Pub Date : 2025-03-08DOI: 10.1016/j.ijplas.2025.104305
Julian N. Heidenreich, Dirk Mohr
Minimal State Cells (MSCs) have successfully overcome the self-consistency and state space issues of standard RNNs when modeling the large deformation response of solids. However, in case of rate- and temperature-dependent materials, MSC-based stress predictions still suffer from instabilities when refining the input path discretization. To resolve this issue, we develop an extended minimal state cell (EMSC) which provides self-consistent predictions irrespective of the type of material. Similar to the original MSC model, the EMSC decouples the number of state variables from fitting parameters, allowing a minimal number of state variables for high physical interpretability without compromising expressivity. The EMSC is trained and validated using 1D and 3D random walk datasets generated with micro-mechanical models of composites, basic rheological models, advanced thermo-visco-plasticity theories, as well as rate- and temperature-dependent von Mises, Hill’48, and Yld2000–3d models. It is demonstrated that compact EMSC models with less than 25,000 parameters and the same number of state variables as their physics-based counterparts provide accurate predictions of the large deformation response of all materials. With its minimal state space, compact parameter space, high expressivity, and computational stability, the EMSC is a promising candidate for surrogate modeling, in particular for materials for which reliable micromechanical models are available to generate rich training data.
{"title":"Extended minimal state cells (EMSC): Self-consistent recurrent neural networks for rate- and temperature dependent plasticity","authors":"Julian N. Heidenreich, Dirk Mohr","doi":"10.1016/j.ijplas.2025.104305","DOIUrl":"10.1016/j.ijplas.2025.104305","url":null,"abstract":"<div><div>Minimal State Cells (MSCs) have successfully overcome the self-consistency and state space issues of standard RNNs when modeling the large deformation response of solids. However, in case of rate- and temperature-dependent materials, MSC-based stress predictions still suffer from instabilities when refining the input path discretization. To resolve this issue, we develop an extended minimal state cell (EMSC) which provides self-consistent predictions irrespective of the type of material. Similar to the original MSC model, the EMSC decouples the number of state variables from fitting parameters, allowing a minimal number of state variables for high physical interpretability without compromising expressivity. The EMSC is trained and validated using 1D and 3D random walk datasets generated with micro-mechanical models of composites, basic rheological models, advanced thermo-visco-plasticity theories, as well as rate- and temperature-dependent von Mises, Hill’48, and Yld2000–3d models. It is demonstrated that compact EMSC models with less than 25,000 parameters and the same number of state variables as their physics-based counterparts provide accurate predictions of the large deformation response of all materials. With its minimal state space, compact parameter space, high expressivity, and computational stability, the EMSC is a promising candidate for surrogate modeling, in particular for materials for which reliable micromechanical models are available to generate rich training data.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104305"},"PeriodicalIF":9.4,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143576386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-05DOI: 10.1016/j.ijplas.2025.104292
Zeng Huang , Shuai Luo , Guangyu Wang , Haohong Wu , Zhanguang Zheng , Haiming Zhang
This study investigates the effects of large pre-compression deformation on strain-hardening and the twinning-induced plasticity (TWIP) effect in high-manganese steel, addressing a critical limitation of traditional TWIP steels, i.e., relatively low yield strength. Using advanced ex-situ electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM), we reveal the roles of nanotwins, high-density dislocations, and substructure evolution in enhancing the mechanical response under complex strain paths. Results indicate that large pre-compression significantly elevates yield and ultimate tensile strength while preserving elongation, a unique strength-ductility synergy rarely achieved in pre-strained steels. The intricate coexistence of high-density dislocation and nanotwin microstructural networks under significant pre-deformation complicates dislocation slip pathways, contributing to a unique strength-ductility balance and enhancing work-hardening capability. Changes in strain paths activate new deformation twins, which, being dynamically nucleated, introduce new interfaces and alter the crystallographic orientations, thereby enhancing the material's dislocation storage capacity and maintaining a high work-hardening rate. Pre-compression-induced heterogeneous microstructure exhibits significant hetero-deformation-induced (HDI) hardening during tensile loading, enhancing tensile strength, delaying necking, and improving deformation stability. Cross-slip in fine-grained regions (FGs) promotes dislocation interaction and the formation of robust dislocation networks, further improving the strain-hardening capability of the steel. Finally, a parametric model is proposed to quantify the synergetic contributions of twins, grain boundaries (GBs), dislocations, and HDI-hardening in optimizing the properties of pre-strained steel, providing a foundational understanding of TWIP steel behavior under varying strain path loading conditions. These insights advance the fundamental principles governing TWIP steel deformation, supporting the development of high-performance Fe-Mn-C-Al alloys for automotive applications.
{"title":"Mechanistic exploration of high strain-hardening and TWIP effects in Fe-15.5Mn-0.6C-1.4Al steel under compression-tensile loading","authors":"Zeng Huang , Shuai Luo , Guangyu Wang , Haohong Wu , Zhanguang Zheng , Haiming Zhang","doi":"10.1016/j.ijplas.2025.104292","DOIUrl":"10.1016/j.ijplas.2025.104292","url":null,"abstract":"<div><div>This study investigates the effects of large pre-compression deformation on strain-hardening and the twinning-induced plasticity (TWIP) effect in high-manganese steel, addressing a critical limitation of traditional TWIP steels, i.e., relatively low yield strength. Using advanced ex-situ electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM), we reveal the roles of nanotwins, high-density dislocations, and substructure evolution in enhancing the mechanical response under complex strain paths. Results indicate that large pre-compression significantly elevates yield and ultimate tensile strength while preserving elongation, a unique strength-ductility synergy rarely achieved in pre-strained steels. The intricate coexistence of high-density dislocation and nanotwin microstructural networks under significant pre-deformation complicates dislocation slip pathways, contributing to a unique strength-ductility balance and enhancing work-hardening capability. Changes in strain paths activate new deformation twins, which, being dynamically nucleated, introduce new interfaces and alter the crystallographic orientations, thereby enhancing the material's dislocation storage capacity and maintaining a high work-hardening rate. Pre-compression-induced heterogeneous microstructure exhibits significant hetero-deformation-induced (HDI) hardening during tensile loading, enhancing tensile strength, delaying necking, and improving deformation stability. Cross-slip in fine-grained regions (FGs) promotes dislocation interaction and the formation of robust dislocation networks, further improving the strain-hardening capability of the steel. Finally, a parametric model is proposed to quantify the synergetic contributions of twins, grain boundaries (GBs), dislocations, and HDI-hardening in optimizing the properties of pre-strained steel, providing a foundational understanding of TWIP steel behavior under varying strain path loading conditions. These insights advance the fundamental principles governing TWIP steel deformation, supporting the development of high-performance Fe-Mn-C-Al alloys for automotive applications.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104292"},"PeriodicalIF":9.4,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143551004","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 : 2025-03-05DOI: 10.1016/j.ijplas.2025.104295
Zhuang Cui , Yukai Xiong , Yang Liu , Ying Zeng , Manping Liu , Xiaochun Liu , Zhuoran Zeng , Xu Zhang , Shiwei Xu
The improvement of creep resistance remains an important challenge for engineering applications of magnesium (Mg) alloys at elevated temperatures. Based on the experimental investigations and crystal plastic finite element method (CPFEM), the creep deformation mechanisms of the AC3 (Mg-5Al-3Ca) and ZC1 (Mg-5Zn-1Ca) alloys (both in wt.%) were proposed separately in this study. The results indicate that the ZC1 alloy with lower content of Ca and hierarchical distribution of strengthening phases exhibits superior creep resistance compared to the AC3 alloy. This superiority of ZC1 alloy is attributed to the low mechanical incompatibility between the skeleton Ca2Mg6Zn3 phases and the α-Mg matrix, as well as the presence of small dispersed particles in the grain interior surrounded by stable skeleton phases. The interconnectedness of the skeleton intermetallic phase affects the creep resistance of Mg alloys. During the creep process of the AC3 alloy, local stress concentration led to the cracking of the hard skeleton Al2Ca phase, grain boundaries (GBs) sliding, and grain coarsening/rotating, resulting in large creep rate. In the ZC1 alloy, the skeleton Ca2Mg6Zn3 phases distributed along the GBs act as barriers to GB sliding. In addition, the particle precipitates inside the grains which have an orientation relationship with the α-Mg matrix can additionally strengthen the matrix, effectively preventing the motion of basal 〈a〉 dislocations. The findings of this study provide a strategy to design high creep-resistant Mg alloys by synergistic effect of the stable skeleton phase and dispersed particle phase.
{"title":"Lowering creep rate in Mg-Zn-Ca magnesium alloy with hierarchical distribution of phases","authors":"Zhuang Cui , Yukai Xiong , Yang Liu , Ying Zeng , Manping Liu , Xiaochun Liu , Zhuoran Zeng , Xu Zhang , Shiwei Xu","doi":"10.1016/j.ijplas.2025.104295","DOIUrl":"10.1016/j.ijplas.2025.104295","url":null,"abstract":"<div><div>The improvement of creep resistance remains an important challenge for engineering applications of magnesium (Mg) alloys at elevated temperatures. Based on the experimental investigations and crystal plastic finite element method (CPFEM), the creep deformation mechanisms of the AC3 (Mg-5Al-3Ca) and ZC1 (Mg-5Zn-1Ca) alloys (both in wt.%) were proposed separately in this study. The results indicate that the ZC1 alloy with lower content of Ca and hierarchical distribution of strengthening phases exhibits superior creep resistance compared to the AC3 alloy. This superiority of ZC1 alloy is attributed to the low mechanical incompatibility between the skeleton Ca<sub>2</sub>Mg<sub>6</sub>Zn<sub>3</sub> phases and the α-Mg matrix, as well as the presence of small dispersed particles in the grain interior surrounded by stable skeleton phases. The interconnectedness of the skeleton intermetallic phase affects the creep resistance of Mg alloys. During the creep process of the AC3 alloy, local stress concentration led to the cracking of the hard skeleton Al<sub>2</sub>Ca phase, grain boundaries (GBs) sliding, and grain coarsening/rotating, resulting in large creep rate. In the ZC1 alloy, the skeleton Ca<sub>2</sub>Mg<sub>6</sub>Zn<sub>3</sub> phases distributed along the GBs act as barriers to GB sliding. In addition, the particle precipitates inside the grains which have an orientation relationship with the α-Mg matrix can additionally strengthen the matrix, effectively preventing the motion of basal 〈a〉 dislocations. The findings of this study provide a strategy to design high creep-resistant Mg alloys by synergistic effect of the stable skeleton phase and dispersed particle phase.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104295"},"PeriodicalIF":9.4,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143546440","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 : 2025-03-04DOI: 10.1016/j.ijplas.2025.104293
Zhenyang Cao , Luqing Cui , Sihai Luo , Hao Su , Zhicong Pang , Wang Zhao , Liyin Zhang , Weifeng He , Xiaoqing Liang
TC6 titanium alloy is widely utilized in the blades and fastener structures of aeroengines, where fretting wear failure is a common issue. To address this challenge, various surface treatment techniques have been employed, with laser shock peening (LSP) garnering significant attention due to its excellent surface integrity. Although LSP has been extensively applied to improve the fatigue and friction properties of titanium alloys, its impact on the fretting wear performance and relevant strengthening mechanisms remains insufficiently explored. In this work, we demonstrate that the continuous formation of stable gradient nanograin-amorphous substructures, facilitated by the LSP-induced work-hardening layer, results in a remarkable 51.9 % reduction in the wear rates of titanium alloys under high-load fretting conditions, decreasing from 4.147 × 10–6 mm3 N-1 m-1 to 1.996 × 10–6 mm3 N-1 m-1. Furthermore, through the application of multiple microscopic techniques and energy-based analyses, the gradient mechanics, surface morphology, energy dissipation, microstructural evolution, and dislocation behavior of titanium alloys pre- and post-friction tests are systematically investigated. The superior fretting wear resistance of titanium alloys stems from the synergistic effects of the surface hardening layer, compressive residual stress, and the evolution of gradient nanograin-amorphous substructures, which inhibit the matrix removal and accommodate large plastic strains under fretting slip. This work provides a comprehensive and in-depth understanding of the strengthening mechanisms of the LSP-induced stable gradient nanostructures, offering new insights into the targeted design optimization of surface microstructures for titanium alloys.
{"title":"Superior fretting wear resistance of titanium alloys from stable gradient nanostructures induced by laser shock peening","authors":"Zhenyang Cao , Luqing Cui , Sihai Luo , Hao Su , Zhicong Pang , Wang Zhao , Liyin Zhang , Weifeng He , Xiaoqing Liang","doi":"10.1016/j.ijplas.2025.104293","DOIUrl":"10.1016/j.ijplas.2025.104293","url":null,"abstract":"<div><div>TC6 titanium alloy is widely utilized in the blades and fastener structures of aeroengines, where fretting wear failure is a common issue. To address this challenge, various surface treatment techniques have been employed, with laser shock peening (LSP) garnering significant attention due to its excellent surface integrity. Although LSP has been extensively applied to improve the fatigue and friction properties of titanium alloys, its impact on the fretting wear performance and relevant strengthening mechanisms remains insufficiently explored. In this work, we demonstrate that the continuous formation of stable gradient nanograin-amorphous substructures, facilitated by the LSP-induced work-hardening layer, results in a remarkable 51.9 % reduction in the wear rates of titanium alloys under high-load fretting conditions, decreasing from 4.147 × 10<sup>–6</sup> mm<sup>3</sup> N<sup>-1</sup> m<sup>-1</sup> to 1.996 × 10<sup>–6</sup> mm<sup>3</sup> N<sup>-1</sup> m<sup>-1</sup>. Furthermore, through the application of multiple microscopic techniques and energy-based analyses, the gradient mechanics, surface morphology, energy dissipation, microstructural evolution, and dislocation behavior of titanium alloys pre- and post-friction tests are systematically investigated. The superior fretting wear resistance of titanium alloys stems from the synergistic effects of the surface hardening layer, compressive residual stress, and the evolution of gradient nanograin-amorphous substructures, which inhibit the matrix removal and accommodate large plastic strains under fretting slip. This work provides a comprehensive and in-depth understanding of the strengthening mechanisms of the LSP-induced stable gradient nanostructures, offering new insights into the targeted design optimization of surface microstructures for titanium alloys.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104293"},"PeriodicalIF":9.4,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143546441","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 : 2025-02-26DOI: 10.1016/j.ijplas.2025.104291
Minghao Hu , Chong Li , Shengyu Zhou , Qianying Guo , Zongqing Ma , Huijun Li , Xingchuan Xia , Yongchang Liu
The intra-granular γ′ phase and inter-granular M23C6 in a polycrystalline Ni3Al-based superalloy are cooperatively controlled through a two-stage-cooling solution treatment. The rapid cooling stage suppresses the coarsening of the γ′ phase, while the subsequent slow cooling stage promotes the precipitation of M23C6. The co-strengthening of intra- and inter-granular particles leads to a longer creep life. Intra-granularly, topologically inverse microstructures are formed, the deformation is dominated by the motion of antiphase boundary coupled superpartials. Inter-granularly, the movement of superdislocations towards the grain boundary is obstructed by the M23C6. Based on these observations, theoretical models are employed to construct the relationship between the creep properties and the micro/sub-structures. The threshold stress against dislocation movement contributed by γ′ phase, the boundary obstacle stress induced by M23C6 and the energy barrier for inter-granular cavity nucleation are calculated for discussion.
{"title":"Cooperatively controlling γ′ phase and M23C6 of a polycrystalline Ni3Al-based superalloy: Microstructure and creep resistance","authors":"Minghao Hu , Chong Li , Shengyu Zhou , Qianying Guo , Zongqing Ma , Huijun Li , Xingchuan Xia , Yongchang Liu","doi":"10.1016/j.ijplas.2025.104291","DOIUrl":"10.1016/j.ijplas.2025.104291","url":null,"abstract":"<div><div>The intra-granular γ′ phase and inter-granular M<sub>23</sub>C<sub>6</sub> in a polycrystalline Ni<sub>3</sub>Al-based superalloy are cooperatively controlled through a two-stage-cooling solution treatment. The rapid cooling stage suppresses the coarsening of the γ′ phase, while the subsequent slow cooling stage promotes the precipitation of M<sub>23</sub>C<sub>6</sub>. The co-strengthening of intra- and inter-granular particles leads to a longer creep life. Intra-granularly, topologically inverse microstructures are formed, the deformation is dominated by the motion of antiphase boundary coupled superpartials. Inter-granularly, the movement of superdislocations towards the grain boundary is obstructed by the M<sub>23</sub>C<sub>6</sub>. Based on these observations, theoretical models are employed to construct the relationship between the creep properties and the micro/sub-structures. The threshold stress against dislocation movement contributed by γ′ phase, the boundary obstacle stress induced by M<sub>23</sub>C<sub>6</sub> and the energy barrier for inter-granular cavity nucleation are calculated for discussion.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"187 ","pages":"Article 104291"},"PeriodicalIF":9.4,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143496029","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 : 2025-02-24DOI: 10.1016/j.ijplas.2025.104284
Damien Texier , Julien Genée , Vincent Velay , Antonio Castro Moreno , Daniel Monceau , Eric Andrieu
Surface effects were investigated using ultrathin specimens with thicknesses in the order of the grain size of the material. The candidate material was a polycrystalline Ni-based superalloy (Alloy 718) purposely heat treated to document both the effects of the grain size and the metallurgical state, , solid solution and precipitation hardened state, on the polycrystalline-to-multicrystalline behavior. Ultrathin tensile specimens were prepared with a dedicated technique to obtain specimens with thicknesses ranging between 20 and 550 , then tensile tested at room temperature. The polycrystalline-to-multicrystalline transition (PMT) was found to depend on the material grain size relative to the specimen thickness and to impair severely the tensile strength of the material. The yield strength, ultimate tensile strength (maximal stress on the stress–strain curve) and strain-to-failure severely dropped for specimens thinner than approximately two times the grain size of the material regardless of the metallurgical state. Such a decrease in tensile properties is mainly attributed to free-surface effects acting as an escape sink of dislocations, thus leading to a significant decrease of the primary dislocations density within the surface grains in comparison with the core grains. Interestingly, difference in work-hardening behavior with size reduction was found between both precipitation states, the solid solution state being more sensitive with the size reduction. The decrease in tensile properties was not found as expected from the commonly reported “thickness/grain size ()” ratio. Therefore, a numerical approach using a modified Berveiller–Zaoui self-consistent model based on a continuum crystal plasticity approach was conducted in the present paper to distinguish microstructural features acting as strengthening (dislocation accumulation) and softening (dislocation escape at the free-surface) features. 3D numerical materials were produced using Voronoi tessellation methods to represent the fraction of “core grains” versus “surface grains”. These fractions were then used as microstructural parameters for the identification of a crystal plasticity model using mean-field homogenization with different populations of grains, , core versus surface features. The present work aimed at distinguishing the mechanical behavior of surface grains from core grains in Alloy 718 Ni-based superalloys using various thicknesses of specimens and different microstructure and metallurgical state variants.
{"title":"Size effects on the plastic behavior of polycrystalline materials: Grain size, precipitation state and free-surface effects","authors":"Damien Texier , Julien Genée , Vincent Velay , Antonio Castro Moreno , Daniel Monceau , Eric Andrieu","doi":"10.1016/j.ijplas.2025.104284","DOIUrl":"10.1016/j.ijplas.2025.104284","url":null,"abstract":"<div><div>Surface effects were investigated using ultrathin specimens with thicknesses in the order of the grain size of the material. The candidate material was a polycrystalline Ni-based superalloy (Alloy 718) purposely heat treated to document both the effects of the grain size and the metallurgical state, <span><math><mrow><mi>i</mi><mo>.</mo><mi>e</mi><mo>.</mo></mrow></math></span>, solid solution and precipitation hardened state, on the polycrystalline-to-multicrystalline behavior. Ultrathin tensile specimens were prepared with a dedicated technique to obtain specimens with thicknesses ranging between 20 and 550 <span><math><mrow><mi>μ</mi><mtext>m</mtext></mrow></math></span>, then tensile tested at room temperature. The polycrystalline-to-multicrystalline transition (PMT) was found to depend on the material grain size relative to the specimen thickness and to impair severely the tensile strength of the material. The yield strength, ultimate tensile strength (maximal stress on the stress–strain curve) and strain-to-failure severely dropped for specimens thinner than approximately two times the grain size of the material regardless of the metallurgical state. Such a decrease in tensile properties is mainly attributed to free-surface effects acting as an escape sink of dislocations, thus leading to a significant decrease of the primary dislocations density within the surface grains in comparison with the core grains. Interestingly, difference in work-hardening behavior with size reduction was found between both precipitation states, the solid solution state being more sensitive with the size reduction. The decrease in tensile properties was not found as expected from the commonly reported “thickness/grain size (<span><math><mrow><mi>t</mi><mo>/</mo><mi>D</mi></mrow></math></span>)” ratio. Therefore, a numerical approach using a modified Berveiller–Zaoui self-consistent model based on a continuum crystal plasticity approach was conducted in the present paper to distinguish microstructural features acting as strengthening (dislocation accumulation) and softening (dislocation escape at the free-surface) features. 3D numerical materials were produced using Voronoi tessellation methods to represent the fraction of “core grains” versus “surface grains”. These fractions were then used as microstructural parameters for the identification of a crystal plasticity model using mean-field homogenization with different populations of grains, <span><math><mrow><mi>i</mi><mo>.</mo><mi>e</mi><mo>.</mo></mrow></math></span>, core versus surface features. The present work aimed at distinguishing the mechanical behavior of surface grains from core grains in Alloy 718 Ni-based superalloys using various thicknesses of specimens and different microstructure and metallurgical state variants.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104284"},"PeriodicalIF":9.4,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143477593","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 : 2025-02-24DOI: 10.1016/j.ijplas.2025.104289
X.P. Zhang , C.F. Fang , R. Wang , C.J. Li , Y. Zhao , J.T. Feng , W.Y. Li , S.B. Mi , Y.M. Wang
Texture weakening by dynamic recrystallization (DRX) control has been a challenging issue on improving the mechanical performance of wrought Mg alloys. Here we report the attainment of bi-directional DRX in an AZ31-0.9Nd-0.3Y alloy, which accelerated DRX and weakened the basal texture. The nature and content of secondary phase particles in the solidification microstructures were modified by the mixed-addition of rare-earth elements, and a dispersive distribution of Al11RE3 particles located at grain boundaries (GBs) and grain-interior Al2RE particles was achieved in the AZ31-0.9Nd-0.3Y alloy. Compared with the AZ31 and the alloys with sole-element addition, DRX in AZ31-0.9Nd-0.3Y occurred at a smaller critical strain at the same strain rate and extrusion temperature. Upon extrusion, GB bulging, continuous DRX, twin-induced nucleation and particle-stimulated nucleation (PSN) were operative but play a different part in the different stages of deformation. The Al11RE3 and Al2RE particles induced respectively inward and outward growth of DRXed grains at large strains, representing a bi-directional DRX behavior. The twin-induced DRX ceased to occur while the PSN carried by grain-interior particles caused substantial orientation randomness of the DRXed grains. Multiple dislocation slip systems were activated in the particle deformation zones to form dislocation cells, nucleating DRXed grains with a rich variety of orientations in the neighborhood of the particles. The extruded AZ31-0.9Nd-0.3Y alloy exhibited simultaneous improvement of strength and ductility performance.
{"title":"Bi-directional dynamic recrystallization behavior of AZ31 alloy by Al-RE precipitation control","authors":"X.P. Zhang , C.F. Fang , R. Wang , C.J. Li , Y. Zhao , J.T. Feng , W.Y. Li , S.B. Mi , Y.M. Wang","doi":"10.1016/j.ijplas.2025.104289","DOIUrl":"10.1016/j.ijplas.2025.104289","url":null,"abstract":"<div><div>Texture weakening by dynamic recrystallization (DRX) control has been a challenging issue on improving the mechanical performance of wrought Mg alloys. Here we report the attainment of bi-directional DRX in an AZ31-0.9Nd-0.3Y alloy, which accelerated DRX and weakened the basal texture. The nature and content of secondary phase particles in the solidification microstructures were modified by the mixed-addition of rare-earth elements, and a dispersive distribution of Al<sub>11</sub>RE<sub>3</sub> particles located at grain boundaries (GBs) and grain-interior Al<sub>2</sub>RE particles was achieved in the AZ31-0.9Nd-0.3Y alloy. Compared with the AZ31 and the alloys with sole-element addition, DRX in AZ31-0.9Nd-0.3Y occurred at a smaller critical strain at the same strain rate and extrusion temperature. Upon extrusion, GB bulging, continuous DRX, twin-induced nucleation and particle-stimulated nucleation (PSN) were operative but play a different part in the different stages of deformation. The Al<sub>11</sub>RE<sub>3</sub> and Al<sub>2</sub>RE particles induced respectively inward and outward growth of DRXed grains at large strains, representing a bi-directional DRX behavior. The twin-induced DRX ceased to occur while the PSN carried by grain-interior particles caused substantial orientation randomness of the DRXed grains. Multiple dislocation slip systems were activated in the particle deformation zones to form dislocation cells, nucleating DRXed grains with a rich variety of orientations in the neighborhood of the particles. The extruded AZ31-0.9Nd-0.3Y alloy exhibited simultaneous improvement of strength and ductility performance.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"187 ","pages":"Article 104289"},"PeriodicalIF":9.4,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143485530","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 : 2025-02-23DOI: 10.1016/j.ijplas.2025.104288
Hang Zhang, Xuanzhe Li, Jinyu Zhang, Suzhi Li, Shaohua Gao, Gang Liu, Jun Sun
Design structural characteristics of interfaces is the key for ultra-strong titanium (Ti) alloys by tuning polymorphic α-precipitates. However, the conventional tri-modal structure, characterized by various interfaces, usually shows large ductility but low yield strength caused by numerous soft α-precipitates. This work focuses on manipulating multiple interfacial structures to endow a newly designed tri-modal Ti-4.9Al-4.4Cr-2.45Mo-1.6Zr alloys with the superior strength-ductility synergy assisted by interstitial solutes, beyond conventional high-strength Ti alloys. Here, an interstitial solute alloying strategy is utilized not only to form hard-yet-deformable α-precipitates, but also to achieve the controllably stepwise α-precipitation sequence to manipulate interfacial structures and thus slip transmission modes in Ti alloys. In particular, the coherent twin boundaries (CTBs) between secondary α-nanolamellae formed via dislocation-interstitial atom interactions can efficiently hinder dislocation motion but promote dislocation transmission in the soft transformed β-matrix. This strategy provides new insights into designing high-performance interstitial solute-tolerant alloys for cost-effective and lightweight applications.
{"title":"Manipulating the interfacial structures in titanium alloys containing interstitial solutes delivers ultra-high strength and ductility","authors":"Hang Zhang, Xuanzhe Li, Jinyu Zhang, Suzhi Li, Shaohua Gao, Gang Liu, Jun Sun","doi":"10.1016/j.ijplas.2025.104288","DOIUrl":"10.1016/j.ijplas.2025.104288","url":null,"abstract":"<div><div>Design structural characteristics of interfaces is the key for ultra-strong titanium (Ti) alloys by tuning polymorphic α-precipitates. However, the conventional tri-modal structure, characterized by various interfaces, usually shows large ductility but low yield strength caused by numerous soft α-precipitates. This work focuses on manipulating multiple interfacial structures to endow a newly designed tri-modal Ti-4.9Al-4.4Cr-2.45Mo-1.6Zr alloys with the superior strength-ductility synergy assisted by interstitial solutes, beyond conventional high-strength Ti alloys. Here, an interstitial solute alloying strategy is utilized not only to form hard-yet-deformable α-precipitates, but also to achieve the controllably stepwise α-precipitation sequence to manipulate interfacial structures and thus slip transmission modes in Ti alloys. In particular, the coherent twin boundaries (CTBs) between secondary α-nanolamellae formed via dislocation-interstitial atom interactions can efficiently hinder dislocation motion but promote dislocation transmission in the soft transformed β-matrix. This strategy provides new insights into designing high-performance interstitial solute-tolerant alloys for cost-effective and lightweight applications.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"187 ","pages":"Article 104288"},"PeriodicalIF":9.4,"publicationDate":"2025-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143473530","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 : 2025-02-22DOI: 10.1016/j.ijplas.2025.104286
Guanghao Guo , Wenqiang Zhang , Bin Zhang , Jiachen Xu , Shuang Chen , Xianjue Ye , Yuefei Zhang , Ze Zhang
In this study, in-situ tensile experiments were conducted on three samples containing different precipitate phases (δ, γ″ and γ′) to investigate the effects of these precipitates on the tensile deformation mechanisms of Alloy 718. Local plastic deformation was characterized by digital image correlation (DIC) and electron back-scatter diffraction (EBSD). The plasticity was analyzed in terms of slip, lattice rotation, slip transfer, and intergranular cooperative deformation. The dislocation accumulation is slower in the γ matrix, promoting uniform plastic deformation within grains via single slip, resulting in excellent intragranular deformation capability for the sample without any precipitates. In contrast, the γ″ and γ′ phases facilitate dislocation multiplication and impede dislocation motion, causing rapid dislocation pile-up within grains, leading to local stress concentrations. These stress concentrations can activate secondary slip systems early, resulting in uneven intragranular deformation and limiting the grains’ plastic deformation capacity for the sample with γ′′ and γ′. At grain boundaries, the δ phase hinders slip transfer, restricting the capacity for intergranular coordinated deformation, resulting in the formation of microcracks along the grain boundaries. These microcracks, along both the δ phase and the grain boundaries, contribute to the reduction in plasticity of the sample with δ phase. The effects of γ″ and γ′ phases are similar, as they limit grain deformation by influencing dislocation accumulation within grains, while the δ phase at grain boundaries reduces the tensile plasticity of Alloy 718 by impeding intergranular deformation coordination.
{"title":"Effect of precipitate phase on the plastic deformation behavior of Alloy 718: In-situ tensile experiment and crystal plasticity simulation","authors":"Guanghao Guo , Wenqiang Zhang , Bin Zhang , Jiachen Xu , Shuang Chen , Xianjue Ye , Yuefei Zhang , Ze Zhang","doi":"10.1016/j.ijplas.2025.104286","DOIUrl":"10.1016/j.ijplas.2025.104286","url":null,"abstract":"<div><div>In this study, in-situ tensile experiments were conducted on three samples containing different precipitate phases (δ, γ″ and γ′) to investigate the effects of these precipitates on the tensile deformation mechanisms of Alloy 718. Local plastic deformation was characterized by digital image correlation (DIC) and electron back-scatter diffraction (EBSD). The plasticity was analyzed in terms of slip, lattice rotation, slip transfer, and intergranular cooperative deformation. The dislocation accumulation is slower in the γ matrix, promoting uniform plastic deformation within grains via single slip, resulting in excellent intragranular deformation capability for the sample without any precipitates. In contrast, the γ″ and γ′ phases facilitate dislocation multiplication and impede dislocation motion, causing rapid dislocation pile-up within grains, leading to local stress concentrations. These stress concentrations can activate secondary slip systems early, resulting in uneven intragranular deformation and limiting the grains’ plastic deformation capacity for the sample with γ′′ and γ′. At grain boundaries, the δ phase hinders slip transfer, restricting the capacity for intergranular coordinated deformation, resulting in the formation of microcracks along the grain boundaries. These microcracks, along both the δ phase and the grain boundaries, contribute to the reduction in plasticity of the sample with δ phase. The effects of γ″ and γ′ phases are similar, as they limit grain deformation by influencing dislocation accumulation within grains, while the δ phase at grain boundaries reduces the tensile plasticity of Alloy 718 by impeding intergranular deformation coordination.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"187 ","pages":"Article 104286"},"PeriodicalIF":9.4,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143471080","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 : 2025-02-22DOI: 10.1016/j.ijplas.2025.104287
Xiaocong Yang , Yuezhang Ju , Chengning Li , Chang Gao , Lingzhi Ba , Shipin Wu , Ce Wang , Taihao Ding , Ying Wang , Xinjie Di
In this study, the low-carbon ultra-high-strength steels with precipitation-free were prepared using quenching processes, and the co-precipitation strengthening of multi-scale Cu-rich and NiAl were designed to enhance fatigue performance through quenching-tempering (QT) and quenching-partitioning-tempering (QPT) processes respectively. The microstructure of quenched steel shows a typical mixed microstructure of lath martensite (LM) and granular bainite (GB). After aging at 550 °C for 1 h, the high density (1.945 × 1023 m-3) of B2-NiAl and B2 core-9R shell nanoparticles were uniformly co-precipitated and greatly increased the yield strength and high-cycle fatigue strength from 965 MPa and 384.6 MPa to 1548 MPa and 510.7 MPa, respectively. The substantial improvement in fatigue performance is attributed to the large number of small-sized nanoparticles that hinder the movement of dislocations to form high-density dislocation tangles (HDDTs) and cell structures, reducing the stress concentration at grain boundaries. Furthermore, geometric phase analysis (GPA) revealed the existence of micro-strain around small-sized multi-component precipitates, which is less likely to cause micro-crack initiation, thereby enhancing the fatigue performance. After QPT treatment, the co-precipitated nanoparticles exhibited multi-scale distribution with a significantly reduced number density of 1.005 × 1023 m-3, and the typical large-sized FCC-Cu particles are identified, which weakens the precipitation strengthening and leads to the yield strength and fatigue strength reached 1396 MPa and 424.5 MPa respectively. Furthermore, the GNDs obviously accumulate at the interface between reversed austenite (RA) and matrix by the movement of dislocations and bypassed nanoparticles, which increases the tendency of microcrack initiation at the interface. In addition, the high strain accumulated at the interface of FCC-Cu particles increases the risk of fatigue damage and limits the improvement of fatigue performance.
{"title":"Enhancing fatigue life of low-carbon ultra-high strength steel by inducing multi-component precipitates","authors":"Xiaocong Yang , Yuezhang Ju , Chengning Li , Chang Gao , Lingzhi Ba , Shipin Wu , Ce Wang , Taihao Ding , Ying Wang , Xinjie Di","doi":"10.1016/j.ijplas.2025.104287","DOIUrl":"10.1016/j.ijplas.2025.104287","url":null,"abstract":"<div><div>In this study, the low-carbon ultra-high-strength steels with precipitation-free were prepared using quenching processes, and the co-precipitation strengthening of multi-scale Cu-rich and NiAl were designed to enhance fatigue performance through quenching-tempering (QT) and quenching-partitioning-tempering (QPT) processes respectively. The microstructure of quenched steel shows a typical mixed microstructure of lath martensite (LM) and granular bainite (GB). After aging at 550 °C for 1 h, the high density (1.945 × 10<sup>23</sup> m<sup>-3</sup>) of B2-NiAl and B2 core-9R shell nanoparticles were uniformly co-precipitated and greatly increased the yield strength and high-cycle fatigue strength from 965 MPa and 384.6 MPa to 1548 MPa and 510.7 MPa, respectively. The substantial improvement in fatigue performance is attributed to the large number of small-sized nanoparticles that hinder the movement of dislocations to form high-density dislocation tangles (HDDTs) and cell structures, reducing the stress concentration at grain boundaries. Furthermore, geometric phase analysis (GPA) revealed the existence of micro-strain around small-sized multi-component precipitates, which is less likely to cause micro-crack initiation, thereby enhancing the fatigue performance. After QPT treatment, the co-precipitated nanoparticles exhibited multi-scale distribution with a significantly reduced number density of 1.005 × 10<sup>23</sup> m<sup>-3</sup>, and the typical large-sized FCC-Cu particles are identified, which weakens the precipitation strengthening and leads to the yield strength and fatigue strength reached 1396 MPa and 424.5 MPa respectively. Furthermore, the GNDs obviously accumulate at the interface between reversed austenite (RA) and matrix by the movement of dislocations and bypassed nanoparticles, which increases the tendency of microcrack initiation at the interface. In addition, the high strain accumulated at the interface of FCC-Cu particles increases the risk of fatigue damage and limits the improvement of fatigue performance.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"187 ","pages":"Article 104287"},"PeriodicalIF":9.4,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143471082","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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