Energies of formation and activation for migration of grain-boundary vacancies in a nickel bicrystal containing a disclination

The energies of formation and activation for migration of vacancies in the [001] tilt boundary containing a wedge disclination have been calculated with the help of atomistic computer simulation using a multiparticle interatomic potential based on the embedded-atom method. The Sigma = 5 (310) theta = 53.13 degrees tilt boundary that contains a negative disclination of strength omega = -4.98 degrees and a positive disclination of strength omega = 5.21 degrees has been investigated. It has been shown that high internal disclination-induced stresses exert a very strong effect on the diffusion coefficient. In the region of about 5 nm around the disclination core, the energy characteristics of vacancies may differ markedly from those typical of a defect-free boundary.