The formation and migration of vacancies under elastic strains, ranging from 10% compression to 20% elongation, were studied by computer simulation; using the effective medium theory potential. The model lattice was elastically deformed along the <110> and <100> directions. The Poisson’s ratio was chosen to minimize the total energy. After full relaxation of the lattice by using the static (Newton-Raphson) method, under fixed boundary conditions, a vacancy was introduced and the change (formation energy) in the total energy was calculated. The migration energy of the vacancies was defined as the total energy difference between the model lattice with an atom at the lattice point, and the atom at the saddle point. High strain dependences of these energies were noted. The formation and the migration energies of vacancies were 1.21 and 0.79eV, respectively, in the absence of deformation. The formation energy in <100> deformation was 1.09 and 1.13eV for 10% compression and 10% elongation, respectively. The migration energies and the migration distances varied with migration direction. The migration energy for the shortest migration distance in <100> deformation was reduced to 0.45 and 0.26eV by 10% compression and 10% elongation, respectively. That for the longest migration distance was increased to 1.29eV by 10% compression. The results were explained in terms of the configurations of neighboring atoms nearest to the vacancy.

Computer Simulation of Formation Energy and Migration Energy of Vacancies under High Strain in Cu. K.Sato, T.Yoshiie, Y.Satoh, Q.Xu: Materials Transactions, 2004, 45[3], 833-8