Self-diffusion and 182Ta diffusion in amorphous samples was studied by using radiotracer techniques, combined with ion-beam sputter sectioning. It was found that, in unrelaxed metallic glasses, the diffusion was controlled by an indirect mechanism in which supersaturated vacancies acted as a diffusion medium. However, in the relaxed amorphous state, diffusion took place via direct collective diffusion mechanisms which ranged from thermally activated atomic displacement chains (large diffusing atoms in densely-packed matrices) to single-atom jumps into neighboring vacant spaces that were temporarily provided by thermal fluctuations (small diffusants in loosely-packed matrices).

P.Scharwächter, W.Frank, H.Kronmüller: Zeitschrift für Metallkunde, 1996, 87[11], 885-91