Molecular dynamics simulations were performed, using the embedded-atom method, of the self-diffusion of an interstitial in the body-centered cubic metal at 2000K. It was found that the interstitial moved only along <111> diagonals, and that switches to other non-parallel directions took place via a 2-dimensional process. The <011> dumb-bell was essential to this process. Movement along the <111> diagonals took place via <111> crowdions which occupied 2 to 6 lattice sites. The probabilities of a direction switch and a move were 0.249 and 0.751, respectively. Upon converting the complicated movement mechanism into a simple picture involving interstitial hopping between lattice points, the diffusion velocity was deduced to be 520m/s, and the activation energy for interstitial self-diffusion was calculated to be 0.54eV/interstitial.

Dynamics of Self-Interstitial Structures in Body-Centred-Cubic W Studied by Molecular Dynamics Simulation. M.H.Carlberg, E.P.Münger, L.Hultman: Journal of Physics - Condensed Matter, 2000, 12[1], 79-86