1. An unprecedented synergy of high-temperature tensile strength and ductility in a NiCoCrAlTi high-entropy alloy
- Author
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Zhang, Hongmin, Meng, Fanchao, Meng, Haoyan, Tong, Yang, Liaw, Peter K., Yang, Xiao, Zhao, Lei, Wang, Haizhou, Gao, Yanfei, and Chen, Shuying
- Subjects
Condensed Matter - Materials Science - Abstract
The present work reported a novel L12-strengthening NiCoCrAlTi high entropy alloy (HEA) with an outstanding synergy of tensile strength and ductility at both ambient and high temperatures. Transmission electron microscopy (TEM) characterization revealed a high density of rod-like and spheroidal L12 precipitates distributing in the micro/nanograins and non-recrystallized regions in the annealed specimens. The tremendously high yield stress, ultimate tensile stress (UTS), and ductility of the HEA at 600 C were ~1060 MPa, 1271 MPa, and 25%, respectively, which were significantly superior to most reported HEAs and Co- and Ni-based superalloys to date. Systematic TEM analysis unveiled that the cooperation among L12 precipitation, extensive stacking faults (SFs), deformation twins (DTs), immobile Lomer-Cottrell (L-C) locks formed from interactions between SFs and SFs/DTs, hierarchical SFs/DTs networks, as well as hetero-deformation-induced strengthening dominated the plastic deformation at 600 C. Such a unique deformation mechanism enabled extremely high tensile strength and sustained ductility of the HEA at a high temperature.
- Published
- 2023