Impact of different Cr contents on microstructural evolution and mechanical behaviour of CoCrxCuFeMnNiV high-entropy alloys

作者：He, Wen^*; Zeng, Cong; Yang, Wei; Chen, Weihua; Ai, Yunlong

来源：Journal of Materials Research and Technology-JMR&T, 2022, 21: 4577-4590.

DOI：10.1016/j.jmrt.2022.11.072

• CoCrxCuFeMnNiV high-entropy alloy
• Cr content
• Sigma phase
• Microstructure evolution
• Mechanical properties

The CoCrxCuFeMnNiV (x 1/4 0, 0.25, 0.5, 0.75, 1) high-entropy alloy was prepared via vacuum arc smelting, and the effect of different Cr contents on the microstructure evolution and me-chanical properties of it was evaluated. The results show that the CoCuFeMnNiV alloy is composed of FCC1+FCC2 phases, while Cr-added CoCrxCuFeMnNiV alloy is composed of FCC1+FCC2+sigma phases; moreover, the amount of sigma phase increases with the Cr con-tent. Through calculations, a phase formation criterion suitable for the CoCrxCuFeMnNiV alloy was established. It was observed that adding Cr does not affect the early solidification behaviour of the FCC1 and FCC2 phases; however, it affects the stability of the FCC1 phase and promotes the transformation of this phase into the sigma phase, as well as secondary precipitation of a nanoscale copper-rich phase on this phase. The formation of sigma phase has a significant strengthening effect on the alloy but reduces its plasticity. The CoCr0.5CuFeMnNiV alloy has favourable comprehensive properties; specifically, its yield strength, compressive strength, microhardness, and fracture strain are 820 MPa, 1050 MPa, 320 HV, and 22.5%, respectively. With an increase in Cr content, the alloy fracture mode changes from ductile to brittle.

• 单位
  南昌航空大学