International Journal of Plasticity最新文献

{"title":"A generalised framework for modelling anisotropic creep-ageing deformation and strength evolution of 2xxx aluminium alloys","authors":"Xi Wang ,&nbsp;Zhusheng Shi ,&nbsp;Jianguo Lin","doi":"10.1016/j.ijplas.2024.104114","DOIUrl":"10.1016/j.ijplas.2024.104114","url":null,"abstract":"<div><div>The 2xxx aluminium alloys are extensively applied in the aerospace industry due to their lightweight and balanced performance characteristics. However, a comprehensive method for modelling both the anisotropic creep deformation and strengthening behaviour in creep age forming (CAF) for 2xxx aluminium alloys remains lacking. This paper presents a generalised framework for establishing constitutive models capable of describing the anisotropic creep deformation coupled with the microstructure and material strength evolutions during creep-ageing of both the original and the pre-deformed 2xxx series Al alloys. This framework extends the rolling direction-based material model to anisotropic scenarios at varying angles between the loading and rolling directions, by employing the non-uniform rational B-splines (NURBS). The details about the anisotropic model calibration and numerical simulation implementation are demonstrated. The feasibility of this method was verified by its application to various 2xxx series aluminium alloys with or without pre-deformation, through constitutive modelling and numerical simulation, with satisfactory agreements between prediction and experimental data. For the first time, the proposed framework provides a generalised routine for establishing anisotropic creep-ageing models for various 2xxx aluminium alloys.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"182 ","pages":"Article 104114"},"PeriodicalIF":9.4,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142322192","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":"Atomistic analysis of the mechanisms underlying irradiation-hardening in Fe–Ni–Cr alloys","authors":"A. Ustrzycka ,&nbsp;F.J. Dominguez-Gutierrez ,&nbsp;W. Chromiński","doi":"10.1016/j.ijplas.2024.104118","DOIUrl":"10.1016/j.ijplas.2024.104118","url":null,"abstract":"<div><p>This work presents a comprehensive examination of the physical mechanisms driving hardening in irradiated face-centered cubic FeNiCr alloys. The evolution of irradiation-induced defects during shear deformation is modeled by atomistic simulations through overlapping cascade simulations, where the nucleation and evolution of dislocation loops is validated by transmission electron microscopy images obtained from irradiated FeNiCr alloys using tandem accelerator. The effect of different shear rates on the microstructure of irradiated materials with a specific focus on the changes in the density of voids and dislocation loops induced by irradiation was analyzed. Additionally, the fundamental interaction processes between single irradiation-induced defects contributing to irradiation hardening, such as voids and dislocation loops in the alloy are explained. The analysis at atomic level indicates that both the dislocation loops and the voids exhibit strengthening effects. Furthermore, the nanometric voids are much stronger obstacles than dislocation loops of comparable size. The mechanism of cutting the voids leads to an increase of voids density and thus contributes to an increase in irradiation hardening. The mechanism of collapse of small voids into dislocation loops leads to decrease of voids density and at the same time increase of loops density. The coupling effect between the density of voids and dislocation loops is determined. Finally, the novel, physical mechanisms-based model of irradiation hardening and dislocation-radiation defect reaction kinetics are developed, which consider the mechanisms of void cutting, void shrink and void collapse to dislocation loop.</p></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"182 ","pages":"Article 104118"},"PeriodicalIF":9.4,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0749641924002456/pdfft?md5=eb28f8260505ab7f8addce4c82c45db4&pid=1-s2.0-S0749641924002456-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142157430","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":"Tailoring Mechanical Properties of Pearlitic Steels through Size Regulation of Multiscale Microstructures: Experiments and Simulations","authors":"Xutao Huang ,&nbsp;Yinping Chen ,&nbsp;Jianjun Wang ,&nbsp;Wenxin Wang ,&nbsp;Gang Lu ,&nbsp;Sixin Zhao ,&nbsp;Qian Li ,&nbsp;Yujie Liu ,&nbsp;Chunming Liu","doi":"10.1016/j.ijplas.2024.104110","DOIUrl":"10.1016/j.ijplas.2024.104110","url":null,"abstract":"<div><div>Pearlitic steels possess excellent mechanical properties due to their multiscale microstructures, yet this configuration introduces complex size and interface effects, impeding the elucidation of their microscopic deformation mechanisms. In this study, a predictive framework that combines a high-resolution reconstruction algorithm with a strain gradient crystal plasticity model was developed to investigate the relationship between local deformation behaviors in nodules, colonies, and lamellae of various sizes and their mechanical properties. This approach effectively reconstructs the multiscale structures of pearlite and accurately tracks the dynamic mechanical responses. The integrated experimental and computational findings highlight the critical role of microstructure sizes in regulating strain delocalization and dislocation dynamics, which, through strain partitioning and interface density, are vital for optimizing mechanical properties. Notably, a decrease in lamellar spacing and nodule size significantly enhances both strength and toughness, while smaller nodules and colonies promote increased plasticity. Finally, a dual-parameter Hall-Petch equation incorporating lamellar spacing and nodule size is introduced, enabling precise quantification of the impact of all microstructures in pearlite on mechanical properties with robust predictive capabilities.</div></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"182 ","pages":"Article 104110"},"PeriodicalIF":9.4,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312414","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 flexible yield criterion for strength modeling from biaxial compression to biaxial tension","authors":"Lihuang Zheng ,&nbsp;Jeong Whan Yoon","doi":"10.1016/j.ijplas.2024.104113","DOIUrl":"10.1016/j.ijplas.2024.104113","url":null,"abstract":"<div><p>Accurate strength modeling from equi-biaxial tension (EBT) to equi-biaxial compression (EBC) is critical for the plastic behavior prediction covering the wide-range of stress triaxiality encountered in sheet metal forming. To date, however, few yield criteria are available that can precisely model the initial yield and hardening behavior under six typical stress states between EBC and EBT, simultaneously. Furthermore, there is still a lack of a unified yield criterion for accurate strength modeling across various stress state ranges. To address the issues, a theoretical framework for constructing yield criteria dependent on stress states is provided and a new analytically described isotropic yield criterion is presented in this study. The flexibility in terms of the yield locus and application range is thoroughly explored to make the new yield criterion general. Subsequently, the isotropic yield criterion is extended into an analytically described anisotropic-asymmetric yield criterion. Furthermore, the extended yield criterion is applied to capture the initial yield behavior of DP980, AA5754-O, and AZ31 sheets, and the strain hardening behavior of QP1180 sheets at various stress states ranging from EBC to EBT along different loading directions. The predicted results from the extended criterion agree well with the corresponding experimental findings. The applications demonstrate that the proposed anisotropic-asymmetric yield criterion can effectively model the initial yield and hardening behavior of HCP, BCC, and FCC metal sheets under EBT, EBC, uniaxial tension (UT), plane strain tension (PST), shear (SH), and uniaxial compression (UC) in an analytical way.</p></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"182 ","pages":"Article 104113"},"PeriodicalIF":9.4,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142235111","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":"Local element segregation-induced cellular structures and dominant dislocation planar slip enable exceptional strength-ductility synergy in an additively-manufactured CoNiV multicomponent alloy with ageing treatment","authors":"Kefu Gan ,&nbsp;Weiying Huang ,&nbsp;Wei Zhang ,&nbsp;Ruidi Li ,&nbsp;Yong Zhang ,&nbsp;Weisong Wu ,&nbsp;Pengda Niu ,&nbsp;Pengfei Wu","doi":"10.1016/j.ijplas.2024.104112","DOIUrl":"10.1016/j.ijplas.2024.104112","url":null,"abstract":"<div><p>We proposed an additively manufactured equiatomic CoNiV multicomponent alloy (MCA) using a conventional laser powder bed fusion (LPBF) method, and an exceptional strength-ductility synergy of the alloy was attained through a simple post-ageing treatment. Pronounced hierarchical microstructures were achieved in our printed alloys, including heterogeneous grain structures, and intragranular cellular structures composed of interior domain with limited dislocations and cell walls led by significant vanadium local segregation. Besides the outstanding mechanical properties at room temperature of 298 K, a giga-pascal yielding strength (&gt; 1.1 GP) and over 40% uniform elongation were attained in the aged specimen deformed at a cryogenic temperature of 77 K, predominating the mechanical properties of many alloys reported in previous works. Such exceptional performance of the aged alloy can be mainly ascribed to considerable local chemical orders (LCOs), aggravated elemental fluctuation in the alloy matrix, and intensified vanadium segregation at walls of intragranular cellular structures which can strongly interact with dislocations. As a result, a planar slip array of dislocations with an extremely high density, namely large numbers of slip bands that can sustain and transfer high strains, dominates the deformation microstructures, thus efficiently strengthening and toughening the aged alloy, especially at a low temperature like 77 K. The above post-ageing strategy is readily and low-costly employed on additively manufactured MCAs with relatively high stacking fault energy (SFE) and proved as a feasible method to produce high-performance structural materials for extreme conditions.</p></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"182 ","pages":"Article 104112"},"PeriodicalIF":9.4,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142157475","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":"Influence of textural variability on plastic response of porous crystal embedded in polycrystalline aggregate: A crystal plasticity study","authors":"Sagar Chandra ,&nbsp;Suranjit Kumar ,&nbsp;Mahendra K. Samal ,&nbsp;Vivek M. Chavan","doi":"10.1016/j.ijplas.2024.104117","DOIUrl":"10.1016/j.ijplas.2024.104117","url":null,"abstract":"<div><p>Damage evolution in polycrystalline aggregates is complicated by the intricate interplay of crystallographic orientation of the porous grain and the surrounding anisotropic matrix. Therefore, formulation of design rules and damage models for polycrystalline materials proves daunting due to relative lack of thorough understanding of the underlying heterogeneity at the mesoscale. This work explores the orientation dependent void growth in a porous crystal embedded in an anisotropic polycrystalline matrix with different initial textures. Polycrystalline face-centered cubic based aggregate is simulated within the framework of crystal plasticity finite element method. Porosity is first modeled in the form of a single pre-existing spherical void in the central grain of the randomly oriented polycrystal. One-hundred crystallographic orientations of the central grain in three-dimensional Euler space are analyzed to reveal the orientation dependent trends of the porous grain. To account for textural variability, the analysis is repeated for polycrystals exhibiting preferred textures like Cube, Brass, Copper and Goss. In this manner, interesting orientation dependent trends in basic tenets of void growth like yield strength, coalescence strain and porosity evolution are unraveled across various polycrystalline textures. To account for spatial heterogeneity as well, porosity in the central grain is then re-distributed and the aforementioned analysis is repeated for all the crystallographic orientations of the central grain embedded in polycrystals with different textures. Owing to the large amount of data thus generated, statistical analysis is invoked to identify stimulating trends and key statistical variables governing the strength and toughness. Consequently, a statistical void growth model is also presented by assessing the CP simulation results and identifying suitable distribution function governing the growth of voids in polycrystals. The modeling framework is expected to inform porous plasticity models aimed at capturing damage evolution in porous grains embedded in polycrystalline materials exhibiting topological and crystallographic anisotropy.</p></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"182 ","pages":"Article 104117"},"PeriodicalIF":9.4,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142157474","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":"Automated analysis framework of strain partitioning and deformation mechanisms via multimodal fusion and computer vision","authors":"Ran Ni ,&nbsp;Carl J. Boehlert ,&nbsp;Ying Zeng ,&nbsp;Bo Chen ,&nbsp;Saijun Huang ,&nbsp;Jiang Zheng ,&nbsp;Hao Zhou ,&nbsp;Qudong Wang ,&nbsp;Dongdi Yin","doi":"10.1016/j.ijplas.2024.104119","DOIUrl":"10.1016/j.ijplas.2024.104119","url":null,"abstract":"<div><p>Simultaneously investigating strain partitioning and the underlying deformation mechanisms for both the grain interior and the grain boundary (GB) is essential for understanding the complex plastic deformation of hexagonal close-packed metals. To this end, an automated analysis framework based on high-resolution digital image correlation (HRDIC) and electron backscatter diffraction (EBSD) data fusion and computer vision, integrating nanoscale resolution and a large field of view, is proposed. This framework consists of: (1) HRDIC-EBSD data fusion; (2) Segmenting the strain field into individual grains each with a core and a mantle; (3) Data clustering of the Matrix and slip bands (SBs) for each grain; (4) Full slip system (SS) identification and SS assignment to the SBs. The capabilities of this framework were demonstrated on Mg-10Y during compression. The strain field data, which was segmented into different clusters, including grain mantle, grain core, Matrix, and SBs, was analyzed statistically and quantitatively. The pixel-based slip activity, which considers the SB morphology, was obtained from a statistical perspective. Inter-granular accommodating mechanisms, including GB strain, slip transfer, and GB sliding, were quantitatively analyzed. Overall, this analysis framework, which can be applied to other materials, can automatically and statistically evaluate both nanoscale strain fields and underlying intra- and inter-granular deformation mechanisms grain-by-grain. This work provides valuable experimental insights into plastic deformation and accommodation mechanisms for polycrystals.</p></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"182 ","pages":"Article 104119"},"PeriodicalIF":9.4,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142168540","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":"Near-α titanium alloy dwell load-induced deformation twinning to coordinate the deformation mechanism associated with crack initiation","authors":"Boning Wang ,&nbsp;Weidong Zeng ,&nbsp;Zibo Zhao ,&nbsp;Runchen Jia ,&nbsp;Jianwei Xu ,&nbsp;Qingjiang Wang","doi":"10.1016/j.ijplas.2024.104116","DOIUrl":"10.1016/j.ijplas.2024.104116","url":null,"abstract":"<div><p>In this study, we identified a specific phenomenon of coordinated deformation of twins in near-α titanium alloys during dwell fatigue (DF). The main crack source regions and internal cracks in the micro-texture region (MTR) and no-MTR samples with inconsistent orientation characteristics were characterized. The results demonstrate that the main cracks in all specimens are aligned with the (0001) basal plane, which is associated with basal slip. Notably, twins are found and confirmed to be involved in the DF crack initiation process in high Al content near-α Ti60 alloys where deformation twins are rare, and tend to nucleate at the DF basal cracks. Further in-situ dwell investigation reveals and proposes that the dislocation pile-up and prismatic-basal (PB) interfacial features between soft/hard grains lead to deformation twin nucleation and growth from hard grain boundaries. Concurrently, the pyramidal 〈c+a〉 dislocation slip is observed to be in concurrent operation with the induced twins. These findings suggest that deformation twins not only coordinate basal grain deformation but also hinder the initiation and propagation of basal cracks caused by basal 〈a〉 slip. Moreover, a high density of pyramidal 〈c+a〉 dislocations within the twin and their dissociation to form basal stacking faults (SFTs) with a specific nanometric spacing make the twinning process accompanied by significant lattice distortions inside the twin. These newly formed nanotwin boundaries and SFTs act as barriers to dislocation motion, enhancing the strength and DF lifetime of near-α Ti60 alloys and effectively reducing the dwell sensitivity of no-MTR alloys. Our findings extend the understanding of the coordinated roles of dislocation slip, twin nucleation and formation of basal SFTs in near-α titanium alloys in dwell fatigue.</p></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"182 ","pages":"Article 104116"},"PeriodicalIF":9.4,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142158955","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":"Exceptional strength-ductility synergy in the novel metastable FeCoCrNiVSi high-entropy alloys via tuning the grain size dependency of the transformation-induced plasticity effect","authors":"Mohammad Sajad Mehranpour ,&nbsp;Mohammad Javad Sohrabi ,&nbsp;Alireza Kalhor ,&nbsp;Jae Heung Lee ,&nbsp;Ali Heydarinia ,&nbsp;Hamed Mirzadeh ,&nbsp;Saeed Sadeghpour ,&nbsp;Kinga Rodak ,&nbsp;Mahmoud Nili-Ahmadabadi ,&nbsp;Reza Mahmudi ,&nbsp;Hyoung Seop Kim","doi":"10.1016/j.ijplas.2024.104115","DOIUrl":"10.1016/j.ijplas.2024.104115","url":null,"abstract":"<div><p>In-depth knowledge of the coupling between grain refinement and the transformation-induced plasticity (TRIP) effect in metastable alloys is a viable approach for the improvement of strength-ductility synergy, which needs systematic research with consideration of commercial austenitic stainless steels and novel high-entropy alloys (HEAs). Accordingly, in the present work, two Si-containing metastable HEAs in the Fe₄₇Co₃₀Cr₁₀Ni₅V_8-<em>_x</em>Si<em>_x</em> system (<em>x</em> = 3 and 6 at.%) were designed, and the TRIP-assisted AISI 304L stainless steel was also considered for comparison. The alloys were processed by cold rolling and annealing to obtain different grain sizes. Reducing the stacking fault energy (SFE) through adjusting chemical composition contributes to minimizing the detrimental effect of grain refinement on the ductility of TRIP alloys, while extremely low SFE must be avoided owing to the fast kinetics of deformation-induced martensitic phase transformation, which leads to the deterioration of ductility. In contrast to AISI 304L stainless steel, a strong TRIP effect was maintained upon grain refinement in the Fe₄₇Co₃₀Cr₁₀Ni₅V₂Si₆ HEA due to the remaining apparent SFE in the appropriate TRIP range. The tuned kinetics of martensitic transformation was found to be responsible for the exceptional ductility (∼65 %) of Fe₄₇Co₃₀Cr₁₀Ni₅V₂Si₆ HEA at an ultrahigh tensile strength of ∼1230 MPa. Therefore, considering the identical trend of SFE with grain size, an appropriate initial SFE value is important for tuning the grain size dependency of the TRIP effect. Moreover, the ultrahigh strength was attributed to the high volume fraction of α΄-martensite as well as the high strength of the martensite phase due to the high Si content. Accordingly, for achieving strong-yet-ductile HEAs, a high Si content is recommended to benefit from solid solution strengthening in the martensite phase, a specially-designed chemical composition is needed for attaining a high volume fraction of α΄-martensite, and SFE should be in a desirable range to tune the kinetics of martensitic phase transformation.</p></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"182 ","pages":"Article 104115"},"PeriodicalIF":9.4,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142157473","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":"Excellent strength-ductility synergy assisted by dislocation dipole-induced plasticity in Co-free precipitate-strengthened medium-entropy alloy","authors":"Jinsheng Wang ,&nbsp;Jiantao Wang ,&nbsp;Bangsheng Wu ,&nbsp;Lin Wang ,&nbsp;Zhipeng Long ,&nbsp;Xing Yu ,&nbsp;Long Hou ,&nbsp;Xue Fan ,&nbsp;Baode Sun ,&nbsp;Xi Li","doi":"10.1016/j.ijplas.2024.104109","DOIUrl":"10.1016/j.ijplas.2024.104109","url":null,"abstract":"<div><p>Precipitation strengthening is one of the most effective approaches for developing advanced structural materials with outstanding strength-ductility combinations. However, most compositional designs of precipitate-strengthened HEAs/MEAs compromise the cost-property tradeoff owing to the addition of expensive Co element. In this study, a Co-free FeCrNi-based precipitate-strengthened medium entropy alloy (denoted as Al_0.2Cr_0.9FeNi_2.2Ti_0.2) with a near-equiatomic FeCrNi matrix and a high content (∼ 35 %) L1₂ nanoprecipitates was designed using a mixing strategy. The microstructural features, mechanical performance, deformation substructure evolution, and strengthening mechanisms were systematically investigated using EBSD, TEM, and APT. Tensile tests indicated that the current alloy aged within a moderate temperature range achieved an exceptional strength-ductility combination compared to existing Co-containing and Co-free HEAs/MEAs. Particularly, the alloy aged at 700 ℃ (denoted as 700A) demonstrated a high ultimate tensile strength of 1606 MPa and a large ductility of 25 %, benefiting from both precipitation hardening and an unusual strain-hardening sustainability. Such anomalous strain-hardening sustainability can be attributed to the dislocation dipole-induced plasticity. High-density dislocation dipoles can simultaneously provide additional strain hardening by reducing the dislocation mean free path and enhance plastic deformation compatibility by acting as stress delocalization origins, thereby contributing to excellent strength-ductility synergy. These findings will not only open a new door for the future development of high-performance Co-free precipitate-strengthened HEAs/MEAs, but also deepen the understanding of the work-hardening mechanisms in these alloys.</p></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"181 ","pages":"Article 104109"},"PeriodicalIF":9.4,"publicationDate":"2024-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142095940","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}