文献类型：期刊文献

英文题名：Multiscale heterostructures in L-PBF additively manufactured (CoCrNi)94Al3Ti3 medium-entropy alloy for superior strength-ductility synergy at cryogenic, room, and elevated temperatures

作者：Cheng, Yun[1];Zhang, Jianrui[1,2];Li, Bo[1,2]

机构：[1]East China Univ Sci & Technol, Sch Mech & Power Engn, Shanghai 200237, Peoples R China;[2]East China Univ Sci & Technol, Addit Mfg & Intelligent Equipment Res Inst, Shanghai 200237, Peoples R China

年份：2026

卷号：974

外文期刊名：MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

收录：;EI(收录号：20263021155205);Scopus(收录号：2-s2.0-105045255506);WOS:【SCI-EXPANDED(收录号:WOS:001833471700001)】；

基金：This research work is sponsored by National Key R & D Program of China (Grant No. 2022YFB4602102) .

语种：英文

外文关键词：Additive manufacturing; Hierarchical microstructures; Medium-entropy alloys; Strength-ductility synergy; Wide temperature range

摘要：Laser powder bed fusion (L-PBF) provides access to nonequilibrium microstructures, but coordinating precipitation and structural heterogeneity across multiple length scales remains challenging. Here, a non-isothermal aging (NIA) strategy was applied to an L-PBF-fabricated (CoCrNi)94Al3Ti3 medium-entropy alloy to construct a hierarchical heterostructure comprising microscale partially recrystallized/non-recrystallized regions, retained submicron cellular networks, and region-dependent coherent L12 precipitates, including spherical precipitates in the non-recrystallized regions and particle-and rod-like precipitates in the partially recrystallized regions. The resulting NIA550 alloy achieves yield strength/ultimate tensile strength/elongation combinations of 1231 MPa/ 1655 MPa/21.7% at 77 K, 1075 MPa/1301 MPa/28.6% at 293 K, and 865 MPa/1018 MPa/20.8% at 873 K. Quantitative analysis identifies coherent L12 precipitation as the dominant strengthening contribution, while strain partitioning between the partially recrystallized and non-recrystallized regions and dislocation storage at retained cellular boundaries sustain work hardening and ductility. The temperature-dependent plastic response is further accommodated by stacking-fault-, twinning-, and 9R-mediated deformation at 77 K, precipitate shearing at 293 K, and increasingly homogeneous dislocation slip at 873 K. These results demonstrate that non-isothermal aging can integrate precipitation strengthening with heterostructure-enabled strain accommodation to achieve strength-ductility synergy across a wide temperature range.