First-Principles Study on Migration of Vacancy in Tungsten

Abstract

We calculated the binding and migration energies of mono-vacancies and di-vacancies in tungsten material using density functional theory. Mono-vacancies diffuse in the [111] direction easier than in the [001] direction. The migration energies of mono-vacancies and di-vacancies are almost the same; moreover, the migration of mono-vacancies and di-vacancies is nearly similar. The di-vacancy binding energies are almost zero or negative. The interactions between two vacancies in tungsten material are repulsive from the second to the fifth nearest neighbors. The vacancies are difficult to aggregate because di-vacancies are less stable than mono-vacancies.