Dual-Phase Laser Scanning for Enhanced Mechanical Properties in Laser Powder Bed Fusion Deposited 17-4PH Stainless Steel

Dual-Phase Laser Scanning for Enhanced Mechanical Properties in Laser Powder Bed Fusion Deposited 17-4PH Stainless Steel | 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 Dual-Phase Laser Scanning for Enhanced Mechanical Properties in Laser Powder Bed Fusion Deposited 17-4PH Stainless Steel Dan Nguyen, Madhavan Radhakrishnan, Narendra Dahotre, Reza Mirshams This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6976526/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract This study investigates the application of the dual-phase laser scanning (DPLS) technique in laser powder bed fusion (LPBF) to enhance mechanical properties of 17 − 4 precipitation hardened (PH) stainless steel. While LPBF is widely used for its precision and ability to produce complex geometries, challenges such as porosity and inconsistent material properties remain significant hurdles. The DPLS technique, incorporating an initial melt followed by a remelt, aims to address these challenges by improving interlayer bonding and relative density (RD). Experimental evaluations, including Archimedes’ method and X-ray tomography, revealed that despite a marginal decrease in relative density compared to single-phase scanning, the DPLS process yielded notable improvements in mechanical properties. Samples fabricated using repeated-pattern DPLS, exhibited an ultimate tensile strength (UTS) of 1222.8 ± 30.5 MPa and a yield strength (YS) of 955.2 ± 26.8 MPa, demonstrating significant enhancements in strength and ductility. Similarly, samples fabricated using non-repeated-pattern DPLS achieved the UTS of 1193.4 ± 18.2 MPa and the YS of 722.9 ± 21.9 MPa, with improved elongation attributed to favorable crystallographic orientations. Additionally, comparisons with hot isostatic pressing (HIP)-treated samples, which exhibited the UTS of 910.3 ± 7.9 MPa and the YS of 598.8 ± 36.9 MPa, suggest that DPLS can potentially reduce reliance on costly post-processing treatments. These findings highlight the potential of DPLS to optimize mechanical performance in LPBF-fabricated 17-4PH stainless steel components, offering a pathway toward more efficient and cost-effective additive manufacturing solutions. 17-4PH stainless steel Laser Powder Bed Fusion (LPBF) Dual-Phase Laser Scanning (DPLS) X-ray Computed Tomography (XCT) Tensile testing Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 1. Introduction Additive manufacturing (AM) has revolutionized the production of complex geometries with high precision and reduced material waste, making it a preferred choice in various industries, including aerospace, medical, and automotive [ 1 ], [ 2 ]. Among the different AM techniques, laser powder bed fusion (LPBF) is widely utilized for fabricating metal components due to its ability to achieve fine microstructures and excellent mechanical properties [ 3 ]. However, challenges such as porosity and inconsistent material properties persist, affecting the overall performance of LPBF-fabricated parts. For instance, achieving a consistently high relative density above 99% in 17-4PH stainless steel remains a significant challenge due to the complexity of optimizing process parameters such as laser power, scanning speed, and layer thickness [ 4 ]. To overcome these issues, advanced scanning strategies like dual-phase laser scanning (DPLS) have been introduced to enhance material density and mechanical properties. Layer remelting strategy in LPBF, which has gained attention in recent years for its potential to enhance part density, mechanical performance, and microstructural homogeneity. This technique involves re-scanning a melted layer one or more times before applying a new powder layer, aiming to improve interlayer bonding and reduce porosity. Several studies have explored the effectiveness of this approach on various alloys, including titanium and nickel-titanium (Ni-Ti) alloys. A study by Sinclair et al. on Ti-6Al-4V alloy demonstrated that remelting could significantly enhance pore healing and reduce surface roughness, leading to improved mechanical properties [ 5 ]. However, the research also indicated that excessive remelting might result in material degradation and increased energy consumption, highlighting the need for careful parameter optimization. Another investigation by Chmielewska et al. on Ni-Ti alloy revealed that remelting contributed to improved homogeneity in chemical and phase composition [ 6 ]. The study found that remelting reduced elemental segregation and enhanced microstructural uniformity, ultimately leading to more consistent mechanical properties. Similarly, a review by Luo et al. on LPBF of beta-type titanium alloys emphasized that remelting can aid in improving part quality and reducing porosity, while also noting potential drawbacks such as increased processing times and the need for precise control to avoid defects like keyhole pores and thermal distortions [ 7 ]. While promising results have been demonstrated in titanium and Ni-Ti alloys, recent studies have begun applying remelting strategies to Fe-based and stainless-steel alloys. Ali et al. explored the effects of in-situ heating combined with laser remelting on 15-5PH stainless steel fabricated by LPBF [ 8 ]. Their study demonstrated that remelting and substrate heating reduced porosity, increased ductility by approximately 25%, and promoted a higher martensite fraction. However, aggressive remelting introduced thermal cracking without preheating, which highlights the necessity of thermal management during processing. Similarly, Rashid et al. examined the impact of a double-scan strategy in LPBF of 17-4PH stainless steel [ 9 ]. The remelting approach enhanced as-built microstructural homogeneity, increased martensitic transformation, and marginally improved hardness and density compared to single-scan strategies. Nonetheless, dimensional deviations and slight variations in retained austenite fraction content between the surface and interior were observed, suggesting that double scanning can influence build precision and heterogeneous phase distribution. Comparative work on Inconel 625 by Ledwig et al. further confirmed the general benefits of laser remelting across Fe-based alloys [ 10 ]. Their study reported that remelting significantly improved ductility—achieving elongation above 50%—while maintaining competitive tensile strength. The findings also indicated reduced porosity and enhanced surface quality, although anisotropic mechanical behavior persisted due to strong grain alignment and minor yield strength reductions at high remelting energies. Despite these advances, gaps remain in how remelting parameters and scan path design affect 17-4PH stainless steel specifically. While prior studies have examined the benefits of laser remelting and double scanning in LPBF processes, most efforts remain limited to single remelt strategies or generic double-scan approaches without clear control over scan path orientation or phase balance. Existing research on 17-4PH stainless steel lacks systematic evaluation of how remelting sequence, path design, and scanning parameters interact to influence microstructural evolution and mechanical outcomes. This study introduces a novel dual-phase laser scanning (DPLS) technique, implemented in two distinct variants: a repeated-path strategy and a non-repeated, perpendicular-path strategy with tuned scan speed. Unlike conventional remelting methods, these DPLS patterns are designed to manipulate thermal history and grain morphology layer by layer. Through detailed analysis of porosity, EBSD grain metrics, crystallographic texture, and tensile properties, this research reveals that DPLS can significantly enhance mechanical strength and ductility—even when relative density slightly decreases. The findings suggest that DPLS offers a viable in-situ alternative to costly post-processing methods such as HIP, representing a scalable approach for producing high-performance 17-4PH parts with minimized processing steps. This work fills a critical gap by demonstrating how laser path design in remelting can be leveraged as a microstructural control mechanism, with implications for both fundamental process science and industrial AM application. 2. Experimental Procedure 2.1. Laser Fabrication Of 17-4PH Stainless Steel 2.1.1. Singular-Phase Laser Scanning The singular-phase laser scanning process in LPBF follows the standard approach, where each deposited layer is scanned and melted once using the laser (see Fig. 1 -a). Using Trumpf TruPrint Series 1000 LPBF printer, the optimized process parameters employed in this study included a laser power of 182.4 W, a scanning speed of 115 mm/s, a hatch spacing of 100 µm, and a layer thickness of 60 µm (Table 1 ). The 17-4PH stainless steel powder used in this process was supplied by Emerson Automation Solutions – Pressure Management Global Headquarters, McKinney, TX. The powder particles were predominantly spherical in shape (with average peak diameter at 38.13 µm), and the particle size distribution, defined by D-values, was D₃₀ = 32.35 µm, D₅₀ = 38.13 µm, and D₉₀ = 62.84 µm. A zig-zag scanning pattern with a non-connected trajectory was utilized, incorporating a 67° rotation angle between successive layers. The use of a 67° rotation angle has been demonstrated to improve print quality by reducing residual stress and anisotropy and enhancing density [ 11 ]. This scanning strategy was adopted to manufacture the first group of samples, designated as group A, which included 8x8x8mm blocks for XCT and EBSD, and 55x15x10mm block for tensile testing. No post-processing treatments were applied to group A, making it the baseline for comparison in this study. 2.1.2. Dual-Phase Laser Scanning (DPLS) The dual-phase laser scanning (DPLS) technique involves two phases: an initial melt followed by a remelt before depositing a new powder layer. Two variations of the DPLS technique were implemented in this study: repeated pattern scanning and non-repeated pattern scanning. In the repeated pattern DPLS, the laser rescanned each layer using the same process parameters as the previous melt before adding a new layer (Fig. 1 -b). The samples produced using his strategy were labelled as group C (see Table 1 ). In the non-repeated pattern DPLS process, the laser performed a remelting operation by rescanning each layer with a modified scanning strategy: the remelt path was oriented perpendicular to the initial melt path and utilized an adjusted scanning speed (Fig. 1 -c). Samples processed using this approach were labelled as group S (see Table 1 ). This strategy was designed to improve thermal distribution and enhance material fusion. These strategies were developed to investigate the impact of additional remelting on density and mechanical properties. 2.1.3. Single-Phase Laser Scanning with HIP Treatment for Mechanical Properties Comparison Purpose In addition to Groups A, C, and S, an additional set of singular-phase laser scanning samples (made with the same process parameter as group A) were fabricated to perform hot isostatic pressing (HIP) as a post-processing phase. The HIP treatment was conducted at 1150°C for 4 hours under a pressure of 100 MPa using an American Isostatic Presses (AIP) 6-30H system [ 12 ]. These samples, referred to as group HT (see Table 1 ), were subjected to HIP to evaluate the effectiveness of post-processing in enhancing mechanical properties. Table 1. Process Parameters employed in the LPBF of 17-4PH stainless steels. 2.2. Porosity Testing 2.2.1. Archimedes Density Measurement for Sample Groups A, C, and S Porosity evaluation was conducted using Archimedes method in accordance with ASTM B962 standards [ 13 ]. For this test, 8x8x8 mm cubic samples were prepared. Each group contained five samples to ensure statistical reliability. The relative density was determined based on the measured weight in air and water, and the mean value and standard deviation were calculated to assess consistency within each group. 2.2.2. X-Ray Tomography Analysis for Sample Groups A, C and S X-ray tomography was performed using a ZEISS-XRADIA Crystal CT machine (XCT), with Dragonfly software employed for data analysis. Cylindrical samples with a diameter of 2 mm and a height of 8 mm were extracted from the 8x8x8 mm blocks of sample groups A, C, and S for tomography analysis. The test involved collecting data on voxel distribution to determine relative density, as well as measurements of volume, spherical index, Feret diameter, and spherical diameter. Tomographic images provided insights into the internal porosity distribution and enabled the detection of irregular pore shapes within the samples. 2.3. Tensile Testing for all sample groups A, C, S, and HT The tensile tests were conducted using an Instron 8872 universal testing machine (25kN load cell), with Bluehill 3 software used for data acquisition and analysis, following ASTM standard E8 [ 14 ]. Additional miniature tensile tests were performed using a Kammrath-Weiss table-top tester with a 10 kN load cell. All tensile specimens were extracted perpendicular to the build direction of the 55x15x10 mm bulk blocks, using electrical discharge machining (EDM), then metallographically polished to remove surface irregularities caused by EDM. A 10 mm gauge length was used for both the Instron-tested and Kammrath-Weiss-tested specimens. Five samples per group were tested to obtain average values and standard deviations. Results were used to evaluate yield strength, ultimate tensile strength, and elongation to failure. 2.4. Electron Backscatter Diffraction (EBSD) Analysis Microstructure characterization of the printed 17-4PH steels were performed using scanning electron microscope (SEM) based electron back scattered diffraction (EBSD) technique to examine the grain structure, grain sizes, and crystal orientation across all sample groups. A Thermo-Fisher Apreo 2C SEM equipped with an EDAX EBSD camera was used for data acquisition, and TSL OIM 8.6 software was used for data analyses purposes. The scanning was conducted on the mid-section cross-sectional plane of the printed samples along the built direction. EBSD data provided valuable insights into grain size distribution, with mean, median, and standard deviation values calculated. These results were correlated with tensile testing outcomes to understand the relationship between microstructure and mechanical behavior. 3. Results and discussion 3.1. Porosity evaluation in the printed steels Porosity evaluation was conducted using the Archimedes method to measure the density of the fabricated samples. The relative density (RD) of each sample was calculated by comparing the measured density to the theoretical bulk density of 7.8 g/cm³ for fully dense 17-4PH stainless steel [ 15 ]. The density measurements indicated that group A samples exhibited the highest RD, achieving 97.5 ± 0.7%. A decreasing trend was observed in the DPLS-applied samples, with group C reaching 96.8 ± 0.6% and group S having the lowest RD at 95.4 ± 0.4% (Fig. 3 ). The relative density measured using Archimedes method was compared with values obtained using X-ray tomography. In all sample groups, the XCT reveals a higher RD% while maintaining the same decreasing trend. In Fig. 3 , the XCT results showed an RD of 99.98% for group A, 99.42% for group C, and 99.21% for group S. The discrepancy in relative density measurements between the Archimedes method and XCT scanning can be attributed to differences in sensitivity to surface porosity, sample preparation, and measurement limitations. In the Archimedes method, 8x8x8 mm cubic samples were used to determine actual bulk density by measuring the buoyant force when submerged in a fluid. This technique is highly sensitive to surface-connected porosity, as the fluid can infiltrate open pores, potentially leading to an underestimation of density, of near fully dense parts [ 16 ]. In contrast, tomography scanning was performed on cylindrical samples with a diameter of 2 mm and a length of 8 mm, providing a detailed 3D representation of internal porosity. However, tomography's voxel resolution limits the detection of very fine pores and pores below the detection threshold remain undetected, which may result in misrepresentation of actual porosity level and overestimation of density [ 17 ]. Sample preparation also plays a significant role in these differences. The larger cubic sample used in the Archimedes method encompasses a broader volume, including surface imperfections and porosity, which can contribute to a lower density reading. On the other hand, the tomography scanning of a smaller cylindrical sample, which was machined before scanning, may have removed surface imperfections, leading to a higher density measurement. According to Kan et al., the accuracy of the Archimedes method can be compromised by surface roughness effects, whereas tomography provides a non-destructive analysis that offers insights into pore morphology but lacks sensitivity to surface defects [ 16 ]. Tomographic analysis was conducted using Dragonfly software to characterize porosity in 3D for each sample group. The scanned volume dimensions were 1,268 pixels (2,326.65 µm) in width, 4,381 pixels (8,038.70 µm) in height, and 1,389 pixels (2,548.68 µm) in depth, with data extracted for pore volume, sphericity index (0–1), Feret diameter, and equivalent spherical diameter (see Fig. 4 ). In sample A, a total of 4,637 porosity counts were identified, with most volumes equal to or less than 702.2 µm³. The largest observed porosity had a volume of 178,187.7 µm³. Approximately 69.29% of the detected porosities exhibited near-spherical shapes, with a sphericity index greater than 0.9. For sample C, 99.93% of the porosities (31,702 counts) had volumes ranging from 30.89 µm³ to 37,605.28 µm³, with a tight spherical diameter range from 4.91 µm to 5.92 µm. However, an abnormally large porosity with a volume of approximately 9,619,075.77 µm³ with Feret Diameter of 574.79 µm was identified (see Fig. 4 -h), which is attributed to the double-laser scanning method. In Fig. 4 -d, the proportion of near-spherical porosities (sphericity index above 0.9) was significantly lower at 32%, approximately 2.16 times lower than sample A. Similarly, sample S exhibited 99.42% (or 6,488 counts) of porosities within the volume range of 6.18 µm³ to 27,853.21 µm³. The largest porosity identified had a Feret diameter of 630.86 µm. In addition to the largest donut-shaped pore, this sample contained several mid-sized to large pores with Feret diameter ranging from 32.15 µm to 66.50 µm (Fig. 4 -i). The proportion of spherical-shaped pores increased to 73.35%, representing a measurable improvement over the previous samples. Comparative analysis showed that Samples C and S (both with DPLS) had fewer mid-to-large pores and narrower Feret/spherical diameter distributions than Sample A. Specifically, 85.62% of spherical pores in Sample C had diameters < 4.91 µm, while 74.39% of irregular pores had Feret diameters < 6.74 µm. Sample S followed a similar trend, with 53.69% of spherical pores ≤ 3.20 µm and 66.29% of non-spherical pores ≤ 5.16 µm. In contrast, Sample A had 71.42% and 70.89% of its spherical and non-spherical pores below 4.91 µm and 6.72 µm, respectively. The spatial uniformity and reduced occurrence of larger pores in Samples C and S suggest a more favorable stress distribution under load, likely contributing to improved mechanical properties. Tomography also revealed a distinctive “donut-shaped” pore in Sample C, while Sample S exhibited similar and additional large pore structures, consistent with melt pool instabilities discussed in section 3.2 . 3.2. Effect of laser scanning strategies on the evolution of porosities The increased porosity observed in samples C and S following the application of dual laser pass strategies in LPBF can be primarily attributed to melt pool instability, gas entrapment, and localized overheating. Both scanning strategies—repeat-pattern (sample C) and non-repeat-pattern (sample S)—led to varying degrees of thermal accumulation, vaporization, and remelting, all of which contributed to the formation of pores and a reduction in relative density. Localized overheating during the secondary laser passes likely caused excessive vaporization and keyhole instability. As vapor pressure sustained open cavities in the melt pool, gases became trapped upon solidification, forming mid-to-large pores. This effect was especially evident in sample S, where the non-repeat DPLS strategy introduced perpendicular scan paths, promoting uneven energy distribution and turbulent melt pool dynamics. Kan et al. noted that such conditions increase the likelihood of keyhole porosity, which aligns with the pore morphology observed in this sample [ 16 ]. Sample C, using a repeat-pattern scanning approach, exhibited isolated “donut-shaped” pores. These features suggest gas entrapment due to re-melting of already solidified regions without sufficient time for gas escape. Mandev et al. reported similar behavior, where repeated laser passes—without optimized dwell time—can seal gas pockets despite improving densification in other areas [ 18 ]. The repeated thermal cycling in sample C may have locally intensified solidification constraints, leading to enclosed porosity. Overall, while dual laser scanning was intended to improve material quality, improper control of energy input and scan path interaction significantly affected porosity formation. The differences in pore morphology between samples C and S highlight the critical influence of scanning strategy on melt pool behavior and gas entrapment mechanisms. 3.3. Tensile Test Result 3.3.1. Correlating porosity morphology with mechanical behavior in regular LPBF 17-4PH Stainless Steel and DPLS samples Although the Archimedes and XCT measurements revealed that sample A exhibited the highest relative density, its mechanical properties, including yield strength, ultimate tensile strength, and ductility, were inferior compared to samples C and S (Fig. 5 ). The group A samples exhibited an average yield strength (YS) of 615.2 ± 85.7 MPa, an ultimate tensile strength (UTS) of 1148.2 ± 40.6 MPa, and an elongation of 6.69 ± 0.02%; Group C samples demonstrated superior mechanical performance, with a YS of 955.2 ± 26.8 MPa, a UTS of 1222.8 ± 30.5 MPa, and an elongation of 12.02 ± 0.09%, effectively doubling the ductility compared to group A; Group S samples showed moderate improvements, with a YS of 722.9 ± 21.9 MPa, a UTS of 1193.4 ± 18.2 MPa, and an elongation of 9.61 ± 0.20%. Despite the presence of larger individual pores, particularly the donut-shaped keyhole-type porosities identified in Samples C and S through tomography (Fig. 4 ), these two groups demonstrated superior mechanical performance. These results indicate that tensile behavior in LPBF 17-4PH stainless steel is influenced more strongly by pore morphology and distribution than by total porosity volume alone. In the research of Kim et al. and Wilson-Heid et al., lack-of-fusion (LOF) defects, characterized by irregular and sharp-edged morphologies, are known to be significantly more detrimental to mechanical strength compared to smooth, nearly spherical pores [ 19 ], [ 20 ]. In contrast, keyhole-induced pores, like those observed in samples C and S, tend to be smoother and more rounded, making them less severe as stress concentrators unless they are excessively large [ 21 ]. Studies on LPBF 316L stainless steel have similarly shown that while overall porosity impacts mechanical properties, samples dominated by LOF defects suffered more dramatic reductions in tensile strength and ductility than those containing only keyhole pores [ 22 ]. Therefore, although sample C and sample S each exhibited a significant isolated pore, the smoother morphology and relatively isolated nature of these defects reduced their detrimental effects on mechanical performance compared to a scenario where numerous irregular LOF defects might dominate [ 23 ]. In sample A, the higher number of smaller but irregularly shaped pores, coupled with their less uniform spatial distribution, likely contributed to more distributed stress concentrations during loading, promoting earlier crack initiation and propagation. Conversely, in samples C and S, the pores appeared to be better distributed and fewer in number, minimizing the accumulation of critical stress concentrations. This interpretation aligns well with related studies on LPBF 316L and maraging steels. In LPBF 316L, Wilson-Heid et al. observed that mechanical properties remained relatively stable despite minor variations in total porosity, provided that large, irregular pores were absent [ 20 ]. Similarly, in maraging steels, isolated spherical pores had less impact on tensile strength than elongated or irregular lack-of-fusion defects, and performance degradation correlated strongly with the presence of clustered or aligned pores [ 24 ]. These findings suggest that the donut-shaped pores seen in samples C and S, although individually large, did not severely degrade mechanical properties because they were isolated and surrounded by refined, stronger microstructures. 3.3.2. Comparing mechanical properties of DPLS samples to Hot Isostatic Pressing (HIP) samples Group HT samples, subjected to Hot Isostatic Pressing (HIP) at 1150°C for 4 hours at 100 MPa​, presented the YS of 598.8 ± 36.9 MPa, a UTS of 910.3 ± 7.9 MPa, and an elongation of 6.22 ± 0.16%. The HIP treatment aimed to reduce porosity and relieve residual stresses and been shown to improve the mechanical properties of 17-4PH stainless steel by increasing relative density (RD%) and reducing internal stresses [ 12 ], [ 25 ]​. However, the present results reveal that the HIP-treated samples (HT) did not exhibit superior mechanical properties compared to the non-post-processed samples A, C, and S. Contrary to expectations, the tensile properties of the HIP-treated samples fell short, particularly in terms of strength and ductility, highlighting the potential limitations of HIP in the specific context of LPBF 17-4PH stainless steel with the applied processing parameters. These findings suggest that the DPLS technique may eliminate the need for post-processing treatments if optimized effectively. The ability to manipulate the secondary phase of laser in DPLS might achieve desirable mechanical properties without relying on additional post-processing steps. 3.4. Evolution of microstructure 3.4.1. General observation of phase/ crystal Structure To further investigate the underlying reasons behind the lack of improvement in mechanical properties in the HIP-treated samples, EBSD analyses were carried out. The 17-4PH stainless steel is a martensitic precipitation-hardening alloy primarily composed of body-centered tetragonal (BCT) structures [ 26 ]. Following the LPBF process and subsequent HIP treatment, EBSD phase mapping confirmed that all samples comprised complete martensite phase (Fig. 6 ). The dominance of the BCC/BCT phases directly correlates with the tensile properties observed in the study. The high ultimate tensile strength (UTS) and yield strength in Samples A, C, and S can be attributed to the martensitic structure, which is known for its inherent high dislocation density and hardness. The mechanical properties observed in the tensile tests (see section 3.3.1 .) further confirm that the dual-phase laser scanning (DPLS) technique influenced the grain refinement and phase retention, leading to variations in strength and ductility across the samples. 3.4.2. Influence of DPLS and HIP on grain, crystal structure and mechanical properties of LPBF 17-4Ph stainless steel: 3.4.2.1. Sample A (Single-Phase Laser Scanning) Sample A exhibited a non-uniform grain size distribution (Fig. 6 -a). The mean grain diameter was 10.06 ± 2.02 µm, with a significant proportion of smaller grains (0–5 µm) and occasional larger grains exceeding 30 µm (see Fig. 7 -a-iv). The mixed grain size distribution suggests moderate strength and ductility; Consistent with the Hall-Petch relationship, the moderate grain refinement in Sample A correlated with intermediate mechanical properties compared to other groups. 3.4.2.2. Sample C (Repeated-Pattern DPLS): Sample C demonstrated a finer and more uniform grain size distribution compared to Sample A. The mean grain diameter was reduced to 5.52 ± 0.67 µm, indicating significant grain refinement and improved homogeneity (see Fig. 6 -b and Fig. 7 -a-iii). The refined microstructure contributed to the highest observed mechanical properties, with a yield strength of 955.19 MPa and an ultimate tensile strength (UTS) of 1222.76 MPa (showed in Fig. 7 -b). The Hall-Petch effect was clearly manifested, where smaller grain size enhanced strength by impeding dislocation motion, while the uniform crystallographic orientation further supported improved ductility (elongation of 12.02%). To sum up, there are three factors that contributed to the superior performance of Sample C: Smaller and more uniform grain structure enhanced strength and ductility via grain boundary strengthening [ 27 ]. Balanced crystallographic orientation (notably the presence of [001] orientations) facilitated multidirectional plastic deformation. This observation is consistent with research of Gao et al. who reported that orientations such as [001] in alloy structure effectively accommodate tensile stress, enhancing both strength and ductility [ 28 ]. Thermal Stabilization of Martensitic Phase: The dual-phase laser scanning technique may have facilitated controlled thermal conditions, refined the martensitic phase and ensured better mechanical performance despite a slight decrease in relative density [ 29 ]. 3.4.2.3. Sample S (Non-Repeated-Pattern DPLS) Sample S exhibited a mean grain diameter of 8.75 ± 1.55 µm (Fig. 7 -a-ii), with a greater fraction of smaller grains relative to Sample A. Crystallographic analysis indicated a dominance of [001] and [101] orientations, promoting improved ductility. Although the grain size was finer than Sample A, it was a little coarser than Sample C, resulting in mechanical properties intermediate between the two. Sample S achieved a favorable elongation value, attributed to enhanced grain boundary sliding associated with the higher fraction of smaller grains and favorable orientations. However, the non-uniform grain size distribution introduced localized plastic deformation zones, potentially impacting mechanical uniformity under load. 3.4.2.4. Sample HT (HIP-Treated Single-Phase Laser Scanning) Sample HT exhibited the largest grain sizes among all groups, with a mean diameter of 14.89 ± 1.65 µm. The grains were more uniformly distributed due to the prolonged exposure to high temperatures during the HIP process. The crystal orientations were predominantly within the [111] and [001] directions. Despite expectations for improved mechanical properties post-HIP, the tensile test results indicated no significant enhancement. The larger grain sizes observed in this sample align with findings from Mao et al.​, who reported that HIP treatment on 316L stainless steel resulted in significant grain coarsening due to high temperatures and extended processing times [ 30 ]. Similarly, Pei et al.​ demonstrated that grain growth is accelerated at 1150°C due to enhanced atomic diffusion, leading to decreased strength and plasticity [ 29 ]. These studies emphasize that high-temperature HIP treatments can contribute to abnormal grain growth, which negatively affects mechanical properties by reducing grain boundary strengthening effects. The common findings from both studies suggest that elevated HIP temperatures promote grain coarsening, which can lead to a reduction in strength and ductility [ 29 ], [ 30 ]. In the context of this research, the HIP-treated samples did not meet the expected improvement in mechanical properties, reinforcing the conclusion that DPLS could potentially serve as an alternative to post-processing methods such as HIP. 3.4.3. Grain Size–Mechanical Property Correlation The mechanical performance of all samples exhibited a strong dependence on grain size, consistent with the Hall-Petch relationship. As shown in Fig. 7 -b, a decrease in mean grain size from 14.89 µm (Sample HT) to 5.52 µm (Sample C) corresponded to a significant increase in yield strength and UTS. Conversely, ductility decreased slightly with grain coarsening, as Sample C exhibited the highest elongation among all groups. These results validate the critical role of grain refinement in enhancing both strength and ductility in LPBF-fabricated 17-4PH stainless steel. Overall, the DPLS strategy, particularly the repeated-pattern approach (Sample C), effectively refined the microstructure, improved grain orientation distribution, and enhanced mechanical performance without the need for costly post-processing such as HIP. The findings demonstrate that optimized dual-phase laser scanning during LPBF processing can offer significant production and cost benefits for high-performance stainless-steel components. 4. Conclusion This study demonstrated the effectiveness of dual-phase laser scanning (DPLS) in enhancing the mechanical performance and microstructural characteristics of LPBF-fabricated 17-4PH stainless steel. The application of DPLS led to significant improvements in tensile properties, achieving a yield strength of 955.2 MPa, an ultimate tensile strength of 1222.8 MPa, and an elongation of 12.02% in the repeated-pattern DPLS sample. These results represent a substantial enhancement compared to conventional single-phase scanning strategies, effectively doubling the ductility while maintaining high strength levels. The superior mechanical behavior achieved through DPLS is attributed to the formation of finer, more uniform grain structures, favorable crystallographic orientation distributions, and refined pore morphology characterized by spherical or near-spherical shapes. Additionally, the minimized clustering of pores and improved stress redistribution within the surrounding microstructure contributed to potentially delaying crack initiation and enhancing overall mechanical stability under tensile loading. This integrated control of microstructure and porosity highlights the advantages of DPLS in tailoring mechanical properties directly during fabrication. Importantly, DPLS offers a direct process-level solution for optimizing mechanical performance without the need for post-processing treatments such as HIP, enabling more efficient and cost-effective manufacturing of high-performance stainless-steel components. These findings underscore the potential of advanced laser scanning strategies to engineer microstructure and porosity morphology synergistically, paving the way for the next generation of additive manufacturing solutions in demanding structural applications. Declarations Author Contribution Dan T. Nguyen: Conceptualization, Methodology (process parameter optimization), Investigation (sample fabrication, tensile testing, polishing, XCT, EBSD), Data curation (XCT, tensile, EBSD data), Formal analysis (mechanical property calculations, porosity analysis), Visualization, Writing – original draft.Madhavan Radhakrishnan: Supervision, Investigation (EBSD study), Data curation (EBSD), Methodology, Writing – review & editing.Narendra Dahotre: Supervision, Resources, Writing – review & editing.Reza Mirshams: Supervision, Project administration, Writing – review & editing. Acknowledgement Authors acknowledge Emerson Automation Solutions – Pressure Management Global Headquarters, located in McKinney, TX, for providing 17-4PH stainless steel powder, which was essential for conducting this research. Authors acknowledge the Center for Advanced Additive Manufacturing (CAAAM) funded through State of Texas Appropriation: 190405-105-805008-220 for the infrastructure support. DTN wishes to thank Mr. Shelden Dowden for sharing his expertise and providing training on manufacturing and testing equipment used in this study, and Dr. Rajiv Mishra for granting access to Buehler VibroMet polisher and polishing solutions used in sample preparation process. References P. V. Cobbinah, R. A. Nzeukou, O. T. Onawale, and W. R. Matizamhuka, “Laser powder bed fusion of potential superalloys: A review,” Jan. 01, 2021, MDPI AG . doi: 10.3390/met11010058. J. P. Oliveira, A. D. LaLonde, and J. Ma, “Processing parameters in laser powder bed fusion metal additive manufacturing,” Mater Des , vol. 193, Aug. 2020, doi: 10.1016/j.matdes.2020.108762. S. A. Khairallah, A. T. Anderson, A. Rubenchik, and W. E. King, “Laser powder-bed fusion additive manufacturing: Physics of complex melt flow and formation mechanisms of pores, spatter, and denudation zones,” Acta Mater , vol. 108, pp. 36–45, Apr. 2016, doi: 10.1016/j.actamat.2016.02.014. T. Kim, M. K. Kim, Y. Fang, and J. Suhr, “Moisture Effects on Qualities and Properties of Laser Powder Bed Fusion (LPBF) Additive Manufacturing of As-Built 17-4PH Stainless Steel Parts,” Metals (Basel) , vol. 13, no. 9, Sep. 2023, doi: 10.3390/met13091550. L. Sinclair et al. , “In situ radiographic and ex situ tomographic analysis of pore interactions during multilayer builds in laser powder bed fusion,” Addit Manuf , vol. 36, Dec. 2020, doi: 10.1016/j.addma.2020.101512. A. Chmielewska et al. , “Laser powder bed fusion (LPBF) of NiTi alloy using elemental powders: the influence of remelting on printability and microstructure,” Rapid Prototyp J , vol. 28, no. 10, pp. 1845–1868, Oct. 2022, doi: 10.1108/RPJ-08-2021-0216. X. Luo, C. Yang, D. Li, and L. C. Zhang, “Laser Powder Bed Fusion of Beta-Type Titanium Alloys for Biomedical Application: A Review,” Jan. 01, 2024, Springer . doi: 10.1007/s40195-023-01654-0. M. Ali, A. Almotari, and A. Qattawi, “Influence of in situ heating and laser remelting on martensitic precipitation-hardening stainless steel fabricated by laser powder bed fusion,” Progress in Additive Manufacturing , 2024, doi: 10.1007/s40964-024-00906-4. R. Rashid, S. H. Masood, D. Ruan, S. Palanisamy, R. A. Rahman Rashid, and M. Brandt, “Effect of scan strategy on density and metallurgical properties of 17-4PH parts printed by Selective Laser Melting (SLM),” J Mater Process Technol , vol. 249, pp. 502–511, Nov. 2017, doi: 10.1016/j.jmatprotec.2017.06.023. P. Ledwig et al. , “Tailoring Microstructure and Mechanical Properties of Additively Manufactured Inconel 625 by Remelting Strategy in Laser Powder Bed Fusion,” Metall Mater Trans A Phys Metall Mater Sci , vol. 55, no. 7, pp. 2485–2508, Jul. 2024, doi: 10.1007/s11661-024-07412-w. Z. Sun, S. P. Tsai, P. Konijnenberg, J. Y. Wang, and S. Zaefferer, “A large-volume 3D EBSD study on additively manufactured 316L stainless steel,” Scr Mater , vol. 238, Jan. 2024, doi: 10.1016/j.scriptamat.2023.115723. S. Sabooni et al. , “Laser powder bed fusion of 17–4 PH stainless steel: A comparative study on the effect of heat treatment on the microstructure evolution and mechanical properties,” Addit Manuf , vol. 46, Oct. 2021, doi: 10.1016/j.addma.2021.102176. ASTM International, “Standard Test Methods for Density of Compacted or Sintered Powder Metallurgy (PM) Products Using Archimedes’ Principle 1,” West Conshohocken, PA, Jun. 2017. doi: https://doi.org/10.1520/B0962-17. ASTM International, “ASTM Standard E8/E8M − 21 Standard Test Methods for Tension Testing of Metallic Materials”, doi: 10.1520/E0008_E0008M-21. T. W. Liu, T. L. Cheng, K. C. Chiu, and J. K. Chen, “Permeability of Additive Manufactured Cellular Structures—A Parametric Study on 17-4 PH Steels, Inconel 718, and Ti-6Al-4V Alloys,” Journal of Manufacturing and Materials Processing , vol. 6, no. 5, Oct. 2022, doi: 10.3390/jmmp6050114. W. H. Kan et al. , “A critical review on the effects of process-induced porosity on the mechanical properties of alloys fabricated by laser powder bed fusion,” Jun. 01, 2022, Springer . doi: 10.1007/s10853-022-06990-7. S. K. Rauniyar and K. Chou, “Porosity analysis and pore tracking of metal AM tensile specimen by Micro-CT,” The University of Texas at Austin, Austin, TX, May 2019. Accessed: Apr. 11, 2025. [Online]. Available: https://repositories.lib.utexas.edu/items/57c8c8aa-8769-4173-a3c7-2dd609d4e7ed Y. Z. Mandev, E. Mandev, and A. F. Yetim, “Effects of Laser Powder Bed Fusion Process Parameters on Porosity, Liquid Retention, and Thermal and Surface Properties for 316L, CoCrW and Ti6Al4V Alloys,” J Mater Eng Perform , 2024, doi: 10.1007/s11665-024-09381-y. F. H. Kim, S. P. Moylan, T. Q. Phan, and E. J. Garboczi, “Investigation of the Effect of Artificial Internal Defects on the Tensile Behavior of Laser Powder Bed Fusion 17–4 Stainless Steel Samples: Simultaneous Tensile Testing and X-Ray Computed Tomography,” Exp Mech , vol. 60, no. 7, pp. 987–1004, Sep. 2020, doi: 10.1007/s11340-020-00604-6. A. E. Wilson-Heid, T. C. Novak, and A. M. Beese, “Characterization of the Effects of Internal Pores on Tensile Properties of Additively Manufactured Austenitic Stainless Steel 316L,” Exp Mech , vol. 59, no. 6, pp. 793–804, Jul. 2019, doi: 10.1007/s11340-018-00465-0. E. Jost, J. Miers, A. Robbins, D. Moore, C. Saldana, and G. W. Woodruff, “Effects of Spatial Energy Distribution-Induced Porosity on Mechanical Properties of Laser Powder Bed Fusion 316L Stainless Steel,” , GeorgeW. Woodruff School of Mechanical Engineering, Georgia Insititute of TechnologyAtlanta, GA, Mar. 2021. doi: https://doi.org/10.1016/j.addma.2021.101875. N. Diaz Vallejo, N. Kljestan, N. Ayers, M. Knezevic, and Y. Sohn, “Flaw Type Dependent Tensile Properties of 316L Stainless Steel Additively Manufactured by Laser Powder Bed Fusion,” Results in Materials , vol. 13, Mar. 2022, doi: https://doi.org/10.1016/j.rinma.2022.100315. B. L. Boyce et al. , “Extreme-Value Statistics Reveal Rare Failure-Critical Defects in Additive Manufacturing *,” Adv Eng Mater , vol. 19, no. 8, pp. 1198–1205, Jun. 2017, doi: https://doi.org/10.1002/adem.201700102. P. M. Cerezo, J. A. Aguilera, A. Garcia-Gonzalez, and P. Lopez-Crespo, “Tomography of Laser Powder Bed Fusion Maraging Steel,” Materials , vol. 17, no. 4, Feb. 2024, doi: 10.3390/ma17040891. C. Ye, C. Zhang, J. Zhao, and Y. Dong, “Effects of Post-processing on the Surface Finish, Porosity, Residual Stresses, and Fatigue Performance of Additive Manufactured Metals: A Review,” Sep. 01, 2021, Springer . doi: 10.1007/s11665-021-06021-7. H. R. Lashgari, C. Kong, E. Adabifiroozjaei, and S. Li, “Microstructure, post thermal treatment response, and tribological properties of 3D printed 17-4 PH stainless steel,” Wear , vol. 456–457, Sep. 2020, doi: 10.1016/j.wear.2020.203367. S. Dangwal, K. Edalati, R. Z. Valiev, and T. G. Langdon, “Breaks in the Hall–Petch Relationship after Severe Plastic Deformation of Magnesium, Aluminum, Copper, and Iron,” Crystals (Basel) , vol. 13, no. 3, Mar. 2023, doi: 10.3390/cryst13030413. X. Gao, Z. Zhang, L. Liu, and C. Tao, “Lattice Rotation and Deformation Mechanisms under Tensile Loading in a Single-Crystal Superalloy with [001] Misorientation,” Materials , vol. 17, no. 6, Mar. 2024, doi: 10.3390/ma17061368. Y. Pei, X. Qu, Q. Ge, and T. Wang, “Effect of heat treatment temperature on microstructure and properties of pm borated stainless steel prepared by hot isostatic pressing,” Materials , vol. 14, no. 16, Aug. 2021, doi: 10.3390/ma14164646. Y. Mao, J. Yuan, Y. Heng, K. Feng, D. Cai, and Q. Wei, “Effect of hot isostatic pressing treatment on porosity reduction and mechanical properties enhancement of 316L stainless steel fabricated by binder jetting,” Virtual Phys Prototyp , vol. 18, no. 1, 2023, doi: 10.1080/17452759.2023.2174703. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted 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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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6976526","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":479667786,"identity":"bb2dc139-b71c-4c29-8cbf-4158048783c6","order_by":0,"name":"Dan Nguyen","email":"","orcid":"","institution":"University of North Texas","correspondingAuthor":false,"prefix":"","firstName":"Dan","middleName":"","lastName":"Nguyen","suffix":""},{"id":479667789,"identity":"73b1c633-fbf0-4e89-b157-650ac980f5b1","order_by":1,"name":"Madhavan Radhakrishnan","email":"","orcid":"","institution":"University of North Texas","correspondingAuthor":false,"prefix":"","firstName":"Madhavan","middleName":"","lastName":"Radhakrishnan","suffix":""},{"id":479667790,"identity":"ac559df7-9892-4dfd-a983-88fd976c4755","order_by":2,"name":"Narendra Dahotre","email":"","orcid":"","institution":"University of North Texas","correspondingAuthor":false,"prefix":"","firstName":"Narendra","middleName":"","lastName":"Dahotre","suffix":""},{"id":479667791,"identity":"3a8fa069-59f5-4e89-9942-f5268d4514c0","order_by":3,"name":"Reza Mirshams","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3ElEQVRIiWNgGAWjYPACCTBiYKiAc4nWcoaBgYdILVBljG1EaDFvb3/4gTHHIl9+dvPTjT/nHc6zZ2A+eJsHjxaZMweSJRi3SVhuuHPM7DbvtsPFPAxsydb4tEhIJBwAaTEwkEgwu8247XBiDwOPmTReLfIPm3+AtMjPSP928+cckBb+b/i1SDCzgW1huJFjdoO3AWwLG34tPGlsFokgh93IKbvNcyw9secwm7HlHHxa2I8/vvFxWx3IYdtu/qixTmxvb3544w0eLWCQgMJjJqR8FIyCUTAKRgFBAAB9VUa9DRssMwAAAABJRU5ErkJggg==","orcid":"","institution":"University of North Texas","correspondingAuthor":true,"prefix":"","firstName":"Reza","middleName":"","lastName":"Mirshams","suffix":""}],"badges":[],"createdAt":"2025-06-25 16:08:19","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6976526/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6976526/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":86010891,"identity":"5c225e48-a6cd-41a5-89a5-0d87cc008685","added_by":"auto","created_at":"2025-07-04 09:44:39","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":222205,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic showing laser scanning strategies: a) Singular-phase laser scanning; b) Repeated-Dual-phase laser scanning; c) Non-Repeated-Dual laser scanning – with a 67° rotation of laser scanning path after every successive layer in LPBF process\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6976526/v1/236a61ffde209bb12edb63d9.png"},{"id":86010890,"identity":"7dd99e54-72fe-41ac-aa56-9047b3a8ca55","added_by":"auto","created_at":"2025-07-04 09:44:39","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":212218,"visible":true,"origin":"","legend":"\u003cp\u003ePreparation and geometry of miniature tensile specimens: a) Additively manufactured bulk blocks (Groups A, C, and S) fabricated using different processing parameters; b) Schematic illustration showing the extraction of miniature tensile specimens (1 mm thick) from the 55 × 15 × 10 mm bulk blocks, with the build direction oriented vertically; c) Detailed dimensions of the miniature tensile specimen.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6976526/v1/65c223d91447fc1a5b757faa.png"},{"id":86011198,"identity":"271a5a8b-db3b-48e7-bf05-5e5529a7a3ff","added_by":"auto","created_at":"2025-07-04 09:52:39","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":26530,"visible":true,"origin":"","legend":"\u003cp\u003eCorrelation of relative density (%) between Archimedes’ method and XCT measurements for group samples A, C, and S.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6976526/v1/32ab3235b2ef5ca0f8dd9d81.png"},{"id":86010894,"identity":"47454647-58e2-4de0-9c63-8e4c7e16f08f","added_by":"auto","created_at":"2025-07-04 09:44:39","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":927576,"visible":true,"origin":"","legend":"\u003cp\u003eXCT results of 3 samples-17-4ph stainless steel. A) Sample A spherical index; b) Sample C spherical index; c) Sample S spherical index; d) Sphericity of porosity; e) Feret diameter of porosity; f) Spherical diameter of porosity; g) Largest pore in sample A; h) Largest pore in sample C; i) Largest pore in sample S.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-6976526/v1/4125bca7a5d47c76e1502990.png"},{"id":86010903,"identity":"641f3640-37f0-49ad-976c-c07259844aa4","added_by":"auto","created_at":"2025-07-04 09:44:40","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":69956,"visible":true,"origin":"","legend":"\u003cp\u003eStress–strain response of 17-4PH stainless steel produced under various laser scanning and heat treatment conditions (Groups A, C, S, and HT).\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-6976526/v1/bfc0693c675744a77d0ec986.png"},{"id":86010909,"identity":"da56b3e5-6e41-4993-948b-72e7a723e32d","added_by":"auto","created_at":"2025-07-04 09:44:40","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":580228,"visible":true,"origin":"","legend":"\u003cp\u003eEBSD inverse pole figure (IPF) maps and corresponding phase distribution maps of 17-4PH stainless steel samples. (a, e) Sample A; (b, f) Sample C; (c, g) Sample S; and (d, h) Sample HT. Figures (a–d) show IPF orientation maps, while (e–h) display Face-centered cubic (FCC) vs Body-centered cubic (BCC) phase maps obtained from EBSD analysis.\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-6976526/v1/275c91bf92bea5b88bdecaa6.png"},{"id":86010896,"identity":"ae27d856-36db-484d-af89-2f65f59e701f","added_by":"auto","created_at":"2025-07-04 09:44:39","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":56481,"visible":true,"origin":"","legend":"\u003cp\u003eGrain size distribution for 4 samples: a-i) Sample HT; a-ii) Sample S; a-iii) Sample C; a-iv) Sample A and average grain diameter vs mechanical properties of 17-4PH stainless steel samples: b-i) Ductility (%) vs Average grain diameter (μm); b-ii) Yield strength (MPa) vs average grain diameter (μm); b-iii) Ultimate tensile strength (MPa) vs average grain diameter (μm).\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-6976526/v1/705b0fd4f3606b45a447bfa4.png"},{"id":89191189,"identity":"e54001ab-e170-44eb-988f-b5818d7a2617","added_by":"auto","created_at":"2025-08-16 09:01:48","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2928439,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6976526/v1/d334795f-ef66-41ab-9ba9-880b79fa1b31.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Dual-Phase Laser Scanning for Enhanced Mechanical Properties in Laser Powder Bed Fusion Deposited 17-4PH Stainless Steel","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eAdditive manufacturing (AM) has revolutionized the production of complex geometries with high precision and reduced material waste, making it a preferred choice in various industries, including aerospace, medical, and automotive [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e], [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Among the different AM techniques, laser powder bed fusion (LPBF) is widely utilized for fabricating metal components due to its ability to achieve fine microstructures and excellent mechanical properties [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. However, challenges such as porosity and inconsistent material properties persist, affecting the overall performance of LPBF-fabricated parts. For instance, achieving a consistently high relative density above 99% in 17-4PH stainless steel remains a significant challenge due to the complexity of optimizing process parameters such as laser power, scanning speed, and layer thickness [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. To overcome these issues, advanced scanning strategies like dual-phase laser scanning (DPLS) have been introduced to enhance material density and mechanical properties.\u003c/p\u003e \u003cp\u003eLayer remelting strategy in LPBF, which has gained attention in recent years for its potential to enhance part density, mechanical performance, and microstructural homogeneity. This technique involves re-scanning a melted layer one or more times before applying a new powder layer, aiming to improve interlayer bonding and reduce porosity. Several studies have explored the effectiveness of this approach on various alloys, including titanium and nickel-titanium (Ni-Ti) alloys. A study by Sinclair et al. on Ti-6Al-4V alloy demonstrated that remelting could significantly enhance pore healing and reduce surface roughness, leading to improved mechanical properties [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. However, the research also indicated that excessive remelting might result in material degradation and increased energy consumption, highlighting the need for careful parameter optimization. Another investigation by Chmielewska et al. on Ni-Ti alloy revealed that remelting contributed to improved homogeneity in chemical and phase composition [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. The study found that remelting reduced elemental segregation and enhanced microstructural uniformity, ultimately leading to more consistent mechanical properties. Similarly, a review by Luo et al. on LPBF of beta-type titanium alloys emphasized that remelting can aid in improving part quality and reducing porosity, while also noting potential drawbacks such as increased processing times and the need for precise control to avoid defects like keyhole pores and thermal distortions [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eWhile promising results have been demonstrated in titanium and Ni-Ti alloys, recent studies have begun applying remelting strategies to Fe-based and stainless-steel alloys. Ali et al. explored the effects of in-situ heating combined with laser remelting on 15-5PH stainless steel fabricated by LPBF [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Their study demonstrated that remelting and substrate heating reduced porosity, increased ductility by approximately 25%, and promoted a higher martensite fraction. However, aggressive remelting introduced thermal cracking without preheating, which highlights the necessity of thermal management during processing. Similarly, Rashid et al. examined the impact of a double-scan strategy in LPBF of 17-4PH stainless steel [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. The remelting approach enhanced as-built microstructural homogeneity, increased martensitic transformation, and marginally improved hardness and density compared to single-scan strategies. Nonetheless, dimensional deviations and slight variations in retained austenite fraction content between the surface and interior were observed, suggesting that double scanning can influence build precision and heterogeneous phase distribution. Comparative work on Inconel 625 by Ledwig et al. further confirmed the general benefits of laser remelting across Fe-based alloys [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Their study reported that remelting significantly improved ductility\u0026mdash;achieving elongation above 50%\u0026mdash;while maintaining competitive tensile strength. The findings also indicated reduced porosity and enhanced surface quality, although anisotropic mechanical behavior persisted due to strong grain alignment and minor yield strength reductions at high remelting energies.\u003c/p\u003e \u003cp\u003eDespite these advances, gaps remain in how remelting parameters and scan path design affect 17-4PH stainless steel specifically. While prior studies have examined the benefits of laser remelting and double scanning in LPBF processes, most efforts remain limited to single remelt strategies or generic double-scan approaches without clear control over scan path orientation or phase balance. Existing research on 17-4PH stainless steel lacks systematic evaluation of how remelting sequence, path design, and scanning parameters interact to influence microstructural evolution and mechanical outcomes.\u003c/p\u003e \u003cp\u003eThis study introduces a novel dual-phase laser scanning (DPLS) technique, implemented in two distinct variants: a repeated-path strategy and a non-repeated, perpendicular-path strategy with tuned scan speed. Unlike conventional remelting methods, these DPLS patterns are designed to manipulate thermal history and grain morphology layer by layer. Through detailed analysis of porosity, EBSD grain metrics, crystallographic texture, and tensile properties, this research reveals that DPLS can significantly enhance mechanical strength and ductility\u0026mdash;even when relative density slightly decreases. The findings suggest that DPLS offers a viable in-situ alternative to costly post-processing methods such as HIP, representing a scalable approach for producing high-performance 17-4PH parts with minimized processing steps. This work fills a critical gap by demonstrating how laser path design in remelting can be leveraged as a microstructural control mechanism, with implications for both fundamental process science and industrial AM application.\u003c/p\u003e"},{"header":"2. Experimental Procedure","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Laser Fabrication Of 17-4PH Stainless Steel\u003c/h2\u003e \u003cdiv id=\"Sec4\" class=\"Section3\"\u003e \u003ch2\u003e2.1.1. Singular-Phase Laser Scanning\u003c/h2\u003e \u003cp\u003eThe singular-phase laser scanning process in LPBF follows the standard approach, where each deposited layer is scanned and melted once using the laser (see Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e-a). Using Trumpf TruPrint Series 1000 LPBF printer, the optimized process parameters employed in this study included a laser power of 182.4 W, a scanning speed of 115 mm/s, a hatch spacing of 100 \u0026micro;m, and a layer thickness of 60 \u0026micro;m (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The 17-4PH stainless steel powder used in this process was supplied by Emerson Automation Solutions \u0026ndash; Pressure Management Global Headquarters, McKinney, TX. The powder particles were predominantly spherical in shape (with average peak diameter at 38.13 \u0026micro;m), and the particle size distribution, defined by D-values, was D₃₀ = 32.35 \u0026micro;m, D₅₀ = 38.13 \u0026micro;m, and D₉₀ = 62.84 \u0026micro;m. A zig-zag scanning pattern with a non-connected trajectory was utilized, incorporating a 67\u0026deg; rotation angle between successive layers. The use of a 67\u0026deg; rotation angle has been demonstrated to improve print quality by reducing residual stress and anisotropy and enhancing density [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. This scanning strategy was adopted to manufacture the first group of samples, designated as group A, which included 8x8x8mm blocks for XCT and EBSD, and 55x15x10mm block for tensile testing. No post-processing treatments were applied to group A, making it the baseline for comparison in this study.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section3\"\u003e \u003ch2\u003e2.1.2. Dual-Phase Laser Scanning (DPLS)\u003c/h2\u003e \u003cp\u003eThe dual-phase laser scanning (DPLS) technique involves two phases: an initial melt followed by a remelt before depositing a new powder layer. Two variations of the DPLS technique were implemented in this study: repeated pattern scanning and non-repeated pattern scanning. In the repeated pattern DPLS, the laser rescanned each layer using the same process parameters as the previous melt before adding a new layer (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e-b). The samples produced using his strategy were labelled as group C (see Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). In the non-repeated pattern DPLS process, the laser performed a remelting operation by rescanning each layer with a modified scanning strategy: the remelt path was oriented perpendicular to the initial melt path and utilized an adjusted scanning speed (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e-c). Samples processed using this approach were labelled as group S (see Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). This strategy was designed to improve thermal distribution and enhance material fusion. These strategies were developed to investigate the impact of additional remelting on density and mechanical properties.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section3\"\u003e \u003ch2\u003e2.1.3. Single-Phase Laser Scanning with HIP Treatment for Mechanical Properties Comparison Purpose\u003c/h2\u003e \u003cp\u003eIn addition to Groups A, C, and S, an additional set of singular-phase laser scanning samples (made with the same process parameter as group A) were fabricated to perform hot isostatic pressing (HIP) as a post-processing phase. The HIP treatment was conducted at 1150\u0026deg;C for 4 hours under a pressure of 100 MPa using an American Isostatic Presses (AIP) 6-30H system [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. These samples, referred to as group HT (see Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), were subjected to HIP to evaluate the effectiveness of post-processing in enhancing mechanical properties.\u003c/p\u003e \u003cp\u003eTable 1. Process Parameters employed in the LPBF of 17-4PH stainless steels.\u003c/p\u003e\u003cp\u003e\u003cimg 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\" width=\"573\" height=\"332\"\u003e\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.2. Porosity Testing\u003c/h2\u003e \u003cdiv id=\"Sec8\" class=\"Section3\"\u003e \u003ch2\u003e2.2.1. Archimedes Density Measurement for Sample Groups A, C, and S\u003c/h2\u003e \u003cp\u003ePorosity evaluation was conducted using Archimedes method in accordance with ASTM B962 standards [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. For this test, 8x8x8 mm cubic samples were prepared. Each group contained five samples to ensure statistical reliability. The relative density was determined based on the measured weight in air and water, and the mean value and standard deviation were calculated to assess consistency within each group.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section3\"\u003e \u003ch2\u003e2.2.2. X-Ray Tomography Analysis for Sample Groups A, C and S\u003c/h2\u003e \u003cp\u003eX-ray tomography was performed using a ZEISS-XRADIA Crystal CT machine (XCT), with Dragonfly software employed for data analysis. Cylindrical samples with a diameter of 2 mm and a height of 8 mm were extracted from the 8x8x8 mm blocks of sample groups A, C, and S for tomography analysis. The test involved collecting data on voxel distribution to determine relative density, as well as measurements of volume, spherical index, Feret diameter, and spherical diameter. Tomographic images provided insights into the internal porosity distribution and enabled the detection of irregular pore shapes within the samples.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e2.3. Tensile Testing for all sample groups A, C, S, and HT\u003c/h2\u003e \u003cp\u003eThe tensile tests were conducted using an Instron 8872 universal testing machine (25kN load cell), with Bluehill 3 software used for data acquisition and analysis, following ASTM standard E8 [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Additional miniature tensile tests were performed using a Kammrath-Weiss table-top tester with a 10 kN load cell. All tensile specimens were extracted perpendicular to the build direction of the 55x15x10 mm bulk blocks, using electrical discharge machining (EDM), then metallographically polished to remove surface irregularities caused by EDM. A 10 mm gauge length was used for both the Instron-tested and Kammrath-Weiss-tested specimens. Five samples per group were tested to obtain average values and standard deviations. Results were used to evaluate yield strength, ultimate tensile strength, and elongation to failure.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e2.4. Electron Backscatter Diffraction (EBSD) Analysis\u003c/h2\u003e \u003cp\u003eMicrostructure characterization of the printed 17-4PH steels were performed using scanning electron microscope (SEM) based electron back scattered diffraction (EBSD) technique to examine the grain structure, grain sizes, and crystal orientation across all sample groups. A Thermo-Fisher Apreo 2C SEM equipped with an EDAX EBSD camera was used for data acquisition, and TSL OIM 8.6 software was used for data analyses purposes. The scanning was conducted on the mid-section cross-sectional plane of the printed samples along the built direction. EBSD data provided valuable insights into grain size distribution, with mean, median, and standard deviation values calculated. These results were correlated with tensile testing outcomes to understand the relationship between microstructure and mechanical behavior.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results and discussion","content":"\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.1. Porosity evaluation in the printed steels\u003c/h2\u003e \u003cp\u003ePorosity evaluation was conducted using the Archimedes method to measure the density of the fabricated samples. The relative density (RD) of each sample was calculated by comparing the measured density to the theoretical bulk density of 7.8 g/cm\u0026sup3; for fully dense 17-4PH stainless steel [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. The density measurements indicated that group A samples exhibited the highest RD, achieving 97.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.7%. A decreasing trend was observed in the DPLS-applied samples, with group C reaching 96.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6% and group S having the lowest RD at 95.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4% (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The relative density measured using Archimedes method was compared with values obtained using X-ray tomography. In all sample groups, the XCT reveals a higher RD% while maintaining the same decreasing trend. In Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, the XCT results showed an RD of 99.98% for group A, 99.42% for group C, and 99.21% for group S.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe discrepancy in relative density measurements between the Archimedes method and XCT scanning can be attributed to differences in sensitivity to surface porosity, sample preparation, and measurement limitations. In the Archimedes method, 8x8x8 mm cubic samples were used to determine actual bulk density by measuring the buoyant force when submerged in a fluid. This technique is highly sensitive to surface-connected porosity, as the fluid can infiltrate open pores, potentially leading to an underestimation of density, of near fully dense parts [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. In contrast, tomography scanning was performed on cylindrical samples with a diameter of 2 mm and a length of 8 mm, providing a detailed 3D representation of internal porosity. However, tomography's voxel resolution limits the detection of very fine pores and pores below the detection threshold remain undetected, which may result in misrepresentation of actual porosity level and overestimation of density [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eSample preparation also plays a significant role in these differences. The larger cubic sample used in the Archimedes method encompasses a broader volume, including surface imperfections and porosity, which can contribute to a lower density reading. On the other hand, the tomography scanning of a smaller cylindrical sample, which was machined before scanning, may have removed surface imperfections, leading to a higher density measurement. According to Kan et al., the accuracy of the Archimedes method can be compromised by surface roughness effects, whereas tomography provides a non-destructive analysis that offers insights into pore morphology but lacks sensitivity to surface defects [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTomographic analysis was conducted using Dragonfly software to characterize porosity in 3D for each sample group. The scanned volume dimensions were 1,268 pixels (2,326.65 \u0026micro;m) in width, 4,381 pixels (8,038.70 \u0026micro;m) in height, and 1,389 pixels (2,548.68 \u0026micro;m) in depth, with data extracted for pore volume, sphericity index (0\u0026ndash;1), Feret diameter, and equivalent spherical diameter (see Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). In sample A, a total of 4,637 porosity counts were identified, with most volumes equal to or less than 702.2 \u0026micro;m\u0026sup3;. The largest observed porosity had a volume of 178,187.7 \u0026micro;m\u0026sup3;. Approximately 69.29% of the detected porosities exhibited near-spherical shapes, with a sphericity index greater than 0.9. For sample C, 99.93% of the porosities (31,702 counts) had volumes ranging from 30.89 \u0026micro;m\u0026sup3; to 37,605.28 \u0026micro;m\u0026sup3;, with a tight spherical diameter range from 4.91 \u0026micro;m to 5.92 \u0026micro;m. However, an abnormally large porosity with a volume of approximately 9,619,075.77 \u0026micro;m\u0026sup3; with Feret Diameter of 574.79 \u0026micro;m was identified (see Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e-h), which is attributed to the double-laser scanning method. In Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e-d, the proportion of near-spherical porosities (sphericity index above 0.9) was significantly lower at 32%, approximately 2.16 times lower than sample A. Similarly, sample S exhibited 99.42% (or 6,488 counts) of porosities within the volume range of 6.18 \u0026micro;m\u0026sup3; to 27,853.21 \u0026micro;m\u0026sup3;. The largest porosity identified had a Feret diameter of 630.86 \u0026micro;m. In addition to the largest donut-shaped pore, this sample contained several mid-sized to large pores with Feret diameter ranging from 32.15 \u0026micro;m to 66.50 \u0026micro;m (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e-i). The proportion of spherical-shaped pores increased to 73.35%, representing a measurable improvement over the previous samples.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eComparative analysis showed that Samples C and S (both with DPLS) had fewer mid-to-large pores and narrower Feret/spherical diameter distributions than Sample A. Specifically, 85.62% of spherical pores in Sample C had diameters\u0026thinsp;\u0026lt;\u0026thinsp;4.91 \u0026micro;m, while 74.39% of irregular pores had Feret diameters\u0026thinsp;\u0026lt;\u0026thinsp;6.74 \u0026micro;m. Sample S followed a similar trend, with 53.69% of spherical pores\u0026thinsp;\u0026le;\u0026thinsp;3.20 \u0026micro;m and 66.29% of non-spherical pores\u0026thinsp;\u0026le;\u0026thinsp;5.16 \u0026micro;m. In contrast, Sample A had 71.42% and 70.89% of its spherical and non-spherical pores below 4.91 \u0026micro;m and 6.72 \u0026micro;m, respectively. The spatial uniformity and reduced occurrence of larger pores in Samples C and S suggest a more favorable stress distribution under load, likely contributing to improved mechanical properties. Tomography also revealed a distinctive \u0026ldquo;donut-shaped\u0026rdquo; pore in Sample C, while Sample S exhibited similar and additional large pore structures, consistent with melt pool instabilities discussed in section \u003cspan refid=\"Sec14\" class=\"InternalRef\"\u003e3.2\u003c/span\u003e.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e3.2. Effect of laser scanning strategies on the evolution of porosities\u003c/h2\u003e \u003cp\u003eThe increased porosity observed in samples C and S following the application of dual laser pass strategies in LPBF can be primarily attributed to melt pool instability, gas entrapment, and localized overheating. Both scanning strategies\u0026mdash;repeat-pattern (sample C) and non-repeat-pattern (sample S)\u0026mdash;led to varying degrees of thermal accumulation, vaporization, and remelting, all of which contributed to the formation of pores and a reduction in relative density.\u003c/p\u003e \u003cp\u003eLocalized overheating during the secondary laser passes likely caused excessive vaporization and keyhole instability. As vapor pressure sustained open cavities in the melt pool, gases became trapped upon solidification, forming mid-to-large pores. This effect was especially evident in sample S, where the non-repeat DPLS strategy introduced perpendicular scan paths, promoting uneven energy distribution and turbulent melt pool dynamics. Kan et al. noted that such conditions increase the likelihood of keyhole porosity, which aligns with the pore morphology observed in this sample [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Sample C, using a repeat-pattern scanning approach, exhibited isolated \u0026ldquo;donut-shaped\u0026rdquo; pores. These features suggest gas entrapment due to re-melting of already solidified regions without sufficient time for gas escape. Mandev et al. reported similar behavior, where repeated laser passes\u0026mdash;without optimized dwell time\u0026mdash;can seal gas pockets despite improving densification in other areas [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. The repeated thermal cycling in sample C may have locally intensified solidification constraints, leading to enclosed porosity.\u003c/p\u003e \u003cp\u003eOverall, while dual laser scanning was intended to improve material quality, improper control of energy input and scan path interaction significantly affected porosity formation. The differences in pore morphology between samples C and S highlight the critical influence of scanning strategy on melt pool behavior and gas entrapment mechanisms.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003e3.3. Tensile Test Result\u003c/h2\u003e \u003cdiv id=\"Sec16\" class=\"Section3\"\u003e \u003ch2\u003e3.3.1. Correlating porosity morphology with mechanical behavior in regular LPBF 17-4PH Stainless Steel and DPLS samples\u003c/h2\u003e \u003cp\u003eAlthough the Archimedes and XCT measurements revealed that sample A exhibited the highest relative density, its mechanical properties, including yield strength, ultimate tensile strength, and ductility, were inferior compared to samples C and S (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). The group A samples exhibited an average yield strength (YS) of 615.2\u0026thinsp;\u0026plusmn;\u0026thinsp;85.7 MPa, an ultimate tensile strength (UTS) of 1148.2\u0026thinsp;\u0026plusmn;\u0026thinsp;40.6 MPa, and an elongation of 6.69\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02%; Group C samples demonstrated superior mechanical performance, with a YS of 955.2\u0026thinsp;\u0026plusmn;\u0026thinsp;26.8 MPa, a UTS of 1222.8\u0026thinsp;\u0026plusmn;\u0026thinsp;30.5 MPa, and an elongation of 12.02\u0026thinsp;\u0026plusmn;\u0026thinsp;0.09%, effectively doubling the ductility compared to group A; Group S samples showed moderate improvements, with a YS of 722.9\u0026thinsp;\u0026plusmn;\u0026thinsp;21.9 MPa, a UTS of 1193.4\u0026thinsp;\u0026plusmn;\u0026thinsp;18.2 MPa, and an elongation of 9.61\u0026thinsp;\u0026plusmn;\u0026thinsp;0.20%. Despite the presence of larger individual pores, particularly the donut-shaped keyhole-type porosities identified in Samples C and S through tomography (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e), these two groups demonstrated superior mechanical performance. These results indicate that tensile behavior in LPBF 17-4PH stainless steel is influenced more strongly by pore morphology and distribution than by total porosity volume alone.\u003c/p\u003e \u003cp\u003eIn the research of Kim et al. and Wilson-Heid et al., lack-of-fusion (LOF) defects, characterized by irregular and sharp-edged morphologies, are known to be significantly more detrimental to mechanical strength compared to smooth, nearly spherical pores [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e], [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. In contrast, keyhole-induced pores, like those observed in samples C and S, tend to be smoother and more rounded, making them less severe as stress concentrators unless they are excessively large [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Studies on LPBF 316L stainless steel have similarly shown that while overall porosity impacts mechanical properties, samples dominated by LOF defects suffered more dramatic reductions in tensile strength and ductility than those containing only keyhole pores [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Therefore, although sample C and sample S each exhibited a significant isolated pore, the smoother morphology and relatively isolated nature of these defects reduced their detrimental effects on mechanical performance compared to a scenario where numerous irregular LOF defects might dominate [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn sample A, the higher number of smaller but irregularly shaped pores, coupled with their less uniform spatial distribution, likely contributed to more distributed stress concentrations during loading, promoting earlier crack initiation and propagation. Conversely, in samples C and S, the pores appeared to be better distributed and fewer in number, minimizing the accumulation of critical stress concentrations. This interpretation aligns well with related studies on LPBF 316L and maraging steels. In LPBF 316L, Wilson-Heid et al. observed that mechanical properties remained relatively stable despite minor variations in total porosity, provided that large, irregular pores were absent [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Similarly, in maraging steels, isolated spherical pores had less impact on tensile strength than elongated or irregular lack-of-fusion defects, and performance degradation correlated strongly with the presence of clustered or aligned pores [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. These findings suggest that the donut-shaped pores seen in samples C and S, although individually large, did not severely degrade mechanical properties because they were isolated and surrounded by refined, stronger microstructures.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section3\"\u003e \u003ch2\u003e3.3.2. Comparing mechanical properties of DPLS samples to Hot Isostatic Pressing (HIP) samples\u003c/h2\u003e \u003cp\u003eGroup HT samples, subjected to Hot Isostatic Pressing (HIP) at 1150\u0026deg;C for 4 hours at 100 MPa​, presented the YS of 598.8\u0026thinsp;\u0026plusmn;\u0026thinsp;36.9 MPa, a UTS of 910.3\u0026thinsp;\u0026plusmn;\u0026thinsp;7.9 MPa, and an elongation of 6.22\u0026thinsp;\u0026plusmn;\u0026thinsp;0.16%. The HIP treatment aimed to reduce porosity and relieve residual stresses and been shown to improve the mechanical properties of 17-4PH stainless steel by increasing relative density (RD%) and reducing internal stresses [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]​. However, the present results reveal that the HIP-treated samples (HT) did not exhibit superior mechanical properties compared to the non-post-processed samples A, C, and S. Contrary to expectations, the tensile properties of the HIP-treated samples fell short, particularly in terms of strength and ductility, highlighting the potential limitations of HIP in the specific context of LPBF 17-4PH stainless steel with the applied processing parameters. These findings suggest that the DPLS technique may eliminate the need for post-processing treatments if optimized effectively. The ability to manipulate the secondary phase of laser in DPLS might achieve desirable mechanical properties without relying on additional post-processing steps.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003e3.4. Evolution of microstructure\u003c/h2\u003e \u003cdiv id=\"Sec19\" class=\"Section3\"\u003e \u003ch2\u003e3.4.1. General observation of phase/ crystal Structure\u003c/h2\u003e \u003cp\u003eTo further investigate the underlying reasons behind the lack of improvement in mechanical properties in the HIP-treated samples, EBSD analyses were carried out. The 17-4PH stainless steel is a martensitic precipitation-hardening alloy primarily composed of body-centered tetragonal (BCT) structures [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Following the LPBF process and subsequent HIP treatment, EBSD phase mapping confirmed that all samples comprised complete martensite phase (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e). The dominance of the BCC/BCT phases directly correlates with the tensile properties observed in the study. The high ultimate tensile strength (UTS) and yield strength in Samples A, C, and S can be attributed to the martensitic structure, which is known for its inherent high dislocation density and hardness. The mechanical properties observed in the tensile tests (see section \u003cspan refid=\"Sec16\" class=\"InternalRef\"\u003e3.3.1\u003c/span\u003e.) further confirm that the dual-phase laser scanning (DPLS) technique influenced the grain refinement and phase retention, leading to variations in strength and ductility across the samples.\u003c/p\u003e \u003cp\u003e3.4.2. Influence of DPLS and HIP on grain, crystal structure and mechanical properties of LPBF 17-4Ph stainless steel:\u003c/p\u003e \u003cdiv id=\"Sec20\" class=\"Section4\"\u003e \u003ch2\u003e3.4.2.1. Sample A (Single-Phase Laser Scanning)\u003c/h2\u003e \u003cp\u003eSample A exhibited a non-uniform grain size distribution (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e-a). The mean grain diameter was 10.06\u0026thinsp;\u0026plusmn;\u0026thinsp;2.02 \u0026micro;m, with a significant proportion of smaller grains (0\u0026ndash;5 \u0026micro;m) and occasional larger grains exceeding 30 \u0026micro;m (see Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e-a-iv). The mixed grain size distribution suggests moderate strength and ductility; Consistent with the Hall-Petch relationship, the moderate grain refinement in Sample A correlated with intermediate mechanical properties compared to other groups.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec21\" class=\"Section4\"\u003e \u003ch2\u003e3.4.2.2. Sample C (Repeated-Pattern DPLS):\u003c/h2\u003e \u003cp\u003eSample C demonstrated a finer and more uniform grain size distribution compared to Sample A. The mean grain diameter was reduced to 5.52\u0026thinsp;\u0026plusmn;\u0026thinsp;0.67 \u0026micro;m, indicating significant grain refinement and improved homogeneity (see Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e-b and Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e-a-iii). The refined microstructure contributed to the highest observed mechanical properties, with a yield strength of 955.19 MPa and an ultimate tensile strength (UTS) of 1222.76 MPa (showed in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e-b). The Hall-Petch effect was clearly manifested, where smaller grain size enhanced strength by impeding dislocation motion, while the uniform crystallographic orientation further supported improved ductility (elongation of 12.02%).\u003c/p\u003e \u003cp\u003eTo sum up, there are three factors that contributed to the superior performance of Sample C:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eSmaller and more uniform grain structure enhanced strength and ductility via grain boundary strengthening [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e].\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eBalanced crystallographic orientation (notably the presence of [001] orientations) facilitated multidirectional plastic deformation. This observation is consistent with research of Gao et al. who reported that orientations such as [001] in alloy structure effectively accommodate tensile stress, enhancing both strength and ductility [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e].\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThermal Stabilization of Martensitic Phase: The dual-phase laser scanning technique may have facilitated controlled thermal conditions, refined the martensitic phase and ensured better mechanical performance despite a slight decrease in relative density [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec22\" class=\"Section4\"\u003e \u003ch2\u003e3.4.2.3. Sample S (Non-Repeated-Pattern DPLS)\u003c/h2\u003e \u003cp\u003eSample S exhibited a mean grain diameter of 8.75\u0026thinsp;\u0026plusmn;\u0026thinsp;1.55 \u0026micro;m (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e-a-ii), with a greater fraction of smaller grains relative to Sample A. Crystallographic analysis indicated a dominance of [001] and [101] orientations, promoting improved ductility. Although the grain size was finer than Sample A, it was a little coarser than Sample C, resulting in mechanical properties intermediate between the two. Sample S achieved a favorable elongation value, attributed to enhanced grain boundary sliding associated with the higher fraction of smaller grains and favorable orientations. However, the non-uniform grain size distribution introduced localized plastic deformation zones, potentially impacting mechanical uniformity under load.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec23\" class=\"Section4\"\u003e \u003ch2\u003e3.4.2.4. Sample HT (HIP-Treated Single-Phase Laser Scanning)\u003c/h2\u003e \u003cp\u003eSample HT exhibited the largest grain sizes among all groups, with a mean diameter of 14.89\u0026thinsp;\u0026plusmn;\u0026thinsp;1.65 \u0026micro;m. The grains were more uniformly distributed due to the prolonged exposure to high temperatures during the HIP process. The crystal orientations were predominantly within the [111] and [001] directions. Despite expectations for improved mechanical properties post-HIP, the tensile test results indicated no significant enhancement. The larger grain sizes observed in this sample align with findings from Mao et al.​, who reported that HIP treatment on 316L stainless steel resulted in significant grain coarsening due to high temperatures and extended processing times [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. Similarly, Pei et al.​ demonstrated that grain growth is accelerated at 1150\u0026deg;C due to enhanced atomic diffusion, leading to decreased strength and plasticity [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. These studies emphasize that high-temperature HIP treatments can contribute to abnormal grain growth, which negatively affects mechanical properties by reducing grain boundary strengthening effects. The common findings from both studies suggest that elevated HIP temperatures promote grain coarsening, which can lead to a reduction in strength and ductility [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e], [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. In the context of this research, the HIP-treated samples did not meet the expected improvement in mechanical properties, reinforcing the conclusion that DPLS could potentially serve as an alternative to post-processing methods such as HIP.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec24\" class=\"Section3\"\u003e \u003ch2\u003e3.4.3. Grain Size\u0026ndash;Mechanical Property Correlation\u003c/h2\u003e \u003cp\u003eThe mechanical performance of all samples exhibited a strong dependence on grain size, consistent with the Hall-Petch relationship. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e-b, a decrease in mean grain size from 14.89 \u0026micro;m (Sample HT) to 5.52 \u0026micro;m (Sample C) corresponded to a significant increase in yield strength and UTS. Conversely, ductility decreased slightly with grain coarsening, as Sample C exhibited the highest elongation among all groups. These results validate the critical role of grain refinement in enhancing both strength and ductility in LPBF-fabricated 17-4PH stainless steel.\u003c/p\u003e \u003cp\u003eOverall, the DPLS strategy, particularly the repeated-pattern approach (Sample C), effectively refined the microstructure, improved grain orientation distribution, and enhanced mechanical performance without the need for costly post-processing such as HIP. The findings demonstrate that optimized dual-phase laser scanning during LPBF processing can offer significant production and cost benefits for high-performance stainless-steel components.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eThis study demonstrated the effectiveness of dual-phase laser scanning (DPLS) in enhancing the mechanical performance and microstructural characteristics of LPBF-fabricated 17-4PH stainless steel. The application of DPLS led to significant improvements in tensile properties, achieving a yield strength of 955.2 MPa, an ultimate tensile strength of 1222.8 MPa, and an elongation of 12.02% in the repeated-pattern DPLS sample. These results represent a substantial enhancement compared to conventional single-phase scanning strategies, effectively doubling the ductility while maintaining high strength levels.\u003c/p\u003e \u003cp\u003eThe superior mechanical behavior achieved through DPLS is attributed to the formation of finer, more uniform grain structures, favorable crystallographic orientation distributions, and refined pore morphology characterized by spherical or near-spherical shapes. Additionally, the minimized clustering of pores and improved stress redistribution within the surrounding microstructure contributed to potentially delaying crack initiation and enhancing overall mechanical stability under tensile loading. This integrated control of microstructure and porosity highlights the advantages of DPLS in tailoring mechanical properties directly during fabrication.\u003c/p\u003e \u003cp\u003eImportantly, DPLS offers a direct process-level solution for optimizing mechanical performance without the need for post-processing treatments such as HIP, enabling more efficient and cost-effective manufacturing of high-performance stainless-steel components. These findings underscore the potential of advanced laser scanning strategies to engineer microstructure and porosity morphology synergistically, paving the way for the next generation of additive manufacturing solutions in demanding structural applications.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eDan T. Nguyen: Conceptualization, Methodology (process parameter optimization), Investigation (sample fabrication, tensile testing, polishing, XCT, EBSD), Data curation (XCT, tensile, EBSD data), Formal analysis (mechanical property calculations, porosity analysis), Visualization, Writing \u0026ndash; original draft.Madhavan Radhakrishnan: Supervision, Investigation (EBSD study), Data curation (EBSD), Methodology, Writing \u0026ndash; review \u0026amp; editing.Narendra Dahotre: Supervision, Resources, Writing \u0026ndash; review \u0026amp; editing.Reza Mirshams: Supervision, Project administration, Writing \u0026ndash; review \u0026amp; editing.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eAuthors acknowledge Emerson Automation Solutions \u0026ndash; Pressure Management Global Headquarters, located in McKinney, TX, for providing 17-4PH stainless steel powder, which was essential for conducting this research. Authors acknowledge the Center for Advanced Additive Manufacturing (CAAAM) funded through State of Texas Appropriation: 190405-105-805008-220 for the infrastructure support. DTN wishes to thank Mr. Shelden Dowden for sharing his expertise and providing training on manufacturing and testing equipment used in this study, and Dr. Rajiv Mishra for granting access to Buehler VibroMet polisher and polishing solutions used in sample preparation process.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eP. V. Cobbinah, R. A. Nzeukou, O. T. Onawale, and W. R. Matizamhuka, \u0026ldquo;Laser powder bed fusion of potential superalloys: A review,\u0026rdquo; Jan. 01, 2021, \u003cem\u003eMDPI AG\u003c/em\u003e. doi: 10.3390/met11010058.\u003c/li\u003e\n\u003cli\u003eJ. P. Oliveira, A. D. LaLonde, and J. 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Wei, \u0026ldquo;Effect of hot isostatic pressing treatment on porosity reduction and mechanical properties enhancement of 316L stainless steel fabricated by binder jetting,\u0026rdquo; \u003cem\u003eVirtual Phys Prototyp\u003c/em\u003e, vol. 18, no. 1, 2023, doi: 10.1080/17452759.2023.2174703.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"17-4PH stainless steel, Laser Powder Bed Fusion (LPBF), Dual-Phase Laser Scanning (DPLS), X-ray Computed Tomography (XCT), Tensile testing","lastPublishedDoi":"10.21203/rs.3.rs-6976526/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6976526/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study investigates the application of the dual-phase laser scanning (DPLS) technique in laser powder bed fusion (LPBF) to enhance mechanical properties of 17\u0026thinsp;\u0026minus;\u0026thinsp;4 precipitation hardened (PH) stainless steel. While LPBF is widely used for its precision and ability to produce complex geometries, challenges such as porosity and inconsistent material properties remain significant hurdles. The DPLS technique, incorporating an initial melt followed by a remelt, aims to address these challenges by improving interlayer bonding and relative density (RD). Experimental evaluations, including Archimedes\u0026rsquo; method and X-ray tomography, revealed that despite a marginal decrease in relative density compared to single-phase scanning, the DPLS process yielded notable improvements in mechanical properties. Samples fabricated using repeated-pattern DPLS, exhibited an ultimate tensile strength (UTS) of 1222.8\u0026thinsp;\u0026plusmn;\u0026thinsp;30.5 MPa and a yield strength (YS) of 955.2\u0026thinsp;\u0026plusmn;\u0026thinsp;26.8 MPa, demonstrating significant enhancements in strength and ductility. Similarly, samples fabricated using non-repeated-pattern DPLS achieved the UTS of 1193.4\u0026thinsp;\u0026plusmn;\u0026thinsp;18.2 MPa and the YS of 722.9\u0026thinsp;\u0026plusmn;\u0026thinsp;21.9 MPa, with improved elongation attributed to favorable crystallographic orientations. Additionally, comparisons with hot isostatic pressing (HIP)-treated samples, which exhibited the UTS of 910.3\u0026thinsp;\u0026plusmn;\u0026thinsp;7.9 MPa and the YS of 598.8\u0026thinsp;\u0026plusmn;\u0026thinsp;36.9 MPa, suggest that DPLS can potentially reduce reliance on costly post-processing treatments. These findings highlight the potential of DPLS to optimize mechanical performance in LPBF-fabricated 17-4PH stainless steel components, offering a pathway toward more efficient and cost-effective additive manufacturing solutions.\u003c/p\u003e","manuscriptTitle":"Dual-Phase Laser Scanning for Enhanced Mechanical Properties in Laser Powder Bed Fusion Deposited 17-4PH Stainless Steel","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-04 09:44:35","doi":"10.21203/rs.3.rs-6976526/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"f44004b2-b981-425e-bc1c-28b1a2ff82ef","owner":[],"postedDate":"July 4th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-08-16T08:53:40+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-04 09:44:35","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6976526","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6976526","identity":"rs-6976526","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}