Impact of Cu Content on Microstructural Evolution and Mechanical Behavior of CoCrMo_0.5TiVCu_x High-Entropy Alloys

In this paper, CoCrMo_0.5TiVCu_x (X = 0-1.5) high-entropy alloy was prepared by arc melting, and both the effect of different Cu contents on the microstructure evolution and mechanical properties of CoCrMo_0.5TiVCu_x high-entropy alloy were investigated. The results show that the amount of Cu-rich FCC phase increases with the Cu content, segregated at the dendrites. The CoCrMo0.5TiV alloy is composed of BCC + B2 phases, while the Cu-added CoCrMo0.5TiVCu_x alloy is composed of BCC + B2 + FCC phases, and calculation results of phase formation criterion are suitable for the alloy. It is happened in the CoCrMo0.5TiVCu_x alloy with the increase in the Cu content that Cr, Mo and V elements are segregated at dendrites, while Co and Ti elements are segregated at inter-dendrites. The CoCrMo_0.5TiCu alloy has the most excellent mechanical properties, with a compressive strength of 2043.26 MPa and a fracture strain of 12.43%. The effect of FCC phase on the properties of the CoCrMo0.5TiVCu_x alloy is studied, and it is found that fine and soft Cu-rich FCC phases in the grain boundaries can improve the alloy’s strength and fracture strain, acting as barriers to crack expansion by inducing crack passivation and deflection.