Pub Date : 2025-04-03DOI: 10.1016/j.ijplas.2025.104325
Masoud Taherijam, Hamidreza Abdolvand
Hydrogen partitioning and hydride-induced stress localization are important factors in the degradation of dual-phase alloys. This study investigates these mechanisms by developing a crystal plasticity finite element (CPFE) model that incorporates the two-way interaction between stress and hydrogen concentration. The model considers the effects of hydrogen induced lattice expansion (HILE), phase-dependent hydrogen partitioning, and the transformation strain induced by hydride precipitation. Using this model, the impact of hydrogen on stress distribution and hydride precipitation is examined both in single and dual-phase zirconium alloys with hexagonal close-packed (HCP) and body-centered cubic (BCC) crystals. The results of the model for hydride precipitation are compared with those measured by high-spatial resolution electron backscatter diffraction (EBSD). The findings reveal that HILE effects are more pronounced in dual-phase HCP-BCC alloys due to partitioning of hydrogen between phases. The nonuniform distribution of hydrogen atoms leads to stress localization, which creates favorable conditions for hydride nucleation, particularly near the HCP-BCC interfaces. It is shown that the proposed numerical framework can identify which one of the neighbouring HCP grains is the corresponding parent grain of an intergranular hydride.
{"title":"Hydrogen and Hydride Induced Stress Localization in Single Phase HCP and Dual Phase HCP-BCC Alloys","authors":"Masoud Taherijam, Hamidreza Abdolvand","doi":"10.1016/j.ijplas.2025.104325","DOIUrl":"https://doi.org/10.1016/j.ijplas.2025.104325","url":null,"abstract":"Hydrogen partitioning and hydride-induced stress localization are important factors in the degradation of dual-phase alloys. This study investigates these mechanisms by developing a crystal plasticity finite element (CPFE) model that incorporates the two-way interaction between stress and hydrogen concentration. The model considers the effects of hydrogen induced lattice expansion (HILE), phase-dependent hydrogen partitioning, and the transformation strain induced by hydride precipitation. Using this model, the impact of hydrogen on stress distribution and hydride precipitation is examined both in single and dual-phase zirconium alloys with hexagonal close-packed (HCP) and body-centered cubic (BCC) crystals. The results of the model for hydride precipitation are compared with those measured by high-spatial resolution electron backscatter diffraction (EBSD). The findings reveal that HILE effects are more pronounced in dual-phase HCP-BCC alloys due to partitioning of hydrogen between phases. The nonuniform distribution of hydrogen atoms leads to stress localization, which creates favorable conditions for hydride nucleation, particularly near the HCP-BCC interfaces. It is shown that the proposed numerical framework can identify which one of the neighbouring HCP grains is the corresponding parent grain of an intergranular hydride.","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"12 1","pages":""},"PeriodicalIF":9.8,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143766637","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 : 2025-04-03DOI: 10.1016/j.ijplas.2025.104326
Samuel B. Inman , Kevin W. Garber , Andreas E. Robertson , Nathan K. Brown , Remi Dingreville , Brad L. Boyce
The creep behavior of 316 L stainless steel at room temperature was evaluated as a function of time and applied stress using a new high-throughput approach. Several common creep models were evaluated against the observations, leading to deeper analysis of a stress-dependent modified logarithmic creep model. Within this model, multiple sources of uncertainty were compared. Aleatoric stochastic variation between samples under nominally identical conditions was identified as the primary contributor to uncertainty in creep response. Under any particular set of conditions, the sample-to-sample variability in creep strain was as high as a factor of two, highlighting the engineering importance of characterizing large statistical datasets. The model's extrapolation capabilities were assessed by comparing predictions derived from calibration on partial, shorter-duration subsets of the data. These findings underscore the importance of accounting for stochastic effects in predictive modeling of aging phenomena.
{"title":"Stochastic room temperature creep of 316 L stainless steel","authors":"Samuel B. Inman , Kevin W. Garber , Andreas E. Robertson , Nathan K. Brown , Remi Dingreville , Brad L. Boyce","doi":"10.1016/j.ijplas.2025.104326","DOIUrl":"10.1016/j.ijplas.2025.104326","url":null,"abstract":"<div><div>The creep behavior of 316 L stainless steel at room temperature was evaluated as a function of time and applied stress using a new high-throughput approach. Several common creep models were evaluated against the observations, leading to deeper analysis of a stress-dependent modified logarithmic creep model. Within this model, multiple sources of uncertainty were compared. Aleatoric stochastic variation between samples under nominally identical conditions was identified as the primary contributor to uncertainty in creep response. Under any particular set of conditions, the sample-to-sample variability in creep strain was as high as a factor of two, highlighting the engineering importance of characterizing large statistical datasets. The model's extrapolation capabilities were assessed by comparing predictions derived from calibration on partial, shorter-duration subsets of the data. These findings underscore the importance of accounting for stochastic effects in predictive modeling of aging phenomena.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"189 ","pages":"Article 104326"},"PeriodicalIF":9.4,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143766633","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 : 2025-04-03DOI: 10.1016/j.ijplas.2025.104313
Xiangyu Xie , Chunliang Mao , Chenxi Liu , Junting Luo , Yongchang Liu
A continuum damage mechanics (CDM) creep model was developed based on the microstructure, which could precisely delineate the evolution of mobile dislocations, dipole dislocations, boundary dislocations, and martensitic laths in the RAFM steel during creep process. The addition of Ta/Zr elements promoted the precipitation of MX carbide particles, which could pin the mobile dislocations, and restrain the transformation of mobile dislocations into dipole dislocations, thereby slowing the decrease in statistically stored dislocation (SSD) density during creep. A large number of fine MX and M23C6 carbide particles sourcing from the addition of Ta/Zr elements could effectively delay the reduction in geometrically necessary dislocation (GND) density, and restrict GNDs transforming into sub-grain boundaries. By manipulating single-factor variables, the increase in precipitate damage factors strongly affected the steady creep stage and accelerated creep stage, especially for the precipitate damage factor of M23C6, which significantly accelerates the onset of the accelerated creep stage. The higher coarsening rate of M23C6 in RAFM steel without Ta/Zr was one of the reasons for its premature creep failure, as comparing with RAFM steel with Ta/Zr. During short-term (< 1000 h) creep, fine Laves phase functions similarly to M23C6 particles, serving the purpose of precipitation strengthening. In the intermediate-term (< 10,000 h) creep process, the Laves phase undergoes a certain degree of coarsening, but the coarsening-induced cavities damage is still not the primary cause of creep fracture. Thus, it was inferred that the depletion of W elements in the matrix sourcing from the coarsening of Laves phase is the main reason for the premature creep failure. In the intermediate-term creep of RAFM steel, the ability of Ta/Zr elements to significantly reduce the coarsening rate of Laves is a key factor for contributing to the significant extension of creep rupture time for RAFM steel.
{"title":"Revealing the mechanism for enhancing the creep property by adding Ta/Zr elements in RAFM steel: Experimental and modeling study","authors":"Xiangyu Xie , Chunliang Mao , Chenxi Liu , Junting Luo , Yongchang Liu","doi":"10.1016/j.ijplas.2025.104313","DOIUrl":"10.1016/j.ijplas.2025.104313","url":null,"abstract":"<div><div>A continuum damage mechanics (CDM) creep model was developed based on the microstructure, which could precisely delineate the evolution of mobile dislocations, dipole dislocations, boundary dislocations, and martensitic laths in the RAFM steel during creep process. The addition of Ta/Zr elements promoted the precipitation of MX carbide particles, which could pin the mobile dislocations, and restrain the transformation of mobile dislocations into dipole dislocations, thereby slowing the decrease in statistically stored dislocation (SSD) density during creep. A large number of fine MX and M<sub>23</sub>C<sub>6</sub> carbide particles sourcing from the addition of Ta/Zr elements could effectively delay the reduction in geometrically necessary dislocation (GND) density, and restrict GNDs transforming into sub-grain boundaries. By manipulating single-factor variables, the increase in precipitate damage factors strongly affected the steady creep stage and accelerated creep stage, especially for the precipitate damage factor of M<sub>23</sub>C<sub>6</sub>, which significantly accelerates the onset of the accelerated creep stage. The higher coarsening rate of M<sub>23</sub>C<sub>6</sub> in RAFM steel without Ta/Zr was one of the reasons for its premature creep failure, as comparing with RAFM steel with Ta/Zr. During short-term (< 1000 h) creep, fine Laves phase functions similarly to M<sub>23</sub>C<sub>6</sub> particles, serving the purpose of precipitation strengthening. In the intermediate-term (< 10,000 h) creep process, the Laves phase undergoes a certain degree of coarsening, but the coarsening-induced cavities damage is still not the primary cause of creep fracture. Thus, it was inferred that the depletion of W elements in the matrix sourcing from the coarsening of Laves phase is the main reason for the premature creep failure. In the intermediate-term creep of RAFM steel, the ability of Ta/Zr elements to significantly reduce the coarsening rate of Laves is a key factor for contributing to the significant extension of creep rupture time for RAFM steel.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104313"},"PeriodicalIF":9.4,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760479","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 : 2025-04-03DOI: 10.1016/j.ijplas.2025.104316
Tao Zhang , Shuang Xu , Lisheng Liu , Maoyuan Jiang
The accumulation of geometrically necessary dislocations (GND) at grain boundaries is a primary source of long-range internal stress (LRIS) in polycrystals. The distribution of GNDs is typically inhomogeneous, and certain dislocation substructures with concentrated GNDs introduce a strong non-local effect. While many studies have explored the relationship between LRIS and the density of GNDs in polycrystals, few have discussed the influences of GND distribution patterns on LRIS calculations. This study employs dislocation dynamics (DD) simulations to investigate the LRIS of non-uniform GNDs confined within a grain boundary facet. First, the stress fields of three elementary types of GND bands with twist, tilt, and epitaxial dislocations are systematically analyzed using DD simulations. Considering the finite-size effect, scaling coefficients for recovering the LRIS around these GND bands are identified. Subsequently, non-uniform dislocation patterns are built to examine the distribution of LRIS at varying distances from grain boundary facets. In line with determining LRIS derived from an averaged surface GND density, an improved calculation method that accounts for the non-homogeneity of GNDs is developed. Finally, this method is applied to predict the LRIS of a set of GND facets with more complex dislocation patterns extracted from face-centered cubic grains. The predictions show good agreement with stress results computed by DD simulations, suggesting potential for further improvement of the dislocation density-based constitutive approach.
{"title":"Long-range internal stress from non-uniform geometrically necessary dislocations: A prediction method refined by dislocation dynamics simulations","authors":"Tao Zhang , Shuang Xu , Lisheng Liu , Maoyuan Jiang","doi":"10.1016/j.ijplas.2025.104316","DOIUrl":"10.1016/j.ijplas.2025.104316","url":null,"abstract":"<div><div>The accumulation of geometrically necessary dislocations (GND) at grain boundaries is a primary source of long-range internal stress (LRIS) in polycrystals. The distribution of GNDs is typically inhomogeneous, and certain dislocation substructures with concentrated GNDs introduce a strong non-local effect. While many studies have explored the relationship between LRIS and the density of GNDs in polycrystals, few have discussed the influences of GND distribution patterns on LRIS calculations. This study employs dislocation dynamics (DD) simulations to investigate the LRIS of non-uniform GNDs confined within a grain boundary facet. First, the stress fields of three elementary types of GND bands with twist, tilt, and epitaxial dislocations are systematically analyzed using DD simulations. Considering the finite-size effect, scaling coefficients for recovering the LRIS around these GND bands are identified. Subsequently, non-uniform dislocation patterns are built to examine the distribution of LRIS at varying distances from grain boundary facets. In line with determining LRIS derived from an averaged surface GND density, an improved calculation method that accounts for the non-homogeneity of GNDs is developed. Finally, this method is applied to predict the LRIS of a set of GND facets with more complex dislocation patterns extracted from face-centered cubic grains. The predictions show good agreement with stress results computed by DD simulations, suggesting potential for further improvement of the dislocation density-based constitutive approach.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104316"},"PeriodicalIF":9.4,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143766634","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 : 2025-04-02DOI: 10.1016/j.ijplas.2025.104324
Wei Liu , Kaile Wang , Yuntao Zhang , Chuan Shuai , Taoze Xie , Wenyu Liu , Hua Hou , Yuhong Zhao
To overcome bottleneck of strength-ductility trade-off is a challenge in Mg-Zn-based alloys. In this work, we develop an age-hardening Mg-1.0Zn-0.1Ca-0.1Al-0.1Mn (wt. %) hot-extruded alloy with better strength-ductility synergy by synergistic heterostructure and nanoprecipitate, exhibiting a tensile yield strength of 352 MPa, an ultimate tensile strength of 413 MPa and an elongation of 15.2 %, respectively. Besides, dynamic recrystallization and dynamic precipitation at different die angles (30° and 90°) and extrusion temperatures (220 °C, 235 °C and 250 °C), and aging precipitation are systematically investigated. Particle pinning effect on grain boundary (GB) considering particle radius and strengthening effects are further clarified. Firstly, under large die angle (90°) and low extrusion temperature (220 °C), typical heterostructure containing recrystallized regions and non-recrystallized regions is achieved due to significant particle pinning effect of nanoscale Ca2Mg6Zn3 and Al8Mn5 particles, and solute dragging effect of Zn and Ca elements on GB. Phase-field simulation and experimental validation showing the evolution of bow-shape GB under significant particle pinning force during the particle-GB interaction. Meanwhile, the phase-field simulations show that the maximum particle pinning force is enhanced as increasing of the particle radius. Secondly, upon ageing at 180 °C, a distinct double peak-aging characteristic emerges in the hetero-structured Mg-1.0Zn-0.1Ca-0.1Al-0.1Mn hot-extruded alloy. The first ageing peak mainly arises from the precipitation of GP zones, while the second ageing peak primarily originates from the co-precipitation of β1’ and β2’ phases. Finally, hetero-deformation induced strengthening, nanoprecipitate-reinforced Orowan strengthening and deformation coordination by twins and non-basal slips contribute to the strength-ductility synergy. These results provide valuable insights for developing high-performance Mg-Zn-based alloys.
{"title":"Particle pinning effect on grain boundary and double peak-aging characteristic in a hot-extruded Mg-Zn-based alloy","authors":"Wei Liu , Kaile Wang , Yuntao Zhang , Chuan Shuai , Taoze Xie , Wenyu Liu , Hua Hou , Yuhong Zhao","doi":"10.1016/j.ijplas.2025.104324","DOIUrl":"10.1016/j.ijplas.2025.104324","url":null,"abstract":"<div><div>To overcome bottleneck of strength-ductility trade-off is a challenge in Mg-Zn-based alloys. In this work, we develop an age-hardening Mg-1.0Zn-0.1Ca-0.1Al-0.1Mn (wt. %) hot-extruded alloy with better strength-ductility synergy by synergistic heterostructure and nanoprecipitate, exhibiting a tensile yield strength of 352 MPa, an ultimate tensile strength of 413 MPa and an elongation of 15.2 %, respectively. Besides, dynamic recrystallization and dynamic precipitation at different die angles (30° and 90°) and extrusion temperatures (220 °C, 235 °C and 250 °C), and aging precipitation are systematically investigated. Particle pinning effect on grain boundary (GB) considering particle radius and strengthening effects are further clarified. Firstly, under large die angle (90°) and low extrusion temperature (220 °C), typical heterostructure containing recrystallized regions and non-recrystallized regions is achieved due to significant particle pinning effect of nanoscale Ca<sub>2</sub>Mg<sub>6</sub>Zn<sub>3</sub> and Al<sub>8</sub>Mn<sub>5</sub> particles, and solute dragging effect of Zn and Ca elements on GB. Phase-field simulation and experimental validation showing the evolution of bow-shape GB under significant particle pinning force during the particle-GB interaction. Meanwhile, the phase-field simulations show that the maximum particle pinning force is enhanced as increasing of the particle radius. Secondly, upon ageing at 180 °C, a distinct double peak-aging characteristic emerges in the hetero-structured Mg-1.0Zn-0.1Ca-0.1Al-0.1Mn hot-extruded alloy. The first ageing peak mainly arises from the precipitation of GP zones, while the second ageing peak primarily originates from the co-precipitation of β<sub>1</sub>’ and β<sub>2</sub>’ phases. Finally, hetero-deformation induced strengthening, nanoprecipitate-reinforced Orowan strengthening and deformation coordination by twins and non-basal slips contribute to the strength-ductility synergy. These results provide valuable insights for developing high-performance Mg-Zn-based alloys.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"189 ","pages":"Article 104324"},"PeriodicalIF":9.4,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143766636","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 : 2025-03-30DOI: 10.1016/j.ijplas.2025.104322
Fusheng Tan , Zijie Shi , Quanfeng He , Bin Liu , Ao Fu , Zecheng Wu , Zhenbo Wang , Peter K. Liaw , Jia Li , Yong Yang , Qihong Fang
Multi-principal element alloys (MPEAs) have garnered significant attention due to their exceptional performance under extreme conditions such as high temperatures and irradiation, yet their diffusion behavior and mechanisms at elevated temperatures remain elusive. In this work, we investigate the diffusivity of a NixCoCr alloy system under high temperature conditions as a model for MPEAs. Our findings reveal that, the alloys with high mixing entropy exhibit unexpectedly diffusivity at ultra-high temperatures, challenging the conventional wisdom that diffusion in high-entropy alloys is typically sluggish. Based on tight-binging model, it is revealed that severe lattice distortion and electron interaction in high-entropy systems markedly weaken the atomic bonding strength. This phenomenon significantly reduces the vacancy formation energy and substantially increases the vacancy concentration especially at high temperature, thereby counteracting the inhibitory effect of reduced vacancy jump frequency on diffusion due to lattice distortion. This discovery not only provides new insights into the diffusion mechanisms of high-entropy alloys under extreme conditions but also holds significant implications for the design and optimization of high-performance materials suitable for extreme environments.
{"title":"Ultra-high temperature diffusion in multi-principal element alloys: Experiment, simulation and theory","authors":"Fusheng Tan , Zijie Shi , Quanfeng He , Bin Liu , Ao Fu , Zecheng Wu , Zhenbo Wang , Peter K. Liaw , Jia Li , Yong Yang , Qihong Fang","doi":"10.1016/j.ijplas.2025.104322","DOIUrl":"10.1016/j.ijplas.2025.104322","url":null,"abstract":"<div><div>Multi-principal element alloys (MPEAs) have garnered significant attention due to their exceptional performance under extreme conditions such as high temperatures and irradiation, yet their diffusion behavior and mechanisms at elevated temperatures remain elusive. In this work, we investigate the diffusivity of a Ni<sub>x</sub>CoCr alloy system under high temperature conditions as a model for MPEAs. Our findings reveal that, the alloys with high mixing entropy exhibit unexpectedly diffusivity at ultra-high temperatures, challenging the conventional wisdom that diffusion in high-entropy alloys is typically sluggish. Based on tight-binging model, it is revealed that severe lattice distortion and electron interaction in high-entropy systems markedly weaken the atomic bonding strength. This phenomenon significantly reduces the vacancy formation energy and substantially increases the vacancy concentration especially at high temperature, thereby counteracting the inhibitory effect of reduced vacancy jump frequency on diffusion due to lattice distortion. This discovery not only provides new insights into the diffusion mechanisms of high-entropy alloys under extreme conditions but also holds significant implications for the design and optimization of high-performance materials suitable for extreme environments.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104322"},"PeriodicalIF":9.4,"publicationDate":"2025-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143736356","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 : 2025-03-28DOI: 10.1016/j.ijplas.2025.104321
Keyan Wang, Zijian Cheng, Changyu Liu, Haiping Yu, Zhiliang Ning, Parthiban Ramasamy, Jürgen Eckert, Jianfei Sun, Yongjiang Huang, Yanming Zhang, Alfonso H.W. Ngan
This study systematically investigates the deformation mechanism and strengthening effects of the CoCrFeNiMn0.75Cu0.25 high-entropy alloy (HEA) under dynamic tensile loading across a wide temperature range (93 K to 1073 K). The HEA exhibits a ∼30% enhancement in strength and ductility at 93 K relative to its performance at 298 K. These superior properties result from the synergistic interactions among deformation bands, stacking faults (SFs), multiscale twinning, dislocations, and Lomer-Cottrell (L-C) locks, which enhance work hardening and delay fracture. At 873 K, dislocation slip becomes dominant, and dynamic recovery is activated, facilitating stress redistribution and more uniform macroscopic deformation. At 1073 K, discontinuous dynamic recrystallization (DDRX) occurs within deformation bands, producing refined grains that redistribute stress and maintain elongation above 60%, ensuring superior plasticity despite thermal softening. These findings indicate that temperature strongly influences microstructural evolution, with thermally activated dislocation motion, recovery, and recrystallization playing critical roles in determining the deformation response at high strain rates. This study provides new insights into the temperature-dependent strengthening mechanisms in HEAs, which have implications for the development of advanced materials for extreme environments.
{"title":"Deformation behavior and strengthening mechanisms of high-entropy alloys under high strain rate across wide temperature ranges","authors":"Keyan Wang, Zijian Cheng, Changyu Liu, Haiping Yu, Zhiliang Ning, Parthiban Ramasamy, Jürgen Eckert, Jianfei Sun, Yongjiang Huang, Yanming Zhang, Alfonso H.W. Ngan","doi":"10.1016/j.ijplas.2025.104321","DOIUrl":"https://doi.org/10.1016/j.ijplas.2025.104321","url":null,"abstract":"This study systematically investigates the deformation mechanism and strengthening effects of the CoCrFeNiMn<sub>0.75</sub>Cu<sub>0.25</sub> high-entropy alloy (HEA) under dynamic tensile loading across a wide temperature range (93 K to 1073 K). The HEA exhibits a ∼30% enhancement in strength and ductility at 93 K relative to its performance at 298 K. These superior properties result from the synergistic interactions among deformation bands, stacking faults (SFs), multiscale twinning, dislocations, and Lomer-Cottrell (L-C) locks, which enhance work hardening and delay fracture. At 873 K, dislocation slip becomes dominant, and dynamic recovery is activated, facilitating stress redistribution and more uniform macroscopic deformation. At 1073 K, discontinuous dynamic recrystallization (DDRX) occurs within deformation bands, producing refined grains that redistribute stress and maintain elongation above 60%, ensuring superior plasticity despite thermal softening. These findings indicate that temperature strongly influences microstructural evolution, with thermally activated dislocation motion, recovery, and recrystallization playing critical roles in determining the deformation response at high strain rates. This study provides new insights into the temperature-dependent strengthening mechanisms in HEAs, which have implications for the development of advanced materials for extreme environments.","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"215 1","pages":""},"PeriodicalIF":9.8,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143723415","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 : 2025-03-25DOI: 10.1016/j.ijplas.2025.104320
Li-Wen Xue , Hai-Long Jia , Jin-Kai Wang , Min Zha , Shen-Bao Jin , Hui-Yuan Wang
In this work, a double-stage aging (i.e., pre-aging plus second-aging) strategy has been conducted on an Al-8Si-2Cu-0.5Mg alloy to comprehensively investigate the formation of solute clusters during pre-aging and their impact on the subsequent precipitation behavior during second-aging. Particularly, strengthening and toughening mechanisms for enhanced mechanical properties of the double-stage aged (DA) Al-8Si-2Cu-0.5Mg alloy have been revealed in comparison to the single-stage aged (SA) counterpart. A combination of Cs-corrected transmission electron microscope (TEM), atom probe tomography (APT), first-principles calculations and molecular dynamic (MD) simulations is employed. The results reveal a marked tendency for Mg-Si-Cu cluster formation during pre-aging. This cluster growth is accompanied by preferential Mg enrichment within the clusters, i.e., the Mg:(Si+Cu) ratio of clusters shows an increasing trend during second-aging at 165 °C. This results in a high density of both Mg-Si-Cu clusters and mixed sub-unit precipitates in the peak-aged DA Al-Si-Cu-Mg alloy, which demonstrates a superior synergy of strength and ductility. The yield strength (YS) of both the peak-aged SA and DA alloys are nearly identical (∼295 MPa), while the elongation (EL) of the peak-aged DA alloy (∼14.2 %) is superior to that of the peak-aged SA alloy (∼9.2 %). MD simulations elucidate the toughening mechanism, i.e., Mg-Si-Cu clusters and mixed sub-unit precipitates induce weak stress concentrations, present a viable option for optimizing the strength-ductility balance. This research provides valuable insights into the microstructure evolution of Al-Si-Cu-Mg alloys during aging treatments, offering potential avenues for strength-ductility synergy of Al-Si-Cu-Mg alloys.
{"title":"Superior strength-ductility synergy of Al-Si-Cu-Mg alloys achieved by regulating solute clusters and precipitates: Experimental validation and numerical simulation","authors":"Li-Wen Xue , Hai-Long Jia , Jin-Kai Wang , Min Zha , Shen-Bao Jin , Hui-Yuan Wang","doi":"10.1016/j.ijplas.2025.104320","DOIUrl":"10.1016/j.ijplas.2025.104320","url":null,"abstract":"<div><div>In this work, a double-stage aging (i.e., pre-aging plus second-aging) strategy has been conducted on an Al-8Si-2Cu-0.5Mg alloy to comprehensively investigate the formation of solute clusters during pre-aging and their impact on the subsequent precipitation behavior during second-aging. Particularly, strengthening and toughening mechanisms for enhanced mechanical properties of the double-stage aged (DA) Al-8Si-2Cu-0.5Mg alloy have been revealed in comparison to the single-stage aged (SA) counterpart. A combination of Cs-corrected transmission electron microscope (TEM), atom probe tomography (APT), first-principles calculations and molecular dynamic (MD) simulations is employed. The results reveal a marked tendency for Mg-Si-Cu cluster formation during pre-aging. This cluster growth is accompanied by preferential Mg enrichment within the clusters, i.e., the Mg:(Si+Cu) ratio of clusters shows an increasing trend during second-aging at 165 °C. This results in a high density of both Mg-Si-Cu clusters and mixed sub-unit precipitates in the peak-aged DA Al-Si-Cu-Mg alloy, which demonstrates a superior synergy of strength and ductility. The yield strength (YS) of both the peak-aged SA and DA alloys are nearly identical (∼295 MPa), while the elongation (EL) of the peak-aged DA alloy (∼14.2 %) is superior to that of the peak-aged SA alloy (∼9.2 %). MD simulations elucidate the toughening mechanism, i.e., Mg-Si-Cu clusters and mixed sub-unit precipitates induce weak stress concentrations, present a viable option for optimizing the strength-ductility balance. This research provides valuable insights into the microstructure evolution of Al-Si-Cu-Mg alloys during aging treatments, offering potential avenues for strength-ductility synergy of Al-Si-Cu-Mg alloys.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104320"},"PeriodicalIF":9.4,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703288","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 investigates size effect in nickel-titanium (NiTi) shape memory alloys (SMAs), focusing on their elastic deformation and phase transformation behaviors. A series of experiments, including bulk-scale tension tests, micro-scale tension, compression, and cantilever bending tests, were conducted to observe the effect of specimen dimensions on SMA behavior. Micro-scale tension and compression tests unveiled a notable asymmetry in the phase transformation stress, irrespective of specimen dimensions. Moreover, micro-cantilever bending tests, spanning a thickness range from to , revealed a significant increase in both the effective elastic modulus and phase transformation stress as the beam thickness decreased. A constitutive model has been developed to address the tension/compression asymmetry and size effect based on couple stress theory, and implemented in finite element analysis of beam structures. Finally, experimental results were compared with simulation outcomes, and the deformation mechanisms responsible for size effect were discussed. The growing prominence of SMAs in micro/nano-scale applications highlights the necessity of understanding and accounting for size effect. Therefore, developing the capability to measure and simulate size effect is crucial for ensuring the effective utilization of SMAs in these scales.
{"title":"Strain gradient-induced size effect of Nickel-Titanium shape memory alloys","authors":"Jae-Hoon Choi , Hyemin Ryu , Ji-Young Kim , Kwang-Hyeok Lim , Gi-Dong Sim","doi":"10.1016/j.ijplas.2025.104309","DOIUrl":"10.1016/j.ijplas.2025.104309","url":null,"abstract":"<div><div>This study investigates size effect in nickel-titanium (NiTi) shape memory alloys (SMAs), focusing on their elastic deformation and phase transformation behaviors. A series of experiments, including bulk-scale tension tests, micro-scale tension, compression, and cantilever bending tests, were conducted to observe the effect of specimen dimensions on SMA behavior. Micro-scale tension and compression tests unveiled a notable asymmetry in the phase transformation stress, irrespective of specimen dimensions. Moreover, micro-cantilever bending tests, spanning a thickness range from <span><math><mrow><mn>1.9</mn></mrow></math></span> to <span><math><mrow><mn>21.0</mn><mspace></mspace><mrow><mi>μ</mi><mi>m</mi></mrow></mrow></math></span>, revealed a significant increase in both the effective elastic modulus and phase transformation stress as the beam thickness decreased. A constitutive model has been developed to address the tension/compression asymmetry and size effect based on couple stress theory, and implemented in finite element analysis of beam structures. Finally, experimental results were compared with simulation outcomes, and the deformation mechanisms responsible for size effect were discussed. The growing prominence of SMAs in micro/nano-scale applications highlights the necessity of understanding and accounting for size effect. Therefore, developing the capability to measure and simulate size effect is crucial for ensuring the effective utilization of SMAs in these scales.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104309"},"PeriodicalIF":9.4,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143695298","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 : 2025-03-24DOI: 10.1016/j.ijplas.2025.104311
Jan Schmidt , Surya R. Kalidindi , Alexander Hartmaier
Conventional yield criteria for anisotropic plasticity rely on linear transformations of the stress tensor to map the directional dependence of critical stress tensors at yield onset onto a unit sphere in stress space. These linear transformations are made material specific by a number of anisotropic parameters, which need to be determined by experimental procedures for each material. One drawback of this approach is that these anisotropic parameters cannot be explicitly expressed as functions of the crystallographic texture. Hence, any change in the texture of a material, as it occurs during cold deformation, requires a complete re-parametrization of the yield function. In this work, we present a data-oriented yield criterion based on Support Vector Classification (SVC) that is an explicit function of the crystallographic texture. This texture-dependency is achieved by including the coefficients of the general spherical harmonics (GSH) series expansion of the orientation distribution function (ODF) to the feature space of the machine learning model. The capabilities of the proposed yield criterion are demonstrated by training the model on a dataset containing micromechanical data from over 8000 distinct cubic-orthorhombic textures. The trained SVC combines the efficiency of classical phenomenological models with the flexibility of elaborate CP models. It provides a path to efficient hierarchical materials modeling as the anisotropy of the macroscopic yield onset is explicitly linked to the crystallographic texture.
{"title":"A texture-dependent yield criterion based on Support Vector Classification","authors":"Jan Schmidt , Surya R. Kalidindi , Alexander Hartmaier","doi":"10.1016/j.ijplas.2025.104311","DOIUrl":"10.1016/j.ijplas.2025.104311","url":null,"abstract":"<div><div>Conventional yield criteria for anisotropic plasticity rely on linear transformations of the stress tensor to map the directional dependence of critical stress tensors at yield onset onto a unit sphere in stress space. These linear transformations are made material specific by a number of anisotropic parameters, which need to be determined by experimental procedures for each material. One drawback of this approach is that these anisotropic parameters cannot be explicitly expressed as functions of the crystallographic texture. Hence, any change in the texture of a material, as it occurs during cold deformation, requires a complete re-parametrization of the yield function. In this work, we present a data-oriented yield criterion based on Support Vector Classification (SVC) that is an explicit function of the crystallographic texture. This texture-dependency is achieved by including the coefficients of the general spherical harmonics (GSH) series expansion of the orientation distribution function (ODF) to the feature space of the machine learning model. The capabilities of the proposed yield criterion are demonstrated by training the model on a dataset containing micromechanical data from over 8000 distinct cubic-orthorhombic textures. The trained SVC combines the efficiency of classical phenomenological models with the flexibility of elaborate CP models. It provides a path to efficient hierarchical materials modeling as the anisotropy of the macroscopic yield onset is explicitly linked to the crystallographic texture.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104311"},"PeriodicalIF":9.4,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143695299","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}
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