Vacancy diffusion along twist grain boundaries in copper

Vacancy diffusion along two different high-angle twist grain boundaries (Σ5 and Σ13) was studied using the Embedded Atom Method (EAM). Vacancy formation energies in all the possible sites were calculated and found to be directly related to the degree of coincidence with the neighboring crystal planes. Optimal migration paths and migration energies were determined and found to be very low. The activation energies for self-diffusion at the boundaries were found to be less than half of the bulk value.