Solid solutions between -U and -Zr were studied, at temperatures ranging from 973 to 1223K, for Zr atomic fractions of between 0.1 and 0.95. It was noted that the data for temperatures below 1223K exhibited a dip at Zr atomic fractions of between 0.2 and 0.4. The dependences of the data upon composition and temperature were consistent with variations in the thermodynamic factor, whose values were deduced from the activity coefficients for the system. It was found that the interdiffusion coefficient in the neighborhood of a Zr atomic fraction of 0.3 could not be expressed by a single frequency-factor/activation-energy pair because of a significant effect of the thermodynamic factor upon the interdiffusivity.

T.Ogata, M.Akabori, A.Itoh, T.Ogawa: Journal of Nuclear Materials, 1996, 232[2-3], 125-30