Vacancy migration and accretion in Ni observed by perturbedγ-γangular correlations

Abstract

Defect migration and accretion are observed in ${}_{}{}^{111}{}_{}{}^{}\mathrm{doped}$ Ni, using perturbed γ-γ angular correlations. Our samples were damaged by variable doses of proton irradiations and deformation at 200 K, well below resistivity stage III. Subsequent isochronal annealing extended to 900 K. When combined with previous work on ion-implanted Ni, the present work leads to a plausible recovery model in Ni which assumes vacancies migrate in stage III. The model includes the free migration and trapping of vacancy defects in the range 270<T<400 K, enhanced diffusion and trapping of vacancy defects in the range 200<T<300 K, and the formation of at least three, variable-sized multivacancy clusters above 350 K.