Effects associated with the Flow of Vacancies in Intermetallic Diffusion

Abstract

Experiments on the interdiffusion of copper-alpha-brass and copper-nickel couples and sandwiches have shown that there is an increase of volume in the diffusion zone as a result of diffusion This increase in volume is associated with the formation, in the diffusion zone, of voids with crystallographic faces These voids appear near to the original interface and on that side from which there is a net loss of atoms, or a net gain of vacancies, as shown by the movement of inert markers Grain boundaries influence the movement of the markers in regions where there has been preferential grain-boundary diffusion A close micrographical examination of the diffusion zone shows it to have an unusual structure, various observations pointing to the presence of strain, and x-ray back reflection photographs of a copper-nickel couple show that the diffusion zone is polygonized Subsidiary experiments suggest how strain in the diffusion zone arises