International Journal of Plasticity最新文献

{"title":"Understanding the influence of high-strength submicron precipitate on the fracture performance of additively-manufactured aluminum alloy","authors":"Li Cao ,&nbsp;Renyi Lu ,&nbsp;Zheng Dou ,&nbsp;Min Zheng ,&nbsp;Xiao Han ,&nbsp;Yu Hao ,&nbsp;Li Zhang ,&nbsp;Jinfang Zhang ,&nbsp;Bin Liu ,&nbsp;Xiaofeng Li","doi":"10.1016/j.ijplas.2025.104306","DOIUrl":"10.1016/j.ijplas.2025.104306","url":null,"abstract":"<div><div>The formation of intermetallic compound has been widely considered as an effective strengthening approach in Al alloy. Its precipitate dimension is a key factor influencing the mechanical performance. Except for the pinning effect of nanosized precipitate, the contribution of submicron precipitate is also nonnegligible. Therefore, establishing the mechanism framework for the relationship of manufacturing process-precipitate structure-fracture performance is of great significance, which is essential and foundational for optimizing the practical service performance of alloys parts. Herein, by taking the Al-Cu-Ni series alloy (e.g. RR350) as background, the study reveals the microstructure evolution of high-strength submicron Al₇Cu₄Ni precipitate from fabrication (additive manufacturing-heat treatment) to failure, and its influence mechanism on the fracture behavior. Through the microstructure regulation, a high elongation rate of ∼28.5 % and slightly-deteriorated ultimate tensile strength of ∼305.2 MPa are achieved. The <em>in-situ</em> and <em>ex-situ</em> characterizations are employed to analyze the synergy mechanism of strength-ductility performance. Some novel findings are obtained that the submicron grain-boundary precipitates can interrupt the intergranular crack by influencing the stress status, thus decreasing the crack propagation rate and altering its propagation pathways. The entangled dislocation also presents an obstruction impact on the intragranular crack extension by its hardening effect. Moreover, the submicron Al₇Cu₄Ni precipitates with high bonding strength can withstand the concentrated stress to maintain a stable structure during alloy fracture, meanwhile present a strengthening effect on α-Al matrix to ameliorate the deterioration of tensile strength. The characterization of dislocation and microcrack evolution, provides direct evidence to the mechanism framework above, and could also provide insights into the strength-ductility coordination for other Al alloys.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104306"},"PeriodicalIF":9.4,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143599778","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":"Simulation of fracture behaviors in hydrogenated zirconium alloys using a crystal plasticity coupled phase-field fracture model","authors":"X.D. Zan ,&nbsp;X. Guo ,&nbsp;G.J. Weng","doi":"10.1016/j.ijplas.2025.104304","DOIUrl":"10.1016/j.ijplas.2025.104304","url":null,"abstract":"<div><div>Zirconium (Zr) alloys are widely used as fuel cladding materials in nuclear reactors; however, the formation of hydride precipitates within these alloys during service significantly reduces their ductility. The effects of hydrides on the fracture behavior of Zr alloys, particularly the role of misfit strain induced by hydride precipitation, remains inadequately understood. Additionally, there is a lack of robust mesoscale models to accurately describe the failure mechanisms of hydrogenated Zr alloys. In response, we develop a crystal plasticity coupled phase-field fracture model that accounts for the evolution of dislocation density, the degradation of critical energy release rate, and the coupling effects between plasticity and damage. The model is employed to investigate the effects of misfit strain induced by hydride precipitation, hydride orientation, and hydride volume fraction on the fracture behavior of hydrogenated Zr alloys. The study also explores the underlying microscopic fracture mechanisms in detail. The results demonstrate that the proposed model effectively captures the influences of hydrides on the ductility of Zr alloys. Specifically, an increase in hydride volume fraction leads to a significant reduction in the ductility and toughness of Zr alloys. The microscopic fracture characteristics of hydrogenated Zr alloys differ significantly between those containing circumferential and radial hydrides, resulting in substantially lower ductility and toughness in samples with radial hydrides under the same conditions. Most importantly, our simulations reveal that misfit strain induced by hydride precipitation is an indispensable factor leading to hydrogen embrittlement in Zr alloys. This research provides valuable insights into the failure mechanisms of hydrogenated Zr alloys and offers a powerful tool for accurately modeling their fracture behavior.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104304"},"PeriodicalIF":9.4,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143576110","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":"The quantitative evaluation of the plasticity of Nb/amorphous CuNb nanolayered thin films by micro-pillar compressions and micro-indentations as well as their correlation","authors":"Feng Qin ,&nbsp;Yaodong Wang ,&nbsp;Jie Chen ,&nbsp;Shaohua Chen ,&nbsp;Jianjun Li","doi":"10.1016/j.ijplas.2025.104294","DOIUrl":"10.1016/j.ijplas.2025.104294","url":null,"abstract":"<div><div>Micro-indentation (MI) tests have been widely used to investigate the deformation of nanolayered metallic films (NMFs) due to the convenience, simplicity and low cost. However, MI is unable to directly provide a quantitative information on the plasticity of the NMFs because of the complex 3-D stress state. Here, a combinational approach is proposed to address the above critical issue, in which systematic micro-pillar (MC) tests has been first conducted to investigate the strength and plasticity of Nb/amorphous CuNb NMFs with layer thicknesses of 100 nm, 40 nm and 5 nm. Then, an effective strain based theoretical model has been developed to derive a homogeneous deformation strain (HDS) by distinguishing the shear banding-induced strain localization region from the non-localized one for the MI-induced 3-D stress state. The MI-derived HDS can be directly compared with the MC-measured one that is determined as the maximum applied strain without causing shear banding and micro/nano-cracks in the deformed pillars. The results show that the MI-evaluated HDSs are in quantitatively agreement with the MC-measured ones, revealing the best plasticity (i.e., with HDS of 48.5 %) in the 40 nm sample. The enhanced plasticity in the 40 nm sample is attributed to the deformation twinning in the Nb layers as revealed by the transmission electron microscopy analysis and molecular dynamics simulations. The above findings demonstrated that the plasticity of NMFs can be quantitatively evaluated by several simple MI tests with the aid of the developed combinational approach, in which the time-consuming and costly MC tests could be avoided.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104294"},"PeriodicalIF":9.4,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143576111","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":"Hierarchical Nonequilibrium Thermodynamics of Thermally Activated Dislocation Plasticity of Metals and Alloys","authors":"David L. McDowell ,&nbsp;Zi-Kui Liu","doi":"10.1016/j.ijplas.2025.104303","DOIUrl":"10.1016/j.ijplas.2025.104303","url":null,"abstract":"<div><div>The Gibbs equilibrium thermodynamic framework has demonstrated high utility in computational thermodynamics for prediction of stable phases and a wide range of properties of metals and alloys. Hillert nonequilibrium thermodynamics is a generalization of the Gibbs framework suitable for nonequilibrium evolution processes, including nucleation and migration of defects (Liu, 2024a,b). Based on a sequence of local equilibrium states that reflect the heterogeneity of material structure, including defect distribution, Hillert nonequilibrium thermodynamics considers the increment of both thermal and configurational entropy changes associated with irreversible processes along a nonequilibrium trajectory. In the context of thermally activated dislocation plasticity (McDowell, 2024a,b,c), the present paper considers the Hillert generalization of Gibbs equilibrium thermodynamics in terms of internal state variable theories based on evolving constrained local equilibrium states of subsystems such as grains and phases that comprise the overall system or ensemble. We discuss the enumeration of configurations of defects to construct configurational entropy, distinguish between driving forces and probabilities of pending reactions based on local constrained equilibrium states and the entropy change due to nonequilibrium state transitions, and provide insights into both the second law of thermodynamics and the heuristic principle of maximal internal entropy production. Finally, we discuss the use of this framework as a strategy to inform reduced order internal state variable models for crystal plasticity relations of hierarchically structured alloys.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104303"},"PeriodicalIF":9.4,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143576108","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":"Extended minimal state cells (EMSC): Self-consistent recurrent neural networks for rate- and temperature dependent plasticity","authors":"Julian N. Heidenreich,&nbsp;Dirk Mohr","doi":"10.1016/j.ijplas.2025.104305","DOIUrl":"10.1016/j.ijplas.2025.104305","url":null,"abstract":"<div><div>Minimal State Cells (MSCs) have successfully overcome the self-consistency and state space issues of standard RNNs when modeling the large deformation response of solids. However, in case of rate- and temperature-dependent materials, MSC-based stress predictions still suffer from instabilities when refining the input path discretization. To resolve this issue, we develop an extended minimal state cell (EMSC) which provides self-consistent predictions irrespective of the type of material. Similar to the original MSC model, the EMSC decouples the number of state variables from fitting parameters, allowing a minimal number of state variables for high physical interpretability without compromising expressivity. The EMSC is trained and validated using 1D and 3D random walk datasets generated with micro-mechanical models of composites, basic rheological models, advanced thermo-visco-plasticity theories, as well as rate- and temperature-dependent von Mises, Hill’48, and Yld2000–3d models. It is demonstrated that compact EMSC models with less than 25,000 parameters and the same number of state variables as their physics-based counterparts provide accurate predictions of the large deformation response of all materials. With its minimal state space, compact parameter space, high expressivity, and computational stability, the EMSC is a promising candidate for surrogate modeling, in particular for materials for which reliable micromechanical models are available to generate rich training data.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104305"},"PeriodicalIF":9.4,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143576386","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":"Mechanistic exploration of high strain-hardening and TWIP effects in Fe-15.5Mn-0.6C-1.4Al steel under compression-tensile loading","authors":"Zeng Huang ,&nbsp;Shuai Luo ,&nbsp;Guangyu Wang ,&nbsp;Haohong Wu ,&nbsp;Zhanguang Zheng ,&nbsp;Haiming Zhang","doi":"10.1016/j.ijplas.2025.104292","DOIUrl":"10.1016/j.ijplas.2025.104292","url":null,"abstract":"<div><div>This study investigates the effects of large pre-compression deformation on strain-hardening and the twinning-induced plasticity (TWIP) effect in high-manganese steel, addressing a critical limitation of traditional TWIP steels, i.e., relatively low yield strength. Using advanced ex-situ electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM), we reveal the roles of nanotwins, high-density dislocations, and substructure evolution in enhancing the mechanical response under complex strain paths. Results indicate that large pre-compression significantly elevates yield and ultimate tensile strength while preserving elongation, a unique strength-ductility synergy rarely achieved in pre-strained steels. The intricate coexistence of high-density dislocation and nanotwin microstructural networks under significant pre-deformation complicates dislocation slip pathways, contributing to a unique strength-ductility balance and enhancing work-hardening capability. Changes in strain paths activate new deformation twins, which, being dynamically nucleated, introduce new interfaces and alter the crystallographic orientations, thereby enhancing the material's dislocation storage capacity and maintaining a high work-hardening rate. Pre-compression-induced heterogeneous microstructure exhibits significant hetero-deformation-induced (HDI) hardening during tensile loading, enhancing tensile strength, delaying necking, and improving deformation stability. Cross-slip in fine-grained regions (FGs) promotes dislocation interaction and the formation of robust dislocation networks, further improving the strain-hardening capability of the steel. Finally, a parametric model is proposed to quantify the synergetic contributions of twins, grain boundaries (GBs), dislocations, and HDI-hardening in optimizing the properties of pre-strained steel, providing a foundational understanding of TWIP steel behavior under varying strain path loading conditions. These insights advance the fundamental principles governing TWIP steel deformation, supporting the development of high-performance Fe-Mn-C-Al alloys for automotive applications.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104292"},"PeriodicalIF":9.4,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143551004","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":"Lowering creep rate in Mg-Zn-Ca magnesium alloy with hierarchical distribution of phases","authors":"Zhuang Cui ,&nbsp;Yukai Xiong ,&nbsp;Yang Liu ,&nbsp;Ying Zeng ,&nbsp;Manping Liu ,&nbsp;Xiaochun Liu ,&nbsp;Zhuoran Zeng ,&nbsp;Xu Zhang ,&nbsp;Shiwei Xu","doi":"10.1016/j.ijplas.2025.104295","DOIUrl":"10.1016/j.ijplas.2025.104295","url":null,"abstract":"<div><div>The improvement of creep resistance remains an important challenge for engineering applications of magnesium (Mg) alloys at elevated temperatures. Based on the experimental investigations and crystal plastic finite element method (CPFEM), the creep deformation mechanisms of the AC3 (Mg-5Al-3Ca) and ZC1 (Mg-5Zn-1Ca) alloys (both in wt.%) were proposed separately in this study. The results indicate that the ZC1 alloy with lower content of Ca and hierarchical distribution of strengthening phases exhibits superior creep resistance compared to the AC3 alloy. This superiority of ZC1 alloy is attributed to the low mechanical incompatibility between the skeleton Ca₂Mg₆Zn₃ phases and the α-Mg matrix, as well as the presence of small dispersed particles in the grain interior surrounded by stable skeleton phases. The interconnectedness of the skeleton intermetallic phase affects the creep resistance of Mg alloys. During the creep process of the AC3 alloy, local stress concentration led to the cracking of the hard skeleton Al₂Ca phase, grain boundaries (GBs) sliding, and grain coarsening/rotating, resulting in large creep rate. In the ZC1 alloy, the skeleton Ca₂Mg₆Zn₃ phases distributed along the GBs act as barriers to GB sliding. In addition, the particle precipitates inside the grains which have an orientation relationship with the α-Mg matrix can additionally strengthen the matrix, effectively preventing the motion of basal 〈a〉 dislocations. The findings of this study provide a strategy to design high creep-resistant Mg alloys by synergistic effect of the stable skeleton phase and dispersed particle phase.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104295"},"PeriodicalIF":9.4,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143546440","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":"Superior fretting wear resistance of titanium alloys from stable gradient nanostructures induced by laser shock peening","authors":"Zhenyang Cao ,&nbsp;Luqing Cui ,&nbsp;Sihai Luo ,&nbsp;Hao Su ,&nbsp;Zhicong Pang ,&nbsp;Wang Zhao ,&nbsp;Liyin Zhang ,&nbsp;Weifeng He ,&nbsp;Xiaoqing Liang","doi":"10.1016/j.ijplas.2025.104293","DOIUrl":"10.1016/j.ijplas.2025.104293","url":null,"abstract":"<div><div>TC6 titanium alloy is widely utilized in the blades and fastener structures of aeroengines, where fretting wear failure is a common issue. To address this challenge, various surface treatment techniques have been employed, with laser shock peening (LSP) garnering significant attention due to its excellent surface integrity. Although LSP has been extensively applied to improve the fatigue and friction properties of titanium alloys, its impact on the fretting wear performance and relevant strengthening mechanisms remains insufficiently explored. In this work, we demonstrate that the continuous formation of stable gradient nanograin-amorphous substructures, facilitated by the LSP-induced work-hardening layer, results in a remarkable 51.9 % reduction in the wear rates of titanium alloys under high-load fretting conditions, decreasing from 4.147 × 10^–6 mm³ N^-1 m^-1 to 1.996 × 10^–6 mm³ N^-1 m^-1. Furthermore, through the application of multiple microscopic techniques and energy-based analyses, the gradient mechanics, surface morphology, energy dissipation, microstructural evolution, and dislocation behavior of titanium alloys pre- and post-friction tests are systematically investigated. The superior fretting wear resistance of titanium alloys stems from the synergistic effects of the surface hardening layer, compressive residual stress, and the evolution of gradient nanograin-amorphous substructures, which inhibit the matrix removal and accommodate large plastic strains under fretting slip. This work provides a comprehensive and in-depth understanding of the strengthening mechanisms of the LSP-induced stable gradient nanostructures, offering new insights into the targeted design optimization of surface microstructures for titanium alloys.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104293"},"PeriodicalIF":9.4,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143546441","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":"Cooperatively controlling γ′ phase and M23C6 of a polycrystalline Ni3Al-based superalloy: Microstructure and creep resistance","authors":"Minghao Hu ,&nbsp;Chong Li ,&nbsp;Shengyu Zhou ,&nbsp;Qianying Guo ,&nbsp;Zongqing Ma ,&nbsp;Huijun Li ,&nbsp;Xingchuan Xia ,&nbsp;Yongchang Liu","doi":"10.1016/j.ijplas.2025.104291","DOIUrl":"10.1016/j.ijplas.2025.104291","url":null,"abstract":"<div><div>The intra-granular γ′ phase and inter-granular M₂₃C₆ in a polycrystalline Ni₃Al-based superalloy are cooperatively controlled through a two-stage-cooling solution treatment. The rapid cooling stage suppresses the coarsening of the γ′ phase, while the subsequent slow cooling stage promotes the precipitation of M₂₃C₆. The co-strengthening of intra- and inter-granular particles leads to a longer creep life. Intra-granularly, topologically inverse microstructures are formed, the deformation is dominated by the motion of antiphase boundary coupled superpartials. Inter-granularly, the movement of superdislocations towards the grain boundary is obstructed by the M₂₃C₆. Based on these observations, theoretical models are employed to construct the relationship between the creep properties and the micro/sub-structures. The threshold stress against dislocation movement contributed by γ′ phase, the boundary obstacle stress induced by M₂₃C₆ and the energy barrier for inter-granular cavity nucleation are calculated for discussion.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"187 ","pages":"Article 104291"},"PeriodicalIF":9.4,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143496029","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 effects on the plastic behavior of polycrystalline materials: Grain size, precipitation state and free-surface effects","authors":"Damien Texier ,&nbsp;Julien Genée ,&nbsp;Vincent Velay ,&nbsp;Antonio Castro Moreno ,&nbsp;Daniel Monceau ,&nbsp;Eric Andrieu","doi":"10.1016/j.ijplas.2025.104284","DOIUrl":"10.1016/j.ijplas.2025.104284","url":null,"abstract":"<div><div>Surface effects were investigated using ultrathin specimens with thicknesses in the order of the grain size of the material. The candidate material was a polycrystalline Ni-based superalloy (Alloy 718) purposely heat treated to document both the effects of the grain size and the metallurgical state, <span><math><mrow><mi>i</mi><mo>.</mo><mi>e</mi><mo>.</mo></mrow></math></span>, solid solution and precipitation hardened state, on the polycrystalline-to-multicrystalline behavior. Ultrathin tensile specimens were prepared with a dedicated technique to obtain specimens with thicknesses ranging between 20 and 550 <span><math><mrow><mi>μ</mi><mtext>m</mtext></mrow></math></span>, then tensile tested at room temperature. The polycrystalline-to-multicrystalline transition (PMT) was found to depend on the material grain size relative to the specimen thickness and to impair severely the tensile strength of the material. The yield strength, ultimate tensile strength (maximal stress on the stress–strain curve) and strain-to-failure severely dropped for specimens thinner than approximately two times the grain size of the material regardless of the metallurgical state. Such a decrease in tensile properties is mainly attributed to free-surface effects acting as an escape sink of dislocations, thus leading to a significant decrease of the primary dislocations density within the surface grains in comparison with the core grains. Interestingly, difference in work-hardening behavior with size reduction was found between both precipitation states, the solid solution state being more sensitive with the size reduction. The decrease in tensile properties was not found as expected from the commonly reported “thickness/grain size (<span><math><mrow><mi>t</mi><mo>/</mo><mi>D</mi></mrow></math></span>)” ratio. Therefore, a numerical approach using a modified Berveiller–Zaoui self-consistent model based on a continuum crystal plasticity approach was conducted in the present paper to distinguish microstructural features acting as strengthening (dislocation accumulation) and softening (dislocation escape at the free-surface) features. 3D numerical materials were produced using Voronoi tessellation methods to represent the fraction of “core grains” versus “surface grains”. These fractions were then used as microstructural parameters for the identification of a crystal plasticity model using mean-field homogenization with different populations of grains, <span><math><mrow><mi>i</mi><mo>.</mo><mi>e</mi><mo>.</mo></mrow></math></span>, core versus surface features. The present work aimed at distinguishing the mechanical behavior of surface grains from core grains in Alloy 718 Ni-based superalloys using various thicknesses of specimens and different microstructure and metallurgical state variants.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"188 ","pages":"Article 104284"},"PeriodicalIF":9.4,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143477593","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}