Characterization of the reaction layer in U–7wt%Mo/Al diffusion couples

The reaction layer in chemical diffusion couples U–7wt%Mo/Al was investigated using optical and scanning electron microscopy, electron probe microanalysis and X-ray diffraction (XRD) techniques. When the U–7wt%Mo alloy was previously homogenized and the γ(U, Mo) phase was retained, the formation of (U, Mo)Al3 and (U, Mo)Al4 was observed at 580 °C. Also a very thin band was detected close to the Al side, the structure of the ternary compound Al20UMo2 might be assigned to it. When the decomposition of the γ(U, Mo) took place, a drastic change in the diffusion behavior was observed. In this case, XRD indicated the presence of phases with the structures of (U, Mo)Al3, Al43U6Mo4, γ(U, Mo) and α(U) in the reaction layer.