The predominance of vacancy migration in grain boundary self-diffusion was established by molecular-dynamics simulation of a body-centered cubic iron  tilt boundary. The data yielded a reasonable value of the activation energy for migration and showed that the jump processes were highly structure dependent. The use of a temperature-dependent transition-probability matrix to describe the diffusion of the vacancies in the grain boundary was suggested. Formation of one type of boundary interstitial was observed, and the interstitial was found to be immobile during its lifetime.

Evidence for Vacancy Mechanism in Grain Boundary Diffusion in BCC Iron: a Molecular-Dynamics Study. Kwok, T., Ho, P.S., Yip, S., Balluffi, R.W., Bristowe, P.D., Brokman, A.: Physical Review Letters, 1981, 47[16], 1148-51