International Journal of Plasticity最新文献

{"title":"Anomalous dynamic recrystallization during hot deformation in refractory high entropy superalloy: the role of grain boundary chemistry","authors":"Yu Zhang ,&nbsp;Hongyi Li ,&nbsp;Junxiao Xu ,&nbsp;Yiren Wang ,&nbsp;Wei Wu ,&nbsp;Fuhua Cao ,&nbsp;Zheng Peng ,&nbsp;Yan Chen ,&nbsp;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_0.5NbTa_0.8Ti_1.5V_0.2Zr 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 Al_0.5NbTa_0.8Ti_1.5V_0.2Zr 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":"2025-12-01","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}

{"title":"Critical role of L21 and L12 phase in deformation behaviors of additively manufactured FeCrNiAlTi alloy","authors":"Xiaopei Wang ,&nbsp;Yan Wang ,&nbsp;Wu Gong ,&nbsp;Wenhua Wu ,&nbsp;Youyou Zhang ,&nbsp;Stefanus Harjo ,&nbsp;Zhigang Yang ,&nbsp;Hao Chen","doi":"10.1016/j.ijplas.2025.104502","DOIUrl":"10.1016/j.ijplas.2025.104502","url":null,"abstract":"<div><div>Precipitation hardening is a widely used strategy to enhance the strength of face-centered cubic (FCC) alloys, but it often comes at the expense of ductility. However, the precipitates may also influence the deformation behaviors of the FCC matrix, such as strain induced stacking faults and twins, which could potentially mitigate or eliminate the loss in ductility caused by the increase in strength. In this work, we fabricated an FeCrNiAlTi FCC alloy via laser additive manufacturing, in which high density incoherent L2₁ phase and coherent L1₂ phase were introduced at cell walls and within cells respectively. An excellent balance between strength and ductility was achieved at both ambient and cryogenic temperatures by controlling the precipitation of intermetallic phases. It was found that the high density precipitates not only provide substantial strengthening but also promote deformation-induced stacking faults (SFs) and twinning, thereby enhancing work hardening through the creation of strain heterogeneity. In-situ neutron diffraction results reveal that the lattice strain after the yielding of the alloy is the predominant factors governing the formation of SFs and twins. Numerical simulation results exhibit that the large interfacial misfit of the incoherent L2₁ phase with the FCC matrix significantly enhances the local strain. Additionally, the combination of larger size and greater spacing of the L1₂ phase increases the local strain. Both L2₁ phase and L1₂ phase contribute to the enlarged local strain heterogeneity, thereby enhancing the stacking fault probability and promoting the formation of nano SFs and twins. This study presents the critical role of precipitates in tailoring deformation behaviors, thereby providing a new insight for designing strong yet ductile FCC alloys via engineering high density precipitates.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"195 ","pages":"Article 104502"},"PeriodicalIF":12.8,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145255204","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}

{"title":"Mechanical response of metastable grain boundaries under shear deformation: A multi-scale study","authors":"V.S. Krasnikov,&nbsp;K.D. Manukhina,&nbsp;F.T. Latypov,&nbsp;D.S. Voronin,&nbsp;A.E. Mayer","doi":"10.1016/j.ijplas.2025.104524","DOIUrl":"10.1016/j.ijplas.2025.104524","url":null,"abstract":"<div><div>The work presents a multiscale investigation of deformation mechanisms in nanocrystalline (NC) aluminum, combining large-scale molecular dynamics (MD) simulations with machine learning techniques to transfer MD data into continuum mechanics simulation at macroscale. We examine symmetric tilt grain boundaries (GBs) with misorientation angles ranging from 8.79° (Σ85a) to 36.87° (Σ5), establishing the dependence of GB mechanical response on GB structure within fixed misorientation angle. Three distinct plastic relaxation mechanisms are identified: 1) GB migration in low-angle systems; 2) coupled GB sliding and grain rotation in intermediate- and high-angle systems; and 3) dislocation plasticity. The first two mechanisms (GB migration and coupled sliding/rotation) predominantly serve as the primary plastic relaxation pathways during initial deformation stages, while dislocation plasticity activates at the late deformation stages. The dislocation plasticity initiation depends on the primary deformation mechanism: 1) following GB migration, dislocation activity originates from segment emission at annihilation sites of the migrating dislocation walls; 2) in systems with GB sliding/rotation, the transition to dislocation-mediated plasticity occurs when localized GB stresses exceed critical thresholds (4–5 GPa in 1 nm regions). The timing of this transition varies significantly (50–600 ps) depending on GB character, reflecting fundamental differences in defect nucleation barriers between low-angle and high-angle GB systems. A new hardening phenomenon is discovered during GB sliding with grain rotation, resulting from arising normal stress components that oppose sliding. The MD results demonstrate that statistical treatment of atomistic-scale data is essential for reliable transfer to continuum-level modeling. Our analysis reveals critical aspects demanding careful statistical consideration: 1) GB migration stresses vary by 35–40%; 2) sliding activation stress shows 80% variation. The MD results are transferred to continuum modeling through an artificial neural network framework approximating plastic potential reconstructed from the MD. Implemented within smoothed particle hydrodynamics simulations, this data-driven approach provides an efficient procedure to transfer atomistic data to continuum level for prediction of NC aluminum behavior.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"195 ","pages":"Article 104524"},"PeriodicalIF":12.8,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145463291","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}

{"title":"Theoretical and numerical investigations of dislocation evolution and anisotropic plasticity in UO2","authors":"Mengke Cai ,&nbsp;Tenglong Cong ,&nbsp;Yinan Cui ,&nbsp;Yang Li ,&nbsp;Zhifang Qiu ,&nbsp;Zhipeng Sun ,&nbsp;Hanyang Gu","doi":"10.1016/j.ijplas.2025.104538","DOIUrl":"10.1016/j.ijplas.2025.104538","url":null,"abstract":"<div><div>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.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"195 ","pages":"Article 104538"},"PeriodicalIF":12.8,"publicationDate":"2025-12-01","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}

{"title":"Low-energy forest dislocation in dual-heterostructured CNT/2024Al composites and its effect on mechanical properties","authors":"Jun Yan ,&nbsp;Cunsheng Zhang ,&nbsp;Zhenyu Liu ,&nbsp;Zhen Zhang ,&nbsp;Liang Chen ,&nbsp;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":"2025-12-01","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}

{"title":"Hydrogen–vacancy effects on the elastic and plastic behaviour of Ni<100> probed by nanoindentation","authors":"S.P. Murugan,&nbsp;Y. Ben Jedidia,&nbsp;X. Feaugas,&nbsp;A. Oudriss","doi":"10.1016/j.ijplas.2025.104492","DOIUrl":"10.1016/j.ijplas.2025.104492","url":null,"abstract":"<div><div>One of the fundamental aspects of hydrogen embrittlement is based on the impacts of hydrogen on the elementary mechanisms of plasticity. Even though it is well known that the solute hydrogen generally deteriorates the ductility of nickel, it highlighted the existence of antagonistic processes in the hydrogen effect as well, i.e., hydrogen-induced hardening and/or softening without a relevant universal explanation. These effects may also reflect an implication of hydrogen on the modification of the elasticity properties. In this work, the impact of hydrogen on elastic modulus, dislocation nucleation (i.e., pop-in), and hardness was investigated in nickel 〈100〉 single crystal using nanoindentation. The evolution of the different properties during hydrogen desorption offers the opportunity to distinguish the direct impact of hydrogen from those associated with solute-induced defects. The deformed sub-surfaces by nanoindentation were analyzed by TEM to characterise the development of dislocation structures and any other defects, and hence to establish the hydrogen-defect-elasticity-plasticity correlations. Hertz’s theory was used to model the elastic regime and Oliver and Pharr's model (Oliver and Pharr, 1992) was used to analyze the elastoplastic regime of the nanoindentation load-displacement curve. Hydrogen-induced impacts on maximum shear stress to activate dislocations, hardness and elastic modulus were observed. An irreversible reduction in elastic modulus with hydrogen absorption revealed the influence of hydrogen-induced vacancy clusters on elasticity. In addition, the increase in pop-in load and hardness with hydrogen absorption indicated a hardening behaviour in the plastic regime, resulting from the interaction of interstitial hydrogen and vacancy clusters with dislocation nucleation and mobility.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"194 ","pages":"Article 104492"},"PeriodicalIF":12.8,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145153659","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}

{"title":"Gurson revisited and multiscale-multimechanisms modeling","authors":"Gilles Rousselier,&nbsp;Thilo F. Morgeneyer,&nbsp;Jean-Michel Scherer","doi":"10.1016/j.ijplas.2025.104490","DOIUrl":"10.1016/j.ijplas.2025.104490","url":null,"abstract":"<div><div>Ductile fracture of metallic alloys is mainly attributed to initiation, growth and coalescence of micrometric voids. In 1977, Gurson’s kinematic limit analysis of the hollow sphere provided an analytical upper bound of the yield surface in the case of fully plastic flow: Gurson’s famous porous plasticity model. But in the case of flow with a conical rigid section, Gurson only fitted an empirical equation to his ”data points”. In 2004, the numerical limit analysis methods developed by Pastor et al. pointed out the existence of a corner of the yield surface on the hydrostatic axis that is not obtained with the empirical equation. The two parameters of Rousselier’s thermodynamically-derived model provide a good fit to Gurson’s data points in both cases of fully plastic flow and flow with rigid section, simultaneously. It is of utmost importance for ductile fracture modeling as void coalescence involves a transition from fully plastic flow to flow with rigid section. This model yield surface shows a corner with the right slope <span><math><mrow><mo>−</mo><mn>3</mn><mo>/</mo><mn>2</mn></mrow></math></span> corresponding to void coalescence and strain localization in a band normal to the main loading direction. In shear-dominated loadings, rotation and flattening of micrometric voids is also observed. It is usually modeled either with uncoupled failure criteria or with porous plasticity. In the first approach, criteria depending on the third invariant of the stress tensor: the Lode variable, have been developed. In porous plasticity, a second porosity was added to the yield criterion by Gologanu, Madou, Leblond and Morin (1993, 1994, 2012). In this work, the two approaches are combined with a very simple equation for the second porosity evolution depending on the Lode variable. The novelty lies in applying void nucleation, growth, rotation and flattening models also to the secondary nanometric voids that are observed inside the grains and in microscopic shear bands. At this latter scale, a modified Lode variable is used depending on the resolved shear and normal stresses of each slip system. Multiscale modeling is thus required. The dissipative Coulomb-Rousselier-Luo (2014) failure model at the slip system scale is also considered for ductile fracture without voids observed in aluminum alloys. The use of reduced texture polycrystalline models is a good compromise between macroscopic plasticity and crystal plasticity finite element method. Finite element calculations of a notched specimen are performed to illustrate the effects of the various damage models.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"194 ","pages":"Article 104490"},"PeriodicalIF":12.8,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145195418","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}

{"title":"A crystal plasticity-informed data-driven model for magnesium alloys","authors":"Ding Tang ,&nbsp;Shikun Qi ,&nbsp;Kecheng Zhou ,&nbsp;May Haggag ,&nbsp;Xiaochuan Sun ,&nbsp;Dayong Li ,&nbsp;Huamiao Wang ,&nbsp;Peidong Wu","doi":"10.1016/j.ijplas.2025.104480","DOIUrl":"10.1016/j.ijplas.2025.104480","url":null,"abstract":"<div><div>In the past few years, data-driven models based on artificial neural network (ANN) have been successfully developed and applied to investigate the macro- and micro-mechanical behaviors of various materials. However, these data-driven models are either too complex in structure or lack interpretable physical insights. In the present work, a crystal plasticity-informed data-driven (CPIDD) model is proposed, which updates the microstructural information and parameters associated with the macroscopic constitutive model using a parallel ANN structure, and combines conventional constitutive equations to obtain the stress-strain response, ensuring efficient and stable calculations. In conjunction with the finite element (FE) method, the FE-CPIDD model simulates the micro- and macro-mechanical behaviors of magnesium (Mg) alloys under uniaxial loading, non-proportional loading, four-point bending and unloading. The comparison between the simulations and available experiments (or crystal plasticity simulations) demonstrates the accuracy and effectiveness of the proposed CPIDD model. Using Mg alloys as a representative case, the CPIDD model provides an operational and extensional tool for the design, fabrication, manufacturing, and service of the metallic components.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"194 ","pages":"Article 104480"},"PeriodicalIF":12.8,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145043055","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}

{"title":"Prolonged work hardening in bimodal grain structured aluminum matrix composites: a sequential heterostructure effect","authors":"Zhiqi Guo ,&nbsp;Xiaotong Li ,&nbsp;Sijie Wang ,&nbsp;Zhanqiu Tan ,&nbsp;Zhenming Yue ,&nbsp;Bo Cui ,&nbsp;Genlian Fan ,&nbsp;Zhiqiang Li ,&nbsp;Di Zhang","doi":"10.1016/j.ijplas.2025.104485","DOIUrl":"10.1016/j.ijplas.2025.104485","url":null,"abstract":"<div><div>High-strength aluminum matrix composites (AMCs) suffer from poor ductility, due to the limited work hardening capacity. In this study, a remarkable prolonged work hardening is sustained in ultrastrong Al-5Mg matrix composites via an optimized bimodal grain heterostructure, with triple or even fourfold uniform elongation and raised tensile/yield strength. The prolonged work hardening proceeds through two sequential deformation stages. In the first stage with minor strains (&lt;2.5%), a high gradient of geometrically necessary dislocations in soft coarse-grained (CG) zones generates strong back stress, which promotes not only hetero-deformation induced (HDI) hardening but also dislocation multiplication in hard ultrafine-grained (UFG) zones. The work hardening of UFG is thus improved with higher density of dislocations interacting with some nanoparticles. Subsequently, the stress of UFG zones rises sufficiently to induce dispersed microvoids formation within UFG zones, instead of localized cracking at hetero-zone boundaries. Therefore, an effective HDI hardening depending on the well-bonded hetero zones is sustained in the second stage (strain &gt;2.5%). Such a sequential heterostructure effect is analyzed to obtain an appropriate width range of soft zones for bimodal grained AMCs, improving the conventional empirical heterostructure design principle. This work advances the understandings on heterostructured AMCs that when employing intermediate-sized soft zones, the hard UFG zones play a key role in obtaining good ductility, instead of only providing high strength.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"194 ","pages":"Article 104485"},"PeriodicalIF":12.8,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145083954","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}

{"title":"Functional fatigue and restoration in superelastic NiTi shape-memory alloys","authors":"Junyu Chen ,&nbsp;Wenqiang Wang ,&nbsp;Fei Liu ,&nbsp;Boxin Wei ,&nbsp;Liping Lei ,&nbsp;Gang Fang ,&nbsp;Robert O. Ritchie ,&nbsp;Upadrasta Ramamurty","doi":"10.1016/j.ijplas.2025.104483","DOIUrl":"10.1016/j.ijplas.2025.104483","url":null,"abstract":"<div><div>Functional fatigue in NiTi-based shape-memory alloys (SMAs), a critical barrier to their widespread adoption for a variety of technologies, remains a key challenge with incomplete mechanistic understanding. Here we investigate functional fatigue and its restoration in superelastic NiTi SMAs with wide-ranging grain sizes and subjected to elastocaloric cycling under varying maximum applied stresses (<em>σ</em>_max). Results show that larger grain sizes and/or higher <em>σ</em>_max significantly exacerbate the kinematic irreversibility caused by the fatigue-induced increased dislocation density and martensite retention. It is demonstrated that functional restoration can be achieved through a simple overheating treatment (‘healing’) after cycling, which reverts the retained martensite into austenite for subsequent transformation while preserving dislocations. Retained martensite alone lowers the critical forward transformation stress during cycling, but its effect is fully reversible by healing, irrespective of grain size and <em>σ</em>_max. Both dislocations and retained martensite impair the cyclic transformation capacity of the material, leading to elastocaloric degradation. The contribution of retained martensite, which can be revoked by healing for elastocaloric restoration, increases with <em>σ</em>_max and eventually outweighs the influence of dislocations; refinement in the grain size accelerates this transition. The work provides quantitative insights into the micro-mechanisms underlying functional fatigue and restoration in NiTi SMAs, advancing the development of sustainable elastocaloric technologies.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"194 ","pages":"Article 104483"},"PeriodicalIF":12.8,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145084028","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}