Influence of continuous Cu-rich phase on the deformation mechanism in as-cast CoCrFeNiCu high-entropy alloy

Since the high resistance to deformation and low thermal conductivity of high-entropy alloys (HEAs), the strengthening and toughening strategies based on thermomechanical processing are time-consuming and costly. Thus, it is more practical to enhance the strength and ductility of the as-cast HEAs. In this work, an equiatomic CoCrFeNiCu HEA was prepared, and that exhibited a yield strength (R p0.2 ) of 318 MPa and elongation to failure (EL) of 65%, which has an increment R p0.2 of 148 MPa and comparable EL comparing with that of the as-cast CoCrFeNi HEA. The experimental observations and molecular dynamics (MD) simulation demonstrated that, these superior tensile properties were caused by the coherent interface induced by the continues Cu-rich phase, which can not only effectively refine the FCC matrix size, but also alleviate the stress concentration at the interface. These findings provide a template for simultaneously improving the yield strength and ductility of other as-cast HEAs by introducing coherent interfaces.