DIFFUSION IN AMORPHOUS METALLIC ALLOYS

A representative selection of experimental data as well as molecular-dynamics simulations serve as a basis for elucidating the atomic mechanisms of self-diffusion in amorphous and nanocrystalline metallic alloys. In particular, it is concluded that in as-produced amorphous alloys self-diffusion occurs indirectly via quasi-vacancies. whereas in relaxed amorphous alloys self-diffusion is controlled by direct collective mechanisms, among which thermally activated displacement chains play a major role. These mechanisms are contrasted with those governing transition metal diffusion in amorphous silicon.