Pub Date : 2025-04-22DOI: 10.1016/j.ijplas.2025.104341
Marie-Christine Reuvers, Christopher Dannenberg, Sameer Kulkarni, Michael Johlitz, Alexander Lion, Stefanie Reese, Tim Brepols
In order to achieve process stability in the industrial thermoforming of fiber reinforced polymers (FRPs), typically, cost- and time-intensive trial-and-error-processes are required. The experimental boundary conditions, as well as the material composition and component design optimization, are highly dependent on material phenomena related to various material scales and constituents. It is therefore necessary to develop finite element constitutive models that are validated against experimental results and incorporate various material phenomena in order to reduce the experimental effort and evaluate the composite’s performance with reliable predictions. In this work, an existing thermo-mechanically coupled constitutive model for polyamide 6 is extended in a thermodynamically consistent manner to represent the anisotropic composite behavior, including anisotropic conduction, thermal expansion as well as internal heat generation associated with irreversible processes. Furthermore, the crystallization process is incorporated using experimental standard (S-DSC) and flash (F-DSC) differential scanning calorimetry results. The thermal and mechanical model parameters of the homogenized macroscopic material formulation are identified and the model response is successfully validated with a data base comprising both experimental and virtual results. Finally, the model capabilities are assessed in several thermo-mechanical structural computations, including a 3D thermoforming example in comparison with experimental results. In particular, the influence of the anisotropy on material self-heating, thermal expansion and the resulting crystalline state is investigated, demonstrating the potential of this new approach to efficiently and accurately predict FRPs in the future. Our source code, data, and exemplary input files are available under https://doi.org/10.5281/zenodo.15052983.
{"title":"An anisotropic thermo-mechanically coupled constitutive model for glass fiber reinforced polyamide 6 including crystallization kinetics","authors":"Marie-Christine Reuvers, Christopher Dannenberg, Sameer Kulkarni, Michael Johlitz, Alexander Lion, Stefanie Reese, Tim Brepols","doi":"10.1016/j.ijplas.2025.104341","DOIUrl":"https://doi.org/10.1016/j.ijplas.2025.104341","url":null,"abstract":"In order to achieve process stability in the industrial thermoforming of fiber reinforced polymers (FRPs), typically, cost- and time-intensive trial-and-error-processes are required. The experimental boundary conditions, as well as the material composition and component design optimization, are highly dependent on material phenomena related to various material scales and constituents. It is therefore necessary to develop finite element constitutive models that are validated against experimental results and incorporate various material phenomena in order to reduce the experimental effort and evaluate the composite’s performance with reliable predictions. In this work, an existing thermo-mechanically coupled constitutive model for polyamide 6 is extended in a thermodynamically consistent manner to represent the anisotropic composite behavior, including anisotropic conduction, thermal expansion as well as internal heat generation associated with irreversible processes. Furthermore, the crystallization process is incorporated using experimental standard (S-DSC) and flash (F-DSC) differential scanning calorimetry results. The thermal and mechanical model parameters of the homogenized macroscopic material formulation are identified and the model response is successfully validated with a data base comprising both experimental and virtual results. Finally, the model capabilities are assessed in several thermo-mechanical structural computations, including a 3D thermoforming example in comparison with experimental results. In particular, the influence of the anisotropy on material self-heating, thermal expansion and the resulting crystalline state is investigated, demonstrating the potential of this new approach to efficiently and accurately predict FRPs in the future. Our source code, data, and exemplary input files are available under <span><span>https://doi.org/10.5281/zenodo.15052983</span><svg aria-label=\"Opens in new window\" focusable=\"false\" height=\"20\" viewbox=\"0 0 8 8\"><path d=\"M1.12949 2.1072V1H7V6.85795H5.89111V2.90281L0.784057 8L0 7.21635L5.11902 2.1072H1.12949Z\"></path></svg></span>.","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"112 1","pages":""},"PeriodicalIF":9.8,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862280","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}
Mg96.3Ho1.6Y1.2Zn0.8Zr0.1 (at.%) alloy with sub-micron ultrafine grains containing nano-spacing solute-enriched planar defects is developed to exhibit high strengths (yield strength = ∼ 382 MPa and ultimate tensile strength = ∼ 426 MPa) and good ductility (fracture elongation = 19%), compared to the as-homogenized counterpart (yield strength = ∼ 160 MPa, ultimate tensile strength = ∼ 225 MPa, and fracture elongation = 7.5%). Ultrafine grains with an average grain size of ∼ 940 nm is attained via particle-stimulated nucleation mechanism induced by the second Mg12(Ho,Y)Zn phase during hot extrusion. A substantial number of ultrafine grains are formed surrounding these second-phase grains. The addition of Ho/Y/Zn elements lowers the I1 stacking fault energy, facilitating the formation of I1-type fault loops and promoting the activity of <c+a> dislocations. Meanwhile, the nano-spacing solute-enriched planar defects (including long-period stacking order structure and I2-type stacking faults) effectively hinder the motion of <c+a> dislocations, increasing flow stress while simultaneously promoting the activation of new <c+a> dislocations. As a result, the synergistic effect between ultrafine grains and solute-enriched planar defects significantly enhances the yield strength and facilitates the numerous non-basal dislocation activity responsible for significantly improved ductility. In addition, the refined second deformable Mg12(Ho,Y)Zn phase further strengthens the alloy and effectively delays the formation of macrocracks to improve the ductility. This study not only present an efficient strategy for developing high-strength, high-ductility Mg alloys but also provides new insights into the interplay between planar defects and dislocations.
{"title":"Ultra-strong and ductile magnesium alloy enabled by ultrafine grains with nano-spacing solute-enriched planar defects","authors":"Zhi Zhang, Jinshu Xie, Jinghuai Zhang, Ruizhi Wu, Jian Wang, Xu-Sheng Yang","doi":"10.1016/j.ijplas.2025.104348","DOIUrl":"https://doi.org/10.1016/j.ijplas.2025.104348","url":null,"abstract":"Mg<sub>96.3</sub>Ho<sub>1.6</sub>Y<sub>1.2</sub>Zn<sub>0.8</sub>Zr<sub>0.1</sub> (at.%) alloy with sub-micron ultrafine grains containing nano-spacing solute-enriched planar defects is developed to exhibit high strengths (yield strength = ∼ 382 MPa and ultimate tensile strength = ∼ 426 MPa) and good ductility (fracture elongation = 19%), compared to the as-homogenized counterpart (yield strength = ∼ 160 MPa, ultimate tensile strength = ∼ 225 MPa, and fracture elongation = 7.5%). Ultrafine grains with an average grain size of ∼ 940 nm is attained via particle-stimulated nucleation mechanism induced by the second Mg<sub>12</sub>(Ho,Y)Zn phase during hot extrusion. A substantial number of ultrafine grains are formed surrounding these second-phase grains. The addition of Ho/Y/Zn elements lowers the <em>I</em><sub>1</sub> stacking fault energy, facilitating the formation of <em>I</em><sub>1</sub>-type fault loops and promoting the activity of <c+a> dislocations. Meanwhile, the nano-spacing solute-enriched planar defects (including long-period stacking order structure and <em>I<sub>2</sub></em>-type stacking faults) effectively hinder the motion of <c+a> dislocations, increasing flow stress while simultaneously promoting the activation of new <c+a> dislocations. As a result, the synergistic effect between ultrafine grains and solute-enriched planar defects significantly enhances the yield strength and facilitates the numerous non-basal dislocation activity responsible for significantly improved ductility. In addition, the refined second deformable Mg<sub>12</sub>(Ho,Y)Zn phase further strengthens the alloy and effectively delays the formation of macrocracks to improve the ductility. This study not only present an efficient strategy for developing high-strength, high-ductility Mg alloys but also provides new insights into the interplay between planar defects and dislocations.","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"65 1","pages":""},"PeriodicalIF":9.8,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143853155","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}
Additive manufacturing (AM) of high-entropy alloys (HEAs) typically results in the formation of unique microstructures and deformation mechanisms, sparking widespread research interest. This study delves into the deformation behavior and strengthening mechanisms of an AMed HEA with hierarchical heterostructures. The results show that the alloy consists of the FCC matrix, coherent L12 precipitates, incoherent L21 precipitates with lens-shaped inclusions, and chemical cells. The distribution of the L21 phase and the lens-shaped inclusions are unique phenomena, mainly attributed to local chemical fluctuations during the AM process. The FCC matrix primarily contributes to plastic deformation, with L12 precipitates enhancing strength through ordered strengthening, and L21 precipitates providing strengthening via Orowan bypassing mechanism. Additionally, dislocation strengthening also contributes to the overall strength. Notably, the lens-shaped structures within the L21 phase undergo a stress-induced martensitic transformation during deformation, attributed to their inherent metastability, favorable microstructural locations and grain orientations. These findings deepen the understanding of the microstructures and deformation mechanisms of AMed HEAs, offering valuable insights for the design and optimization of high-performance HEAs in the future.
{"title":"Deformation Behavior and Strengthening Mechanisms of an Additively Manufactured High-Entropy Alloy with Hierarchical Heterostructures","authors":"Yunjian Bai, Yadong Li, Yizhe Liu, Cheng Yang, Yun-Jiang Wang, Kun Zhang, Bingchen Wei","doi":"10.1016/j.ijplas.2025.104347","DOIUrl":"https://doi.org/10.1016/j.ijplas.2025.104347","url":null,"abstract":"Additive manufacturing (AM) of high-entropy alloys (HEAs) typically results in the formation of unique microstructures and deformation mechanisms, sparking widespread research interest. This study delves into the deformation behavior and strengthening mechanisms of an AMed HEA with hierarchical heterostructures. The results show that the alloy consists of the FCC matrix, coherent L1<sub>2</sub> precipitates, incoherent L2<sub>1</sub> precipitates with lens-shaped inclusions, and chemical cells. The distribution of the L2<sub>1</sub> phase and the lens-shaped inclusions are unique phenomena, mainly attributed to local chemical fluctuations during the AM process. The FCC matrix primarily contributes to plastic deformation, with L1<sub>2</sub> precipitates enhancing strength through ordered strengthening, and L2<sub>1</sub> precipitates providing strengthening via Orowan bypassing mechanism. Additionally, dislocation strengthening also contributes to the overall strength. Notably, the lens-shaped structures within the L2<sub>1</sub> phase undergo a stress-induced martensitic transformation during deformation, attributed to their inherent metastability, favorable microstructural locations and grain orientations. These findings deepen the understanding of the microstructures and deformation mechanisms of AMed HEAs, offering valuable insights for the design and optimization of high-performance HEAs in the future.","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"268 1","pages":""},"PeriodicalIF":9.8,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143853156","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 : 2025-04-18DOI: 10.1016/j.ijplas.2025.104345
Jianfeng Zhao , Xu Zhang , Songjiang Lu , Dabiao Liu , Hui Chen , Guozheng Kang
The size effect in the initial yielding of metallic materials with deformation heterogeneity has garnered significant attention. However, the underlying physics of this effect remains unclear, and physically grounded models that quantify the relationship between microstructure and mechanical properties are still lacking. Here, we revisit both stress and strain gradient plasticity models, focusing particularly on the stress gradient model due to its physical material length scale and straightforward numerical implementation. By deriving yield stress models based on single-ended dislocation pileup, we identify a critical issue in stress gradient models: the assumption of dislocation pile-up configurations significantly affects yield stress predictions. To elucidate the dislocation mechanisms driving the size-dependent yielding behavior, we investigate two benchmark cases in gradient theories: homogeneous materials undergoing nonuniform deformation and heterostructured materials undergoing uniform deformation, utilizing nonlocal crystal plasticity and discrete dislocation dynamics simulations, respectively. The results not only clarify the issue raised in stress gradient theory, but also suggest the mechanism that pileup-induced stress plays a dominant role in governing the size effect during initial yielding for both homogeneous materials and heterostructured materials. These insights lead to the development of a new physically grounded model based on pileup-induced internal stress, i.e., back stress, which quantitatively predicts the size effect in the initial yielding of heterostructured material under tension and homogeneous material under torsion. This work clarifies the dislocation mechanisms governing extra strengthening in metallic materials with deformation heterogeneity and introduces a physically-based model quantitatively correlating the microstructures with the mechanical properties of heterostructured materials.
{"title":"A Physically Grounded Model for Size Effects in the Initial Yielding of Metallic Materials with Deformation Heterogeneity","authors":"Jianfeng Zhao , Xu Zhang , Songjiang Lu , Dabiao Liu , Hui Chen , Guozheng Kang","doi":"10.1016/j.ijplas.2025.104345","DOIUrl":"10.1016/j.ijplas.2025.104345","url":null,"abstract":"<div><div>The size effect in the initial yielding of metallic materials with deformation heterogeneity has garnered significant attention. However, the underlying physics of this effect remains unclear, and physically grounded models that quantify the relationship between microstructure and mechanical properties are still lacking. Here, we revisit both stress and strain gradient plasticity models, focusing particularly on the stress gradient model due to its physical material length scale and straightforward numerical implementation. By deriving yield stress models based on single-ended dislocation pileup, we identify a critical issue in stress gradient models: the assumption of dislocation pile-up configurations significantly affects yield stress predictions. To elucidate the dislocation mechanisms driving the size-dependent yielding behavior, we investigate two benchmark cases in gradient theories: homogeneous materials undergoing nonuniform deformation and heterostructured materials undergoing uniform deformation, utilizing nonlocal crystal plasticity and discrete dislocation dynamics simulations, respectively. The results not only clarify the issue raised in stress gradient theory, but also suggest the mechanism that pileup-induced stress plays a dominant role in governing the size effect during initial yielding for both homogeneous materials and heterostructured materials. These insights lead to the development of a new physically grounded model based on pileup-induced internal stress, i.e., back stress, which quantitatively predicts the size effect in the initial yielding of heterostructured material under tension and homogeneous material under torsion. This work clarifies the dislocation mechanisms governing extra strengthening in metallic materials with deformation heterogeneity and introduces a physically-based model quantitatively correlating the microstructures with the mechanical properties of heterostructured materials.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"189 ","pages":"Article 104345"},"PeriodicalIF":9.4,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143849745","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}
Ti-containing face centred cubic (FCC) high entropy alloys (HEAs) have garnered significant attention due to their exceptional mechanical properties. Nevertheless, the role of Ti on contributory strengthening mechanisms and the corresponding deformation behavior remains less explored till date. The present study sheds light on evolution of microscale plastic deformation mechanism and the associated strengthening effects induced by Ti addition in a novel spark plasma sintered Ni46-xCo18-xAl12Cr8Fe12Mo4-yTi2z (x = 0, y = 0, z = 0; x = 0, 1 and 2, y = 2, z = 1, 2 and 3 at. %) HEA through a combination of experimental analyses and molecular dynamics (MD) simulations. The sintered compacts were composed of FCC solid solution with presence of minor amounts of brittle Cr-rich and Mo-rich sigma (σ) phases, along with essential L12 phase in the FCC matrix. Yield strength and compressive strength increased continuously with increasing Ti content, from 1130 MPa and 1809 MPa in Ti-free HEA to 1452 MPa and 2011 MPa in 6 at. % Ti containing HEA, respectively, while maintaining an appreciable fracture strain > 26 % in all the consolidated HEAs. Such remarkable mechanical properties are primarily attributed to inherent solid solution strengthening from Ti-induced lattice distortion, along with synergistic effect of narrow twin boundaries, finer grain size and precipitation strengthening from L12 phase. Furthermore, MD simulation revealed that increasing Ti content lowered stacking fault energy of the HEAs and promoted formation of deformation twins (DTs) and stacking faults (SFs). Characterization of deformed microstructures at sequential strain levels showed that plastic deformation in Ti-free HEA was primarily mediated by ordinary dislocation slip, whereas with increase in Ti content, plastic deformation predominantly proceeded through formation of SF networks and DTs, alongside dislocation gliding. Additionally, increased dynamic recrystallization fraction in higher Ti-containing HEAs during loading, attributed to increased pre-existing strain within grains, contributed in retaining impressive ductility. This study provides comprehensive insights into the deformation mechanisms in Ti-added Ni-rich FCC HEAs and offers guidance for designing high-performance HEAs.
{"title":"Unravelling the deformation mechanisms in Ni-rich high entropy alloy with tailored Ti content: An experimental and atomistic approach","authors":"Sudhansu Maharana, Sankalp Biswal, Manashi Sabat, D.K.V.D. Prasad, Tapas Laha","doi":"10.1016/j.ijplas.2025.104346","DOIUrl":"10.1016/j.ijplas.2025.104346","url":null,"abstract":"<div><div>Ti-containing face centred cubic (FCC) high entropy alloys (HEAs) have garnered significant attention due to their exceptional mechanical properties. Nevertheless, the role of Ti on contributory strengthening mechanisms and the corresponding deformation behavior remains less explored till date. The present study sheds light on evolution of microscale plastic deformation mechanism and the associated strengthening effects induced by Ti addition in a novel spark plasma sintered Ni<sub>46-x</sub>Co<sub>18-x</sub>Al<sub>12</sub>Cr<sub>8</sub>Fe<sub>12</sub>Mo<sub>4-y</sub>Ti<sub>2z</sub> (<em>x</em> = 0, <em>y</em> = 0, <em>z</em> = 0; <em>x</em> = 0, 1 and 2, <em>y</em> = 2, <em>z</em> = 1, 2 and 3 at. %) HEA through a combination of experimental analyses and molecular dynamics (MD) simulations. The sintered compacts were composed of FCC solid solution with presence of minor amounts of brittle Cr-rich and Mo-rich sigma (σ) phases, along with essential L1<sub>2</sub> phase in the FCC matrix. Yield strength and compressive strength increased continuously with increasing Ti content, from 1130 MPa and 1809 MPa in Ti-free HEA to 1452 MPa and 2011 MPa in 6 at. % Ti containing HEA, respectively, while maintaining an appreciable fracture strain > 26 % in all the consolidated HEAs. Such remarkable mechanical properties are primarily attributed to inherent solid solution strengthening from Ti-induced lattice distortion, along with synergistic effect of narrow twin boundaries, finer grain size and precipitation strengthening from L1<sub>2</sub> phase. Furthermore, MD simulation revealed that increasing Ti content lowered stacking fault energy of the HEAs and promoted formation of deformation twins (DTs) and stacking faults (SFs). Characterization of deformed microstructures at sequential strain levels showed that plastic deformation in Ti-free HEA was primarily mediated by ordinary dislocation slip, whereas with increase in Ti content, plastic deformation predominantly proceeded through formation of SF networks and DTs, alongside dislocation gliding. Additionally, increased dynamic recrystallization fraction in higher Ti-containing HEAs during loading, attributed to increased pre-existing strain within grains, contributed in retaining impressive ductility. This study provides comprehensive insights into the deformation mechanisms in Ti-added Ni-rich FCC HEAs and offers guidance for designing high-performance HEAs.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"189 ","pages":"Article 104346"},"PeriodicalIF":9.4,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143846553","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 : 2025-04-15DOI: 10.1016/j.ijplas.2025.104343
Xiaowei Li , Yaxin Zhu , Lv Zhao , Shuang Liang , Minsheng Huang , Zhenhuan Li
The unique two-phase microstructure of nickel-based single crystal superalloys (NBSCSs) imparts exceptional high-temperature mechanical properties, promoting the use of NBSCSs for turbine blades. A moderate addition of rhenium (Re) can further enhance the mechanical properties by influencing dislocation evolution within the two-phase microstructure and mitigating rafting. The present work aims to quantitatively correlate dislocation evolution and rafting in the two-phase microstructure with the macroscopic mechanical behavior of NBSCSs. To this end, a representative volume element (RVE) consisting of a cubic precipitate surrounded by horizontal and vertical matrix channels is built, and a micromechanical homogenization method based on small perturbation analysis is adopted. To improve the computational efficiency while maintaining a reasonable accuracy, an approximate algorithm is proposed. Based on this, a two-phase microstructure-based crystal plasticity (CP) constitutive model that incorporates Re-influenced dislocation evolution mechanisms and accounts for Re-influenced evolution of the two-phase microstructure (i.e., rafting) has been developed. Using a unified set of constitutive parameters, this CP model successfully predicts both the instantaneous plasticity and prolonged-time creep behaviors of NBSCSs under various temperatures, loading rates and loading orientations. It is noteworthy that the influence of Re doping on both dislocation evolution and rafting is considered in the present CP model, significantly enhancing its ability for describing the mechanical behavior of NBSCSs.
{"title":"Two-phase microstructure-based crystal plasticity constitutive model for nickel-based single crystal superalloys incorporating Re effects on rafting and dislocation evolution","authors":"Xiaowei Li , Yaxin Zhu , Lv Zhao , Shuang Liang , Minsheng Huang , Zhenhuan Li","doi":"10.1016/j.ijplas.2025.104343","DOIUrl":"10.1016/j.ijplas.2025.104343","url":null,"abstract":"<div><div>The unique two-phase microstructure of nickel-based single crystal superalloys (NBSCSs) imparts exceptional high-temperature mechanical properties, promoting the use of NBSCSs for turbine blades. A moderate addition of rhenium (Re) can further enhance the mechanical properties by influencing dislocation evolution within the two-phase microstructure and mitigating rafting. The present work aims to quantitatively correlate dislocation evolution and rafting in the two-phase microstructure with the macroscopic mechanical behavior of NBSCSs. To this end, a representative volume element (RVE) consisting of a cubic precipitate surrounded by horizontal and vertical matrix channels is built, and a micromechanical homogenization method based on small perturbation analysis is adopted. To improve the computational efficiency while maintaining a reasonable accuracy, an approximate algorithm is proposed. Based on this, a two-phase microstructure-based crystal plasticity (CP) constitutive model that incorporates Re-influenced dislocation evolution mechanisms and accounts for Re-influenced evolution of the two-phase microstructure (i.e., rafting) has been developed. Using a unified set of constitutive parameters, this CP model successfully predicts both the instantaneous plasticity and prolonged-time creep behaviors of NBSCSs under various temperatures, loading rates and loading orientations. It is noteworthy that the influence of Re doping on both dislocation evolution and rafting is considered in the present CP model, significantly enhancing its ability for describing the mechanical behavior of NBSCSs.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"189 ","pages":"Article 104343"},"PeriodicalIF":9.4,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143836870","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 : 2025-04-12DOI: 10.1016/j.ijplas.2025.104339
Wen An , Jiang-Peng Yang , Chuan-Zhi Liu , Qi-Lin Xiong
As one of the most important plastic deformation mechanisms of high-entropy alloys, deformation twinning can increase the strength without losing plasticity. Nevertheless, recent studies have shown that high-density twins can form "soft spots" and promote the occurrence of shear localization failure at high strain rates. The extent to which deformation twins contribute to the formation of shear localization remains unclear. In this study, a series of dynamic uniaxial compression experiments have been performed with Al0.1CoCrFeNi HEAs under different conditions to disclose the dynamic recrystallization mechanism. Corresponding to the dynamic recrystallization and plastic dissipation mechanisms at high strain rates, a dislocation entanglement model has been established in conjunction with deformation twinning and physically based heat dissipation to capture the process of shear localization formation. The dislocation entanglement model has been integrated into the theoretical framework of crystal plasticity to perform finite element simulations of high-strain rate deformations. The results predicted by the crystal plasticity simulations are in good agreement with the experimental data, confirming the rationality of the new constitutive model. Deformation twinning can significantly improve strain hardening ability and resistance to shear localization. Interestingly, when the volume fraction of twins reaches a certain level, the mechanism of twin-assisted continuous dynamic recrystallization is triggered due to the interaction between dislocations and twins, resulting in the formation of many “soft spots” (corresponding to the twin region with high density). Upon further deformation, these “soft spots” continue to evolve and aggregate to eventually form the bands of shear localization. Our results can be used for the microstructure design of dynamic high-performance metals with high strength and plasticity to artificially control shear localization.
{"title":"Effect of twinning on shear localization of Al0.1CoCrFeNi high entropy alloy at high strain rates: Experiment and crystal plasticity modeling","authors":"Wen An , Jiang-Peng Yang , Chuan-Zhi Liu , Qi-Lin Xiong","doi":"10.1016/j.ijplas.2025.104339","DOIUrl":"10.1016/j.ijplas.2025.104339","url":null,"abstract":"<div><div>As one of the most important plastic deformation mechanisms of high-entropy alloys, deformation twinning can increase the strength without losing plasticity. Nevertheless, recent studies have shown that high-density twins can form \"soft spots\" and promote the occurrence of shear localization failure at high strain rates. The extent to which deformation twins contribute to the formation of shear localization remains unclear. In this study, a series of dynamic uniaxial compression experiments have been performed with Al<sub>0.1</sub>CoCrFeNi HEAs under different conditions to disclose the dynamic recrystallization mechanism. Corresponding to the dynamic recrystallization and plastic dissipation mechanisms at high strain rates, a dislocation entanglement model has been established in conjunction with deformation twinning and physically based heat dissipation to capture the process of shear localization formation. The dislocation entanglement model has been integrated into the theoretical framework of crystal plasticity to perform finite element simulations of high-strain rate deformations. The results predicted by the crystal plasticity simulations are in good agreement with the experimental data, confirming the rationality of the new constitutive model. Deformation twinning can significantly improve strain hardening ability and resistance to shear localization. Interestingly, when the volume fraction of twins reaches a certain level, the mechanism of twin-assisted continuous dynamic recrystallization is triggered due to the interaction between dislocations and twins, resulting in the formation of many “soft spots” (corresponding to the twin region with high density). Upon further deformation, these “soft spots” continue to evolve and aggregate to eventually form the bands of shear localization. Our results can be used for the microstructure design of dynamic high-performance metals with high strength and plasticity to artificially control shear localization.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"189 ","pages":"Article 104339"},"PeriodicalIF":9.4,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143822646","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 : 2025-04-12DOI: 10.1016/j.ijplas.2025.104342
Yaojie Wen , Yang Gao , Ramasubramanian Lakshmi Narayan , Wei Cai , Pei Wang , Xiaoding Wei , Baicheng Zhang , Upadrasta Ramamurty , Xuanhui Qu
The microstructure and tensile behavior of laser powder bed fusion (LPBF) processed 316L austenitic stainless steel (316L) and Inconel 718 Ni-based superalloy (IN718) coupons with compositionally graded joints (CGJ), spanning lengths of 0, 10 and 20 mm, in the as built and heat-treated conditions, are investigated. In the as built condition, the microstructure of pure 316L and IN718 ligaments consist of micron-sized sub-grains present within 〈001〉 textured columnar grains, whereas CGJs contain a mixture of randomly textured columnar and equiaxed grains. Heat treatment, involving solutionizing above 1040 °C with subsequent ageing at 720 and 620 °C, leads to the recrystallization of portions with > 85 wt. % IN718 of the CGJ coupons. Higher composition gradient span, in both the as built and heat-treated states, improves the yield and tensile strengths of the specimens, but compromises ductility. Simulations indicate that CGJs with shallower composition gradients have lower fluctuations in the stress triaxiality, von mises equivalent stress, and the maximum shear stress compared to those with sharper gradients. These mechanical property variations and the deformation characteristics of the CGJ specimens are analyzed in detail by considering the varying degrees of plastic constraint on the 100 wt. % 316L and the degree of interactions between strain-generated dislocations and geometrically necessary dislocations. Finally, the effectiveness of CGJ in enhancing the tensile properties of the 316L/IN718 joints and the geometrical considerations for designing such joints for different alloy combinations is discussed.
{"title":"Tensile behavior of additively manufactured Inconel 718 and stainless steel 316L with compositionally graded joints","authors":"Yaojie Wen , Yang Gao , Ramasubramanian Lakshmi Narayan , Wei Cai , Pei Wang , Xiaoding Wei , Baicheng Zhang , Upadrasta Ramamurty , Xuanhui Qu","doi":"10.1016/j.ijplas.2025.104342","DOIUrl":"10.1016/j.ijplas.2025.104342","url":null,"abstract":"<div><div>The microstructure and tensile behavior of laser powder bed fusion (LPBF) processed 316L austenitic stainless steel (316L) and Inconel 718 Ni-based superalloy (IN718) coupons with compositionally graded joints (CGJ), spanning lengths of 0, 10 and 20 mm, in the as built and heat-treated conditions, are investigated. In the as built condition, the microstructure of pure 316L and IN718 ligaments consist of micron-sized sub-grains present within 〈001〉 textured columnar grains, whereas CGJs contain a mixture of randomly textured columnar and equiaxed grains. Heat treatment, involving solutionizing above 1040 °C with subsequent ageing at 720 and 620 °C, leads to the recrystallization of portions with > 85 wt. % IN718 of the CGJ coupons. Higher composition gradient span, in both the as built and heat-treated states, improves the yield and tensile strengths of the specimens, but compromises ductility. Simulations indicate that CGJs with shallower composition gradients have lower fluctuations in the stress triaxiality, von mises equivalent stress, and the maximum shear stress compared to those with sharper gradients. These mechanical property variations and the deformation characteristics of the CGJ specimens are analyzed in detail by considering the varying degrees of plastic constraint on the 100 wt. % 316L and the degree of interactions between strain-generated dislocations and geometrically necessary dislocations. Finally, the effectiveness of CGJ in enhancing the tensile properties of the 316L/IN718 joints and the geometrical considerations for designing such joints for different alloy combinations is discussed.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"189 ","pages":"Article 104342"},"PeriodicalIF":9.4,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143822647","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 : 2025-04-11DOI: 10.1016/j.ijplas.2025.104340
Jie Li , Yaxin Zhu , Lv Zhao , Shuang Liang , Minsheng Huang , Zhenhuan Li
Refractory high-entropy alloys (RHEAs) exhibit excellent anti-irradiation properties, making them promising candidates for application in advanced nuclear reactors. In this study, molecular statics (MS) and molecular dynamics (MD) simulations are conducted to investigate the local unstable stacking fault energy (USFE) in RHEAs induced by primary knock-on atoms (PKAs) of displacement cascades. Based on these atomistic simulations, a phase-field dislocation dynamics (PFDD) model is developed, incorporating the effects of chemical composition fluctuations and displacement cascades on local USFE in RHEAs using a random statistical approach. Using this PFDD model, the planar motion of edge and screw dislocations, as well as the cross-slip behavior of screw dislocations, in WTaCrV are examined. The results indicate that the cascade region can effectively pin edge dislocations and hinder the nucleation of kink pairs in screw dislocations, leading to irradiation hardening. However, the low local USFE caused by chemical composition fluctuations in WTaCrV allows edge dislocation segments near pinning sites to bow out, dragging pinned dislocation segments and reducing the pinning effect. Additionally, the low local USFE promotes the nucleation and migration of kink pairs in screw dislocations. Furthermore, for the case of screw dislocation cross-slip, the irradiation hardening is alleviated as nonplanar kink pairs recede to the habit plane. These simulation results reveal the mesoscale internal mechanisms underlying anti-irradiation hardening in RHEAs. Based on these findings, mesoscale theoretical models describing dislocation motion and irradiation hardening are proposed, and they are verified experimentally. With these models, the irradiation hardening behavior of other RHEAs can be predicted. These findings can guide the design and preparation of advanced anti-irradiation RHEAs and contribute to the development of upscaled theoretical models and simulation methods.
{"title":"Investigate irradiation hardening behavior in BCC refractory high-entropy alloys using phase-field modeling informed by atomistic simulations of displacement cascades","authors":"Jie Li , Yaxin Zhu , Lv Zhao , Shuang Liang , Minsheng Huang , Zhenhuan Li","doi":"10.1016/j.ijplas.2025.104340","DOIUrl":"10.1016/j.ijplas.2025.104340","url":null,"abstract":"<div><div>Refractory high-entropy alloys (RHEAs) exhibit excellent anti-irradiation properties, making them promising candidates for application in advanced nuclear reactors. In this study, molecular statics (MS) and molecular dynamics (MD) simulations are conducted to investigate the local unstable stacking fault energy (USFE) in RHEAs induced by primary knock-on atoms (PKAs) of displacement cascades. Based on these atomistic simulations, a phase-field dislocation dynamics (PFDD) model is developed, incorporating the effects of chemical composition fluctuations and displacement cascades on local USFE in RHEAs using a random statistical approach. Using this PFDD model, the planar motion of edge and screw dislocations, as well as the cross-slip behavior of screw dislocations, in WTaCrV are examined. The results indicate that the cascade region can effectively pin edge dislocations and hinder the nucleation of kink pairs in screw dislocations, leading to irradiation hardening. However, the low local USFE caused by chemical composition fluctuations in WTaCrV allows edge dislocation segments near pinning sites to bow out, dragging pinned dislocation segments and reducing the pinning effect. Additionally, the low local USFE promotes the nucleation and migration of kink pairs in screw dislocations. Furthermore, for the case of screw dislocation cross-slip, the irradiation hardening is alleviated as nonplanar kink pairs recede to the habit plane. These simulation results reveal the mesoscale internal mechanisms underlying anti-irradiation hardening in RHEAs. Based on these findings, mesoscale theoretical models describing dislocation motion and irradiation hardening are proposed, and they are verified experimentally. With these models, the irradiation hardening behavior of other RHEAs can be predicted. These findings can guide the design and preparation of advanced anti-irradiation RHEAs and contribute to the development of upscaled theoretical models and simulation methods.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"189 ","pages":"Article 104340"},"PeriodicalIF":9.4,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143820082","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 new plasticity-induced internal length mean field model (ILMF) is developed, based on statistical analyses of geometrically necessary dislocation (GND) densities and total dislocation densities estimated from EBSD and nanoindentation data, respectively. It is applied to a single phase ferritic Al-killed steel, which plastically deforms with the occurrence of heterogeneous intra-granular fields. During tensile tests up to 18% of overall plastic strain, the deformation maps of GND densities due to intra-granular plastic strain gradients are obtained together with nano-hardness maps. The Nye tensor (or dislocation density tensor) is calculated from the 2D EBSD orientations to estimate the intragranular GND density, while a mechanistic model is used to estimate the intragranular total dislocation density from nano-hardness measurements. These data are quantified as a function of the distance to grain boundaries (GBs) to study the development of such plastic strain gradients in the vicinity of GBs. The novel methodology lies in extracting the evolution law of a single plasticity-induced internal length, denoted <span><span style=""></span><span data-mathml='<math xmlns="http://www.w3.org/1998/Math/MathML"><mi is="true">λ</mi></math>' role="presentation" style="font-size: 90%; display: inline-block; position: relative;" tabindex="0"><svg aria-hidden="true" focusable="false" height="1.971ex" role="img" style="vertical-align: -0.235ex;" viewbox="0 -747.2 583.5 848.5" width="1.355ex" xmlns:xlink="http://www.w3.org/1999/xlink"><g fill="currentColor" stroke="currentColor" stroke-width="0" transform="matrix(1 0 0 -1 0 0)"><g is="true"><use xlink:href="#MJMATHI-3BB"></use></g></g></svg><span role="presentation"><math xmlns="http://www.w3.org/1998/Math/MathML"><mi is="true">λ</mi></math></span></span><script type="math/mml"><math><mi is="true">λ</mi></math></script></span>, from the statistical analysis of GND and total dislocation densities spatial distribution. Hence, it is introduced as an evolving variable in an elastoviscoplastic self-consistent model (EVPSC) for a two-phase composite as a new internal mean field (ILMF) approach. Both experimentally quantified microstructural internal lengths defined by the mean grain size and the evolving layer <span><span style=""></span><span data-mathml='<math xmlns="http://www.w3.org/1998/Math/MathML"><mi is="true">λ</mi></math>' role="presentation" style="font-size: 90%; display: inline-block; position: relative;" tabindex="0"><svg aria-hidden="true" focusable="false" height="1.971ex" role="img" style="vertical-align: -0.235ex;" viewbox="0 -747.2 583.5 848.5" width="1.355ex" xmlns:xlink="http://www.w3.org/1999/xlink"><g fill="currentColor" stroke="currentColor" stroke-width="0" transform="matrix(1 0 0 -1 0 0)"><g is="true"><use xlink:href="#MJMATHI-3BB"></use></g></g></svg><span role="presentation"><math xmlns="http://www.w3.org/1998/Math/MathML">
{"title":"A plasticity-induced internal length mean field model based on statistical analyses of EBSD and nanoindentation data","authors":"Layal Chamma, Jean-Marc Pipard, Artem Arlazarov, Thiebaud Richeton, Stéphane Berbenni","doi":"10.1016/j.ijplas.2025.104327","DOIUrl":"https://doi.org/10.1016/j.ijplas.2025.104327","url":null,"abstract":"A new plasticity-induced internal length mean field model (ILMF) is developed, based on statistical analyses of geometrically necessary dislocation (GND) densities and total dislocation densities estimated from EBSD and nanoindentation data, respectively. It is applied to a single phase ferritic Al-killed steel, which plastically deforms with the occurrence of heterogeneous intra-granular fields. During tensile tests up to 18% of overall plastic strain, the deformation maps of GND densities due to intra-granular plastic strain gradients are obtained together with nano-hardness maps. The Nye tensor (or dislocation density tensor) is calculated from the 2D EBSD orientations to estimate the intragranular GND density, while a mechanistic model is used to estimate the intragranular total dislocation density from nano-hardness measurements. These data are quantified as a function of the distance to grain boundaries (GBs) to study the development of such plastic strain gradients in the vicinity of GBs. The novel methodology lies in extracting the evolution law of a single plasticity-induced internal length, denoted <span><span style=\"\"></span><span data-mathml='<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi is=\"true\">&#x3BB;</mi></math>' role=\"presentation\" style=\"font-size: 90%; display: inline-block; position: relative;\" tabindex=\"0\"><svg aria-hidden=\"true\" focusable=\"false\" height=\"1.971ex\" role=\"img\" style=\"vertical-align: -0.235ex;\" viewbox=\"0 -747.2 583.5 848.5\" width=\"1.355ex\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"><g is=\"true\"><use xlink:href=\"#MJMATHI-3BB\"></use></g></g></svg><span role=\"presentation\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi is=\"true\">λ</mi></math></span></span><script type=\"math/mml\"><math><mi is=\"true\">λ</mi></math></script></span>, from the statistical analysis of GND and total dislocation densities spatial distribution. Hence, it is introduced as an evolving variable in an elastoviscoplastic self-consistent model (EVPSC) for a two-phase composite as a new internal mean field (ILMF) approach. Both experimentally quantified microstructural internal lengths defined by the mean grain size and the evolving layer <span><span style=\"\"></span><span data-mathml='<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi is=\"true\">&#x3BB;</mi></math>' role=\"presentation\" style=\"font-size: 90%; display: inline-block; position: relative;\" tabindex=\"0\"><svg aria-hidden=\"true\" focusable=\"false\" height=\"1.971ex\" role=\"img\" style=\"vertical-align: -0.235ex;\" viewbox=\"0 -747.2 583.5 848.5\" width=\"1.355ex\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"><g is=\"true\"><use xlink:href=\"#MJMATHI-3BB\"></use></g></g></svg><span role=\"presentation\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\">","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"75 1","pages":""},"PeriodicalIF":9.8,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143813918","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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