1. A novel formation and structure evolution of Cu-rich precipitates in FeCoNiCuAl high-entropy alloy.
- Author
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Wu, Zhongyuan, Chen, Mengya, Li, Bin, Lv, Mengxin, Zheng, Ruiyi, Yang, Yong, Tan, Xiaohua, and Xu, Hui
- Subjects
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VICKERS hardness , *MAGNETIC properties , *PHASE transitions , *SOLIDIFICATION - Abstract
Cu-rich precipitates were observed in the FeCoNiCuAl high-entropy alloy (HEA). In this paper, the microstructure of Cu-rich precipitates in the as-cast and annealed HEA was studied. A novel mechanism for the formation and microstructural evolution of Cu-rich precipitates has been discovered. In the solidification of alloy preparation, sphere-like precipitates with 9R close-packed (9R) or body-centred cubic (BCC) structures were formed. It was noteworthy that several sphere-like precipitates self-assembled into a large rod-like precipitate when they were close to each other. After the annealing treatment, the Cu-rich precipitates grew and part of them formed a core-shell structure. Cu atoms in the matrix adsorbed on the surface of the original precipitates to form the 9R structure shell, and the original precipitates underwent a phase transformation to form the twin face-center tetragonal (FCT) structure core. In addition, a large number of nano-clusters with sizes of about 3–8 nm were dispersed in the BCC matrix. The magnetic and mechanical properties of HEA were greatly affected by the annealing treatment. The σ max , σ 0.2 , H V , and B r of the alloy were improved 22.5%, 76.7%, 14.2% and 17.7% by annealing treatment, respectively. This work lays the foundation for further improving the mechanical and magnetic properties of HEAs by adjusting the amount, distribution, and structure of the precipitates. • Some precipitates were self-assembled by 9R or BCC precipitates. After annealing, core-shell precipitates and nano-clusters formed. • After annealing treatment, some precipitates grow into core-shell structure. • After annealing treatment, a lot of nano-clusters were dispersed in the BCC matrix. • The magnetic parameters B r and Vickers hardness of the alloy were improved by annealing treatment. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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