Pub Date : 2025-11-03DOI: 10.1016/j.ijplas.2025.104533
Jiawen Zhang , Zhangtao Li , Yuwei Zhang , Hendrik Holz , James P. Best , Oliver Preuß , Zhenyong Chen , Yinan Cui , Xufei Fang , Wenjun Lu
Dislocations in ceramics have recently gained renewed research interest, in contrast to the traditional belief that ceramics are inherently brittle. Understanding dislocation mechanics in representative oxides is beneficial for effective dislocation engineering. Here, we use MgO single crystals with mechanically seeded dislocation densities from ∼1012 to ∼1015 m-2 to investigate the mechanical behavior such as yield and fracture. Micro-pillar compression tests reveal a dislocation density dependent yield strength, mediated by the varying dominating dislocation mechanisms from nucleation to multiplication/motion. In situ TEM compression measurements highlight the dislocation-seeded samples can achieve a much-improved compressive plastic strain beyond ∼70%, with a high yield strength of ∼2.35 GPa (diameter of ∼400 nm), indicating size effect. Complementary bulk compression tests, along with digital image correlation (DIC), demonstrate a consistent dislocation-mediated deformation and a notable size effect, with bulk samples exhibiting much reduced yield strength (∼120 MPa) compared to the nano-/micro-pillars. Using three-dimensional Discrete Dislocation Dynamics (3D-DDD) simulation, we further qualitatively analyze the collective dislocation activities (slip events) and work hardening during compression. This study provides new insights into dislocation-mediated plasticity in MgO, across different length scales, by systematically tuning dislocation density.
{"title":"Scale-bridging dislocation plasticity in MgO at room temperature","authors":"Jiawen Zhang , Zhangtao Li , Yuwei Zhang , Hendrik Holz , James P. Best , Oliver Preuß , Zhenyong Chen , Yinan Cui , Xufei Fang , Wenjun Lu","doi":"10.1016/j.ijplas.2025.104533","DOIUrl":"10.1016/j.ijplas.2025.104533","url":null,"abstract":"<div><div>Dislocations in ceramics have recently gained renewed research interest, in contrast to the traditional belief that ceramics are inherently brittle. Understanding dislocation mechanics in representative oxides is beneficial for effective dislocation engineering. Here, we use MgO single crystals with mechanically seeded dislocation densities from ∼10<sup>12</sup> to ∼10<sup>15</sup> m<sup>-2</sup> to investigate the mechanical behavior such as yield and fracture. Micro-pillar compression tests reveal a dislocation density dependent yield strength, mediated by the varying dominating dislocation mechanisms from nucleation to multiplication/motion. <em>In situ</em> TEM compression measurements highlight the dislocation-seeded samples can achieve a much-improved compressive plastic strain beyond ∼70%, with a high yield strength of ∼2.35 GPa (diameter of ∼400 nm), indicating size effect. Complementary bulk compression tests, along with digital image correlation (DIC), demonstrate a consistent dislocation-mediated deformation and a notable size effect, with bulk samples exhibiting much reduced yield strength (∼120 MPa) compared to the nano-/micro-pillars. Using three-dimensional Discrete Dislocation Dynamics (3D-DDD) simulation, we further qualitatively analyze the collective dislocation activities (slip events) and work hardening during compression. This study provides new insights into dislocation-mediated plasticity in MgO, across different length scales, by systematically tuning dislocation density.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"195 ","pages":"Article 104533"},"PeriodicalIF":12.8,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145428020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-03DOI: 10.1016/j.ijplas.2025.104538
Mengke Cai , Tenglong Cong , Yinan Cui , Yang Li , Zhifang Qiu , Zhipeng Sun , Hanyang Gu
Uranium dioxide (UO2), the most widely used nuclear fuel, exhibits complex plasticity and highly anisotropic mechanical properties. Under high burnup conditions, the rim region is formed with tangled dislocation networks in UO2, involving the propagation and interaction of dislocations in multiple slip systems, leading to distinct behaviors compared to the traditional metals. In this work, we proposed an atomic-informed dislocation mobility law corresponding to both {100} and {110} slip systems, with all parameters calibrated from experiments. By employing this newly developed mobility law as well as a thermally activated cross-slip model, we carried out three-dimensional discrete dislocation dynamics (DDD) simulations to explore the anisotropic plastic responses of UO2 across a wide range of temperatures from 900 K to 1900 K. The temperature dependence of critical resolved shear stress of {100} and {110} slip systems has been successfully reproduced by our simulations, which agrees well with experimental data. A strong orientation and temperature dependent yield strength has been observed from the single crystal UO2 tensile tests, which agrees well with experiments. Notably, the experimentally observed yield stress drop of UO2 is reproduced in our DDD simulations, rooted in the slip system transition from the {110} (hard) to {100} (easy) slip systems. To highlight the interplay of dislocations in different slip systems, a dislocation density evolution model was established, incorporating dislocation multiplication, annihilation, cross-slip, and junction formation mechanisms. This model not only accurately predicts the dislocation density evolution for both {100} and {110} slip systems, but also reveals the underlying mechanism for the aforementioned slip transition behaviors. In conjunction with the dislocation mobility law, a dislocation-based crystal plasticity model was developed which can accurately predict the macroscopic mechanical response of single crystal UO2 under different temperatures and strain rates. These insights are expected to shed light on understanding the mechanical anisotropy of UO2 under high irradiation dose and complex loading conditions.
{"title":"Theoretical and numerical investigations of dislocation evolution and anisotropic plasticity in UO2","authors":"Mengke Cai , Tenglong Cong , Yinan Cui , Yang Li , Zhifang Qiu , Zhipeng Sun , Hanyang Gu","doi":"10.1016/j.ijplas.2025.104538","DOIUrl":"10.1016/j.ijplas.2025.104538","url":null,"abstract":"<div><div>Uranium dioxide (UO<sub>2</sub>), the most widely used nuclear fuel, exhibits complex plasticity and highly anisotropic mechanical properties. Under high burnup conditions, the rim region is formed with tangled dislocation networks in UO<sub>2</sub>, involving the propagation and interaction of dislocations in multiple slip systems, leading to distinct behaviors compared to the traditional metals. In this work, we proposed an atomic-informed dislocation mobility law corresponding to both {100} and {110} slip systems, with all parameters calibrated from experiments. By employing this newly developed mobility law as well as a thermally activated cross-slip model, we carried out three-dimensional discrete dislocation dynamics (DDD) simulations to explore the anisotropic plastic responses of UO<sub>2</sub> across a wide range of temperatures from 900 K to 1900 K. The temperature dependence of critical resolved shear stress of {100} and {110} slip systems has been successfully reproduced by our simulations, which agrees well with experimental data. A strong orientation and temperature dependent yield strength has been observed from the single crystal UO<sub>2</sub> tensile tests, which agrees well with experiments. Notably, the experimentally observed yield stress drop of UO<sub>2</sub> is reproduced in our DDD simulations, rooted in the slip system transition from the {110} (hard) to {100} (easy) slip systems. To highlight the interplay of dislocations in different slip systems, a dislocation density evolution model was established, incorporating dislocation multiplication, annihilation, cross-slip, and junction formation mechanisms. This model not only accurately predicts the dislocation density evolution for both {100} and {110} slip systems, but also reveals the underlying mechanism for the aforementioned slip transition behaviors. In conjunction with the dislocation mobility law, a dislocation-based crystal plasticity model was developed which can accurately predict the macroscopic mechanical response of single crystal UO<sub>2</sub> under different temperatures and strain rates. These insights are expected to shed light on understanding the mechanical anisotropy of UO<sub>2</sub> under high irradiation dose and complex loading conditions.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"195 ","pages":"Article 104538"},"PeriodicalIF":12.8,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145434832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-01DOI: 10.1016/j.ijplas.2025.104454
T. Virazels , J. García-Molleja , J.C. Nieto-Fuentes , M. Gonzales , F. Sket , J.A. Rodríguez-Martínez
<div><div>This paper investigates the mechanics of high-velocity fragmentation and spall fracture of steel AF9628. For this purpose, we have conducted an experimental campaign comprising 25 ring expansion tests and 36 planar plate impact experiments utilizing a single-stage light-gas gun, resulting in the largest and most comprehensive investigation to date on the dynamic fracture properties of AF9628. The ring expansion tests involve the axial impact of a conical-nosed cylindrical projectile on a stationary thin-walled tube, over which the specimen is inserted. The cross-section of the cylindrical part of the projectile exceeds the inner diameter of the tube, prompting expansion of the sample as the projectile advances, ultimately leading to the formation of multiple necks and fractures across the circumference of the ring. The experiments were documented using two high-speed cameras to capture time-resolved insights into the specimen’s deformation and fracture mechanisms. The video footage was synchronized with a photonic Doppler velocimetry system to measure the time evolution of the radial speed of the ring, thereby establishing a correlation between the nucleation of necks, the formation of fragments, and the actual strain rate in the specimens, which ranged from <span><math><mrow><mo>≈</mo><mn>8000</mn><mspace></mspace><msup><mrow><mtext>s</mtext></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span> to <span><math><mrow><mo>≈</mo><mn>15</mn><mspace></mspace><mn>000</mn><mspace></mspace><msup><mrow><mtext>s</mtext></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span> for the range of impact velocities investigated, spanning from <span><math><mrow><mo>≈</mo><mn>240</mn><mspace></mspace><mtext>m/s</mtext></mrow></math></span> to <span><math><mrow><mo>≈</mo><mn>370</mn><mspace></mspace><mtext>m/s</mtext></mrow></math></span>. The fragments were soft-recovered, weighed, sized, and the fracture surfaces were analyzed utilizing scanning electron microscopy and X-ray tomography. The experimental results demonstrate a general increase in both the number of necks and fragments with expansion velocity. The fractographic investigation and the 3D reconstruction of the fracture surfaces showed a mix of equiaxed dimples indicative of tensile failure and elliptical dimples suggestive of shear failure, with the predominance of each type varying across fractures. The planar plate impact experiments consists of propelling a disc-like projectile toward a stationary disc-like target at velocities ranging from <span><math><mrow><mo>≈</mo><mn>380</mn><mspace></mspace><mtext>m/s</mtext></mrow></math></span> to <span><math><mrow><mo>≈</mo><mn>780</mn><mspace></mspace><mtext>m/s</mtext></mrow></math></span>. The target is twice the thickness of the projectile, positioning the spall plane approximately at the center of the target. A photonic Doppler velocimetry system was utilized to measure the axial velocity of the free surface of the
{"title":"High-velocity fragmentation and spall fracture of steel AF9628","authors":"T. Virazels , J. García-Molleja , J.C. Nieto-Fuentes , M. Gonzales , F. Sket , J.A. Rodríguez-Martínez","doi":"10.1016/j.ijplas.2025.104454","DOIUrl":"10.1016/j.ijplas.2025.104454","url":null,"abstract":"<div><div>This paper investigates the mechanics of high-velocity fragmentation and spall fracture of steel AF9628. For this purpose, we have conducted an experimental campaign comprising 25 ring expansion tests and 36 planar plate impact experiments utilizing a single-stage light-gas gun, resulting in the largest and most comprehensive investigation to date on the dynamic fracture properties of AF9628. The ring expansion tests involve the axial impact of a conical-nosed cylindrical projectile on a stationary thin-walled tube, over which the specimen is inserted. The cross-section of the cylindrical part of the projectile exceeds the inner diameter of the tube, prompting expansion of the sample as the projectile advances, ultimately leading to the formation of multiple necks and fractures across the circumference of the ring. The experiments were documented using two high-speed cameras to capture time-resolved insights into the specimen’s deformation and fracture mechanisms. The video footage was synchronized with a photonic Doppler velocimetry system to measure the time evolution of the radial speed of the ring, thereby establishing a correlation between the nucleation of necks, the formation of fragments, and the actual strain rate in the specimens, which ranged from <span><math><mrow><mo>≈</mo><mn>8000</mn><mspace></mspace><msup><mrow><mtext>s</mtext></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span> to <span><math><mrow><mo>≈</mo><mn>15</mn><mspace></mspace><mn>000</mn><mspace></mspace><msup><mrow><mtext>s</mtext></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span> for the range of impact velocities investigated, spanning from <span><math><mrow><mo>≈</mo><mn>240</mn><mspace></mspace><mtext>m/s</mtext></mrow></math></span> to <span><math><mrow><mo>≈</mo><mn>370</mn><mspace></mspace><mtext>m/s</mtext></mrow></math></span>. The fragments were soft-recovered, weighed, sized, and the fracture surfaces were analyzed utilizing scanning electron microscopy and X-ray tomography. The experimental results demonstrate a general increase in both the number of necks and fragments with expansion velocity. The fractographic investigation and the 3D reconstruction of the fracture surfaces showed a mix of equiaxed dimples indicative of tensile failure and elliptical dimples suggestive of shear failure, with the predominance of each type varying across fractures. The planar plate impact experiments consists of propelling a disc-like projectile toward a stationary disc-like target at velocities ranging from <span><math><mrow><mo>≈</mo><mn>380</mn><mspace></mspace><mtext>m/s</mtext></mrow></math></span> to <span><math><mrow><mo>≈</mo><mn>780</mn><mspace></mspace><mtext>m/s</mtext></mrow></math></span>. The target is twice the thickness of the projectile, positioning the spall plane approximately at the center of the target. A photonic Doppler velocimetry system was utilized to measure the axial velocity of the free surface of the ","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"194 ","pages":"Article 104454"},"PeriodicalIF":12.8,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144899709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-01DOI: 10.1016/j.ijplas.2025.104537
Yue Wu , Shuai Xu , Renhao Wu , Tao Wang , Hyoung Seop Kim , Haiming Zhang
Conventional crystal plasticity (CP) models, which assume intragranular homogeneity, struggle to capture the complex deformation behavior of additively manufactured (AM) materials that exhibit pronounced initial microstructural heterogeneity. In this study, we develop a novel CP modeling approach that explicitly incorporates initial orientation gradients and dislocation density variations, enabling accurate representation of intragranular heterogeneities. By integrating full-field simulations with in situ tensile testing and high-resolution EBSD, we comparably investigate the mechanical responses and deformation mechanisms of both AM and conventionally manufactured (CM) 316 L stainless steels. The proposed model shows superior agreement with experimental measurements, accurately capturing stress and strain hotpots, dislocation evolution, and the emergence of intragranular shear band networks. These networks, strongly affected by initial microstructure heterogeneity, exhibit complex propagation and interaction behaviors, fundamentally altering strain partitioning path and resulting in persistent differences from predictions of conventional models. While overall stress levels remain comparable between models, the conventional approach significantly underestimates strain heterogeneity and overestimates stress heterogeneity, particularly in AM materials. Notably, the CM samples exhibit strain accumulation at grain boundaries and triple junctions, whereas the AM samples redistribute strain into grain interiors, facilitated by inherited heterogeneity. This enhances intergranular deformation compatibility, suppresses stress triaxiality in critical regions and activates more slip systems, ultimately improving ductility without compromising strength. This work highlights the limitations of traditional CP modeling and establishes the critical importance of incorporating microstructural gradients for accurately predicting mechanical behavior in heterogeneous materials. Beyond validation, the model provides a robust tool for microstructure-informed design, offering new insights for optimizing the strength-ductility synergy in architectured materials such as AM alloys.
{"title":"Microstructure-informed crystal plasticity modeling incorporating initial intragranular heterogeneities: insights into deformation mechanisms of additively manufactured alloy","authors":"Yue Wu , Shuai Xu , Renhao Wu , Tao Wang , Hyoung Seop Kim , Haiming Zhang","doi":"10.1016/j.ijplas.2025.104537","DOIUrl":"10.1016/j.ijplas.2025.104537","url":null,"abstract":"<div><div>Conventional crystal plasticity (CP) models, which assume intragranular homogeneity, struggle to capture the complex deformation behavior of additively manufactured (AM) materials that exhibit pronounced initial microstructural heterogeneity. In this study, we develop a novel CP modeling approach that explicitly incorporates initial orientation gradients and dislocation density variations, enabling accurate representation of intragranular heterogeneities. By integrating full-field simulations with in situ tensile testing and high-resolution EBSD, we comparably investigate the mechanical responses and deformation mechanisms of both AM and conventionally manufactured (CM) 316 L stainless steels. The proposed model shows superior agreement with experimental measurements, accurately capturing stress and strain hotpots, dislocation evolution, and the emergence of intragranular shear band networks. These networks, strongly affected by initial microstructure heterogeneity, exhibit complex propagation and interaction behaviors, fundamentally altering strain partitioning path and resulting in persistent differences from predictions of conventional models. While overall stress levels remain comparable between models, the conventional approach significantly underestimates strain heterogeneity and overestimates stress heterogeneity, particularly in AM materials. Notably, the CM samples exhibit strain accumulation at grain boundaries and triple junctions, whereas the AM samples redistribute strain into grain interiors, facilitated by inherited heterogeneity. This enhances intergranular deformation compatibility, suppresses stress triaxiality in critical regions and activates more slip systems, ultimately improving ductility without compromising strength. This work highlights the limitations of traditional CP modeling and establishes the critical importance of incorporating microstructural gradients for accurately predicting mechanical behavior in heterogeneous materials. Beyond validation, the model provides a robust tool for microstructure-informed design, offering new insights for optimizing the strength-ductility synergy in architectured materials such as AM alloys.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"195 ","pages":"Article 104537"},"PeriodicalIF":12.8,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145411931","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 : 2025-10-30DOI: 10.1016/j.ijplas.2025.104510
Mingyu Lei , Jie Huang , Yifei Xing , Yiyuan Qian , Xiaohua Li , Xiaojun Wang , Xu Li , Bin Wen
Accurate prediction of creep behavior is crucial for ensuring the reliability and safety of structural materials in high-temperature applications. Existing creep models, however, often require extensive experimental calibration and are constrained by idealized assumptions or incomplete representation of fundamental physical mechanisms. Consequently, a critical knowledge gap remains in understanding the coupled effects of different creep mechanisms, which reduces the predictive capability under complex material and loading conditions. In this work, we propose a multi-mechanism coupled creep constitutive model with computable parameters to quantitatively link microstructural characteristics to macroscopic creep response without relying on experimental data fitting. Within a unified thermodynamic framework, the model explicitly incorporates the contributions of vacancy diffusion, dislocation slip, and climb, grain boundary (GB) sliding, deformation twinning, and void evolution. Comprehensive analyses are conducted to investigate the coupling effects among various creep mechanisms. Applications to representative metals and alloys demonstrate that the model accurately captures the entire creep process under diverse microstructural conditions, thereby validating its predictive accuracy and robustness. This work not only enhances the mechanistic understanding of creep but also provides a powerful computational tool for designing advanced materials under extreme loading conditions.
{"title":"A multi-mechanism coupled creep constitutive modeling with computable parameters","authors":"Mingyu Lei , Jie Huang , Yifei Xing , Yiyuan Qian , Xiaohua Li , Xiaojun Wang , Xu Li , Bin Wen","doi":"10.1016/j.ijplas.2025.104510","DOIUrl":"10.1016/j.ijplas.2025.104510","url":null,"abstract":"<div><div>Accurate prediction of creep behavior is crucial for ensuring the reliability and safety of structural materials in high-temperature applications. Existing creep models, however, often require extensive experimental calibration and are constrained by idealized assumptions or incomplete representation of fundamental physical mechanisms. Consequently, a critical knowledge gap remains in understanding the coupled effects of different creep mechanisms, which reduces the predictive capability under complex material and loading conditions. In this work, we propose a multi-mechanism coupled creep constitutive model with computable parameters to quantitatively link microstructural characteristics to macroscopic creep response without relying on experimental data fitting. Within a unified thermodynamic framework, the model explicitly incorporates the contributions of vacancy diffusion, dislocation slip, and climb, grain boundary (GB) sliding, deformation twinning, and void evolution. Comprehensive analyses are conducted to investigate the coupling effects among various creep mechanisms. Applications to representative metals and alloys demonstrate that the model accurately captures the entire creep process under diverse microstructural conditions, thereby validating its predictive accuracy and robustness. This work not only enhances the mechanistic understanding of creep but also provides a powerful computational tool for designing advanced materials under extreme loading conditions.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"195 ","pages":"Article 104510"},"PeriodicalIF":12.8,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145404349","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 : 2025-10-30DOI: 10.1016/j.ijplas.2025.104536
Yu Zhang , Hongyi Li , Junxiao Xu , Yiren Wang , Wei Wu , Fuhua Cao , Zheng Peng , Yan Chen , Lanhong Dai
The limited understanding of thermomechanical deformation mechanisms in refractory high-entropy superalloys (RSAs) hinders the advancement of thermomechanical processing strategies for microstructure-property optimization. This study investigates hot-deformation and recrystallization behaviors of an Al0.5NbTa0.8Ti1.5V0.2Zr RSA, in which hot-deformation resulted in the formation of a characteristic necklace dynamic recrystallization (DRX) structure. The recrystallization fraction and grain size increase with rising temperature and decreasing strain rate, reaching maximum values of 19% recrystallized fraction and 16 μm grain size. Both discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) mechanisms operate, in which DDRX dominates initial recrystallization, while recrystallized grains exhibit hybrid DDRX-CDRX mechanisms. The redistribution of Al and Zr promotes key recrystallization processes involving GB bulging and substructure development, revealing a diffusion assisted recrystallization mechanism. These findings provide the first direct evidence of the pivotal role of Al-Zr GB phase dissolve and diffusion on the recrystallization behavior. The present study featuring diffusion assisted recrystallization mechanism in Al0.5NbTa0.8Ti1.5V0.2Zr RSA provided insights into the thermal deformation mechanism of analogous RSA and other BCCHEAs.
{"title":"Anomalous dynamic recrystallization during hot deformation in refractory high entropy superalloy: the role of grain boundary chemistry","authors":"Yu Zhang , Hongyi Li , Junxiao Xu , Yiren Wang , Wei Wu , Fuhua Cao , Zheng Peng , Yan Chen , Lanhong Dai","doi":"10.1016/j.ijplas.2025.104536","DOIUrl":"10.1016/j.ijplas.2025.104536","url":null,"abstract":"<div><div>The limited understanding of thermomechanical deformation mechanisms in refractory high-entropy superalloys (RSAs) hinders the advancement of thermomechanical processing strategies for microstructure-property optimization. This study investigates hot-deformation and recrystallization behaviors of an Al<sub>0.5</sub>NbTa<sub>0.8</sub>Ti<sub>1.5</sub>V<sub>0.2</sub>Zr RSA, in which hot-deformation resulted in the formation of a characteristic necklace dynamic recrystallization (DRX) structure. The recrystallization fraction and grain size increase with rising temperature and decreasing strain rate, reaching maximum values of 19% recrystallized fraction and 16 μm grain size. Both discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) mechanisms operate, in which DDRX dominates initial recrystallization, while recrystallized grains exhibit hybrid DDRX-CDRX mechanisms. The redistribution of Al and Zr promotes key recrystallization processes involving GB bulging and substructure development, revealing a diffusion assisted recrystallization mechanism. These findings provide the first direct evidence of the pivotal role of Al-Zr GB phase dissolve and diffusion on the recrystallization behavior. The present study featuring diffusion assisted recrystallization mechanism in Al<sub>0.5</sub>NbTa<sub>0.8</sub>Ti<sub>1.5</sub>V<sub>0.2</sub>Zr RSA provided insights into the thermal deformation mechanism of analogous RSA and other BCC<img>HEAs.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"195 ","pages":"Article 104536"},"PeriodicalIF":12.8,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145396700","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 : 2025-10-28DOI: 10.1016/j.ijplas.2025.104535
Ronghai Wu , Lei Zeng , Zanpeng Shangguan , Yuxin Zhang , Zichao Peng , Xuqing Wang , Heng Li
Dislocation patterns reflect the complex self-organization nature of dislocations and have strong influence on the mechanical properties of crystalline materials. Although the law of similitude has been widely accepted to quantify the relation between saturation resolved shear stress and pattern wavelength, it remains a big challenge to link the major inputs (e.g. saturation resolved shear stress, crystal orientation and applied strain amplitude) and major outputs (e.g. wave-type and wave-length) of dislocation patterns. In the present work, we develop two black-box machine learning methods to predict the wave-type and wave-length, as well as two white-box machine learning methods to discover explicit formulas linking major inputs and wave-length of dislocation patterns, based on the experimental data of room temperature fully reversed fatigue of FCC metals. Data of single crystal Cu are used for training and validation, and data of bicrystal Cu and polycrystal Ni are used for testing. The results show that the black-box machine learning methods can well predict over twenty types of patterns consisting of five constitutive patterns (i.e. wall, vein, ladder, labyrinth and cell structures) and their wavelengths. The traditional law of similitude, as well as an improved version that additionally incorporates crystal orientation, are surprisingly discovered from experimental data under the guidance of expert knowledge and physical constraints in the white-box machine learning methods. This improved formulation represents a significant advancement toward establishing a more comprehensive law of similitude.
{"title":"Predicting dislocation patterns and discovering the law of similitude: Machine learning based on fully reversed fatigue of FCC metals","authors":"Ronghai Wu , Lei Zeng , Zanpeng Shangguan , Yuxin Zhang , Zichao Peng , Xuqing Wang , Heng Li","doi":"10.1016/j.ijplas.2025.104535","DOIUrl":"10.1016/j.ijplas.2025.104535","url":null,"abstract":"<div><div>Dislocation patterns reflect the complex self-organization nature of dislocations and have strong influence on the mechanical properties of crystalline materials. Although the law of similitude has been widely accepted to quantify the relation between saturation resolved shear stress and pattern wavelength, it remains a big challenge to link the major inputs (e.g. saturation resolved shear stress, crystal orientation and applied strain amplitude) and major outputs (e.g. wave-type and wave-length) of dislocation patterns. In the present work, we develop two black-box machine learning methods to predict the wave-type and wave-length, as well as two white-box machine learning methods to discover explicit formulas linking major inputs and wave-length of dislocation patterns, based on the experimental data of room temperature fully reversed fatigue of FCC metals. Data of single crystal Cu are used for training and validation, and data of bicrystal Cu and polycrystal Ni are used for testing. The results show that the black-box machine learning methods can well predict over twenty types of patterns consisting of five constitutive patterns (i.e. wall, vein, ladder, labyrinth and cell structures) and their wavelengths. The traditional law of similitude, as well as an improved version that additionally incorporates crystal orientation, are surprisingly discovered from experimental data under the guidance of expert knowledge and physical constraints in the white-box machine learning methods. This improved formulation represents a significant advancement toward establishing a more comprehensive law of similitude.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"195 ","pages":"Article 104535"},"PeriodicalIF":12.8,"publicationDate":"2025-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145383040","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 : 2025-10-27DOI: 10.1016/j.ijplas.2025.104534
Jun Yan , Cunsheng Zhang , Zhenyu Liu , Zhen Zhang , Liang Chen , Guoqun Zhao
Designing aluminum alloys and composites with synergistic combinations of strength and ductility is urgently demanded but challenging. In this work, a novel approach is proposed: dual-heterostructured CNT/2024Al composites with low-energy forest dislocations were fabricated via accumulative extrusion bonding and heat treatment. The composites comprise two levels of heterogeneous architecture: first level heterogeneous CNTs distribution and second level heterogeneous zones with different grain sizes. The heterogenous distributed CNTs not only enhance the strength of hard zone, but also induce CTE gradients within the composites, which play a significant role in the formation of low-energy forest dislocations and helical dislocations. The two-beam diffraction and stereo-pair analyses results depict that the forest dislocations are edge dislocations, and the slip systems could be determined to (001)[110] and (113). Forest dislocations belong to non-octahedral slip systems of face-centered cubic crystals, and act as barriers to mobile dislocations on octahedral slip systems. Therefore, the composite with dual-heterostructure and forest dislocations exhibits synergistic combinations of strength and ductility. Schmid factor and dislocation analysis indicate that junction nodes with one degree of freedom are formed by the reaction of forest and mobile dislocations, which play a pinning role on mobile dislocations. Moreover, the high-resolution digital image correlation results indicate that heterogenous deformation occurs at the interface region during tensile deformation, which plays a significant role in the formation of GNDs. This work provides a new approach to fabricating dual-heterostructured composites with superior mechanical properties.
{"title":"Low-energy forest dislocation in dual-heterostructured CNT/2024Al composites and its effect on mechanical properties","authors":"Jun Yan , Cunsheng Zhang , Zhenyu Liu , Zhen Zhang , Liang Chen , Guoqun Zhao","doi":"10.1016/j.ijplas.2025.104534","DOIUrl":"10.1016/j.ijplas.2025.104534","url":null,"abstract":"<div><div>Designing aluminum alloys and composites with synergistic combinations of strength and ductility is urgently demanded but challenging. In this work, a novel approach is proposed: dual-heterostructured CNT/2024Al composites with low-energy forest dislocations were fabricated via accumulative extrusion bonding and heat treatment. The composites comprise two levels of heterogeneous architecture: first level heterogeneous CNTs distribution and second level heterogeneous zones with different grain sizes. The heterogenous distributed CNTs not only enhance the strength of hard zone, but also induce CTE gradients within the composites, which play a significant role in the formation of low-energy forest dislocations and helical dislocations. The two-beam diffraction and stereo-pair analyses results depict that the forest dislocations are edge dislocations, and the slip systems could be determined to (001)[110] and (113)<span><math><mrow><mo>[</mo><mover><mn>1</mn><mo>¯</mo></mover><mn>10</mn><mo>]</mo></mrow></math></span>. Forest dislocations belong to non-octahedral slip systems of face-centered cubic crystals, and act as barriers to mobile dislocations on octahedral slip systems. Therefore, the composite with dual-heterostructure and forest dislocations exhibits synergistic combinations of strength and ductility. Schmid factor and dislocation analysis indicate that junction nodes with one degree of freedom are formed by the reaction of forest and mobile dislocations, which play a pinning role on mobile dislocations. Moreover, the high-resolution digital image correlation results indicate that heterogenous deformation occurs at the interface region during tensile deformation, which plays a significant role in the formation of GNDs. This work provides a new approach to fabricating dual-heterostructured composites with superior mechanical properties.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"195 ","pages":"Article 104534"},"PeriodicalIF":12.8,"publicationDate":"2025-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145383068","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 : 2025-10-26DOI: 10.1016/j.ijplas.2025.104532
Wei Zhang , Gang Ma , Jiangzhou Mei , Rui Wang , Daren Zhang , Wanda Cao , Wei Zhou
The spatiotemporal evolution of local plastic zones, where particles undergo irreversible and cooperative rearrangements, governs the shear band formation and macroscopic yielding of granular materials. Although prior studies have shown that these zones undergo a percolation-like transition from localized to system-spanning scales under external shear, the underlying mechanisms driving this evolution remain poorly understood. In this study, we conduct in situ X-ray computed tomography (CT) triaxial shear tests on Ottawa sand, enabling high-resolution reconstruction of particle-scale kinematics. We identify active clusters characterized by intense nonaffine motion and systematically track their spatiotemporal evolution throughout the entire shearing process. By integrating structural and dynamic attributes of these clusters, we introduce a metric termed adaptability to quantify their resilience and persistence under shear. We demonstrate that, analogous to natural selection in ecological systems, clusters with higher adaptability are more likely to survive, proliferate, and merge with neighboring clusters. This self-reinforcing process enhances the overall adaptability of the granular system and governs the development of shear localization in dense assemblies. Our work provides the first experimental characterization of dynamic heterogeneity in irregular granular materials and offers a novel perspective on the underlying mechanisms governing shear localization, with broad implications for the study of granular materials.
{"title":"Dynamic heterogeneity of irregular granular materials captured by in situ X-ray imaging","authors":"Wei Zhang , Gang Ma , Jiangzhou Mei , Rui Wang , Daren Zhang , Wanda Cao , Wei Zhou","doi":"10.1016/j.ijplas.2025.104532","DOIUrl":"10.1016/j.ijplas.2025.104532","url":null,"abstract":"<div><div>The spatiotemporal evolution of local plastic zones, where particles undergo irreversible and cooperative rearrangements, governs the shear band formation and macroscopic yielding of granular materials. Although prior studies have shown that these zones undergo a percolation-like transition from localized to system-spanning scales under external shear, the underlying mechanisms driving this evolution remain poorly understood. In this study, we conduct <em>in situ</em> X-ray computed tomography (CT) triaxial shear tests on Ottawa sand, enabling high-resolution reconstruction of particle-scale kinematics. We identify active clusters characterized by intense nonaffine motion and systematically track their spatiotemporal evolution throughout the entire shearing process. By integrating structural and dynamic attributes of these clusters, we introduce a metric termed adaptability to quantify their resilience and persistence under shear. We demonstrate that, analogous to natural selection in ecological systems, clusters with higher adaptability are more likely to survive, proliferate, and merge with neighboring clusters. This self-reinforcing process enhances the overall adaptability of the granular system and governs the development of shear localization in dense assemblies. Our work provides the first experimental characterization of dynamic heterogeneity in irregular granular materials and offers a novel perspective on the underlying mechanisms governing shear localization, with broad implications for the study of granular materials.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"195 ","pages":"Article 104532"},"PeriodicalIF":12.8,"publicationDate":"2025-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145383073","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 : 2025-10-24DOI: 10.1016/j.ijplas.2025.104522
Sihao Han, Chunlei Li, Qiang Han, Xiaohu Yao
The yield surface defines the elastic-to-plastic transition in materials. However, accurately capturing the multiaxial yield surfaces of anisotropic metamaterials remains challenging with conventional criteria, and active tailoring of yield surfaces is also underdeveloped. Here, a novel machine learning framework (Q-TEncMLP) is proposed for predicting and on-demand tailoring anisotropic yield surfaces in origami metamaterials. First, a predictive deep learning model (TEncMLP) is trained on limited data to achieve end-to-end mapping from topologies to multiaxial yield surfaces. Through transfer learning with frozen parameters, the model generalizes to new yield surfaces using only 20% of additional data, enhancing efficiency across different stress states and geometric variations. Beyond prediction, attention-weight analysis provides mechanical interpretability by revealing the roles of key parameters in anisotropic yielding. Furthermore, TEncMLP is embedded into reinforcement learning as a digital twin environment, where mechanics-informed reward functions facilitate demand-driven tailoring of yield surfaces. This allows tailored yield surfaces for various objectives, including max/minimization, target matching, and lightweighting while preserving mechanical performance. Overall, this work not only clarifies the key mechanisms governing anisotropic yield in origami metamaterials, but also provides a general paradigm for intelligent constitutive modeling, shifting from experience-driven to demand-driven.
{"title":"Demand-driven predictive tailoring of anisotropic yield surfaces in origami metamaterials via machine learning","authors":"Sihao Han, Chunlei Li, Qiang Han, Xiaohu Yao","doi":"10.1016/j.ijplas.2025.104522","DOIUrl":"10.1016/j.ijplas.2025.104522","url":null,"abstract":"<div><div>The yield surface defines the elastic-to-plastic transition in materials. However, accurately capturing the multiaxial yield surfaces of anisotropic metamaterials remains challenging with conventional criteria, and active tailoring of yield surfaces is also underdeveloped. Here, a novel machine learning framework (Q-TEncMLP) is proposed for predicting and on-demand tailoring anisotropic yield surfaces in origami metamaterials. First, a predictive deep learning model (TEncMLP) is trained on limited data to achieve end-to-end mapping from topologies to multiaxial yield surfaces. Through transfer learning with frozen parameters, the model generalizes to new yield surfaces using only 20% of additional data, enhancing efficiency across different stress states and geometric variations. Beyond prediction, attention-weight analysis provides mechanical interpretability by revealing the roles of key parameters in anisotropic yielding. Furthermore, TEncMLP is embedded into reinforcement learning as a digital twin environment, where mechanics-informed reward functions facilitate demand-driven tailoring of yield surfaces. This allows tailored yield surfaces for various objectives, including max/minimization, target matching, and lightweighting while preserving mechanical performance. Overall, this work not only clarifies the key mechanisms governing anisotropic yield in origami metamaterials, but also provides a general paradigm for intelligent constitutive modeling, shifting from experience-driven to demand-driven.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"195 ","pages":"Article 104522"},"PeriodicalIF":12.8,"publicationDate":"2025-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145397697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号