Quantitative estimation of coarsening behavior of L12 domains in Ni–Al–V alloys by a first-principles calculation

Abstract

Ni–Al–V based alloys possess superior creep resistance at higher temperatures because of the sluggish interdiffusion of constituent elements within the L12-Ni3(Al, V) matrix. In this study, intrinsic diffusion coefficients of Ni, Al and V in quasi-binary Ni3Al1-xVx (x = 0, 0.125, 0.25, 0.5) were quantified based on a first-principles calculation for elucidating the effect of V concentration on the coarsening behavior of L12 domains. From the results of the estimated formation energies, migration energies and activation energies, it was found that intrinsic diffusion coefficients of Ni and Al are decreased by the addition of V, while intrinsic diffusion coefficient of V remains two or three orders of magnitude smaller than them. Such a suppressed diffusion of Ni and Al by V addition well explains the experimentally obtained lower coarsening rates of L12 domains in Ni3Al0.58V0.42 and Ni3Al0.48V0.52 alloys.