Stacking Fault Energies, Crystal Elasticity and Their Relation to the Mechanical Properties of L12-Ordered Alloys

Abstract

ABSTRACTFirst-principles calculations of the stacking fault energies of Ni3Al, and the linear elastic constants of Ni3Al and Pt3Al are presented. The anomalous (positive) temperature dependence of flow stress in Ni3Al and its absence in Pt3Al are fully rationalized in terms of the present results and cross-slip pinning mechanism. It is found that the elastic shear anisotropy factor plays an equally (or even more) important role than the anisotropy of antiphase-phase boundary energy in determining the plastic flow behavior of L12-ordered alloys.