ON THE DIFFUSION OF SCANDIUM AND HAFNIUM IN TUNGSTEN

The modified thermodynamic model of impurity diffusion in BCC metals, which is based on the assumption that monovacancy jumps to nearest and next-nearest neighbour positions are responsible for the transport, i s applied to the diffusion of Sc and Hf in tungsten. The agreement wit h experimental data reveals that the applicability of the model is not restricted to impurities of the groups V to VII of the periodic syste m. (C) 1998 Elsevier Science B.V. All rights reserved.