Using diffusion couples, an investigation was made of the effect of Zr additions to U-Mo, and of Si additions to Al, upon interdiffusion between U-Mo and Al. The phase stability of the γ heat-treated alloys during high-temperature annealing was determined. By using X-ray diffraction, it was observed that γ-phase U-7Mo-Zr alloys, with more than 2wt%Zr, decomposed faster than U-7Mo alloy. The diffusion couples showed that a Zr addition to U-7Mo, and the addition of Si to Al, reduced the interaction-layer growth-rates. However, Zr additions to U-Mo were most effective in reducing the overall interdiffusion rates when combined with Si additions to Al. Decomposition of the metastable U-Mo γ-phase during diffusion tests appeared to have a significant effect upon the overall interdiffusion rates.

Effect of Si and Zr on the Interdiffusion of U-Mo Alloy and Al. J.M.Park, H.J.Ryu, S.J.Oh, D.B.Lee, C.K.Kim, Y.S.Kim, G.L.Hofman: Journal of Nuclear Materials, 2008, 374[3], 422-30