Pub Date : 2025-12-03DOI: 10.1016/j.ijplas.2025.104573
Liang Xue , Jian-Ying Wu
This study proposes a generalized variational framework for mixed-mode crack regularization. It addresses two critical challenges of existing phase-field models, i.e., mis-predictions of mode-dependent fracture energy and of the crack propagation direction. For the former, a cohesive phase-field model with one single field variable and two distinct fracture energies is established for mixed-mode failure. Regarding the a priori unknown crack direction indispensable for the orthogonal energy decomposition, the criterion of minimum potential energy is derived within the generalized variational framework. Rational and robust crack paths can be predicted across a large range of material parameters and loading scenarios. Abrupt jumps in the crack direction and the resulting numerical instabilities exhibited by the criterion of maximum crack driving force are eliminated. Finally, the proposed variational framework is verified by a series of benchmark numerical examples involving complex crack propagation.
{"title":"A generalized variational framework for crack regularization: Mixed-mode fracture and crack propagation direction","authors":"Liang Xue , Jian-Ying Wu","doi":"10.1016/j.ijplas.2025.104573","DOIUrl":"10.1016/j.ijplas.2025.104573","url":null,"abstract":"<div><div>This study proposes a generalized variational framework for mixed-mode crack regularization. It addresses two critical challenges of existing phase-field models, i.e., mis-predictions of mode-dependent fracture energy and of the crack propagation direction. For the former, a cohesive phase-field model with <em>one single field variable</em> and <em>two distinct fracture energies</em> is established for mixed-mode failure. Regarding the <em>a priori</em> unknown crack direction indispensable for the orthogonal energy decomposition, the criterion of minimum potential energy is derived within the generalized variational framework. Rational and robust crack paths can be predicted across a large range of material parameters and loading scenarios. Abrupt jumps in the crack direction and the resulting numerical instabilities exhibited by the criterion of maximum crack driving force are eliminated. Finally, the proposed variational framework is verified by a series of benchmark numerical examples involving complex crack propagation.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"196 ","pages":"Article 104573"},"PeriodicalIF":12.8,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145657431","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}
A combination of experiments and molecular dynamics (MD) simulations was used to explore deformation twinning in hexagonal titanium. These were tensile twins, and their relative area fractions were governed by crystallography. High-resolution microtexture measurements distinguished them as S-type and N-type. S-type involved ‘visible’ slip transfer. In particular, a near-boundary misorientation build-up in the twin-neighbor grain was observed. The N-type twins, in contrast, exhibited no such misorientation development. Collectively, N-type twins grew faster, but a few of them also had comparable growth rates as S-type twins. Mesoscopic differences in twin growth were supported microscopically. Only a few of the grain boundary microscopic deformation twins grew. Further, twin-matrix interfaces exhibited microscopic differences in morphologies and local residual strains. To expand the microstructural observations and to explore associated mechanism(s), focused MD-simulations were conducted. Deformation twins were simulated on bi-crystal models, incorporating differences in twin-neighbor slip transfer. S-type twins occurred at lower stresses and exhibited noticeable relative atomic displacements across twin-neighbor boundaries. This mimicked experimental misorientation build-up. Though nucleation and growth of all deformation twins introduced atomic shuffle, S-type twins were preceded by the formation of stacking faults and atomic shear. Further, the simulated growth of deformation twins was governed by stress-relaxation in the twin-embryo stage and by the accumulation of twin-matrix interfacial dislocations during subsequent twin growth. In summary, this study brought out a novel perspective on growth selection of deformation twinning in hexagonal titanium.
{"title":"Growth selection of deformation twins in hexagonal titanium","authors":"Bhargav R. Sudhalkar , Rakesh Kumar Barik , Anirban Patra , Komal Kapoor , Rajeev Kapoor , Ankit Agrawal , Indradev Samajdar","doi":"10.1016/j.ijplas.2025.104574","DOIUrl":"10.1016/j.ijplas.2025.104574","url":null,"abstract":"<div><div>A combination of experiments and molecular dynamics (MD) simulations was used to explore deformation twinning in hexagonal titanium. These were <span><math><mrow><mo>{</mo><mrow><mn>10</mn><mover><mn>1</mn><mo>¯</mo></mover><mn>2</mn></mrow><mo>}</mo></mrow></math></span> tensile twins, and their relative area fractions were governed by crystallography. High-resolution microtexture measurements distinguished them as S-type and N-type. S-type involved ‘visible’ slip transfer. In particular, a near-boundary misorientation build-up in the twin-neighbor grain was observed. The N-type twins, in contrast, exhibited no such misorientation development. Collectively, N-type twins grew faster, but a few of them also had comparable growth rates as S-type twins. Mesoscopic differences in twin growth were supported microscopically. Only a few of the grain boundary microscopic deformation twins grew. Further, twin-matrix interfaces exhibited microscopic differences in morphologies and local residual strains. To expand the microstructural observations and to explore associated mechanism(s), focused MD-simulations were conducted. Deformation twins were simulated on bi-crystal models, incorporating differences in twin-neighbor slip transfer. S-type twins occurred at lower stresses and exhibited noticeable relative atomic displacements across twin-neighbor boundaries. This mimicked experimental misorientation build-up. Though nucleation and growth of all deformation twins introduced atomic shuffle, S-type twins were preceded by the formation of stacking faults and atomic shear. Further, the simulated growth of deformation twins was governed by stress-relaxation in the twin-embryo stage and by the accumulation of twin-matrix interfacial dislocations during subsequent twin growth. In summary, this study brought out a novel perspective on <em>growth selection of deformation twinning in hexagonal titanium</em>.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"196 ","pages":"Article 104574"},"PeriodicalIF":12.8,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145657430","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}
This study establishes a general multiscale constitutive model by integrating micromechanics, thermodynamics, and fractional calculus theory for cold-region rocks under triaxial compression. Conventional triaxial compression tests are conducted on frozen and freeze-thawed rock samples to investigate the macroscopic mechanical properties under the influence of freezing temperature and freeze-thaw (F-T) cycles. Additionally, scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) analyses provide deeper insights into the intrinsic microscale physical mechanisms. Experimental observations reveal that, at the mesoscale, cold-region rocks can be conceptualized as a composite medium composed of a porous matrix interspersed with cracks. At the microscale, the porous matrix itself consists of mineral grains, pore ice, and unfrozen pore water. By quantitatively characterizing the relevant microstructural variables, a two-step homogenization procedure is employed to derive the effective elastic properties of rocks: the self-consistent scheme (SCS) at the microscale and the Mori–Tanaka (M-T) method at the mesoscale. After rigorously deducing the system’s free energy and corresponding state equations, we systematically establish specific criteria of the model: the loading damage evolution associated with crack initiation and propagation, state-dependent friction-cohesive-type yielding induced plastic distortion, and open cracks closure deformation caused nonlinear and Poisson effect. To accurately capture the characteristics of plastic deformation, the non-orthogonal plastic flow rule (NPFR) formulated via fractional differential calculus is adopted. For efficient numerical implementation, a robust stress integration algorithm is developed by combining the line search method (LSM) with conventional return mapping (RM) algorithm. The predictive performance of the proposed model is thoroughly validated through the frozen and F-T red sandstone and granite.
{"title":"Experimental study and micromechanics-based general constitutive theoretical framework for cold-region rocks under triaxial compression","authors":"Wenlin Wu , Yuanming Lai , Mingyi Zhang , Xiangtian Xu , Wansheng Pei , Ruiqiang Bai , Jing Zhang , Yanyan Chen","doi":"10.1016/j.ijplas.2025.104499","DOIUrl":"10.1016/j.ijplas.2025.104499","url":null,"abstract":"<div><div>This study establishes a general multiscale constitutive model by integrating micromechanics, thermodynamics, and fractional calculus theory for cold-region rocks under triaxial compression. Conventional triaxial compression tests are conducted on frozen and freeze-thawed rock samples to investigate the macroscopic mechanical properties under the influence of freezing temperature and freeze-thaw (F-T) cycles. Additionally, scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) analyses provide deeper insights into the intrinsic microscale physical mechanisms. Experimental observations reveal that, at the mesoscale, cold-region rocks can be conceptualized as a composite medium composed of a porous matrix interspersed with cracks. At the microscale, the porous matrix itself consists of mineral grains, pore ice, and unfrozen pore water. By quantitatively characterizing the relevant microstructural variables, a two-step homogenization procedure is employed to derive the effective elastic properties of rocks: the self-consistent scheme (SCS) at the microscale and the Mori–Tanaka (M-T) method at the mesoscale. After rigorously deducing the system’s free energy and corresponding state equations, we systematically establish specific criteria of the model: the loading damage evolution associated with crack initiation and propagation, state-dependent friction-cohesive-type yielding induced plastic distortion, and open cracks closure deformation caused nonlinear and Poisson effect. To accurately capture the characteristics of plastic deformation, the non-orthogonal plastic flow rule (NPFR) formulated via fractional differential calculus is adopted. For efficient numerical implementation, a robust stress integration algorithm is developed by combining the line search method (LSM) with conventional return mapping (RM) algorithm. The predictive performance of the proposed model is thoroughly validated through the frozen and F-T red sandstone and granite.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"195 ","pages":"Article 104499"},"PeriodicalIF":12.8,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145255205","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 : 2025-12-01DOI: 10.1016/j.ijplas.2025.104498
Jiawei Sun, Yuchuan Huang, Yangyang Xu, Jiaxin Yu, Zhihong Ye, Youjie Guo, Fangzhou Qi, Gaoming Zhu, Jie Wang, Guohua Wu, Hezhou Liu, Wencai Liu
The inherently low Young’s modulus and limited strength of Mg-Li alloys have long restricted their structural application potential. In this study, we developed a modulus-oriented TiB2/LAZ532 composite via rotary swaging, integrating particle reinforcement, severe plastic deformation, and interface engineering. Rotary swaging refined the grain structure to the submicron scale and introduced a high density of dislocation substructures, thereby enabling substantial strength improvement. Meanwhile, Li(Al, Zn) precipitates were observed to form at TiB2/matrix interfaces, as confirmed by TEM, phase-field simulations, FEA, and in-situ synchrotron XRD. These interfacial precipitates acted as middle layer reducing stress concentration and enhancing strain transfer across particle/matrix boundaries, thus achieving improved deformation compatibility. Owing to the dual contribution of matrix grain refinement/dislocation hardening and interfacial strain accommodation, the composite achieved an ultimate tensile strength of 455 MPa, Young’s modulus of 61 GPa, and a low density of 1.75 g/cm3. This unique combination of ultra-light weight and mechanical robustness highlights a functionally partitioned strengthening strategy, wherein reinforcement, processing, and interface design contribute complementary roles. The approach provides a generalizable pathway for designing next-generation lightweight Mg-Li structural materials.
{"title":"Achieving superior strength in high modulus Mg-Li matrix composites via rotary swaging with interfacial precipitation-induced strain compatibility","authors":"Jiawei Sun, Yuchuan Huang, Yangyang Xu, Jiaxin Yu, Zhihong Ye, Youjie Guo, Fangzhou Qi, Gaoming Zhu, Jie Wang, Guohua Wu, Hezhou Liu, Wencai Liu","doi":"10.1016/j.ijplas.2025.104498","DOIUrl":"10.1016/j.ijplas.2025.104498","url":null,"abstract":"<div><div>The inherently low Young’s modulus and limited strength of Mg-Li alloys have long restricted their structural application potential. In this study, we developed a modulus-oriented TiB<sub>2</sub>/LAZ532 composite via rotary swaging, integrating particle reinforcement, severe plastic deformation, and interface engineering. Rotary swaging refined the grain structure to the submicron scale and introduced a high density of dislocation substructures, thereby enabling substantial strength improvement. Meanwhile, Li(Al, Zn) precipitates were observed to form at TiB<sub>2</sub>/matrix interfaces, as confirmed by TEM, phase-field simulations, FEA, and in-situ synchrotron XRD. These interfacial precipitates acted as middle layer reducing stress concentration and enhancing strain transfer across particle/matrix boundaries, thus achieving improved deformation compatibility. Owing to the dual contribution of matrix grain refinement/dislocation hardening and interfacial strain accommodation, the composite achieved an ultimate tensile strength of 455 MPa, Young’s modulus of 61 GPa, and a low density of 1.75 g/cm<sup>3</sup>. This unique combination of ultra-light weight and mechanical robustness highlights a functionally partitioned strengthening strategy, wherein reinforcement, processing, and interface design contribute complementary roles. The approach provides a generalizable pathway for designing next-generation lightweight Mg-Li structural materials.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"195 ","pages":"Article 104498"},"PeriodicalIF":12.8,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145255207","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 : 2025-12-01DOI: 10.1016/j.ijplas.2025.104501
Jae-Uk Lee , Hyun-Dong Lee , Sung-Hyun Oh , Young-Dae Shim , Sukkyung Kang , Sanha Kim , Hoo-Jeong Lee , Eun-Ho Lee
As computational costs increase with the increasing use of artificial intelligence, improving the performance and efficiency of semiconductor systems has become an unavoidable challenge. Bumpless bonding is considered an emerging technology for semiconductor stacking to increase input/output density. Some studies have aimed at precisely controlling the bonding temperature and pressure to achieve a reliable Cu–Cu bonding interface. Nevertheless, considerable variations in the interface have been observed, even under identical conditions, which are attributed to the influence of the Cu microstructure. Controlling the microstructure of Cu during bonding still faces many technical challenges, and insufficient research has been conducted. Although some experimental studies exist, they have not fully analyzed the complete mechanism of the microstructural effect, and studies on numerical analysis are lacking. This study developed a modeling framework and simulated the behavior occurring in Cu–Cu bonding by considering microstructural effects. To achieve this, the microstructural vector theory has been extended to consider the distortion of the atomic lattice caused by atomic flux and slip. The model was then implemented using the finite element method (FEM) through the ABAQUS user-defined material subroutine (UMAT). The numerical analysis results showed that the voids at the interface are more significantly affected by pressure than by temperature, and the combination of grains at the interface has a significant impact on interface formation. These simulation results were first used to mechanically analyze and discuss the experimental observations previously reported for Cu–Cu bonding. Furthermore, additional experiments and inverse pole figure (IPF) observations of the Cu–Cu bonding interface were conducted, and the results were found to be consistent with the trends predicted by the model. The research findings demonstrate that the microstructure has a significant impact on the bonding interface formation and confirm the potential for controlling the bonding interface through microstructural control.
{"title":"Modeling framework and discussion of microstructural effects on the formation of Cu–Cu bonding interfaces in semiconductor stacking","authors":"Jae-Uk Lee , Hyun-Dong Lee , Sung-Hyun Oh , Young-Dae Shim , Sukkyung Kang , Sanha Kim , Hoo-Jeong Lee , Eun-Ho Lee","doi":"10.1016/j.ijplas.2025.104501","DOIUrl":"10.1016/j.ijplas.2025.104501","url":null,"abstract":"<div><div>As computational costs increase with the increasing use of artificial intelligence, improving the performance and efficiency of semiconductor systems has become an unavoidable challenge. Bumpless bonding is considered an emerging technology for semiconductor stacking to increase input/output density. Some studies have aimed at precisely controlling the bonding temperature and pressure to achieve a reliable Cu–Cu bonding interface. Nevertheless, considerable variations in the interface have been observed, even under identical conditions, which are attributed to the influence of the Cu microstructure. Controlling the microstructure of Cu during bonding still faces many technical challenges, and insufficient research has been conducted. Although some experimental studies exist, they have not fully analyzed the complete mechanism of the microstructural effect, and studies on numerical analysis are lacking. This study developed a modeling framework and simulated the behavior occurring in Cu–Cu bonding by considering microstructural effects. To achieve this, the microstructural vector theory has been extended to consider the distortion of the atomic lattice caused by atomic flux and slip. The model was then implemented using the finite element method (FEM) through the ABAQUS user-defined material subroutine (UMAT). The numerical analysis results showed that the voids at the interface are more significantly affected by pressure than by temperature, and the combination of grains at the interface has a significant impact on interface formation. These simulation results were first used to mechanically analyze and discuss the experimental observations previously reported for Cu–Cu bonding. Furthermore, additional experiments and inverse pole figure (IPF) observations of the Cu–Cu bonding interface were conducted, and the results were found to be consistent with the trends predicted by the model. The research findings demonstrate that the microstructure has a significant impact on the bonding interface formation and confirm the potential for controlling the bonding interface through microstructural control.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"195 ","pages":"Article 104501"},"PeriodicalIF":12.8,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145255206","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 : 2025-12-01DOI: 10.1016/j.ijplas.2025.104464
Eralp Demir , Anna Kareer , Chris Hardie , Edmund Tarleton
High-resolution electron-backscatter diffraction (HR-EBSD) is widely adopted as a method to obtain local stress and strain distributions in both single-crystal and polycrystalline materials. In this study, we develop a finite element-based method that serves as a numerical correction to refine the relative stress measurements captured experimentally from HR-EBSD and to ensure that the measurements satisfy mechanical equilibrium and traction-free surface constraints. Through calculation of stress for each of the reference points, previously assumed to be zero, the method captures the grain-to-grain variation of stress in polycrystalline EBSD maps. The experimental data, including a cross section of nanoindentation in unirradiated and heavy-ion-irradiated single-crystals of iron as well as polycrystalline austenitic stainless steel are analysed. The method improves the measured stresses near slip bands, grain boundaries, and hard phases while keeping the stresses physically consistent with mechanical equilibrium and ensuring that free surfaces are traction-free. The three-dimensional analysis enables the fulfilment of traction-free surface constraints, resulting in zero out-of-plane shear stress components on the free surfaces while maintaining nonzero out-of-plane shear stress components below the surface. To demonstrate the validity of this approach, the method is also applied to relative stresses, synthetically generated, for a uniform bending case; the method successfully predicts the stress distributions.
{"title":"Using mechanical equilibrium to correct HR-EBSD stress measurements","authors":"Eralp Demir , Anna Kareer , Chris Hardie , Edmund Tarleton","doi":"10.1016/j.ijplas.2025.104464","DOIUrl":"10.1016/j.ijplas.2025.104464","url":null,"abstract":"<div><div>High-resolution electron-backscatter diffraction (HR-EBSD) is widely adopted as a method to obtain local stress and strain distributions in both single-crystal and polycrystalline materials. In this study, we develop a finite element-based method that serves as a numerical correction to refine the relative stress measurements captured experimentally from HR-EBSD and to ensure that the measurements satisfy mechanical equilibrium and traction-free surface constraints. Through calculation of stress for each of the reference points, previously assumed to be zero, the method captures the grain-to-grain variation of stress in polycrystalline EBSD maps. The experimental data, including a cross section of nanoindentation in unirradiated and heavy-ion-irradiated single-crystals of iron as well as polycrystalline austenitic stainless steel are analysed. The method improves the measured stresses near slip bands, grain boundaries, and hard phases while keeping the stresses physically consistent with mechanical equilibrium and ensuring that free surfaces are traction-free. The three-dimensional analysis enables the fulfilment of traction-free surface constraints, resulting in zero out-of-plane shear stress components on the free surfaces while maintaining nonzero out-of-plane shear stress components below the surface. To demonstrate the validity of this approach, the method is also applied to relative stresses, synthetically generated, for a uniform bending case; the method successfully predicts the stress distributions.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"195 ","pages":"Article 104464"},"PeriodicalIF":12.8,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145043119","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 : 2025-11-29DOI: 10.1016/j.ijplas.2025.104572
Saurabh Pawar , K.U. Yazar , Khushahal Thool , Wi-Geol Seo , Chang-Gon Jeong , Yoon-Uk Heo , Shi-Hoon Choi
This study investigates the microstructural evolution and deformation behavior of 316 L stainless steel (SS) fabricated by direct energy deposition under compressive loading at room temperature (RT) and cryogenic temperature (CT), along the scanning (SD) and transverse (TD) directions. Electron backscatter diffraction, transmission electron microscopy, and electron channeling contrast imaging, combined with dislocation-based crystal plasticity simulations, were employed. The as-fabricated microstructure exhibited columnar grains with cellular substructures, and δ-ferrite at cell boundaries enriched in Cr and Mo. At RT, SD samples deformed via dislocation glide and twinning in [001]-oriented grains, gradually reorienting toward the less favorable [110] direction. TD samples predominantly deformed by slip. At CT, yield strength differed significantly between SD and TD samples, indicating mechanical anisotropy arising from grain morphology, local stress heterogeneities, and martensitic transformations (γ → ε → α′ and γ → α′). Simulations incorporating twinning- and transformation-induced plasticity (TWIP and TRIP) showed that [110]- and [111]-oriented grains relative to the loading direction exhibited higher resistance to deformation, consistent with lower twinning and martensite formation. At RT, twinning and screw dislocation glide were dominant, while at CT, anisotropy was governed by the interaction between hard and soft phases, with martensite variant selection playing a central role. The activation of TWIP and TRIP was strongly dependent on crystallographic orientation, with [001]-oriented grains showing greater deformation tendency.
{"title":"Anisotropic compression behavior of 316 L stainless steel at room and cryogenic temperatures: The influence of twinning and transformation mechanisms","authors":"Saurabh Pawar , K.U. Yazar , Khushahal Thool , Wi-Geol Seo , Chang-Gon Jeong , Yoon-Uk Heo , Shi-Hoon Choi","doi":"10.1016/j.ijplas.2025.104572","DOIUrl":"10.1016/j.ijplas.2025.104572","url":null,"abstract":"<div><div>This study investigates the microstructural evolution and deformation behavior of 316 L stainless steel (SS) fabricated by direct energy deposition under compressive loading at room temperature (RT) and cryogenic temperature (CT), along the scanning (SD) and transverse (TD) directions. Electron backscatter diffraction, transmission electron microscopy, and electron channeling contrast imaging, combined with dislocation-based crystal plasticity simulations, were employed. The as-fabricated microstructure exhibited columnar grains with cellular substructures, and δ-ferrite at cell boundaries enriched in Cr and Mo. At RT, SD samples deformed via dislocation glide and twinning in [001]-oriented grains, gradually reorienting toward the less favorable [110] direction. TD samples predominantly deformed by slip. At CT, yield strength differed significantly between SD and TD samples, indicating mechanical anisotropy arising from grain morphology, local stress heterogeneities, and martensitic transformations (γ → ε → α′ and γ → α′). Simulations incorporating twinning- and transformation-induced plasticity (TWIP and TRIP) showed that [110]- and [111]-oriented grains relative to the loading direction exhibited higher resistance to deformation, consistent with lower twinning and martensite formation. At RT, twinning and screw dislocation glide were dominant, while at CT, anisotropy was governed by the interaction between hard and soft phases, with martensite variant selection playing a central role. The activation of TWIP and TRIP was strongly dependent on crystallographic orientation, with [001]-oriented grains showing greater deformation tendency.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"196 ","pages":"Article 104572"},"PeriodicalIF":12.8,"publicationDate":"2025-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145619620","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 : 2025-11-27DOI: 10.1016/j.ijplas.2025.104570
Hai-Le Yan , Ying Zhao , Yudong Zhang , Weimin Gan , Claude Esling , Xiang Zhao , Liang Zuo
Generating a pre-strain by mechanical loading during martensitic transformation stands as a crucial strategy to obtain memory effect in shape memory alloys (SMAs). As martensitic transformation is realized by an anisotropic lattice deformation, the formation of martensite variants is always governed by strain accommodation. In a stress-free state, the orientation variants are organized hierarchically into colonies with a fixed number of variants. Under an external load, the transformation becomes selective. Although variant selection has long been a subject of interest, knowledge on selection via the activation of the transformation shear system under a load and by local strain mitigation is limited. Here, by a combined in-situ neutron diffraction and exhaustive EBSD crystallographic examination, the variant selection under a compressive load during martensitic transformation was thoroughly investigated using Ni51Mn34In15 as an example alloy. Remarkably, a dual-scale selection mechanism, i.e., colony and intra-colony variants, was revealed, which is in stark contrast to the stress-free scenario. For colonies, those containing variants receiving the highest resolved shear stress on their dominant transformation shear system were selected. Within the colonies, the selection is on variant volume fraction. Those making the maximum contribution to the external compression strain were majorly selected. Nevertheless, due to local incompatible strains created by the favorable variants, the variants with deformation opposite to the external compression were also selected to mitigate local incompatible strain and promote further formation of the favorable variants. This study provides useful experimental evidence and analysis data for related crystal plasticity modeling and simulation.
{"title":"Dual-scale selection of martensite variants in shape memory intermetallic compounds during thermomechanical loading","authors":"Hai-Le Yan , Ying Zhao , Yudong Zhang , Weimin Gan , Claude Esling , Xiang Zhao , Liang Zuo","doi":"10.1016/j.ijplas.2025.104570","DOIUrl":"10.1016/j.ijplas.2025.104570","url":null,"abstract":"<div><div>Generating a pre-strain by mechanical loading during martensitic transformation stands as a crucial strategy to obtain memory effect in shape memory alloys (SMAs). As martensitic transformation is realized by an anisotropic lattice deformation, the formation of martensite variants is always governed by strain accommodation. In a stress-free state, the orientation variants are organized hierarchically into colonies with a fixed number of variants. Under an external load, the transformation becomes selective. Although variant selection has long been a subject of interest, knowledge on selection <em>via</em> the activation of the transformation shear system under a load and by local strain mitigation is limited. Here, by a combined <em>in-situ</em> neutron diffraction and exhaustive EBSD crystallographic examination, the variant selection under a compressive load during martensitic transformation was thoroughly investigated using Ni<sub>51</sub>Mn<sub>34</sub>In<sub>15</sub> as an example alloy. Remarkably, a dual-scale selection mechanism, <em>i.e.</em>, colony and intra-colony variants, was revealed, which is in stark contrast to the stress-free scenario. For colonies, those containing variants receiving the highest resolved shear stress on their dominant transformation shear system were selected. Within the colonies, the selection is on variant volume fraction. Those making the maximum contribution to the external compression strain were majorly selected. Nevertheless, due to local incompatible strains created by the favorable variants, the variants with deformation opposite to the external compression were also selected to mitigate local incompatible strain and promote further formation of the favorable variants. This study provides useful experimental evidence and analysis data for related crystal plasticity modeling and simulation.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"196 ","pages":"Article 104570"},"PeriodicalIF":12.8,"publicationDate":"2025-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145608791","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 : 2025-11-27DOI: 10.1016/j.ijplas.2025.104571
Junye Wang, Kaijuan Chen, Chao Yu, Qianhua Kan, Guozheng Kang
In this work, creep, relaxation, and uniaxial and biaxial stress-controlled cyclic tests of nylon-like photosensitive resins with different exposure doses are first performed. The results illustrate that with the increase of exposure dose, the crosslink density of the photosensitive resin increases, the creep strain decreases, the relaxation stress increases, both the recoverable viscoelastic strain and the irrecoverable viscoplastic strain that constitute the ratchetting strain of the resin decrease, and the non-proportional biaxial ratchetting strain is larger than the proportional one. Then, based on the experimental observations, a fractional viscoelastic-viscoplastic constitutive model is constructed from the proposed Gibbs free energy and viscoplastic dissipation potential. The viscoelastic part is described by the fractional Poynting-Thomson model, and the viscoplastic one is reflected by the improved Armstrong-Frederick kinematic hardening rule under the unified viscoplastic model with the fractional derivative. Additionally, the mapping relationships between the crosslink density and the viscoelastic and viscoplastic model parameters are also, respectively, introduced into the proposed model. Furthermore, an implicit stress integration algorithm for the proposed model and a method to determine the model parameters are proposed. Finally, by comparing the predicted results with the experimental ones, the prediction ability of the proposed model to the time-dependent deformation (including creep, stress relaxation, and ratchetting) of photosensitive resins with different exposure doses is verified.
{"title":"A thermodynamically consistent fractional viscoelastic-viscoplastic constitutive model for time-dependent ratchetting of photosensitive resin","authors":"Junye Wang, Kaijuan Chen, Chao Yu, Qianhua Kan, Guozheng Kang","doi":"10.1016/j.ijplas.2025.104571","DOIUrl":"10.1016/j.ijplas.2025.104571","url":null,"abstract":"<div><div>In this work, creep, relaxation, and uniaxial and biaxial stress-controlled cyclic tests of nylon-like photosensitive resins with different exposure doses are first performed. The results illustrate that with the increase of exposure dose, the crosslink density of the photosensitive resin increases, the creep strain decreases, the relaxation stress increases, both the recoverable viscoelastic strain and the irrecoverable viscoplastic strain that constitute the ratchetting strain of the resin decrease, and the non-proportional biaxial ratchetting strain is larger than the proportional one. Then, based on the experimental observations, a fractional viscoelastic-viscoplastic constitutive model is constructed from the proposed Gibbs free energy and viscoplastic dissipation potential. The viscoelastic part is described by the fractional Poynting-Thomson model, and the viscoplastic one is reflected by the improved Armstrong-Frederick kinematic hardening rule under the unified viscoplastic model with the fractional derivative. Additionally, the mapping relationships between the crosslink density and the viscoelastic and viscoplastic model parameters are also, respectively, introduced into the proposed model. Furthermore, an implicit stress integration algorithm for the proposed model and a method to determine the model parameters are proposed. Finally, by comparing the predicted results with the experimental ones, the prediction ability of the proposed model to the time-dependent deformation (including creep, stress relaxation, and ratchetting) of photosensitive resins with different exposure doses is verified.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"196 ","pages":"Article 104571"},"PeriodicalIF":12.8,"publicationDate":"2025-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145609856","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 : 2025-11-26DOI: 10.1016/j.ijplas.2025.104569
Linfeng Jiang , Guisen Liu , Peipeng Jin , Yao Shen , Jian Wang
Deformation twinning, a common deformation mechanism in metals with a hexagonal close-packed (HCP) structure, produces plastic strain accompanied with the creation of twinned domains within the matrix. Phase-field models for deformation twinning often suffer from unphysically diffuse or overly wide interfaces, particularly under large and inhomogeneous driving forces. Maintaining a dynamically stable interface is essential for achieving an accurate description of interface motion. In this work, we propose a Forward-Backward Regularization (FBR) method to control the width of twin interfaces. This is accomplished by introducing an energy penalty term—linked to the gradient magnitude of the order parameter—into the total free energy functional. This method decouples the numerical control of interface width from the physical material parameters (e.g., interfacial energy), thereby preserving their intrinsic physical significance. The FBR method demonstrates robust performance in multiple scenarios, including interfacial energy-driven interface contraction, bulk driving force-induced interface expansion, and mesh size insensitivity to twin propagation. Integrated the FBR model into a coupled Crystal Plasticity Finite Element - Phase Field (CPFE-PF) model, the FBR approach is examined to effectively control interface width, reduce mesh orientation sensitivity, and reproduce twin propagation and transmission across grain boundaries. This robust, computationally efficient FBR model holds promise for broader applications in PF modeling of shear transformation bands with precise interface control.
{"title":"An interface-regularized phase field model for deformation twinning","authors":"Linfeng Jiang , Guisen Liu , Peipeng Jin , Yao Shen , Jian Wang","doi":"10.1016/j.ijplas.2025.104569","DOIUrl":"10.1016/j.ijplas.2025.104569","url":null,"abstract":"<div><div>Deformation twinning, a common deformation mechanism in metals with a hexagonal close-packed (HCP) structure, produces plastic strain accompanied with the creation of twinned domains within the matrix. Phase-field models for deformation twinning often suffer from unphysically diffuse or overly wide interfaces, particularly under large and inhomogeneous driving forces. Maintaining a dynamically stable interface is essential for achieving an accurate description of interface motion. In this work, we propose a Forward-Backward Regularization (FBR) method to control the width of twin interfaces. This is accomplished by introducing an energy penalty term—linked to the gradient magnitude of the order parameter—into the total free energy functional. This method decouples the numerical control of interface width from the physical material parameters (e.g., interfacial energy), thereby preserving their intrinsic physical significance. The FBR method demonstrates robust performance in multiple scenarios, including interfacial energy-driven interface contraction, bulk driving force-induced interface expansion, and mesh size insensitivity to twin propagation. Integrated the FBR model into a coupled Crystal Plasticity Finite Element - Phase Field (CPFE-PF) model, the FBR approach is examined to effectively control interface width, reduce mesh orientation sensitivity, and reproduce twin propagation and transmission across grain boundaries. This robust, computationally efficient FBR model holds promise for broader applications in PF modeling of shear transformation bands with precise interface control.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"196 ","pages":"Article 104569"},"PeriodicalIF":12.8,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145600093","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}
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