Microstructure,phase stability and properties of CoCr0.5CuxFeyMoNi compositionally complex alloys

Liquid-phase separation occurred in CoCrCu_xFeMoNi (x?≥?0.5) alloys when the mixing entropies are positive in our previous work. So in this work, CoCr_0.5Cu_xFe_yMoNi alloys are designed to investigate the microstructure, component phases and properties. FCC and BCC were detected in CoCr_0.5Cu_xFe_yMoNi alloys, accompanied with a topologically close-packed μ phase. A parameter, V_R, was defined, where V_R is the ratio of the volume fraction of BCC plus μ phases and that of FCC phase. The maximum strength and the ductility were obtained at the minimum V_R of the alloys, whereas the hardness increased with the increasing V_R. It can be presumed that the strange balance between strength, ductility and hardness is an indirect result of the degree of brittle failure.