Diffusion of 60Co in Zr50Ti50

The diffusion of 60Co in the b.c.c. phase of a 50:50 at.% Zr-Ti alloy has been measured over the temperature range 600 to 1625 deg C. The diffusivities are very high and close to those for cobalt in #betta#-Zr. The Arrhenius plot is linear between 600 and 1000 deg C, shows a positive curvature from 1000 to 1350 deg C, and then undergoes a change in the sign of the curvature from 1400 to 1625 deg C. The results suggest that diffusion occurs by a combination of interstitial jumps and substitutional solute-vacancy exchanges. Although the shape of the Arrhenius curve cannot be accounted for in terms of a straightforward development of the model, it is accurately represented by an expression which is presented. (author)