Characterization of the interaction layer in diffusion couples U-7 wt.%Mo/Al 6061 alloy at 550 °C and 340 °C.: Effect of the γU(Mo) cellular decomposition

Solid state reaction between U-7 wt.%Mo and Al 6061 alloys at 550 °C and 340 °C was characterized in chemical diffusion couples made by Friction Stir Welding. Results were obtained from optical and scanning electron microscopy, electron probe microanalysis and X-ray diffraction. At 550 °C the interaction layer in γU(Mo)/Al 6061 is formed by U(Al,Si)3 phase but when γU(Mo) cellular decomposition occurs, UAl3 and Al43Mo4U6 also appear in the interaction layer. At 340 °C the use of X-ray diffraction with synchrotron radiation made it possible to analyze the interaction layer. It was found that it is only formed by U3Si5 phase with its cell volume enlarged respect to the original one.