Effect of Atomic Size Difference on the Microstructure and Mechanical Properties of High-Entropy Alloys

Chan-Sheng Wu; Ping-Hsiu Tsai; Chia-Ming Kuo; Che-Wei Tsai

doi:10.3390/e20120967

Effect of Atomic Size Difference on the Microstructure and Mechanical Properties of High-Entropy Alloys

Entropy (Basel). 2018 Dec 14;20(12):967. doi: 10.3390/e20120967.

Authors

Chan-Sheng Wu¹, Ping-Hsiu Tsai¹, Chia-Ming Kuo^{1

2}, Che-Wei Tsai²

Affiliations

¹ Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan.
² High Entropy Materials Center, National Tsing Hua University, Hsinchu 30013, Taiwan.

Abstract

The effects of atomic size difference on the microstructure and mechanical properties of single face-centered cubic (FCC) phase high-entropy alloys are studied. Single FCC phase high-entropy alloys, namely, CoCrFeMnNi, Al_0.2CoCrFeMnNi, and Al_0.3CoCrCu_0.3FeNi, display good workability. The recrystallization and grain growth rates are compared during annealing. Adding Al with 0.2 molar ratio into CoCrFeMnNi retains the single FCC phase. Its atomic size difference increases from 1.18% to 2.77%, and the activation energy of grain growth becomes larger than that of CoCrFeMnNi. The as-homogenized state of Al_0.3CoCrCu_0.3FeNi high-entropy alloy becomes a single FCC structure. Its atomic size difference is 3.65%, and the grain growth activation energy is the largest among these three kinds of single-phase high-entropy alloys. At ambient temperature, the mechanical properties of Al_0.3CoCrCu_0.3FeNi are better than those of CoCrFeMnNi because of high lattice distortion and high solid solution hardening.

Keywords: high-entropy alloys; mechanical property; recrystallization.