Evaluation of Stacking Fault Energy of Copper Alloy using Cluster Expansion Method

Abstract

Stacking fault energies of copper alloys were evaluated by using the first principles calculation and the cluster expansion method. The addition of Zn, Si, and Be, which are HCP stabilizing elements, showed a significant decrease in stacking fault energy, and the addition of Ni, which is FCC stabilizing element, showed an effect of increasing stacking fault energy. Furthermore, the stacking fault energy of Cu–Si, Cu–Zn and Cu–Ni binary alloys reproduced well the experimental values. In the Cu–Si–Zn ternary system, it was confirmed that the stacking fault energy was significantly reduced by the simultaneous addition of Si and Zn. On the other hand, for Cu–Si–Ni and Cu–Be–Co, the effects of the simultaneous addition of solute elements were small, and the results showed that Si and Be dominantly affected stacking fault energy.