Using density functional theory calculations in conjunction with the climbing images nudged elastic band method, vacancy formation and migration in clean and Re-doped Ni3Al were studied. Both the chemical potential of the species and the magnetic effect were considered to determine the vacancy formation energy. The vacancy migration in a complete set of migration paths was also simulated. The evaluated vacancy formation energy and activation energy for the motion of vacancy compared well with the experimental results. Also, the obtained migration ways for the diffusion of Ni and Al atoms were consistent with previous theoretical predictions and experimental observations. Magnetism was found to influence both the vacancy formation and migration. The results revealed that Re doping could inhibit the formation of Ni vacancies but facilitate the formation of Al vacancies, and could also inhibit the migration of neighbouring vacancies. While the doped Re atom on the Al site was stable, the Re atom on the Ni site could diffuse within the Ni-sublattice mediated by Ni vacancies.

First-Principles Study of Vacancy Formation and Migration in Clean and Re-Doped γ′-Ni3Al. Zhang, X., Wang, C.Y.: Acta Materialia, 2009, 57[1], 224-31