ACTIVATION VOLUME FOR DIFFUSION IN A METALLIC-GLASS

In this work we present the results of a study of the effects of a high hydrostatic pressure upon atomic diffusion in an amorphous (FeNi)8(PB)2 alloy. Due to the difficulties inherent to the studies under high pressures and to the measurements of diffusion by tracer methods in amorphous alloys, we have developed a new method: we follow the crystallization kinetics during isothermal annealings under pressure, between 0 and 0.8 GPa. We show how it is possible to deduce from these measurements the true effect of pressure upon diffusion. This effect can be described in the present amorphous alloy by an activation volume of 11 Å3/at, nearly equal to the mean atomic volume. Performing a comparison between diffusion characteristics in crystalline and amorphous forms of the present alloy, we were led to interpret our results as indicating, with a high probability, a vacancy like mechanism. © 1990.