Migration behavior of self-interstitial defects in tungsten and iron

Abstract Based on the basic characteristic of self-interstitial defect, we propose a new method for locating self-interstitial defect in body centered cubic transition metals, with which the migration behavior of self-interstitial defects with up to three self-interstitial atoms in W and Fe is investigated over a wide range of temperatures by molecular dynamics simulations. With increasing temperature, the migration of self-interstitial defects in W exhibits a change in mechanism from one-dimensional to three-dimensional. The one-dimensional diffusion coefficients rise linearly with temperature. For self-interstitial defects in Fe, the three-dimensional migration is observed, and the obtained migration energy of the tri-interstitial is lower than that of the single- and di-interstitial. During the tri-interstitial migration, several different configurations are found with increasing temperature in both W and Fe.