Effect of Stress on Hole Formation during the Diffusion of Zinc from Brass in vacuo

Abstract

IT has been suggested by Greenwood¹ that intergranular fracture during deformation at elevated temperatures, which occurs by the linking together of isolated holes at grain boundaries, is the result of precipitation of excess vacancies produced by the deformation. Some doubts have been cast on this view. For example, in diffusion couples, holes may be formed by the precipitation of excess vacancies produced by the unequal rates of diffusion of the components, but these holes have little preference for grain boundaries. An exception to this can occur, however, during the diffusion of zinc from brass in vacuo, and Balluffi and Seigle² have suggested, without proof, that in this case the preferential formation of holes at grain boundaries is associated with the presence of stress.