Effect of intrinsic point-defect complex on elastic properties of γ′-Ni3Al phases

Abstract

The effect of the intrinsic point-defect complex on the elastic properties of the γ′-Ni3Al phases was investigated through first-principles calculations. The formation enthalpies show that AlNi and NiAl defects dominate in the off-stoichiometric γ′-Ni3Al phases, and the AlNi + AlNi and NiAl + NiAl point-defect complexes most likely emerge in Al-rich and Ni-rich systems, respectively. Our computational results suggest that the shear modulus G, Young’s modulus E, and melting point T m of the Ni3Al phases increase when single anti-site defects form, but decrease when intrinsic point defects combine. With variations in the electronic structures caused by point defects, we explained the adverse effect of the intrinsic point-defect complex on the strength of the γ′-Ni3Al phases.