Theoretical investigation of the elastic constants and shear fault energies of Ni3Si

Abstract

Abstract The ground-state elastic constants and the shear fault energies (antiphase boundaries and superlattice stacking faults) of Ni3Si are determined from first-principles total-energy calculations within the framework of the local-density-functional theory. Within the context of the cross-slip-pinning model, it is predicted that the anomalous (positive) temperature dependence of yield and flow strengths is not likely to occur in stoichiometric Ni3Si at low temperatures. The strength anomaly reported for Ni3 (Si,Ti) is attributed to the increased driving force for cross-slip, which is probably due to the increased elastic anisotropy (from A ≈ 2·0 to A ≈ 2·8) produced by Ti additions.