.com/files/rs-7603587/v1/31c12cd0ff4e2332fe5e839b.png"},{"id":93140674,"identity":"6e48a82e-19af-49a9-819b-abe660edf5c3","added_by":"auto","created_at":"2025-10-09 13:00:29","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":10418694,"visible":true,"origin":"","legend":"\u003cp\u003eSEM images of consolidated Ti50-Ni40-Cu10 (a) and Ti50-Ni30-Cu20 (b) alloys after aging and quenching in -50 °C oil medium.\u003c/p\u003e","description":"","filename":"Figure6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7603587/v1/89f17d1ebb31b58d0092f9f1.jpg"},{"id":93141457,"identity":"ebd359e5-0374-44a1-9e25-f341ad393601","added_by":"auto","created_at":"2025-10-09 13:08:29","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":11573,"visible":true,"origin":"","legend":"\u003cp\u003eDSC patterns of the consolidated alloys after aging and -50 °C oil quenching.\u003c/p\u003e","description":"","filename":"Figure7.png","url":"https://assets-eu.researchsquare.com/files/rs-7603587/v1/a402ac8fc733d618ce3b5e8c.png"},{"id":93140667,"identity":"5307dab9-18f6-4bd6-b146-affff2f5029f","added_by":"auto","created_at":"2025-10-09 13:00:29","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":19633,"visible":true,"origin":"","legend":"\u003cp\u003eThe Potentiodynamic Polarization Curves of TiNi and TiNiCu alloys.\u003c/p\u003e","description":"","filename":"Figure8.png","url":"https://assets-eu.researchsquare.com/files/rs-7603587/v1/f11ac09c2e83cd78b8f4bd2c.png"},{"id":93141461,"identity":"e425a981-925d-46dd-a5e9-9ef91bf5dddd","added_by":"auto","created_at":"2025-10-09 13:08:29","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":11297,"visible":true,"origin":"","legend":"\u003cp\u003eThe Electrochemical Impedance Spectroscopy of TiNi and TiNiCu alloys\u003c/p\u003e","description":"","filename":"Figure9.png","url":"https://assets-eu.researchsquare.com/files/rs-7603587/v1/7fc69c406dd0ad3c980dc91f.png"},{"id":93140670,"identity":"14aa14a0-3d16-4252-b97e-8466adad4ae3","added_by":"auto","created_at":"2025-10-09 13:00:29","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":5797,"visible":true,"origin":"","legend":"\u003cp\u003eHv Hardness of Ti50-Ni50, Ti50-Ni40-Cu10 and Ti50-Ni30-Cu20 alloys.\u003c/p\u003e","description":"","filename":"Figure10.png","url":"https://assets-eu.researchsquare.com/files/rs-7603587/v1/c17dbe4a1c6d5f398ab88f89.png"},{"id":105756129,"identity":"97f40338-84a4-458a-9c43-50436f686afd","added_by":"auto","created_at":"2026-03-30 16:36:08","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":19260252,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7603587/v1/5769949d-2543-4332-a7df-b204c2ed6b4e.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Ti-Ni-Cu Shape Memory Alloy Preparation by Powder Metallurgy and Hot Forging","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eShape memory alloys (SMAs) are an important group of alloys that show a distinctive shape memory effect due to the thermo-elastic transformation, which enables them to be applied in various areas. The alloys are usually in the cubic austenite phase at high temperatures, while they transform into the monoclinic martensite phase upon cooling [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Alloying elements are sometimes added to the alloy to incorporate other benefits, like increasing the corrosion resistance or altering the transformation temperatures [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Additionally, SMAs can be employed in a system to offer actuation, sensing, energy dissipation, monitoring, and structural healing. They have many essential applications in technology [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Due to their many intriguing mechanical and physical qualities, including their long fatigue life, good flexibility, and ability to be used as solid-state refrigeration materials, SMAs are still gaining more attention [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. These characteristics have led to the widespread usage of SMAs in applications including automotive, aerospace, structural, industrial, and biomedical products [\u003cspan additionalcitationids=\"CR8 CR9 CR10\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eGenerally, shape memory alloys were manufactured using various manufacturing techniques, as powder metallurgy (PM) and additive manufacturing (AM) [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Processes such as spark plasma sintering, hot isostatic pressing, conventional sintering, and self-propagating high-temperature synthesis were used, where powder metallurgy has provided the possibility of fine adjustment of the chemical compositions [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. It also enabled the realization of better distribution of fine precipitates that can enhance the overall performance of the alloys [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. In contrast, some AM processes, such as selective laser sintering, laser powder bed fusion, laser-engineered net shaping, arc-melting, and selective laser melting, are used to fabricate parts with complex shapes [\u003cspan additionalcitationids=\"CR17 CR18\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. The Ti-Ni alloy's high-temperature deformation is usually applied as a hot activation process based on energy redistribution and dissipation governed by the flow stress, which is affected by the process parameters: temperature, strain rate, and degree of deformation [\u003cspan additionalcitationids=\"CR21\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Post-sintering thermo-mechanical deformation was used to improve the performance of Ti-Ni alloys through altering the transformation temperatures and increasing the ductility of the alloys by grain refinement [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. As a novel sintering technique, microwave sintering exhibits some advantages, such as increasing heating rates and reducing sintering times and energy consumption [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Consequently, it has been successfully applied to prepare Ni-Ti alloys with enhanced properties [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Hot Isostatic pressing was also one of the promising processes for manufacturing Ti-Ni shape memory alloys. The use of high pressure during consolidation enabled the use of higher temperatures, which eventually enhanced the diffusion [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eEqui-atomic and near equi-atomic Ti-Ni concentrations are widely used in many application fields. While higher Ti is usually used to stabilize the alloy at higher temperatures and to increase the transformation temperatures, Ni has an extraordinary reduction effect on the transformation temperatures [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. In recent years, various investigations have demonstrated how the third element addition influences the transformation temperature and shape recovery of NiTi alloys [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. Cu addition is known to enhance the characteristics of Ti-Ni alloys [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e], and adding more copper to Ni-Ti-based alloys may improve their capacity to repassivate, which would boost their resistance to corrosion [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eBy lowering the temperature hysteresis of TiNiCu and caused the alloy's phase transformation to shift from a one-step (B2\u0026rarr;B19\u0026prime;) to a two-step (B2\u0026rarr;B19\u0026rarr;B19\u0026prime;) thermoelastic phase transformation [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e], and consequently, it is determined that the strengthening of the parent phase with increasing Cu content is the cause of the Cu-content dependency of the transition hysteresis of the B2 \u003cimg src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAC4AAAAWCAYAAAC/kK73AAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAAFiUAABYlAUlSJPAAAAHGSURBVFhH7ZYvq8JQGId/c0FdM6z4J9rUYrKIX0DRYDHvO5jMVoswg6BlzOJnUDFYBQ0LWxBWtQxUEN+bHOydevVe2K5wHzjlfX875+Hs7DCBiAgfSIQXPoV/8aD5F3+X4XAIQRAwn89h2zZvfw+FxH6/p1QqRQBIFEVSVZVHnhKa+I12u02RSIQAEABSFIW22y2P+RDozj1uGAa63S6azSYkSQIAmKaJTCaD8/mM6XTqyddqNSQSCQDAeDz29AB45lksFiiXy3AcB8fjEbIsw7IsKIrCH0Oj0YAsyxgMBrzlPyrX65VarZa7A2EPSZLIcRyuGf5RISKq1+uuqCAIpGkaj/h4W9y2bcrn8wSA4vE4b7/M5XKhYrHoCqfTaTIMg8ce8pZ4oVDwvMbT6cQjL2NZljuPaZq8/S1PxVerFfV6Pcpms+4isViMNpsNjwbOXXFd130fSZij3+9zxfvXIQAsl0voug5N03A4HNx6MpnEZDLxZN9hNpuhUqnw8kNEUUSpVOJl/3X4CFVVKRqNurswGo14JFBeFr/R6XRIFEUCQLlcjrcD4+FRecZut8N6vQYAVKtV3g6EH4n/BUL7rf0tHyv+BeflODzSKYEnAAAAAElFTkSuQmCC\" width=\"46\" height=\"22\"\u003e B19 in Ti-Ni-Cu alloys [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e], Cu can increase the fatigue life and the shape memory effect [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]. Copper addition can also improve the corrosion resistance of the alloy [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. Processing parameters such as the type of consolidation process or heat treatment conditions also affect the performance of the alloys considerably [\u003cspan additionalcitationids=\"CR39 CR40\" citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e]. Moreover, the aging heat treatment parameters and the subsequent quenching medium type and temperature also decide many characteristics of the alloy performance, like the transformation temperatures and the mechanical properties [\u003cspan additionalcitationids=\"CR43\" citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eBecause of its strong and great biocompatibility, Ti-Ni-Cu SMA is classified as a biomedical material and has a wide range of medicinal applications. Compared to the other varieties of Ti-Ni SMAs, the Ti-Ni-Cu SMAs have the greatest damping capacity and the narrowest temperature hysteresis [45]. Cu addition enhances many of the mechanical characteristics of Ti-Ni alloys. Furthermore, Cu exhibits remarkable antitrust and exceptional temperature stability, inhibiting Ti\u003csub\u003e3\u003c/sub\u003eNi\u003csub\u003e4\u003c/sub\u003e dissolution.\u003c/p\u003e\u003cp\u003eNumerous academics have thoroughly examined the mechanical characteristics and microstructure of the Ti-Ni-Cu alloy in detail. Goryczka T., and Humbeeck J. manufactured the porous Ni\u0026ndash;Ti\u0026ndash;Cu shape memory alloys using powder technology [\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e, \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e]. The use of a proper combination of sintering temperature and time led to a homogenous Ti-Ni-Cu alloy. In their respective discussions, Bingfei Liu and Yangjie Hao validated a constitutive model that predicted how various copper contents affected the mechanical characteristics of Ti-Ni-Cu SMA and its tensile and compressive asymmetric properties [\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e]. Yingying Z. et al used coaxial powder-feeding laser additive manufacturing technology to prepare large-size thin-walled Ni50Ti40Cu10 and Ni45Ti40Cu15 alloys with TiB\u003csub\u003e2\u003c/sub\u003e and TiC as inoculants coated on a titanium substrate. They studied the mechanical properties and the microstructure of Ni-Ti-Cu alloys to select appropriate inoculants for wider application. Mohammed S. [\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e] reviewed the studies conducted on Ni-Ti-Cu SMAs and suggested that NiTi-based SMAs have greater technical applicability than the other SMA families [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e]. The aim of the current study is basically to investigate the effect of processing parameters like forging, spark plasma sintering, homogenization, aging, and the subsequent quenching temperatures on the thermoelastic transformation of the Ti-Ni-Cu shape memory alloy.\u003c/p\u003e"},{"header":"2. Experimental Procedures","content":"\u003cp\u003eTi50-Ni40-Cu10 and Ti50-Ni30-Cu20 alloys were prepared using powder metallurgy processes. Pure elemental powders were employed. The average particle size of the powder was determined following ASTM B822, and the chemical purity of the powder was analyzed using ASTM E1479, having the characteristics shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Mechanical alloying was then performed in a planetary ball mill for 8 hours after placing the powder mixtures in the zirconia jar and flowing Ar gas for 5 minutes. Alloy concentrations of atomic percentages Ti50-Ni40-Cu10 and Ti50-Ni30-Cu20 were prepared in this study. A ball-to-powder ratio of 2 to 1 and a speed of 100 rpm were used.\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\u003eElemental powder characteristics.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\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=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePowder\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eManufacturer\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMorphology\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003ePurity [%]\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eAverage particle size [\u0026micro;m]\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTi\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTohtec Inc.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSpongy\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e99.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;45\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNi\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eVale Canada Limited\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eSpiky\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e99.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3\u0026ndash;5\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCu\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNippon Atomized Inc.\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003espherical\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e99.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe powder mixtures were then consolidated using spark plasma sintering (Syntax SPS 1030S) at a temperature of 900\u0026deg;C for 30 minutes in a vacuum atmosphere to consolidate 30 mm diameter and 25 mm height billets. The heating rate was 25\u0026deg;C/min. After that, the forging of the sintered billets was performed at a temperature of 900\u0026deg;C after preheating in Ar atmosphere for 10 minutes using a heating rate of 5\u0026deg;C/min. Open die forging was employed using a hydraulic press at a ram speed of 4 mm/s. Homogenization of the forged billets was then done at 900\u0026deg;C for 12 hrs., followed by aging at 500\u0026deg;C for 1 hr. in an Ar gas atmosphere. The samples were then quenched from the aging temperature into a mixture of liquid nitrogen and oil at a temperature of -50\u0026deg;C. Originally, it was intended to quench the samples after aging at the cryogenic liquid nitrogen \u0026ldquo;LN\u0026rdquo; temperature of -196\u0026deg;C. That was to enhance the shape memory characteristics of the alloys by getting a fully martensitic structure after quenching. However, the practice has proven to be challenging as the LN tends to instantly form a bubble around the quenched sample, which eventually reduces the cooling rate. Hence, a low-freezing-temperature oil was used to mix with the LN to form a low-temperature quenching medium while minimizing its temperature, such that the oil does not solidify, which turned out to be at about \u0026minus;\u0026thinsp;50\u0026deg;C.\u003c/p\u003e\u003cp\u003eThe elemental and mixture powders, as well as the manufactured samples, were then characterized using a scanning electron microscope coupled with EDS analysis (JEOL, JEM-6500F). X-ray diffraction analysis (Shimadzu, XRD-6100) was also used to characterize the phases existing in both the powders and the manufactured samples. Differential scanning calorimetry (DSC-60, Shimadzu) was also used to investigate the pattern and the temperatures of transformation between the austenite and martensite phases in the alloys.\u003c/p\u003e\u003cp\u003eThe TiNiCu alloys have been tested for their corrosion behavior in a simulated body fluid solution, while for comparison, the TiNi alloy was also tested. A typical three-electrode electrochemical cell and an IVUMStat (Potentiostat/Galvanostat) were used to conduct the electrochemical tests. The working electrode was Ti-Ni, while a platinum electrode and a silver-silver electrode were used as counter and reference electrodes, respectively. A simulated body fluid solution was used for electrochemical evaluations to simulate the corrosive environment encountered in the human body. To conduct the electrochemical impedance spectroscopy (EIS) test, a sinusoidal potential excitation amplitude of 5 mV was applied across the frequency range of 100 kHz to 10 mHz.\u003c/p\u003e\u003cp\u003eFor every specimen, the electrochemical tests were conducted at least three times, and the outcomes demonstrated excellent repeatability. Before each test, the electrodes were immersed in the solution for 30 minutes, or until the OCP was reached. Tafel polarization curves were obtained by automatically changing the electrode potential from \u0026minus;\u0026thinsp;1000 to +\u0026thinsp;2500 mV at open-circuit potential (OCP) at a scan rate of 1 mV/s. Starting in the cathodic direction, polarization moved towards the anodic direction.\u003c/p\u003e\u003cp\u003eThrough the Vickers hardness test, five hardness measurement readings were obtained for each sample. It was assessed using a 10 kgf load, and it took 10 seconds for all specimens to make an indentation. The outcomes of the reported Vickers hardness test values of the specimens are compiled.\u003c/p\u003e"},{"header":"3. Results and Discussion","content":"\u003cp\u003eThe scanning electron microscope images of elemental powders, as well as the Ti50-Ni30-Cu20 alloy powder mixture in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, show that the starting powders had quite varying particle sizes. The Ni powder had an average particle size of about 4 \u0026micro;m Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e \u003cb\u003e(b)\u003c/b\u003e, and the Cu powder had an average particle size of 5 \u0026micro;m Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e \u003cb\u003e(c)\u003c/b\u003e, while the Ti powder had a slightly coarser particle size of 45 \u0026micro;m Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e \u003cb\u003e(a).\u003c/b\u003e The Ti50-Ni30-Cu20 alloy mixture powder image in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e \u003cb\u003e(d)\u003c/b\u003e shows that the mixing process resulted in a homogeneous blending of powder types without signs of agglomeration. The difference in particle sizes between Ni, Cu, and Ti powders allows for better powder filling than when powders have similar particle sizes.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe XRD patterns of the consolidated alloys\u0026rsquo; elemental constituents, after mixing and SPS sintering, and after shape memory heat treatment, are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The patterns show that TiNi B2 austenite is the dominant phase in the structure of both alloys, along with Ti2Ni second-phase particles, which are usually present after processing of the alloy at temperatures above 800˚C. It can be shown from the figure that all the elemental constituent XRD peaks of Ti, Ni and Cu powders disappeared from the alloys after SPS processing. This indicates that enough diffusion could be realized during SPS, eventually forming the target alloys. In the case of the current study, the Ti2Ni particles were present after the SPS process performed at 900 ˚C, which may be due to either the effect of some minor localized composition inhomogeneity (sites where the Ti content exceeds 50% atomic percentage) or the high temperature and relatively slow cooling in SPS processing. The non-transforming Ti2NiCu phase is also detectable in both alloys, which was previously reported to exist in the alloy, reducing the heat input (or output) required for the direct transformations between the austenite and martensite phases [\u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e]. The amount of the Ti2NiCu phase increased as the Cu content increased from 10% to 20%.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eFigure \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows that spark plasma sintering resulted in the formation of a network microstructure of TiNi B2 austenite phase (appearing as the lighter areas in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e \u003cb\u003e(a)\u003c/b\u003e, along with less volume fraction of the second-phase regions of Ti2Ni (appearing as darker areas). The above-mentioned phase identification agrees well with the XRD results shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e and is also supported by the EDS analysis shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. In this EDS analysis, it can be seen that points 4, 5, and 6 show higher Ti concentrations, revealing that they relate to the Ti2Ni second phase. On the other hand, the forging of the alloy resulted in the austenite phase encapsulating the Ti2Ni second phase into tiny distributed areas, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e \u003cb\u003e(b).\u003c/b\u003e Furthermore, precipitates of the Ti2NiCu phase can also be observed in the structure of the forged sample. However, homogenization heat treatment, which was performed at a temperature of 900 ˚C for 12 hrs., and the subsequent aging heat treatment resulted in that phase being dissolved in the structure of the alloy while the martensite platelets started to be observable, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e \u003cb\u003e(c).\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eOn the other hand, Ti50-Ni30-Cu20 alloy has shown quite different characteristics, as the fine martensite platelets can be observed even after SPS processing, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e \u003cb\u003e(a)\u003c/b\u003e. The observation of the martensite phase in this alloy, rather than the alloy containing 10% Cu, can be due to the difference in transformation temperatures, as Cu is known to shift the transformation temperatures to higher values. Forging in the case of this alloy has resulted in the formation of finer precipitates of the Ti2NiCu phase, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e \u003cb\u003e(b)\u003c/b\u003e, which are more distributed than in the case of the Ti50-Ni40-Cu10 alloy. The SEM image of the water-quenched alloy, shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e \u003cb\u003e(c)\u003c/b\u003e, shows that the volume fraction of the martensite phase has considerably increased.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eFurthermore, quenching of alloys at the temperature of -50\u0026deg;C has resulted in the formation of a near-fully martensite (about 90%) structure in both alloys, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e. Moreover, the lower temperature of the quenching medium has also resulted in the precipitates almost disappearing from both alloys, apparently as a result of the higher cooling rates that do not allow them to form, Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e \u003cb\u003e(a, b)\u003c/b\u003e. The alloy containing 20% Cu has shown more areas full of martensite phase, as it was previously shown to be due to the difference in transformation temperatures, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e \u003cb\u003e(b)\u003c/b\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe DSC patterns of the consolidated alloys, which were obtained after the samples underwent the SPS, forging, homogenization, aging heat treatments and the subsequent \u0026minus;\u0026thinsp;50\u0026deg;C oil quenching, are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e. Both alloys showed clear single-step transformations from austenite to martensite and vice versa [typical single-stage B2\u0026harr; B19\u0026prime;]. The alloy containing 20% Cu has shown higher transformation temperatures than the alloy containing 10% Cu. Moreover, the 20% Cu alloy has also shown narrower transformation temperature hysteresis than that of the 10% Cu alloy, which was previously shown to be related to the presence of Cu in TiNi-based shape memory alloys. Furthermore, the martensite transition (Ms) of Ti-Ni-Cu alloys showed a tendency of gradual increase as the Cu concentration increased.\u003c/p\u003e\u003cp\u003eThe phases of Cu4Ti3 and NiTi martensite (B19\u0026prime; phase) change as the amount of Cu alloying element increases. It was found that adding Cu increased the initiation temperature for the martensite transition (Ms) of 10% Cu alloys, indicating that Cu most likely replaced Ni in Ni-rich alloys.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eFigure \u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e depicts the Potentiodynamic Polarization Curve (PPC) for the three samples. All three samples exhibit a relatively weak passivation behavior. The Ti50-Ni50 sample shows an active passivation transition. At the low potential level, it shows a clear active response. Then, while the potential increases, a transpassive region with a sharp increase in the current density appears, suggesting a less stable passive film. The transpassive region starts at about 0.5 V. The addition of 10% Cu shows a more stable passive film, even lowering the passive current density and reducing the metal dissolution. It also shifts the onset of the transpassive region to 0.6 V, which also recommends the more pronounced passive film stability. The 20% Cu-containing sample showed further enhanced corrosion resistance, notably in terms of a reduced passive current density. The broad passive region indicates that the transpassive breakdown potential increased significantly. This also reveals the more stable passive layer, even at a wider potential range. Moreover, the copper-containing alloys presented more positive Ecorr values, suggesting better corrosion resistance. This could be due to the synergistic effect of copper with titanium and nickel by forming a more stable oxide (or hydroxide) layer.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eFigure \u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e reveals the Nyquist plots of electrochemical impedance spectroscopy of the alloys. All the plots show a single depressed semi-circular arc indicating a protective film formation. The TiNi alloy exhibits the smallest semi-circular arc, indicating the relatively lowest corrosion resistance. The addition of 10% Cu leads to an increase in the arc, which is indicative of better corrosion resistance. A further increase in Cu-content to 20% shows the highest charge transfer resistance. Those findings are consistent with the potentiodynamic polarization results in suggesting the strong positive influence of Cu addition in enhancing the corrosion resistance of the TiNi alloy.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe Vickers macro hardness test was carried out to measure the apparent hardness of specimens of Ti50-Ni50 alloy and for TiNiCu alloys containing 10% and 20% Cu. Figure\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e establishes the Vickers hardness of different types of investigated alloys, averaged from 5 readings per sample. It can be noticed that the hardness of Ti50-Ni30-Cu20 alloy increased with increasing the addition of copper and has a high value compared to Ti50-Ni50 and Ti50-Ni40-Cu10, which showed a net progressive increased in macro-hardness of (17.9%) and (28.12%), respectively. Still, the Ti50-Ni40-Cu10 decreased with increasing the Cu mass fraction, with a decrease (7.9%) concerning the Ti50-Ni50. The hardness of the Cu-containing Ti-Ni alloys are usually affected by multiple factors simultaneously, which often results in the above mentioned seemingly complex behavior. The decrease in hardness for Ti50-Ni40-Cu10 alloy is mostly due to the solid solution formation, compared with the case of Ti50-Ni30-Cu20 in which a harder Ti\u003csub\u003e2\u003c/sub\u003eNiCu intermetallic compound was formed, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. Other reasons for that softening are both the retention of austenite, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e and the coarsening of the microstructure, clearly observable in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e compared with that of Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e, which is a result of the lack of obstacles to dislocation movement. This softening in the Ti50-Ni40-Cu10 alloy was also previously reported in alloy ribbons [\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e]. On the other hand, the increase in hardness for Ti50-Ni30-Cu20 is mainly due to the hard intermetallic compound formation and the vast increase in the martensite phase, evident in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e"},{"header":"4. Conclusions","content":"\u003cp\u003eTiNiCu alloys containing 10% and 20% Cu were synthesized using the powder metallurgy technique. Spark plasma sintering was employed to consolidate the alloys, followed by hot forging, homogenization, and aging heat treatment, and subsequent quenching in various media (water and \u0026minus;\u0026thinsp;50\u0026deg;C oil). The results show that the conclusions of this study may be as follows;\u003c/p\u003e\u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003eSpark plasma sintering is a process that can be used to consolidate TiNiCu shape memory alloys, as the alloys were formed without any residual elemental constituent powders.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eHot forging can be employed to refine the microstructures of the alloys and to improve the diffusion of the alloying elements.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eThe use of rapid quenching at lower temperatures results in the formation of higher volume fractions of martensite and less possibility of forming precipitates.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eThe processing route used in this study could yield alloys with a clear single-step reversible transformation between the austenite and martensite phases.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eThe Cu addition to the Ti-Ni shape memory alloy increased the transformation temperature with narrower hysteresis.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eIncreased Cu-content to 20% results in the highest charge transfer resistance, indicating Cu-addition's strong positive influence on TiNi alloy corrosion resistance.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eThe Vickers macro hardness test revealed that copper addition enhances the hardness of Ti50-Ni30-Cu20 alloy, while Ti50-Ni40-Cu10 decreases with Cu mass fraction.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e No financial support for this study was provided\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflicts of interest:\u003c/strong\u003e \u0026quot;On behalf of all authors, the corresponding author states that there is no conflict of interest.\u0026quot;. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and material:\u0026nbsp;\u003c/strong\u003eThe datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCode availability\u003c/strong\u003e: No code was used to support this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate:\u003c/strong\u003e Not applicable.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to publish\u003c/strong\u003e \u003cstrong\u003edeclaration:\u003c/strong\u003e Not applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to Participate declaration:\u003c/strong\u003e not applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e: Conceptualization, S.E.-k, A. E.-S., J.U wrote the main manuscript, S.E.-k, A. E.-S., J.U prepared all the figures. All authors conducted experiments, analysed the data and reviewed the manuscript. All authors have read and agreed to the published version of the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eS. Jiang, D. Sun, Y. Zhang, L. Hu, Metals (Basel). 7 8 (2017). doi: 10.3390/met7080294.\u003c/li\u003e\n\u003cli\u003eC. Xiong, Y. Li, J. Zhang, Y. Wang, W. Qu, Y. Ji, J. Alloys Compd. 853 157090(2021). doi: 10.1016/j.jallcom.2020.157090.\u003c/li\u003e\n\u003cli\u003eS. Jasjeevan, G. Simranpreet, D. Manu, S.Shubham, S.Mandeep, D., Shashi, L. Chang, S.Sunpreet \u0026amp; M. Shoaib, S. Bashir, M. Shamseldin, Materials. 15, 5681 (2022), doi:10.3390/ma15165681.\u003c/li\u003e\n\u003cli\u003eB. Mohammed Ibrahim, S. S. Mohammed, and E. Balci, Funct. Mater. 6 2 40\u0026ndash;50(2023). doi: 10.54565/jphcfum.1357636.\u003c/li\u003e\n\u003cli\u003eS. Iyer, P. Hubert, Eng. Res. Express. 4 1 (2022). doi: 10.1088/2631-8695/ac2bf1.\u003c/li\u003e\n\u003cli\u003eY. Cao, X. Zhou, D. Cong, H. Zheng, Y. Cao, Z. Nie, Acta Mater. 194 178\u0026ndash;189 (2020), doi:10.1016/j.actamat.2020.04.007.\u003c/li\u003e\n\u003cli\u003eY. Gao, X. Xue, H. Gao, W. Luo, K. Wang, S. Li, Metals (Basel). 12 10 (2022). doi: 10.3390/met12101562.\u003c/li\u003e\n\u003cli\u003eS. Wen, J. Gan, F. Li, Y. Zhou, C. Yan, Y. Shi, Materials (Basel). 14 16 (2021). doi: 10.3390/ma14164496.\u003c/li\u003e\n\u003cli\u003eJ. Su, O. Mahmoud, J. Su, O. Mahmoud, H. A. Nasr-el-din, Futur. Eng. J. 4 1 (2023). doi:10.54623/fue.fej.4.1.2.\u003c/li\u003e\n\u003cli\u003eS. Santosh, R. Praveen, V. Sampath, Trans. Indian Inst. Met. 72 6 1465\u0026ndash;1468 (2019). doi: 10.1007/s12666-019-01591-6.\u003c/li\u003e\n\u003cli\u003eZ. He, Z. Wang, D. Wang, X. Liu, B. Duan, Materials (Basel) 15 20 (2022). doi:10.3390/ma15207331.\u003c/li\u003e\n\u003cli\u003eE. Farber, J. N. Zhu, A. Popovich, V. Popovich, Mater. Today Proc. 30 761\u0026ndash;767 (2019). doi: 10.1016/j.matpr.2020.01.563.\u003c/li\u003e\n\u003cli\u003eD. F. Abbas, K. K. Resan, A. M. Takhakh, IOP Conf. Ser. Mater. Sci. Eng.671 1 (2020). doi:10.1088/1757899X/671/1/012142.\u003c/li\u003e\n\u003cli\u003eS. L. Zhu, X. J. Yang, F. Hu, S. H. Deng, Z. D. Cui, Mater. Lett. 58 19 2369\u0026ndash;2373 (2004). doi:10.1016/j.matlet.2004.02.017.\u003c/li\u003e\n\u003cli\u003eA. Bahador, E. Hamzah, K. Kondoh,T. Asma Abubakar, F. Yusof, J. Umeda, Trans. Nonferrous Met. Soc. China. 28 3 502\u0026ndash;514 (2018). doi:10.1016/S1003-6326(18)64683-7.\u003c/li\u003e\n\u003cli\u003eZ. Wang, J. Chen, C. Besnard, L. Kunčick\u0026aacute;, R. Kocich, A. M. Korsunsky, Acta Mater., 202 135\u0026ndash;148 (2021). doi:10.1016/j.actamat.2020.10.049.\u003c/li\u003e\n\u003cli\u003eC. Tatar, R. Acar, and I. N. Qader, Eur. Phys. J. Plus. 135 1\u0026ndash;11 (2020). doi:10.1140/epjp/s13360-020-00288-w.\u003c/li\u003e\n\u003cli\u003eZ. Xiong, Z. Li, Z. Sun, S. Hao, Y. Yang, M. Li, J. Mater. Sci. Technol. 35 10 2238\u0026ndash;2242 (2019). doi: 10.1016/j.jmst.2019.05.015.\u003c/li\u003e\n\u003cli\u003eX. Wang, J. Yu, J. Liu, L. Chen, Q. Yang, H. Wei, . Addit. Manuf. 36 (2020). doi:10.1016/j.addma.2020.101545.\u003c/li\u003e\n\u003cli\u003eW. Li, C. Zhao, Crystals. 8 9 (2018). doi:10.3390/cryst8090345.\u003c/li\u003e\n\u003cli\u003eC. Tao, H. Huang, G. Zhou, B. Zheng, X. Zuo, L. Chen Materials (Basel). .14 20 (2021). doi: 10.3390/ma14206173.\u003c/li\u003e\n\u003cli\u003eK. D. Salman, J. Phys. Conf. Ser. 1973 1 (2021). doi:10.1088/17426596/1973/1/012108.\u003c/li\u003e\n\u003cli\u003eA. Shuytcev, G. Markova, A. Kasimtcev, and S. Volod\u0026rsquo;Ko, Mater. Today Proc. 4 3 4685\u0026ndash;4689 (2017). doi: 10.1016/j.matpr.2017.04.052.\u003c/li\u003e\n\u003cli\u003eA. Radi, J. Khalil-Allafi, M. R. Etminanfar, S. Pourbabak, D. Schryvers, and B. Amin-Ahmadi, Mater. Des. 142 93\u0026ndash;100 (2017). doi:10.1016/j.matdes.2018.01.024.\u003c/li\u003e\n\u003cli\u003eQ. Zhang, S. Hao, Y. Liu, Z. Xiong, W. Guo, Y. Yang, Appl. Mater. Today. 19 1\u0026ndash;25 (2020). doi: 10.1016/j.apmt.2019.100547.\u003c/li\u003e\n\u003cli\u003eM. D. McNeese, D. C. Lagoudas, T. C. Pollock, Mater. Sci. Eng. A. 280 2 334\u0026ndash;348 (2000). doi:10.1016/S0921-5093(99)00550-X.\u003c/li\u003e\n\u003cli\u003eC. Machio, M. N. Mathabathe, A. S. Bolokang, J. Alloys Compd. 848:156494 (2020). doi: 10.1016/j.jallcom.2020.156494.\u003c/li\u003e\n\u003cli\u003eF. Dagdelen, M. Aldalawi, M. Kok, I. N. Qader, Eur. Phys. J. Plus. 134 2 1\u0026ndash;6 (2019). doi:10.1140/epjp/i2019-12479-3.\u003c/li\u003e\n\u003cli\u003eN. Sharma, K. K. Jangra, T. Raj, Proc. Inst. Mech. Eng. Part L J. Mater. Des. Appl. 232 3 250\u0026ndash;269 (2018). doi:10.1177/1464420715622494.\u003c/li\u003e\n\u003cli\u003eO. Karakoc, K. C Atli, A. Evirgen, J. Pons, R. Santamarta, O. Benafan, Mater. Sci. Eng. A. 794 (2020) 139857. doi:10.1016/j.msea.2020.139857.\u003c/li\u003e\n\u003cli\u003eS. H. Mohammed, M. A. Mohammed, A. A. Aljubouri, S. H. Shahatha, J. Phys. Conf. Ser. 1963 1 (2021). doi: 10.1088/1742-6596/1963/1/012017.\u003c/li\u003e\n\u003cli\u003eC. Craciunescu, A. S. Hamdy, 8 8, 10320-10334 (2013) . https://doi.org/10.1016/S1452-3981(23)13113-0.\u003c/li\u003e\n\u003cli\u003eF. J. Gil, J. A. Planell, J. Biomed. Mater. Res.. 48 5 682\u0026ndash;688 (1999). doi: 10.1002/(SICI)10974636.\u003c/li\u003e\n\u003cli\u003eNam, Tae-Hyun \u0026amp; Saburi, Toshio \u0026amp; Nakata, Yoshiyuki \u0026amp; Shimizu, Ken\u0026apos;ichi, Materials Transactions, JIM.31. 1050-1056 (1990). doi:10.2320/matertrans1989.31.1050\u003c/li\u003e\n\u003cli\u003eK. Nargatti, S. Ahankari, A Review. J. Intell. Mater. Syst. Struct. 2022; 33 4 503\u0026ndash;531(2022). doi:10.1177/1045389X211023582.\u003c/li\u003e\n\u003cli\u003eK. Tsuji, Y. Takegawa, K. Kojima, Mater. Sci. Eng. A. 136 C 1\u0026ndash;4 (1991). doi:10.1016/09215093(91)90435-P.\u003c/li\u003e\n\u003cli\u003eC. Velmurugan, J. Kesavan, V. Senthilkumar, and K. Ramya, Mater. Today Proc. 43 520\u0026ndash;523 (2020). doi:10.1016/j.matpr.2020.12.027.\u003c/li\u003e\n\u003cli\u003eJ. Mentz, J. Frenzel, M. F X Wagner, K. Neuking, G. Eggeler, H. Buchkremer, Mater. Sci. Eng. A. 491 1\u0026ndash;2 270\u0026ndash;278 (2008). doi: 10.1016/j.msea.2008.01.084.\u003c/li\u003e\n\u003cli\u003eY. Q. Fu, Y. W. Gu, C. Shearwood, J. K. Luo, A. J. Flewitt, and W. I. Milne, Nanotechnology. 17 21 5293\u0026ndash;5298 (2006). doi:10.1088/0957-4484/17/21/002.\u003c/li\u003e\n\u003cli\u003eY. Q. Zhang, S. Y. Jiang, Y. N. Zhao, M. Tang, Nonferrous Met. Soc. China (English Ed.) 22 11 2685\u0026ndash;2690 (2012). doi:10.1016/S1003-6326(11)61518-5.\u003c/li\u003e\n\u003cli\u003eM. Morakabati, S. Kheirandish, M. Aboutalebi, A. K. Taheri, S. M. Abbasi, J. Alloys Compd. 499 1 57\u0026ndash;62 (2010). doi:10.1016/j.jallcom.2010.01.124.\u003c/li\u003e\n\u003cli\u003eA. Sinha, B. Mondal, B. C. Maji, P. P. Chattopadhyay, Mater. Sci. Eng. A. 580 273\u0026ndash;278 (2013). doi: 10.1016/j.msea.2013.05.036.\u003c/li\u003e\n\u003cli\u003eA. Elsayed, J. Umeda,K. Kondoh, J. Alloys Compd. 842 (2020) . doi: 10.1016/j.jallcom.2020.155931.\u003c/li\u003e\n\u003cli\u003eB. Fu, K. Feng, and Z. Li, Mater. Lett.. 220 148\u0026ndash;151 (2018). doi: 10.1016/j.matlet.2018.03.030.\u003c/li\u003e\n\u003cli\u003eF. Villa, A. Nespoli, F. Passaretti, and E. Villa, Materials (Basel). 14 14 107084 (2020). doi: 10.3390/ma14143770.\u003c/li\u003e\n\u003cli\u003eN. Nayan, G. Singh, S. Murty, P. Narayan, M. Mohan,P. Venkitakrishnan, Intermetallics, 131 107084(2021). doi: 10.1016/j.intermet.2021.107084.\u003c/li\u003e\n\u003cli\u003eT. Goryczka, J. Van Humbeeck, J. Alloys Compd. 456(1\u0026ndash;2) 94\u0026ndash;200(2008). doi: 10.1016/j.jallcom.2007.02.094.\u003c/li\u003e\n\u003cli\u003eB. Liu, Y. Hao, C. - Comput. Model. Eng. Sci. 131 3 1601\u0026ndash;1613(2022). doi: 10.32604/cmes.2022.019226.\u003c/li\u003e\n\u003cli\u003eZ. Yingying, L. Hao, H. Man, C. Xia, T. Jian, W. jingmin, Eng. Res. Express 5, 025064(2023). https://doi.org/10.1088/2631-8695/acdce1 \u003c/li\u003e\n\u003cli\u003eR. Qadir, S. Mohammed, M. K\u0026ouml;k, I. Qader, J. Phys. Chem. Funct. Mater. 4 2 49\u0026ndash;56(2021). doi: 10.54565/jphcfum.1018817.\u003c/li\u003e\n\u003cli\u003eM. Valeanu, M. Lucaci, A. D. Crisan, M. Sofronie, L. Leonat, V. Kuncser, J. Alloys Compd. 509 13 4495\u0026ndash;4498 (2011). doi:10.1016/j.jallcom.2011.01.154.\u003c/li\u003e\n\u003cli\u003eK. X. Hau, N. H. Yen, N. H. Ngoc, T. V. Anh, P. T. Thanh, N. V. Toan, N. H. Dan, Mater. Trans. 64 4 849-854 (2023). doi:10.2320/matertrans.MT-M2022161.\u003c/li\u003e\n\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":"discover-materials","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"dime","sideBox":"Learn more about [Discover Materials](https://www.springer.com/journal/43939)","snPcode":"","submissionUrl":"","title":"Discover Materials","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Discover Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Shape Memory Alloy, Powder Metallurgy, Hot Forging, Spark plasma sintering, Microstructure, Corrosion Resistance","lastPublishedDoi":"10.21203/rs.3.rs-7603587/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7603587/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eTi-Ni-Cu shape memory alloys (SMAs), produced through an optimized preparation route including thermo-mechanical deformation, present a promising alternative to traditional Ti-Ni alloys, offering certain advantages. In this study, two Ti-Ni-Cu SMAs were fabricated using powder metallurgy. Fine micron-sized powders were mixed elementally, followed by spark plasma sintering, hot forging, and heat treatment comprising homogenization, solution treatment, aging, and low-temperature quenching. Microstructural evolution across processing stages was examined, and the transformation behavior of heat-treated alloys was characterized by differential scanning calorimetry. Corrosion resistance and hardness were also evaluated. Results revealed relatively high transformation temperatures (60\u0026ndash;75\u0026deg;C) with reduced hysteresis. Hot forging significantly enhanced alloy performance by refining microstructure and improving elemental bonding and diffusion. Corrosion resistance improved notably compared to Ti-Ni alloys, while Ti50-Ni30-Cu20 exhibited a 28% hardness increase. 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