Pub Date : 2026-01-14DOI: 10.1016/j.ijplas.2026.104611
Kunqing Ding , Theodore Zirkle , Xing Liu , Gustavo M. Castelluccio , Bryan D. Miller , Jonathan L. Wormald , Benjamin S. Anglin , Thomas W. Webb , David L. McDowell , Ting Zhu
Ratchetting is the progressive, unidirectional accumulation of plastic strain during asymmetric stress cycling with nonzero mean stress. Modeling ratchetting is challenging, especially under complex cyclic loading conditions. Most existing constitutive models rely on phenomenological back stress formulations to characterize ratchetting responses, but they are only loosely connected to underlying physical mechanisms. This work develops a microstructure-sensitive crystal plasticity (MS-CP) model for ratchetting in face-centered cubic (FCC) alloys, applied to Alloy 600 (A600) and 304L stainless steel (SS). The model incorporates back stress evolution for slip systems, driven by both deformation-induced dislocation substructures and precipitate–dislocation interactions. The simulated monotonic and ratchetting responses at room and elevated temperatures are validated against experimental stress–strain data. Results highlight the strengthening effects of dislocation substructures in both alloys and of precipitates in A600, as well as the role of substructure evolution in ratchetting responses. This MS-CP model provides a physically grounded framework for modeling in FCC alloys under complex cyclic loading, supporting improved life predictions for components in service.
{"title":"Crystal plasticity modeling of ratchetting in FCC alloys","authors":"Kunqing Ding , Theodore Zirkle , Xing Liu , Gustavo M. Castelluccio , Bryan D. Miller , Jonathan L. Wormald , Benjamin S. Anglin , Thomas W. Webb , David L. McDowell , Ting Zhu","doi":"10.1016/j.ijplas.2026.104611","DOIUrl":"10.1016/j.ijplas.2026.104611","url":null,"abstract":"<div><div>Ratchetting is the progressive, unidirectional accumulation of plastic strain during asymmetric stress cycling with nonzero mean stress. Modeling ratchetting is challenging, especially under complex cyclic loading conditions. Most existing constitutive models rely on phenomenological back stress formulations to characterize ratchetting responses, but they are only loosely connected to underlying physical mechanisms. This work develops a microstructure-sensitive crystal plasticity (MS-CP) model for ratchetting in face-centered cubic (FCC) alloys, applied to Alloy 600 (A600) and 304L stainless steel (SS). The model incorporates back stress evolution for slip systems, driven by both deformation-induced dislocation substructures and precipitate–dislocation interactions. The simulated monotonic and ratchetting responses at room and elevated temperatures are validated against experimental stress–strain data. Results highlight the strengthening effects of dislocation substructures in both alloys and of precipitates in A600, as well as the role of substructure evolution in ratchetting responses. This MS-CP model provides a physically grounded framework for modeling in FCC alloys under complex cyclic loading, supporting improved life predictions for components in service.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"198 ","pages":"Article 104611"},"PeriodicalIF":12.8,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145962418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-01-14DOI: 10.1016/j.ijplas.2026.104612
Zhida Liang , Fengxian Liu , Xin Liu , Yang Li , Yinan Cui , Florian Pyczak
In general, the cross-slip of superpartial dislocations ( from planes to planes has been frequently observed in superalloys, which are accompanied by the formation of an antiphase boundary (APB) and driven by thermal activation. However, no prior studies have evidenced the occurrence of Shockley partial dislocation ( cross-slip within the γ′ phase of superalloys. In this work, we present a newly observed cross-slip phenomenon: the Shockley partial dislocations cross-slip from one plane to another conjugate plane, facilitated by the formation of a stair-rod dislocation in the ordered γ′ phase of CoNi-based superalloy. Compression tests were conducted at 1123 K with a strain rate of 10–4 s-1. Defects such as stacking faults and dislocations, along with the associated chemical fluctuations, were characterized using high-resolution scanning transmission electron microscopy (HRSTEM) and energy-dispersive X-ray spectroscopy (EDS). Elemental segregation was found to reduce the activation energy required for cross-slip by decreasing the energies of stacking faults and dislocations. In addition to elemental segregation, local stress concentrations, arising from the combined effects of applied stress, shearing dislocations within the γ' phase, and dislocation pile-ups, also play a critical role in triggering cross-slip. The formation of sessile stair-rod dislocations via this newly identified Shockley partial cross-slip in the γ' phase is beneficial for enhancing the high-temperature deformation resistance of the alloy by increasing the critical resolved shear stress required for further plastic deformation.
{"title":"Segregation-driven cross-slip mechanism of Shockley partials in the γ' phase of CoNi-based superalloys","authors":"Zhida Liang , Fengxian Liu , Xin Liu , Yang Li , Yinan Cui , Florian Pyczak","doi":"10.1016/j.ijplas.2026.104612","DOIUrl":"10.1016/j.ijplas.2026.104612","url":null,"abstract":"<div><div>In general, the cross-slip of superpartial dislocations (<span><math><mrow><mi>a</mi><mo>/</mo><mn>2</mn><mo>〈</mo><mn>011</mn><mo>〉</mo><mo>)</mo></mrow></math></span> from <span><math><mrow><mo>{</mo><mn>111</mn><mo>}</mo><mspace></mspace></mrow></math></span>planes to <span><math><mrow><mo>{</mo><mn>001</mn><mo>}</mo></mrow></math></span> planes has been frequently observed in superalloys, which are accompanied by the formation of an antiphase boundary (APB) and driven by thermal activation. However, no prior studies have evidenced the occurrence of Shockley partial dislocation (<span><math><mrow><mi>a</mi><mo>/</mo><mn>6</mn><mo>〈</mo><mn>112</mn><mo>〉</mo><mo>)</mo></mrow></math></span> cross-slip within the γ′ phase of superalloys. In this work, we present a newly observed cross-slip phenomenon: the Shockley partial dislocations cross-slip from one <span><math><mrow><mo>{</mo><mn>111</mn><mo>}</mo></mrow></math></span> plane to another <span><math><mrow><mo>{</mo><mn>111</mn><mo>}</mo></mrow></math></span> conjugate plane, facilitated by the formation of a stair-rod dislocation in the ordered γ′ phase of CoNi-based superalloy. Compression tests were conducted at 1123 K with a strain rate of 10<sup>–4</sup> s<sup>-1</sup>. Defects such as stacking faults and dislocations, along with the associated chemical fluctuations, were characterized using high-resolution scanning transmission electron microscopy (HRSTEM) and energy-dispersive X-ray spectroscopy (EDS). Elemental segregation was found to reduce the activation energy required for cross-slip by decreasing the energies of stacking faults and dislocations. In addition to elemental segregation, local stress concentrations, arising from the combined effects of applied stress, shearing dislocations within the γ' phase, and dislocation pile-ups, also play a critical role in triggering cross-slip. The formation of sessile stair-rod dislocations via this newly identified Shockley partial cross-slip in the γ' phase is beneficial for enhancing the high-temperature deformation resistance of the alloy by increasing the critical resolved shear stress required for further plastic deformation.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"198 ","pages":"Article 104612"},"PeriodicalIF":12.8,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145993425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-01-11DOI: 10.1016/j.ijplas.2026.104609
Kota Sagara , Mitsuhiro Ito , Takayuki Kitamura , Kazuki Shibanuma
Accurate evaluation of material creep behaviour is essential for the reliable operation of industrial equipment. In this study, we propose a physics-based model capable of quantitatively predicting the deformation of three-dimensional polycrystalline solids due to Coble creep. The proposed model avoids non-physical assumptions commonly adopted in conventional numerical analyses and reproduces stress-induced grain boundary diffusion—the fundamental mechanism underlying Coble creep—in a physically consistent manner. This is achieved by explicitly representing the three-dimensional grain boundary network and accounting for the interaction between stress and atomic diffusion along grain boundaries. To validate the proposed model, its numerical simulation results were compared with the theoretical equation for Coble creep deformation under uniaxial loading and with the established knowledge under multiaxial loading. The model accurately reproduces the dependence of the macroscopic creep strain rate on grain size, applied stress, and temperature, consistent with the theoretical equation. Furthermore, systematic numerical simulations were conducted to investigate the effects of polycrystalline morphology, such as grain size distribution and aspect ratio, on Coble creep deformation. The results demonstrate that variations in grain size distribution and grain aspect ratio in polycrystalline morphology can lead to measurable changes in the macroscopic creep response, even under identical loading and temperature conditions. The proposed model provides a physically grounded tool for predicting Coble creep deformation of materials under arbitrary loading conditions and polycrystalline morphologies. Moreover, it elucidates the role of microstructural factors in determining material performance, thereby advancing the understanding of GB diffusion-controlled deformation mechanisms at low stresses and over extended timescales.
{"title":"A physics-based microscale model for predicting Coble creep deformation: Incorporating stress–diffusion interactions and effects of polycrystalline morphology","authors":"Kota Sagara , Mitsuhiro Ito , Takayuki Kitamura , Kazuki Shibanuma","doi":"10.1016/j.ijplas.2026.104609","DOIUrl":"10.1016/j.ijplas.2026.104609","url":null,"abstract":"<div><div>Accurate evaluation of material creep behaviour is essential for the reliable operation of industrial equipment. In this study, we propose a physics-based model capable of quantitatively predicting the deformation of three-dimensional polycrystalline solids due to Coble creep. The proposed model avoids non-physical assumptions commonly adopted in conventional numerical analyses and reproduces stress-induced grain boundary diffusion—the fundamental mechanism underlying Coble creep—in a physically consistent manner. This is achieved by explicitly representing the three-dimensional grain boundary network and accounting for the interaction between stress and atomic diffusion along grain boundaries. To validate the proposed model, its numerical simulation results were compared with the theoretical equation for Coble creep deformation under uniaxial loading and with the established knowledge under multiaxial loading. The model accurately reproduces the dependence of the macroscopic creep strain rate on grain size, applied stress, and temperature, consistent with the theoretical equation. Furthermore, systematic numerical simulations were conducted to investigate the effects of polycrystalline morphology, such as grain size distribution and aspect ratio, on Coble creep deformation. The results demonstrate that variations in grain size distribution and grain aspect ratio in polycrystalline morphology can lead to measurable changes in the macroscopic creep response, even under identical loading and temperature conditions. The proposed model provides a physically grounded tool for predicting Coble creep deformation of materials under arbitrary loading conditions and polycrystalline morphologies. Moreover, it elucidates the role of microstructural factors in determining material performance, thereby advancing the understanding of GB diffusion-controlled deformation mechanisms at low stresses and over extended timescales.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"197 ","pages":"Article 104609"},"PeriodicalIF":12.8,"publicationDate":"2026-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145956519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-01-07DOI: 10.1016/j.ijplas.2026.104607
Yanan Hu , Mingxue Feng , Chao Yu , Qianhua Kan , Xu Zhang , Shengchuan Wu , Leilei Wang , Feifan Wang , Yanling Xue , Guozheng Kang
This study systematically investigates the deformation behavior and internal damage evolution of wire + arc additively manufactured 2219 aluminum alloy across a temperature range of 133 K to 523 K using in-situ X-ray microtomography. Particular attention is devoted to clarifying the effects of both low and high temperatures on void nucleation, growth, and coalescence within the alloy. The results demonstrate that most voids nucleate through the fracture of eutectic θ (Al2Cu) phases. At elevated temperatures, reduced resistance to void nucleation and growth promotes extensive damage accumulation. In contrast, at cryogenic temperatures, increased resistance to nucleation leads to a lower void density; however, once voids nucleate and locally link, they rapidly coalesce into micro-cracks. Consequently, high-temperature failure is primarily governed by void growth, whereas cryogenic failure is dominated by void nucleation. Based on the identified critical microstructural attributes governing mechanical performance, a micromechanical constitutive model is constructed to describe the deformation behavior of the alloy. In the proposed model, the alloy is regarded as a heterogeneous composite consisting of an Al matrix, manufacturing defects, and eutectic θ phases. The temperature-dependent stress-strain responses are predicted using the Mori-Tanaka homogenization method, with the influence of temperature on damage evolution explicitly incorporated. The model successfully reproduces the stress-strain curves across the investigated temperature range and reflects the effect of damage evolution on the deformation behavior. Furthermore, Shapley additive explanations analysis identifies the temperature as the most influential factor affecting mechanical performance, surpassing the effects of both porosity and phase volume fraction.
{"title":"Unveiling deformation and damage evolution of WAAMed high-strength Al alloys across cryogenic to elevated temperatures","authors":"Yanan Hu , Mingxue Feng , Chao Yu , Qianhua Kan , Xu Zhang , Shengchuan Wu , Leilei Wang , Feifan Wang , Yanling Xue , Guozheng Kang","doi":"10.1016/j.ijplas.2026.104607","DOIUrl":"10.1016/j.ijplas.2026.104607","url":null,"abstract":"<div><div>This study systematically investigates the deformation behavior and internal damage evolution of wire + arc additively manufactured 2219 aluminum alloy across a temperature range of 133 K to 523 K using in-situ X-ray microtomography. Particular attention is devoted to clarifying the effects of both low and high temperatures on void nucleation, growth, and coalescence within the alloy. The results demonstrate that most voids nucleate through the fracture of eutectic θ (Al<sub>2</sub>Cu) phases. At elevated temperatures, reduced resistance to void nucleation and growth promotes extensive damage accumulation. In contrast, at cryogenic temperatures, increased resistance to nucleation leads to a lower void density; however, once voids nucleate and locally link, they rapidly coalesce into micro-cracks. Consequently, high-temperature failure is primarily governed by void growth, whereas cryogenic failure is dominated by void nucleation. Based on the identified critical microstructural attributes governing mechanical performance, a micromechanical constitutive model is constructed to describe the deformation behavior of the alloy. In the proposed model, the alloy is regarded as a heterogeneous composite consisting of an Al matrix, manufacturing defects, and eutectic θ phases. The temperature-dependent stress-strain responses are predicted using the Mori-Tanaka homogenization method, with the influence of temperature on damage evolution explicitly incorporated. The model successfully reproduces the stress-strain curves across the investigated temperature range and reflects the effect of damage evolution on the deformation behavior. Furthermore, Shapley additive explanations analysis identifies the temperature as the most influential factor affecting mechanical performance, surpassing the effects of both porosity and phase volume fraction.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"197 ","pages":"Article 104607"},"PeriodicalIF":12.8,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145920593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-01-06DOI: 10.1016/j.ijplas.2026.104608
Shuaishuai Liu , Liuyong He , Tianjiao Li , Liping Zhong , Mingshuai Huo , Yongjian Wang , Wenzhen Xia , Wenhuan Chen , Wenbin Zhang , Qiyang He , Manoj Gupta , Guangsheng Huang , Bin Jiang , Fusheng Pan
Heterostructured materials provide a promising path to address the strength-ductility trade-off in Mg alloys. However, designs relying solely on grain size heterogeneity often yield limited improvements. Herein, we fabricated multiscale heterostructures in an AZ91 alloy, featuring twin-modified coarse grains and precipitate-hardened fine grains, through a combination of pre-aging, extrusion, and pre-compression treatments. The obtained material exhibits an exceptional strength-ductility combination, outperforming most existing AZ91 alloys. Mechanistic investigations reveal that this favorable combination is primarily driven by enhanced hetero-deformation induced (HDI) strengthening and hardening, which result from the accumulation of geometrically necessary dislocations (GNDs) at multiscale interfaces. Additional contributions arise from twin-matrix interactions that activate non-basal slip systems, as well as a composite strengthening effects induced by precipitates, dislocation cells, and stacking faults. The multiscale heterostructures promote uniform deformation through slip transfer, stress redistribution, and strain delocalization. Strain hardening is initially dominated by HDI effects, while traditional dislocation-mediated mechanisms become predominant at larger strain. The present approach, integrating precipitate engineering, grain size control, and crystallographic design, provides general guidelines for developing advanced lightweight materials.
{"title":"Strong, ductile, and hierarchical multiscale heterostructured magnesium alloy via coarse-grained twins coupled with fine-grained precipitates","authors":"Shuaishuai Liu , Liuyong He , Tianjiao Li , Liping Zhong , Mingshuai Huo , Yongjian Wang , Wenzhen Xia , Wenhuan Chen , Wenbin Zhang , Qiyang He , Manoj Gupta , Guangsheng Huang , Bin Jiang , Fusheng Pan","doi":"10.1016/j.ijplas.2026.104608","DOIUrl":"10.1016/j.ijplas.2026.104608","url":null,"abstract":"<div><div>Heterostructured materials provide a promising path to address the strength-ductility trade-off in Mg alloys. However, designs relying solely on grain size heterogeneity often yield limited improvements. Herein, we fabricated multiscale heterostructures in an AZ91 alloy, featuring twin-modified coarse grains and precipitate-hardened fine grains, through a combination of pre-aging, extrusion, and pre-compression treatments. The obtained material exhibits an exceptional strength-ductility combination, outperforming most existing AZ91 alloys. Mechanistic investigations reveal that this favorable combination is primarily driven by enhanced hetero-deformation induced (HDI) strengthening and hardening, which result from the accumulation of geometrically necessary dislocations (GNDs) at multiscale interfaces. Additional contributions arise from twin-matrix interactions that activate non-basal slip systems, as well as a composite strengthening effects induced by precipitates, dislocation cells, and stacking faults. The multiscale heterostructures promote uniform deformation through slip transfer, stress redistribution, and strain delocalization. Strain hardening is initially dominated by HDI effects, while traditional dislocation-mediated mechanisms become predominant at larger strain. The present approach, integrating precipitate engineering, grain size control, and crystallographic design, provides general guidelines for developing advanced lightweight materials.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"197 ","pages":"Article 104608"},"PeriodicalIF":12.8,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145903361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-01-02DOI: 10.1016/j.ijplas.2025.104605
Tolga Berkay Celebi , Orcun Koray Celebi , Daegun You , Ahmed Sameer Khan Mohammed , Ashley Bucsek , Huseyin Sehitoglu
This study investigates the mechanics of prismatic and first-order pyramidal slip in titanium (Ti), elucidating the physics of easy-glide and cross-slip through a combination of theory and experiments. Screw-character prismatic (Pr) dislocations in Ti are of particular interest because their complex cores can be stable or unstable, leading to activation by either cross-slip or planar glide. To investigate these mechanisms, site-specific micro tensile samples were prepared using focused ion beam (FIB) milling and mounted on a push-to-pull (PTP) device for in-situ transmission electron microscopy (TEM) tensile testing. The in-situ experiments provide direct observations of the onset of dislocation motion and the precise determination of the critical resolved shear stress (CRSS) for the activated mechanisms, and its evolution with load cycling. A comprehensive theory has been developed to predict the CRSS values for easy glide, cross-slip, and multiplication of dislocations. Predicted critical stresses for pyramidal (π)-to-Pr and reverse cross-slip agree closely with the experimental measurements. The latter cross-slip stress is a factor of two higher than that of unobstructed planar slip. The model accounts for overlapping dislocation cores and employs a Wigner-Seitz based cell to evaluate misfit energies. By combining ab initio density functional theory (DFT) with anisotropic elasticity, the framework identifies minimum energy pathways for dislocation glide, which can be intermittent and zig-zag. A simplified expression utilizing (π) and Pr Schmid factor ratios is proposed for critical stress corresponding to (π)-to-Pr cross-slip transition. The results are strongly dependent on crystal orientation, underscoring non-Schmid behavior. Overall, this study explores key critical stress parameters essential for informing higher-scale simulations of plasticity in Ti.
{"title":"Cross-slip and easy-glide CRSS in titanium: Theoretical predictions and in-situ TEM measurements","authors":"Tolga Berkay Celebi , Orcun Koray Celebi , Daegun You , Ahmed Sameer Khan Mohammed , Ashley Bucsek , Huseyin Sehitoglu","doi":"10.1016/j.ijplas.2025.104605","DOIUrl":"10.1016/j.ijplas.2025.104605","url":null,"abstract":"<div><div>This study investigates the mechanics of prismatic and first-order pyramidal <span><math><mrow><mo>〈</mo><mi>a</mi><mo>〉</mo></mrow></math></span> slip in titanium (Ti), elucidating the physics of easy-glide and cross-slip through a combination of theory and experiments. Screw-character prismatic (Pr) dislocations in Ti are of particular interest because their complex cores can be stable or unstable, leading to activation by either cross-slip or planar glide. To investigate these mechanisms, site-specific micro tensile samples were prepared using focused ion beam (FIB) milling and mounted on a push-to-pull (PTP) device for in-situ transmission electron microscopy (TEM) tensile testing. The in-situ experiments provide direct observations of the onset of dislocation motion and the precise determination of the critical resolved shear stress (CRSS) for the activated mechanisms, and its evolution with load cycling. A comprehensive theory has been developed to predict the CRSS values for easy glide, cross-slip, and multiplication of dislocations. Predicted critical stresses for pyramidal (π)-to-Pr and reverse cross-slip agree closely with the experimental measurements. The latter cross-slip stress is a factor of two higher than that of unobstructed planar slip. The model accounts for overlapping dislocation cores and employs a Wigner-Seitz based cell to evaluate misfit energies. By combining ab initio density functional theory (DFT) with anisotropic elasticity, the framework identifies minimum energy pathways for dislocation glide, which can be intermittent and zig-zag. A simplified expression utilizing (π) and Pr Schmid factor ratios is proposed for critical stress corresponding to (π)-to-Pr cross-slip transition. The results are strongly dependent on crystal orientation, underscoring non-Schmid behavior. Overall, this study explores key critical stress parameters essential for informing higher-scale simulations of plasticity in Ti.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"197 ","pages":"Article 104605"},"PeriodicalIF":12.8,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145894272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-01-01DOI: 10.1016/j.ijplas.2025.104606
Minwoo Park , Deunbom Chung , Wanchuck Woo , Seungcheol Oh , Kyeongjae Jeong , Heung Nam Han
This study proposes an integrated finite element (FE) simulation and convolutional neural network (CNN) model designed for the simultaneous prediction of plastic properties and surface in-plane non-equibiaxial residual stress from spherical indentation responses. By eliminating the need for stress-free reference specimens, the proposed framework enables non-destructive prediction. The framework leverages indentation load-depth curves and directional deformation profiles derived from validated FE simulations. Sensitivity analyses identify the indenter radius and penetration ratio as critical factors for improving prediction accuracy and maximizing the sensitivity of indentation responses to variations in residual stress. The influence of non-equibiaxial residual stress states on indentation behavior is further elucidated through a mechanistic investigation, which reveals a close association with cumulative volumetric changes in equivalent plastic strain near the indentation zone. The CNN training performance supports the sensitivity-based determination of optimal indentation settings. The model is shown to achieve a mean absolute error corresponding to below 5 % on average for residual stresses, while the plasticity parameters are also well captured. Experimental assessment on copper specimens with homogeneous residual stress fields verifies the accuracy and adaptability of the developed FE–CNN model. Further validation using additively manufactured stainless steel, exhibiting complex heterogeneous residual stresses, shows strong consistency with neutron diffraction measurements. This FE–CNN framework presents a robust and scalable approach for comprehensive mechanical characterization, offering substantial benefits for assessing structural integrity and reliability across diverse industrial applications without recourse to destructive testing.
{"title":"Indentation-informed convolutional neural network for simultaneous prediction of non-equibiaxial residual stress and plastic flow","authors":"Minwoo Park , Deunbom Chung , Wanchuck Woo , Seungcheol Oh , Kyeongjae Jeong , Heung Nam Han","doi":"10.1016/j.ijplas.2025.104606","DOIUrl":"10.1016/j.ijplas.2025.104606","url":null,"abstract":"<div><div>This study proposes an integrated finite element (FE) simulation and convolutional neural network (CNN) model designed for the simultaneous prediction of plastic properties and surface in-plane non-equibiaxial residual stress from spherical indentation responses. By eliminating the need for stress-free reference specimens, the proposed framework enables non-destructive prediction. The framework leverages indentation load-depth curves and directional deformation profiles derived from validated FE simulations. Sensitivity analyses identify the indenter radius and penetration ratio as critical factors for improving prediction accuracy and maximizing the sensitivity of indentation responses to variations in residual stress. The influence of non-equibiaxial residual stress states on indentation behavior is further elucidated through a mechanistic investigation, which reveals a close association with cumulative volumetric changes in equivalent plastic strain near the indentation zone. The CNN training performance supports the sensitivity-based determination of optimal indentation settings. The model is shown to achieve a mean absolute error corresponding to below 5 % on average for residual stresses, while the plasticity parameters are also well captured. Experimental assessment on copper specimens with homogeneous residual stress fields verifies the accuracy and adaptability of the developed FE–CNN model. Further validation using additively manufactured stainless steel, exhibiting complex heterogeneous residual stresses, shows strong consistency with neutron diffraction measurements. This FE–CNN framework presents a robust and scalable approach for comprehensive mechanical characterization, offering substantial benefits for assessing structural integrity and reliability across diverse industrial applications without recourse to destructive testing.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"197 ","pages":"Article 104606"},"PeriodicalIF":12.8,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145894280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tailoring composition modulation can be a powerful tool to increase strength and ductility of two- and multicomponent alloys. Here we suggest a model that describes the tensile behavior of alloys with three-dimensional composition undulation. Within the model, the stacking fault energy variation, misfit stresses and dislocation pinning by the inhomogeneous solid solution are considered simultaneously. The model reveals that the composition undulation wavelength that provides peak ultimate strength is determined by a balance of three strengthening mechanisms: 1) dislocation pinning by obstacles, which is enhanced at a small undulation wavelength, 2) resistance to dislocation motion due to stacking fault energy variation, which is highest at a moderate undulation wavelength, and 3) dislocation interaction with misfit stresses, which is most pronounced at a high undulation wavelength. In considering the two latter mechanisms we uncovered a sharp transition from the moderate to the high optimum undulation wavelength at a critical value of the ratio of the misfit to the stacking fault energy variation. The two latter mechanisms increase strength at the expense of reduced ductility and do not affect the product of the ultimate strength and the uniform elongation. In contrast, dislocation pinning by obstacles can increase both strength and ductility due to enhanced strain hardening.
{"title":"Modeling strength and ductility of alloys with intragrain compositional inhomogeneities","authors":"A.M. Smirnov , A.G. Sheinerman , X.T. Li , Z.J. Zhang","doi":"10.1016/j.ijplas.2025.104602","DOIUrl":"10.1016/j.ijplas.2025.104602","url":null,"abstract":"<div><div>Tailoring composition modulation can be a powerful tool to increase strength and ductility of two- and multicomponent alloys. Here we suggest a model that describes the tensile behavior of alloys with three-dimensional composition undulation. Within the model, the stacking fault energy variation, misfit stresses and dislocation pinning by the inhomogeneous solid solution are considered simultaneously. The model reveals that the composition undulation wavelength that provides peak ultimate strength is determined by a balance of three strengthening mechanisms: 1) dislocation pinning by obstacles, which is enhanced at a small undulation wavelength, 2) resistance to dislocation motion due to stacking fault energy variation, which is highest at a moderate undulation wavelength, and 3) dislocation interaction with misfit stresses, which is most pronounced at a high undulation wavelength. In considering the two latter mechanisms we uncovered a sharp transition from the moderate to the high optimum undulation wavelength at a critical value of the ratio of the misfit to the stacking fault energy variation. The two latter mechanisms increase strength at the expense of reduced ductility and do not affect the product of the ultimate strength and the uniform elongation. In contrast, dislocation pinning by obstacles can increase both strength and ductility due to enhanced strain hardening.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"197 ","pages":"Article 104602"},"PeriodicalIF":12.8,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-12-29DOI: 10.1016/j.ijplas.2025.104593
Jin Wang , Nicolas J. Peter , Martin Heilmaier , Ruth Schwaiger
Refractory compositionally complex alloys (RCCAs) are known for their exceptional high-temperature resistance. However, their inherent brittleness at room temperature limits broader practical applications. To explore the effects of microstructure and loading conditions on their deformation behavior, micromechanical experiments, including microbending and micropillar compression tests, were performed on two representative RCCAs: equimolar NbMoCrTiAl (ordered B2 crystal structure) and TaNbHfZrTi (disordered A2 crystal structure). Both alloys demonstrated significant plastic deformation, with strains exceeding 40% at room temperature. Despite prior reports of limited ductility in NbMoCrTiAl at the millimeter scale, our micropillar compression tests on single-crystalline pillars oriented along and reveal substantial plasticity. The dominant deformation mechanisms in NbMoCrTiAl were identified as crystallographic slip and cross-slip of screw dislocations. By contrast, TaNbHfZrTi exhibited a broader range of mechanisms, including screw dislocation slip and a high density of non-screw dislocations, accompanied by kink band formation and activation of high-order slip planes, which collectively contribute to its remarkable ductility among the highest reported for body-centered cubic RCCAs. The atomic size mismatch inherent in compositionally complex alloys enhances dislocation mobility, while the random distribution of elements promotes the formation of edge segments, further improving ductility. These findings highlight the critical role of microstructural characteristics in tailoring the deformation behavior of RCCAs for room-temperature applications.
{"title":"A micromechanical investigation of plasticity in ordered NbMoCrTiAl and disordered TaNbHfZrTi refractory compositionally complex alloys at room temperature","authors":"Jin Wang , Nicolas J. Peter , Martin Heilmaier , Ruth Schwaiger","doi":"10.1016/j.ijplas.2025.104593","DOIUrl":"10.1016/j.ijplas.2025.104593","url":null,"abstract":"<div><div>Refractory compositionally complex alloys (RCCAs) are known for their exceptional high-temperature resistance. However, their inherent brittleness at room temperature limits broader practical applications. To explore the effects of microstructure and loading conditions on their deformation behavior, micromechanical experiments, including microbending and micropillar compression tests, were performed on two representative RCCAs: equimolar NbMoCrTiAl (ordered B2 crystal structure) and TaNbHfZrTi (disordered A2 crystal structure). Both alloys demonstrated significant plastic deformation, with strains exceeding 40% at room temperature. Despite prior reports of limited ductility in NbMoCrTiAl at the millimeter scale, our micropillar compression tests on single-crystalline pillars oriented along <span><math><mrow><mo>〈</mo><mn>1</mn><mspace></mspace><mn>0</mn><mspace></mspace><mn>0</mn><mo>〉</mo></mrow></math></span> and <span><math><mrow><mo>〈</mo><mn>1</mn><mspace></mspace><mn>1</mn><mspace></mspace><mn>0</mn><mo>〉</mo></mrow></math></span> reveal substantial plasticity. The dominant deformation mechanisms in NbMoCrTiAl were identified as crystallographic slip and cross-slip of screw dislocations. By contrast, TaNbHfZrTi exhibited a broader range of mechanisms, including screw dislocation slip and a high density of non-screw dislocations, accompanied by kink band formation and activation of high-order slip planes, which collectively contribute to its remarkable ductility among the highest reported for body-centered cubic RCCAs. The atomic size mismatch inherent in compositionally complex alloys enhances dislocation mobility, while the random distribution of elements promotes the formation of edge segments, further improving ductility. These findings highlight the critical role of microstructural characteristics in tailoring the deformation behavior of RCCAs for room-temperature applications.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"197 ","pages":"Article 104593"},"PeriodicalIF":12.8,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145881652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-12-28DOI: 10.1016/j.ijplas.2025.104603
Yufei Chen , Tiwen Lu , Xiyu Chen , Xiaoqi Hu , Ning Yao , Xiaofeng Yang , Haitao Lu , Kaishang Li , Binhan Sun , Yunjie Bi , Xian-Cheng Zhang , Shan-Tung Tu
Additive manufacturing (AM) provides a novel avenue for the fabrication of metal matrix nanocomposites with a uniform distribution of reinforcements and excellent static mechanical properties, while few studies have been conducted on their fatigue behavior. In this study, TiCnp/(CoCrNi)94Al3Ti3 nanocomposites were fabricated using powder bed fusion (PBF), with another representative AM processes-directed energy deposition (DED) as a reference for comparison. In the case of similar low-density defects, though PBF-sample had finer microstructure and higher tensile strength than DED-sample, its fatigue endurance limit (350 MPa) was markedly lower than that of the DED sample (550 MPa). Further investigation revealed that the fatigue initiation sources for DED-samples were pores, while fatigue failure of PBF-samples were mainly initiated from manufactured microcracks. Though the average volume of pores in DED (1.9 × 105 μm3) was significantly larger than microcracks in PBF (1.6 × 104 μm3), the latter posed a more serious threat to fatigue performance. Microcracks were associated with Ti segregation at grain boundaries (GBs) and strong solidification shrinkage, both induced by higher solidification rate of PBF. Finally, two methods were applied to reduce the risk of GB cracking in nanocomposites by adjusting the alloy composition. As a result, segregation at GBs in PBF-fabricated nanocomposites was mitigated, reducing the microcrack density and significantly improving the fatigue resistance. The work reveals the origin of microcrack susceptivity in PBF and offers a microstructural strategy for designing high-strength and fatigue-resistant nanocomposites.
{"title":"Revealing and mitigating the microcrack-sensitive fatigue behavior of laser powder bed fusion fabricated medium-entropy nanocomposites","authors":"Yufei Chen , Tiwen Lu , Xiyu Chen , Xiaoqi Hu , Ning Yao , Xiaofeng Yang , Haitao Lu , Kaishang Li , Binhan Sun , Yunjie Bi , Xian-Cheng Zhang , Shan-Tung Tu","doi":"10.1016/j.ijplas.2025.104603","DOIUrl":"10.1016/j.ijplas.2025.104603","url":null,"abstract":"<div><div>Additive manufacturing (AM) provides a novel avenue for the fabrication of metal matrix nanocomposites with a uniform distribution of reinforcements and excellent static mechanical properties, while few studies have been conducted on their fatigue behavior. In this study, TiC<sub>np</sub>/(CoCrNi)<sub>94</sub>Al<sub>3</sub>Ti<sub>3</sub> nanocomposites were fabricated using powder bed fusion (PBF), with another representative AM processes-directed energy deposition (DED) as a reference for comparison. In the case of similar low-density defects, though PBF-sample had finer microstructure and higher tensile strength than DED-sample, its fatigue endurance limit (350 MPa) was markedly lower than that of the DED sample (550 MPa). Further investigation revealed that the fatigue initiation sources for DED-samples were pores, while fatigue failure of PBF-samples were mainly initiated from manufactured microcracks. Though the average volume of pores in DED (1.9 × 10<sup>5</sup> μm<sup>3</sup>) was significantly larger than microcracks in PBF (1.6 × 10<sup>4</sup> μm<sup>3</sup>), the latter posed a more serious threat to fatigue performance. Microcracks were associated with Ti segregation at grain boundaries (GBs) and strong solidification shrinkage, both induced by higher solidification rate of PBF. Finally, two methods were applied to reduce the risk of GB cracking in nanocomposites by adjusting the alloy composition. As a result, segregation at GBs in PBF-fabricated nanocomposites was mitigated, reducing the microcrack density and significantly improving the fatigue resistance. The work reveals the origin of microcrack susceptivity in PBF and offers a microstructural strategy for designing high-strength and fatigue-resistant nanocomposites.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"197 ","pages":"Article 104603"},"PeriodicalIF":12.8,"publicationDate":"2025-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145844880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号