文献类型：期刊文献

英文题名：Revealing fracture-resistant design principles in harmonic-structured high-entropy alloys using quasi in situ experiments and integrated modeling

作者：Yuan, Ruo-Fei[1];Zhang, Yong[1];Zhang, Yu[1];Dong, Bo[1];Wang, Yong-Ji[1];Zhang, Zhe[2];Gu, Tang[3];Jia, Yun-Fei[1];Xuan, Fu-Zhen[1]

机构：[1]East China Univ Sci & Technol, Minist Educ, Sch Mech & Power Engn, Key Lab Pressure Syst & Safety, Shanghai 200237, Peoples R China;[2]Tianjin Univ, Sch Chem Engn & Technol, Tianjin 300350, Peoples R China;[3]Inst Polytech Sci & Aeronaut IPSA, DR2I, F-94200 Ivry, France

年份：2026

卷号：197

外文期刊名：INTERNATIONAL JOURNAL OF PLASTICITY

收录：;EI(收录号：20260219879528);WOS:【SCI-EXPANDED(收录号:WOS:001657858800001)】；

基金：Y. F. Jia gratefully acknowledges the support of the National Natural Science Foundation of China (52222505, 52575174 and 52321002) , Natural Science Foundation of Shanghai (23ZR1415500) and Shanghai Municipal Education Commission. T. Gu gratefully acknowledges the support of the National Natural Science Foundation of China (grant number 12302093) .

语种：英文

外文关键词：Harmonic structure; High entropy alloy; Crystal plasticity; Cohesive zone model; Fracture mechanisms; Back stress; Energy dissipation

摘要：Harmonic-structured (HS) metallic materials have garnered significant interest owing to their exceptional strength-ductility synergy, yet grain-scale fracture mechanisms remain poorly elucidated, impeding the formulation of predictive strategies for strength-toughness balancing. To address this gap, we fabricated HS CoCrFeMnNi high-entropy alloys with tailored fine-grain (FG) shell fractions. Quasi-in situ tensile experiments monitored via electron backscatter diffraction (EBSD) and crystal plasticity finite element/cohesive zone modeling (CPFEM-CZM) reveal that FG regions exhibit high crack susceptibility due to pronounced strain gradients-particularly at coarse-grain (CG)/FG interfaces and within fine-grained zones-that evolve with strain and intensify stress concentration through deformation incompatibility, thereby promoting preferential crack nucleation and propagation. Conversely, CG regions enable sustained plastic energy dissipation via superior intrinsic deformability. Cracks nucleate and propagate preferentially within FG zones, while CG domains dissipate energy via plasticity and microcracking, diverting energy from primary crack growth. As cracks propagate into CG regions, they activate multiple slip systems, generating strain gradients that increase geometrically necessary dislocation density near crack tips. This elevates back stress, inducing crack blunting and enhancing fracture tolerance. Crucially, an optimal FG fraction (31.4%) prevents premature crack nucleation in FG regions while maintaining strength unattainable in low-FG HS variants, thereby preserving material continuity. This dual-phase synergy ensures superior fracture resistance and strength-toughness balance in HS alloys. Our work elucidates intrinsic fracture resistance mechanisms of HS microstructures and quantifies the effects of FG fraction on damage tolerance, establishing essential microstructural design criteria for advanced metallic materials.