Effect of cold rolling on the microstructure and mechanical properties of Al0.25CoCrFe1.25Ni1.25 high-entropy alloy

Cold rolling can break down the as-cast dendrite microstructure and thus may have pronounced impact on the mechanical behavior of the alloy. In the present study, the effect of cold rolling on the microstructure and mechanical properties of Al0.25CoCrFe1.25Ni1.25 high-entropy alloy in the face-centered cubic structure was investigated. With increasing the thickness reduction from cold rolling, the hardness, the yield strength, and the fracture strength increased at the cost of reducing ductility. At the thickness reduction of 80%, the tensile strength (hardness) was 702 MPa (406 MPa), 1.62 (2.43) times that in the as-cast condition. Compared to traditional alloys, Al0.25CoCrFe1.25Ni1.25 has the highest hardening rate with respect to CR thickness reduction. The phase relation and the mixing properties of Gibbs free energy, enthalpy and entropy of AlxCoCrFe1.25Ni1.25 were predicted using the CALPHAD method.