Pub Date : 2026-03-15Epub Date: 2025-12-26DOI: 10.1016/j.scriptamat.2025.117153
M. Sun , W.B. Jiang , J.F. Peng , Q.F. Fang , X.B. Wu
The detrimental effect of the ordered D03 structure on the magnetostriction of Fe-Ga alloys has been extensively recognized over the past two decades, yet its role in governing magnetic domain behavior and damping characteristics remains poorly understood. In this study, a series of Fe-Ga alloys with systematically varied D03 phase fractions were designed to elucidate the influence of nano-scaled D03 precipitates on defect relaxation, damping performance, and magnetic domain morphology. With increasing Ga content, the D03 phase fraction increases progressively, accompanied by a morphological evolution from spherical to near-rectangular shapes due to spatial confinement. Unexpectedly, the widespread precipitation of D03 does not eliminate magnetic damping, and instead it shifts the onset of magnetic damping to higher strain amplitudes. Moreover, the presence of enlarged D03 precipitates raises the critical amplitude required to initiate magnetic domain motion, below which the domain activity becomes effectively frozen. This work closes a key knowledge gap in the low-amplitude magnetic mechanical hysteresis damping regime and demonstrates that tailoring the size of the second-phase precipitates offers a viable strategy to modulate the amplitude range for achieving high damping.
{"title":"Strain-dependent magnetic domain freezing and unfreezing governed by D03 phase evolution in Fe-Ga alloys","authors":"M. Sun , W.B. Jiang , J.F. Peng , Q.F. Fang , X.B. Wu","doi":"10.1016/j.scriptamat.2025.117153","DOIUrl":"10.1016/j.scriptamat.2025.117153","url":null,"abstract":"<div><div>The detrimental effect of the ordered D0<sub>3</sub> structure on the magnetostriction of Fe-Ga alloys has been extensively recognized over the past two decades, yet its role in governing magnetic domain behavior and damping characteristics remains poorly understood. In this study, a series of Fe-Ga alloys with systematically varied D0<sub>3</sub> phase fractions were designed to elucidate the influence of nano-scaled D0<sub>3</sub> precipitates on defect relaxation, damping performance, and magnetic domain morphology. With increasing Ga content, the D0<sub>3</sub> phase fraction increases progressively, accompanied by a morphological evolution from spherical to near-rectangular shapes due to spatial confinement. Unexpectedly, the widespread precipitation of D0<sub>3</sub> does not eliminate magnetic damping, and instead it shifts the onset of magnetic damping to higher strain amplitudes. Moreover, the presence of enlarged D0<sub>3</sub> precipitates raises the critical amplitude required to initiate magnetic domain motion, below which the domain activity becomes effectively frozen. This work closes a key knowledge gap in the low-amplitude magnetic mechanical hysteresis damping regime and demonstrates that tailoring the size of the second-phase precipitates offers a viable strategy to modulate the amplitude range for achieving high damping.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"274 ","pages":"Article 117153"},"PeriodicalIF":5.6,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-15Epub Date: 2025-12-08DOI: 10.1016/j.scriptamat.2025.117113
Chunguang Tang , Muhammad A. Ghouri , Jiaojiao Yi , Matthew R. Barnett
The Calculation of Phase Diagrams (CALPHAD) method has proven useful in assessing the phase stability of multi-component alloys. This success does not extend to the prediction of stacking fault energy (SFE) in fcc systems. We propose this can be viewed as a consequence of the (largely unknown) compositional dependency of the binary interaction terms. To make the case, we compare CALPHAD-predicted SFEs with atomistic computations based on the axial Ising model. To facilitate the search for new multi-component alloys while acknowledging this shortfall in knowledge, we propose an approach whereby binary interaction terms are refined during the search. As an illustrative case study, we apply this method to a directed search for Cr-Fe-Ni alloys with reduced Ni contents while preserving the value of the SFE.
{"title":"Searching for new multi-component alloys with desirable stacking fault energies: The compositional dependency of binary interaction terms","authors":"Chunguang Tang , Muhammad A. Ghouri , Jiaojiao Yi , Matthew R. Barnett","doi":"10.1016/j.scriptamat.2025.117113","DOIUrl":"10.1016/j.scriptamat.2025.117113","url":null,"abstract":"<div><div>The Calculation of Phase Diagrams (CALPHAD) method has proven useful in assessing the phase stability of multi-component alloys. This success does not extend to the prediction of stacking fault energy (SFE) in fcc systems. We propose this can be viewed as a consequence of the (largely unknown) compositional dependency of the binary interaction terms. To make the case, we compare CALPHAD-predicted SFEs with atomistic computations based on the axial Ising model. To facilitate the search for new multi-component alloys while acknowledging this shortfall in knowledge, we propose an approach whereby binary interaction terms are refined during the search. As an illustrative case study, we apply this method to a directed search for Cr-Fe-Ni alloys with reduced Ni contents while preserving the value of the SFE.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"274 ","pages":"Article 117113"},"PeriodicalIF":5.6,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145735014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We developed a deep learning (DL) framework based on convolutional neural networks (CNNs) to predict elastic constants of hexagonal materials by leveraging high image-recognition capability of CNNs. Resonant frequency data were converted into three-channel RGB images, referred to as ”elasticity images” for CNN training. Without mode identification, the trained models accurately predicted all five independent elastic constants. We reveal that the average Young modulus is a critical for classification of hexagonal materials based on their elasticity images. Furthermore, we extended the Blackman diagram, originally developed for cubic crystals, to hexagonal systems, enabling a substantial reduction of five-dimensional elastic-constant space. We then established a two-step DL scheme: first, classification using the average Young modulus, followed by regression of the five elastic constants in the classified average-Young-modulus class. The prediction error was approximately 5 % for the principal elastic constants and 1.5 % for the average Young modulus.
{"title":"Two-step deep learning for decoding elastic constants of hexagonal-symmetry materials from resonant-spectrum image","authors":"Kazuya Kohira , Shota Nakamura , Hiroki Fukuda , Kazuhiro Kyotani , Hirotsugu Ogi","doi":"10.1016/j.scriptamat.2025.117115","DOIUrl":"10.1016/j.scriptamat.2025.117115","url":null,"abstract":"<div><div>We developed a deep learning (DL) framework based on convolutional neural networks (CNNs) to predict elastic constants of hexagonal materials by leveraging high image-recognition capability of CNNs. Resonant frequency data were converted into three-channel RGB images, referred to as ”elasticity images” for CNN training. Without mode identification, the trained models accurately predicted all five independent elastic constants. We reveal that the average Young modulus is a critical for classification of hexagonal materials based on their elasticity images. Furthermore, we extended the Blackman diagram, originally developed for cubic crystals, to hexagonal systems, enabling a substantial reduction of five-dimensional elastic-constant space. We then established a two-step DL scheme: first, classification using the average Young modulus, followed by regression of the five elastic constants in the classified average-Young-modulus class. The prediction error was approximately 5 % for the principal elastic constants and 1.5 % for the average Young modulus.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"274 ","pages":"Article 117115"},"PeriodicalIF":5.6,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145684056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-15Epub Date: 2025-12-05DOI: 10.1016/j.scriptamat.2025.117123
Chiharu Ota, Johji Nishio, Ryosuke Iijima
We discovered previously unreported defects in the 4H-SiC epilayers that do not lie along the [0001] direction or on the () plane. Each defect consists of a pair of partial dislocations separated by a stacking fault rather than forming a perfect dislocation. Because they have inclination angles of 52° and 65° from the [0001] direction toward the [] direction, we refer to them as “pseudo- threading edge dislocations (TEDs).” The spacing between partial dislocations in the pseudo-TEDs also increases, reaching up to 12 nm at an inclination angle of 90° Based on the observed crystallographic orientation, the pseudo-TEDs appear to stabilize along the () planes. Furthermore, comparison of the elastic strain energy between TEDs in the form of perfect dislocations and the total energy of basal plane dislocations suggests that as the inclination angle increases, the pseudo-TED structure becomes more favorable compared with a perfect dislocation.
{"title":"Inclined TEDs with pairs of partial dislocations located away from the basal plane in 4H-SiC epilayers","authors":"Chiharu Ota, Johji Nishio, Ryosuke Iijima","doi":"10.1016/j.scriptamat.2025.117123","DOIUrl":"10.1016/j.scriptamat.2025.117123","url":null,"abstract":"<div><div>We discovered previously unreported defects in the 4H-SiC epilayers that do not lie along the [0001] direction or on the (<span><math><mrow><mn>11</mn><mover><mn>2</mn><mo>¯</mo></mover><mn>0</mn></mrow></math></span>) plane. Each defect consists of a pair of partial dislocations separated by a stacking fault rather than forming a perfect dislocation. Because they have inclination angles of 52° and 65° from the [0001] direction toward the [<span><math><mrow><mn>11</mn><mover><mn>2</mn><mo>¯</mo></mover><mn>0</mn></mrow></math></span>] direction, we refer to them as “pseudo- threading edge dislocations (TEDs).” The spacing between partial dislocations in the pseudo-TEDs also increases, reaching up to 12 nm at an inclination angle of 90° Based on the observed crystallographic orientation, the pseudo-TEDs appear to stabilize along the (<span><math><mrow><mn>11</mn><mover><mn>2</mn><mo>¯</mo></mover><mrow><mo>(</mo><mrow><mn>2</mn><mi>n</mi></mrow><mo>)</mo></mrow></mrow></math></span>) planes. Furthermore, comparison of the elastic strain energy between TEDs in the form of perfect dislocations and the total energy of basal plane dislocations suggests that as the inclination angle increases, the pseudo-TED structure becomes more favorable compared with a perfect dislocation.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"274 ","pages":"Article 117123"},"PeriodicalIF":5.6,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145683454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-15Epub Date: 2025-12-15DOI: 10.1016/j.scriptamat.2025.117141
Qiyue Zhang , Yang Chen , Bin Liu , Ruiqian Zhang , Qihong Fang , Peter K. Liaw , Jia Li
Refractory multi-principal element alloys (RMPEAs) exhibit outstanding irradiation resistance performance owing to severe lattice distortion and short-range order (SRO). Nevertheless, the influence of SRO on the plastic flow behavior of irradiated RMPEAs remains unclear, hindering development of high radiation-resistant RMPEA. Here, the origin and evolution of defect-free channels in HfNbTa RMPEA is revealed via hybrid MC/MD simulation and discrete dislocation dynamics coupled with random field theory. In HfNbTa RMPEA possessing SRO, a relatively large quantity of narrow defect-free channels alleviates plastic flow localization. The probabilistic distribution of dislocation cross-slip events indicates that SRO expands the high-probability regions for cross-slip, increasing the longitudinal distance traversed by a single dislocation through double cross-slip. This feature enables dislocation loops to escape interactions with dislocations, thereby reducing defect-free channel width and improving irradiation resistance. These findings provide insights into the role of SRO in mitigating irradiation damage and guide the design of irradiation-stable RMPEAs.
{"title":"Short-range order governs plastic flow localization in irradiated multi-principal element alloys","authors":"Qiyue Zhang , Yang Chen , Bin Liu , Ruiqian Zhang , Qihong Fang , Peter K. Liaw , Jia Li","doi":"10.1016/j.scriptamat.2025.117141","DOIUrl":"10.1016/j.scriptamat.2025.117141","url":null,"abstract":"<div><div>Refractory multi-principal element alloys (RMPEAs) exhibit outstanding irradiation resistance performance owing to severe lattice distortion and short-range order (SRO). Nevertheless, the influence of SRO on the plastic flow behavior of irradiated RMPEAs remains unclear, hindering development of high radiation-resistant RMPEA. Here, the origin and evolution of defect-free channels in HfNbTa RMPEA is revealed via hybrid MC/MD simulation and discrete dislocation dynamics coupled with random field theory. In HfNbTa RMPEA possessing SRO, a relatively large quantity of narrow defect-free channels alleviates plastic flow localization. The probabilistic distribution of dislocation cross-slip events indicates that SRO expands the high-probability regions for cross-slip, increasing the longitudinal distance traversed by a single dislocation through double cross-slip. This feature enables dislocation loops to escape interactions with dislocations, thereby reducing defect-free channel width and improving irradiation resistance. These findings provide insights into the role of SRO in mitigating irradiation damage and guide the design of irradiation-stable RMPEAs.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"274 ","pages":"Article 117141"},"PeriodicalIF":5.6,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study presents a thermomechanical processing strategy to improve the resistance to hydrogen embrittlement (HE) in martensitic steels through controlling variant selection at prior austenite grain boundaries (PAGBs), while retaining ultrahigh tensile strength (>1.5 GPa). Under identical hydrogen-charging conditions, the 10% hot-compressed specimen exhibited the highest HE resistance, correlating with its largest fraction of low-angle PAGB segments. Misorientation-distribution analysis and tensile tests revealed a non-monotonic dependence of compressive strain: an optimal compressive level maximized the beneficial stress-assisted variant selection at PAGBs, whereas excessive strains promoted self-accommodation of transformation strain in the work-hardened austenite, diminishing the beneficial effect. The improved HE resistance stems from reduced hydrogen trapping, enhanced strain-dissipating slip transfer, and increased cohesive energy at PAGBs. Tailoring variant selection at PAGBs through this simple process thus provides an industry-feasible route to hydrogen-resistant high-strength martensitic steels.
{"title":"Enhancing hydrogen embrittlement resistance in high-strength martensitic steels via tailoring variant selection at prior austenite grain boundaries","authors":"Xiaodong Lan, Kazuho Okada, Rintaro Ueji, Akinobu Shibata","doi":"10.1016/j.scriptamat.2025.117157","DOIUrl":"10.1016/j.scriptamat.2025.117157","url":null,"abstract":"<div><div>This study presents a thermomechanical processing strategy to improve the resistance to hydrogen embrittlement (HE) in martensitic steels through controlling variant selection at prior austenite grain boundaries (PAGBs), while retaining ultrahigh tensile strength (>1.5 GPa). Under identical hydrogen-charging conditions, the 10% hot-compressed specimen exhibited the highest HE resistance, correlating with its largest fraction of low-angle PAGB segments. Misorientation-distribution analysis and tensile tests revealed a non-monotonic dependence of compressive strain: an optimal compressive level maximized the beneficial stress-assisted variant selection at PAGBs, whereas excessive strains promoted self-accommodation of transformation strain in the work-hardened austenite, diminishing the beneficial effect. The improved HE resistance stems from reduced hydrogen trapping, enhanced strain-dissipating slip transfer, and increased cohesive energy at PAGBs. Tailoring variant selection at PAGBs through this simple process thus provides an industry-feasible route to hydrogen-resistant high-strength martensitic steels.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"274 ","pages":"Article 117157"},"PeriodicalIF":5.6,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Interstitial elements such as nitrogen and oxygen can significantly harden titanium alloys, but they severely compromise plasticity, primarily due to their suppression of deformation twinning and propensity for grain boundary segregation. In this work, our findings reveal that water quenching induces {101}<102> compressive twins and FCC phase formation in ultra-high interstitial Ti alloys, thereby stabilizing the microstructure and mitigating stress localization. Remarkably, water quenching increases the ductility of titanium alloys containing ultra-high interstitial solutes (with nitrogen content exceeding 1.1 wt.%) from 3 % to 11 % while maintaining tensile strength above 1000 MPa, establishing an unprecedented strength-ductility synergy in ultra-high interstitial systems. These insights offer a viable pathway for repurposing Ti scrap with elevated interstitials and designing high-performance alloys through rapid cooling techniques compatible with additive manufacturing.
{"title":"Water quenching enhances ductility of titanium alloys with ultra-high interstitial solutes","authors":"Yahui Yang , Biao Chen , Katsuyoshi Kondoh , Jianghua Shen","doi":"10.1016/j.scriptamat.2025.117144","DOIUrl":"10.1016/j.scriptamat.2025.117144","url":null,"abstract":"<div><div>Interstitial elements such as nitrogen and oxygen can significantly harden titanium alloys, but they severely compromise plasticity, primarily due to their suppression of deformation twinning and propensity for grain boundary segregation. In this work, our findings reveal that water quenching induces {10<span><math><mover><mn>1</mn><mo>¯</mo></mover></math></span>1}<10<span><math><mover><mn>1</mn><mo>¯</mo></mover></math></span>2> compressive twins and FCC phase formation in ultra-high interstitial Ti alloys, thereby stabilizing the microstructure and mitigating stress localization. Remarkably, water quenching increases the ductility of titanium alloys containing ultra-high interstitial solutes (with nitrogen content exceeding 1.1 wt.%) from 3 % to 11 % while maintaining tensile strength above 1000 MPa, establishing an unprecedented strength-ductility synergy in ultra-high interstitial systems. These insights offer a viable pathway for repurposing Ti scrap with elevated interstitials and designing high-performance alloys through rapid cooling techniques compatible with additive manufacturing.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"274 ","pages":"Article 117144"},"PeriodicalIF":5.6,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145836954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-15Epub Date: 2025-12-26DOI: 10.1016/j.scriptamat.2025.117149
Jingxian Zhang, Qianglong Liang, Xiangdong Ding
NiTi-based shape memory alloys are promising candidates for solid-state refrigeration owing to the latent heat associated with stress-induced martensitic transformations. However, the conventional B2→B19′ pathway is constrained by a fundamental trade-off between elastocaloric performance and cyclic stability. In this work, we demonstrate that activating the R→B19′ transformation pathway effectively circumvents this limitation. Differential scanning calorimetry confirms stable and reversible R→B19′ transformations in binary NiTi alloys. The reduced energy barrier between the R-phase and B19′ martensite facilitates a more continuous and efficient transformation, thereby suppressing the accumulation of irreversible defects. Through integrated thermomechanical processing and microstructural characterization, we show that NiTi alloys undergoing reversible R↔B19′ transformations exhibit a large adiabatic temperature change (18.59 K), high recoverable strain (4.86%), and exceptional cycling stability, retaining over 99% of performance after 200 tensile cycles. These findings establish a robust design strategy for high-performance shape memory alloys.
{"title":"Cyclic stable superelasticity and elastocaloric effect via the R→B19′ transformation in NiTi","authors":"Jingxian Zhang, Qianglong Liang, Xiangdong Ding","doi":"10.1016/j.scriptamat.2025.117149","DOIUrl":"10.1016/j.scriptamat.2025.117149","url":null,"abstract":"<div><div>NiTi-based shape memory alloys are promising candidates for solid-state refrigeration owing to the latent heat associated with stress-induced martensitic transformations. However, the conventional B2→B19′ pathway is constrained by a fundamental trade-off between elastocaloric performance and cyclic stability. In this work, we demonstrate that activating the R→B19′ transformation pathway effectively circumvents this limitation. Differential scanning calorimetry confirms stable and reversible R→B19′ transformations in binary NiTi alloys. The reduced energy barrier between the R-phase and B19′ martensite facilitates a more continuous and efficient transformation, thereby suppressing the accumulation of irreversible defects. Through integrated thermomechanical processing and microstructural characterization, we show that NiTi alloys undergoing reversible R↔B19′ transformations exhibit a large adiabatic temperature change (18.59 K), high recoverable strain (4.86%), and exceptional cycling stability, retaining over 99% of performance after 200 tensile cycles. These findings establish a robust design strategy for high-performance shape memory alloys.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"274 ","pages":"Article 117149"},"PeriodicalIF":5.6,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-15Epub Date: 2025-12-17DOI: 10.1016/j.scriptamat.2025.117140
Jee-Hyun Kang, Jeong-Moo Oh
Since Cottrell and Bilby first proposed a kinetic model for strain aging, many refinements have been introduced. In particular, Harper’s model gained attention for BCC steels because it additionally considered the depletion of interstitial atoms in the matrix, which is significant in these alloys. However, for FCC-based steels, Harper’s consideration becomes insufficient owing to their high interstitial solubility; sites adjacent to dislocations become saturated with interstitials more rapidly than the matrix is depleted. In this study, an integrated model was developed by incorporating both Harper’s and Hartley’s considerations. The proposed model was shown to reproduce the main features observed in nitrogen-bearing austenitic stainless steels. More importantly, it converges to Harper’s model under low interstitial concentrations, as in BCC steels, thereby providing a unified kinetic framework for static strain aging across both lattice types.
{"title":"Strain aging kinetics in FCC steels: site saturation vs matrix depletion","authors":"Jee-Hyun Kang, Jeong-Moo Oh","doi":"10.1016/j.scriptamat.2025.117140","DOIUrl":"10.1016/j.scriptamat.2025.117140","url":null,"abstract":"<div><div>Since Cottrell and Bilby first proposed a kinetic model for strain aging, many refinements have been introduced. In particular, Harper’s model gained attention for BCC steels because it additionally considered the depletion of interstitial atoms in the matrix, which is significant in these alloys. However, for FCC-based steels, Harper’s consideration becomes insufficient owing to their high interstitial solubility; sites adjacent to dislocations become saturated with interstitials more rapidly than the matrix is depleted. In this study, an integrated model was developed by incorporating both Harper’s and Hartley’s considerations. The proposed model was shown to reproduce the main features observed in nitrogen-bearing austenitic stainless steels. More importantly, it converges to Harper’s model under low interstitial concentrations, as in BCC steels, thereby providing a unified kinetic framework for static strain aging across both lattice types.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"274 ","pages":"Article 117140"},"PeriodicalIF":5.6,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-15Epub Date: 2025-12-19DOI: 10.1016/j.scriptamat.2025.117136
Nicolás Flores , Daniel Salas Mula , Wenle Xu , Sahu Bibhu , Daniel Lewis , Alexandra Eve Salinas , Samantha Mitra , Raj Mahat , Surya R. Kalidindi , Justin Wilkerson , James Paramore , Ankit Srivastiva , George Pharr , Douglas Allaire , Ibrahim Karaman , Brady Butler , Vahid Attari , Raymundo Arróyave
Structural High Entropy Alloys (HEAs) are crucial in advancing technology across various sectors, including aerospace, automotive, and defense industries. Predictive modeling remains constrained by the extreme imbalance between the vast, continuous compositional design space of HEAs and the scarcity and heterogeneity of reliable experimental data. Identifying meaningful chemistry-property linkages under these constraints remains a key bottleneck in accelerating HEA discovery. Here, we address this challenge though a data-efficient, interpretable modeling framework applied to the BIRDSHOT Ni-Co-Fe-Cr-V-Mn-Cu-Al alloy system. Using sensitivity analyses and isometric log-ratio SHAP attributions, we isolate key elemental effects governing mechanical behavior, including the compositional signatures associated with brittle and fractured nanoindentation responses. Bayesian multi-objective optimization is used to tune sparsely connected, overcomplete encoder-decoder models for mapping alloy composition to six mechanical properties. These models outperform conventional regressors, particularly for yield strength and the UTS/YS ratio, demonstrating robust predictive capability and physically consistent interpretability under data-scarce conditions.
{"title":"Data-driven insights into composition-property relationships in FCC high entropy alloys","authors":"Nicolás Flores , Daniel Salas Mula , Wenle Xu , Sahu Bibhu , Daniel Lewis , Alexandra Eve Salinas , Samantha Mitra , Raj Mahat , Surya R. Kalidindi , Justin Wilkerson , James Paramore , Ankit Srivastiva , George Pharr , Douglas Allaire , Ibrahim Karaman , Brady Butler , Vahid Attari , Raymundo Arróyave","doi":"10.1016/j.scriptamat.2025.117136","DOIUrl":"10.1016/j.scriptamat.2025.117136","url":null,"abstract":"<div><div>Structural High Entropy Alloys (HEAs) are crucial in advancing technology across various sectors, including aerospace, automotive, and defense industries. Predictive modeling remains constrained by the extreme imbalance between the vast, continuous compositional design space of HEAs and the scarcity and heterogeneity of reliable experimental data. Identifying meaningful chemistry-property linkages under these constraints remains a key bottleneck in accelerating HEA discovery. Here, we address this challenge though a data-efficient, interpretable modeling framework applied to the BIRDSHOT Ni-Co-Fe-Cr-V-Mn-Cu-Al alloy system. Using sensitivity analyses and isometric log-ratio SHAP attributions, we isolate key elemental effects governing mechanical behavior, including the compositional signatures associated with brittle and fractured nanoindentation responses. Bayesian multi-objective optimization is used to tune sparsely connected, overcomplete encoder-decoder models for mapping alloy composition to six mechanical properties. These models outperform conventional regressors, particularly for yield strength and the UTS/YS ratio, demonstrating robust predictive capability and physically consistent interpretability under data-scarce conditions.</div></div>","PeriodicalId":423,"journal":{"name":"Scripta Materialia","volume":"274 ","pages":"Article 117136"},"PeriodicalIF":5.6,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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