Influence of Cu Addition on Phase Stability of High-Entropy Alloys

Abstract

In this study, the effect of Cu addition on the phase stability of AlCuXNiCoTi (X = 0.5, 1.0, 1.5, and 2.0) high-entropy alloys was analyzed using the regular solution and Kohler’s models to obtain an enthalpy that is symmetrical with respect to the alloy composition. The change in Gibbs energy of mixing of a quinary alloy system was calculated based on the extended Miedema theory by considering the change in enthalpy of mixing of the solid-solution and amorphous phases of 10 binary alloys. The comparison between the experimental and prediction results suggested the possibility of using the thermodynamic properties to predict the stable phases in multicomponent alloys consisting of equiatomic and near-equiatomic elements. In this paper, the structural instability of the solid-solution state arising from the difference between the valence electron concentrations of the constituent elements of the binary mixture are discussed in the aspect of the influence of alloying elements on phase stability of multicomponent alloys.