Effect of Torsional Deformation on Self-Diffusion in Silver

Abstract

Data are presented to show that plastic deformation by torsion occuring at temperatures between 700° and 800°C enhance self‐diffusion in silver single crystals. The enhancement varies linearly with surface strain rate, is larger the lower the temperature and is independent of surface strain. The results of experiments at constant stress are discussed in relation to ideas developed by Weertmann. The lifetime of point defects (assumed to be vacancies) at 800°C has been measured as about 100 sec. This permitted the calculation of the concentration of vacancies produced per unit strain.