Strategy to enhance intrinsic ductility and surface stability of Mg-Zn-R (R = La to Sm) alloys from a first-principles study

Abstract

The generalized stacking fault energies of the {0001}〈10–10〉, {1–100}〈11–20〉 and {11–22}〈11–23〉 slip systems and surface energies of {0001} surface are investigated on pure Mg, Mg-Zn and Mg-Zn-R (R = La to Sm) models, through first-principles calculations based on density functional theory. The results show that the addition of alloying element R enhances the intrinsic ductility of Mg-Zn alloys. Moreover, the effect of solute concentration on surface stability is examined by Mg-Zn-La model, and the result suggests that the surface becomes more stable with the decrease of solute concentration. Thereby, the formability and surface stability of Mg-Zn alloys can be modified by adding rare-earth elements R.