International Journal of Plasticity最新文献

{"title":"Statistical evaluation of microscale stress conditions leading to void nucleation in the weak shock regime","authors":"Noah J. Schmelzer ,&nbsp;Evan J. Lieberman ,&nbsp;Nan Chen ,&nbsp;Samuel D. Dunham ,&nbsp;Veronica Anghel ,&nbsp;George T. Gray III ,&nbsp;Curt A. Bronkhorst","doi":"10.1016/j.ijplas.2025.104318","DOIUrl":"10.1016/j.ijplas.2025.104318","url":null,"abstract":"<div><div>We investigate the heterogeneity of the stress state driven by anisotropic deformation response at the single crystal level through five statistical volume element (SVE) calculations of polycrystalline BCC tantalum. This work focuses on grain boundaries as a prominent material defect type prone to void nucleation based upon experimental observations of predominantly intergranular void nucleation in this material. The SVEs are constructed to be statistically representative of larger volumes of material and are meshed such that mean and standard deviation of grain size and orientation information is reconstructed. The computational meshes feature hexahedral (brick) elements and smooth conformal grain boundaries where significant stress concentration is known to occur, a tail effect of interest in the extreme events process of dynamic ductile damage. An existing micromechanical crystallographic plasticity model shown to capture the single crystal behavior of BCC tantalum well is used to perform the polycrystal calculations. The model includes representation of the non-Schmid effect of non-planar screw dislocation kinetics in tantalum. A three-dimensional stress state time profile predicted by damage modeling of a flyer plate impact experiment is applied as boundary conditions to each SVE. Resulting grain boundary stress state statistics are strongly non-Gaussian. Significant structural evolution is observed within the compressive hold before unloading into tension in the stress profile. Strong angular dependence of grain boundary traction magnitude with shock direction is observed. Non-Schmid effects continue to suggest their influence on propensity of microstructural defect types to nucleate voids. A general void nucleation criterion is proposed using probability theory. The general framework is specified to polycrystalline BCC tantalum in the weak shock regime to include the SVE calculations and literature molecular dynamics calculations of grain boundary void nucleation strength. Probability density functions (PDFs) are used to describe the interaction between the local stress state heterogeneity and the distributed grain boundary void nucleation strength state. A causation entropy maximization procedure removes the requirement for ad hoc selection of a PDF functional form and provides a rigorous procedure for data-based PDF determination. The resulting physically informed PDF describes the spatial appearance frequency of nucleated voids as a function of applied macroscale pressure. Lower length scale physics are thus packaged in a precise and computationally efficient way to provide computational plasticity insight to macroscale dynamic ductile damage models.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104318"},"PeriodicalIF":9.4,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143675306","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":"Phase-specific tailoring strategy for synergetic and prolonged work hardening to achieve superior strength-plasticity in lamellar-structured alloy","authors":"Yumeng Zhang ,&nbsp;Ran Chen ,&nbsp;Yixuan Hu ,&nbsp;Chenyang Wang ,&nbsp;Yao Shen ,&nbsp;Xiaodong Wang","doi":"10.1016/j.ijplas.2025.104317","DOIUrl":"10.1016/j.ijplas.2025.104317","url":null,"abstract":"<div><div>The pursuit of alloys that integrate high strength and substantial plasticity persists across various industries. Nevertheless, alloys engineered for elevated strength commonly manifest unsustainable work hardening, ultimately leading to a decline in plasticity. Dual- or even multi-phase systems offer vast potential for novel microstructural engineering aimed at harmonizing these inversely related property requirements. Here, heterogeneous lamellar structure consisting of alternating austenite and ferrite lamellae is explored to decouple and leverage the distinct roles of individual phases in a dual-phase system. This phase-specific tailoring strategy meticulously manipulates intra-phase microstructure, and tunes the lamella thickness to promote both high initial strength and prolonged work hardening. The significantly enhanced strength benefits from pre-existing defects, interfaces strengthening and quasi isostrain deformation mode while high plasticity originates from relatively uniform strain partitioning between phases across a wide strain range achieved through exploiting various hardening components. For austenite, prolonged work hardening is achieved by sequential utilization of dislocation hardening followed by martensitic transformation hardening. Moreover, the martensite laths in favorable configuration along with the retained austenite contribute to retarding cracking. For ferrite, wide-range work hardening is ensured by expanding the potential for dislocation activities which lowers initial density and raises peak density through reducing the space in the thickness dimension. Such innovation elevates the traditionally inferior work-hardening capability of high-strength BCC structure to an exceptional level. The resultant alloy, while boosting nearly twice the yield strength of its conventional counterpart, exhibits a total elongation of 45 %. This strategy holds potential for broad application across dual- and multi-phase systems and proposes a new avenue for enhancing plasticity in high-strength lamellar-structured alloys.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104317"},"PeriodicalIF":9.4,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143675304","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":"Deformation mechanism of non-textured and basal-textured polycrystalline Mg alloys: A coupled crystal plasticity-twinning phase field simulation","authors":"Jiachen Hu ,&nbsp;Bo Xu ,&nbsp;Junyuan Xiong ,&nbsp;Chao Yu ,&nbsp;Guozheng Kang","doi":"10.1016/j.ijplas.2025.104312","DOIUrl":"10.1016/j.ijplas.2025.104312","url":null,"abstract":"<div><div>In this work, an improved crystal plasticity coupled twinning phase field is developed by introducing a hyperbolic hardening function describing the hardening resulting from dislocation slipping interactions. This model effectively captures the complex interactions of multiple plasticity mechanisms in non-textured (NT) and basal-textured (BT) polycrystalline Mg alloys under monotonic and tension-compression cyclic loadings. The results indicate that NT polycrystalline Mg alloy exhibit multi-mode plastic deformation combining basal/non-basal slipping and twinning due to random grain orientations, whereas BT polycrystalline Mg alloys predominantly activate one or two plastic deformation modes including the basal slipping, and the texture angle <em>α</em> (characterized the statistical average properties of the grain orientations) modulates plastic mechanism with selective sensitivity. Cyclic loading reveals tension-compression symmetry in NT and BT (<em>α</em> = 45°) systems, but asymmetry in BT (<em>α</em> = 0°/90°) due to alternating plastic mechanisms. De-twinning-induced nonlinear unloading emerges in both NT and BT polycrystalline systems, and inhomogeneous stress near grain boundaries and twin intersection regions impedes complete de-twinning, accumulating residual twins that facilitate subsequent nucleation. Dislocation slipping, particularly the basal slipping, accommodates strain incompatibility at grain boundaries and around twins, and demonstrates dual roles on twinning. Neighboring grain interactions induce anomalous local deformation inconsistent with the Schmid's law. These findings establish microstructure-property relationships supporting the development of texture-based strengthening-toughening strategies for Mg alloys.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104312"},"PeriodicalIF":9.4,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143660548","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":"Tailoring fracture resistance of a metastable Fe42Mn28Co10Cr15Si5 high entropy alloy by intrinsic toughening","authors":"Manoj Yadav ,&nbsp;Niraj Nayan ,&nbsp;Krishanu Biswas ,&nbsp;N.P. Gurao","doi":"10.1016/j.ijplas.2025.104315","DOIUrl":"10.1016/j.ijplas.2025.104315","url":null,"abstract":"<div><div>Metastable high entropy alloys (HEAs) provide an exceptional combination of strength and ductility by the synergistic operation of slip, twinning, and transformation; however, their fracture behaviour remains unexplored. In the present investigation, tensile and elastic-plastic fracture toughness tests with a 2D digital image correlation setup were carried out for different microstructural states of Fe₄₂Mn₂₈Co₁₀Cr₁₅Si₅ HEA. Finite element analysis (FEA) coupled with combinatorial site-specific electron backscatter diffraction helps in developing a meso and micro scale mechanistic understanding of the extrinsic and intrinsic toughening processes. The calculated J-integral and plastic zone size using FEA simulations were corroborated with experimental results. The crack growth resistance (J-R) curve was evaluated across three distinct processing conditions: hot rolled (HR), 1 h annealed at 1173 K (AN1173), and 4 h annealed at 1373 K (AN1373). The HR material exhibited higher strength (yield strength = 630 ± 8 MPa), while the AN1373 demonstrated highest ductility (0.74 ± 0.04). The mode I plane strain fracture toughness was highest for the AN1373 (125.4 ± 15.8 MPa.m^0.5) and lowest for the AN1173 (46.3 ± 7.4 MPa.m^0.5). The Cr-rich sigma phase at grain boundaries in the HR and AN1173 led to pronounced intergranular fracture, resulting in lower fracture toughness and plasticity. The multiple variants of martensite in the AN1373 microstructural state, results in refined microstructure by interactions of transformation variants and dislocations that enhance the strength, ductility, and crack tip plasticity. The findings underscore the significant impact of intrinsic toughening on the fracture and deformation behaviour of the Fe₄₂Mn₂₈Co₁₀Cr₁₅Si₅ HEA.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104315"},"PeriodicalIF":9.4,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143660564","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":"Quantifying power partitioning during void growth for dynamic mechanical loading in reduced form","authors":"Noah J. Schmelzer ,&nbsp;Evan J. Lieberman ,&nbsp;Nan Chen ,&nbsp;Curt A. Bronkhorst","doi":"10.1016/j.ijplas.2025.104314","DOIUrl":"10.1016/j.ijplas.2025.104314","url":null,"abstract":"<div><div>A study of the partitioning of external power into stress power, stored defect energy, thermal energy, and inertia during dynamic void growth is presented. An alternative form for a classical thick-walled sphere governing equation stemming from a local power balance including energetic cost of free surface creation is proposed. The importance of proper energy accounting in the context of dynamic ductile damage is discussed. An isotropic thermodynamically consistent thermomechanical dislocation density-based plasticity model is presented and compared against experimental data for high-purity BCC tantalum. This model accounts for plastic power partitioning to stored defect energy and thermal energy with evolving Taylor-Quinney coefficient. The plasticity model is used to perform a suite of thick-walled sphere calculations spanning a wide range of deformation rates and initial temperatures. Thick-walled sphere geometry and initial porosity are based on post-mortem metallographic analysis of void size and spacing in high-purity tantalum. Stress measures of interest as well as quantities provided by enforced thermodynamic consistency are evaluated across the radius of thick-walled sphere calculations as a function of strain rate and temperature. Agglomeration of the resulting 35 thick-walled sphere simulations provides a database for statistical evaluation. Analysis using information theory yields a simple reduced order functional form for the total thick-walled sphere stress power in terms of surface quantities and solid volume. Validation of the found functional form is performed for five arbitrary loading curves showing good agreement. Implications for the local power balance evolution equation are examined. Suitability of the resulting void governing equation for use in continuum-scale dynamic ductile damage models is discussed.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104314"},"PeriodicalIF":9.4,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143660522","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":"Abnormal high yield strength and strain softening in a metastable β titanium alloy at room temperature","authors":"Tianle Li ,&nbsp;Ning Xu ,&nbsp;Xiang Wu ,&nbsp;Jiaobao Liu ,&nbsp;Xiaochun Liu ,&nbsp;Xifeng Li","doi":"10.1016/j.ijplas.2025.104310","DOIUrl":"10.1016/j.ijplas.2025.104310","url":null,"abstract":"<div><div>Understanding the relationship between deformation behaviors and mechanisms is significant for the processing and application of metastable β titanium alloys. Here we aim to investigate and evaluate the abnormal yield strength and strain softening of a Ti-15.1Mo-2.77Nb-3.1Al-0.21Si alloy at room temperature. This alloy exhibits a high yield strength of 970 MPa, followed by the continuous stress drop behavior in the entire engineering strains (or true strains of 0.018 ∼ 0.056). Digital image correlation (DIC) reveals that the flow stress drop results from local strain softening associated with a local increase in strain rate, instead of Lüders strain. The pinning between dislocations and Si atoms as well as other interstitial atoms at and near grain boundaries is mainly responsible for the high yield strength. Subsequently, dislocations originating from grain boundaries can easily slip in a planar pattern along the {110} 〈111〉 slip systems, resulting in a continuous stress drop. In addition, both the low density of dislocations within β grains and large grain size also provide favorable conditions for dislocation slip over a long distance. This study reveals the mechanisms of both high yield strength and strain softening in the metastable β Ti alloys.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104310"},"PeriodicalIF":9.4,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143639974","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":"Modulating L12 precipitation behavior and mechanical properties in an Fe-rich medium-entropy alloy fabricated via laser powder bed fusion","authors":"Shidong Wang ,&nbsp;Wenhua Wu ,&nbsp;Yuxuan Zhao ,&nbsp;Yue Sun ,&nbsp;Chenghao Song ,&nbsp;Youyou Zhang ,&nbsp;Gang Sha ,&nbsp;Zengbao Jiao ,&nbsp;Tao Yang ,&nbsp;Hao Chen","doi":"10.1016/j.ijplas.2025.104290","DOIUrl":"10.1016/j.ijplas.2025.104290","url":null,"abstract":"<div><div>This study systematically investigates the effects of different annealing treatments before identical aging on precipitation and mechanical properties of an L1₂-strengthened Fe-rich medium-entropy alloy (Fe-MEA) fabricated by laser powder bed fusion (L-PBF). These treatments result in distinct final microstructures characterized by either discontinuous precipitation (DP) or continuous precipitation (CP) dominance, accompanied by varied mechanical properties. The high-density dislocations and coarse grains induced by L-PBF promote CP. In contrast, the fine grains formed via L-PBF and the reduced dislocation density through annealing enhance DP, leading to grain refinement. The L-PBF Fe-MEA subjected to various post-printing heat treatments also demonstrates acceptable mechanical properties. It is revealed that the stacking fault energy (SFE) of the face-centered cubic (fcc) matrix in the direct-aged sample is sufficiently low to facilitate the formation of deformation-induced twinning and stacking faults (SFs) in both the CP and DP regions, indicating that both regions exhibit good deformation capacity. Additionally, hetero-deformation-induced (HDI) strengthening significantly contributes to the strength of the studied samples. In the annealing-aged samples, HDI strengthening primarily originates from the heterogeneous distribution of grains and precipitates (fine grains containing DP and coarse grain including CP). In contrast, in the direct-aged sample, HDI strengthening is attributed not only to the heterogeneous grains and precipitates but also to the heterogeneous dislocation structure. This work may provide guidance for modulating L1₂ precipitation behavior and mechanical properties of high/medium-entropy alloys (H/MEAs) fabricated by L-PBF.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104290"},"PeriodicalIF":9.4,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143640988","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":"Size-dependent strength superiority in multi-principal element alloys versus constituent metals: Insights from machine-learning atomistic simulations","authors":"Fei Shuang ,&nbsp;Yucheng Ji ,&nbsp;Luca Laurenti ,&nbsp;Poulumi Dey","doi":"10.1016/j.ijplas.2025.104308","DOIUrl":"10.1016/j.ijplas.2025.104308","url":null,"abstract":"<div><div>Multi-principal element alloys (MPEAs) are renowned for their enhanced mechanical strength relative to their constituent metals, as evidenced by various experimental techniques such as tension/compression tests and instrumental indentation. Nevertheless, atomistic simulations sometimes produce conflicting results, casting doubt on the consistently superior mechanical properties of MPEAs. In this study, machine-learning interatomic potentials (MLIPs) with first-principles accuracy were developed for body-centered cubic refractory MoNbTaW MPEAs, enabling systematic atomistic simulations under various deformation scenarios. The new MLIPs are supported by a comprehensive dataset encompassing extensive defects, and the established embedded-atom model (EAM) potential was benchmarked against both this dataset and the new MLIP. Simulations covering diverse compositions confirm that both MLIPs and EAM accurately capture the critical strengthening mechanisms in MoNbTaW MPEAs. It is revealed that MPEAs generally exhibit superior mechanical strength compared to their constituent metals in macroscale specimens, primarily due to solid solution strengthening during dislocation motion. However, at the nanoscale—where plasticity is predominantly governed by dislocation nucleation and grain boundary deformation—the constituent metals may outperform MPEAs. A critical length scale is identified above which MPEAs demonstrate enhanced mechanical strength relative to their constituent elements; below this scale, the advantage diminishes, underscoring a significant size-dependent effect that is crucial for optimizing MPEA applications, particularly at the nanoscale.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104308"},"PeriodicalIF":9.4,"publicationDate":"2025-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143631170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shear banding mediated fracture mechanisms in additively manufactured IN738 superalloys under low-strain-rate loading","authors":"Xiaofeng Dang ,&nbsp;Yao Li ,&nbsp;Jie Zheng ,&nbsp;Luqing Cui ,&nbsp;Kaiju Lu ,&nbsp;Xiaoqing Liang ,&nbsp;Sihai Luo ,&nbsp;Guangni Zhou ,&nbsp;Yang Jiao ,&nbsp;Yihua Dou ,&nbsp;Liucheng Zhou ,&nbsp;Weifeng He","doi":"10.1016/j.ijplas.2025.104296","DOIUrl":"10.1016/j.ijplas.2025.104296","url":null,"abstract":"<div><div>Shear banding coupled with grain refinement plays a critical role in fracture behavior under dynamic loading and (very) high-cycle fatigue but is rarely observed during low-strain-rate loading. In this study, we report for the first experimental evidence of shear banding mediated fracture mechanism in an electron beam powder bed fusion (EBPBF) fabricated IN738 superalloy upon low-strain-rate (1 × 10⁻³ s⁻¹) uniaxial tensile loading. The optimized EBPBF process mitigates solidification defects and produces well-aligned columnar grains with a &lt;001&gt; fiber texture along the building direction, achieving superior mechanical properties compared to cast alloys through the synergistic effect of multiple strengthening mechanisms. Notably, the relatively uniform distribution of nano-sized carbides in the EBPBF-fabricated alloys prevents strain-incompatibility cracking caused by coarse carbides in cast alloys and facilitates shear banding mediated transgranular fracture. The shear band, formed due to concentrated plastic deformation along the crack path, is associated with complete grain nanocrystallization and γ′ precipitate fragmentation through intensive dislocations and twinning activities. The formation of shear banding potentially dissipates crack propagation energy and enhances the crack growth resistance. These findings provide new insights into fracture mechanisms and underscore the potential of additive manufacturing for designing damage-tolerant superalloys.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104296"},"PeriodicalIF":9.4,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143599645","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":"Size-dependent mechanical behaviors and mechanisms in CoCrFeNi microfibers","authors":"Le Bo ,&nbsp;Xiaoyu Gao ,&nbsp;Wenjing Song ,&nbsp;Zhiliang Ning ,&nbsp;Jianfei Sun ,&nbsp;Alfonso H.W. Ngan ,&nbsp;Yongjiang Huang","doi":"10.1016/j.ijplas.2025.104307","DOIUrl":"10.1016/j.ijplas.2025.104307","url":null,"abstract":"<div><div>High-entropy alloys (HEAs) exhibit a wide diversity of crystalline defects for property control. Fabricating HEAs in microfiber forms further enhances property controllability due to intrinsic and extrinsic size effects. In this study, CoCrFeNi high entropy alloy microfibers with 30–100 μm diameters (<em>D</em>) and grain sizes (<em>d</em>) of 2.1–60.6 μm, were obtained through drawing, electric current annealing, and electropolishing, and subjected to uniaxial tensile testing. As <em>D</em>/<em>d</em> &gt; 3, the yield strength obeys the Hall-Petch relation concerning <em>d</em> and a smaller-is-weaker effect or is insensitive to <em>D</em>. When <em>D</em>/<em>d</em> &lt; 3, the yield strength deviates positively from the Hall-Petch relationship with respect to <em>d</em> and a smaller-is-stronger effect to <em>D</em>. The <em>D</em>/<em>d</em> &gt; 3 behavior is due to grain boundary strengthening and surface-grain softening, while the <em>D</em>/<em>d</em> &lt; 3 behavior is driven by reduced dislocation accumulation and size effects influenced by the limited number of grains spanning the diameter. These findings illustrate that in small-diameter microfibers, strengthening and weakening mechanisms intertwine to yield complex size effects, thus offering the potential to tailor the mechanical properties of micro-sized polycrystalline components through grain-size control and external-size adjustment.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104307"},"PeriodicalIF":9.4,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143608087","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}