Diffusion behavior in an interface between U–10Zr alloy and HT-9 steel

The diffusion behavior in an interface between a U–10 wt.%Zr alloy and HT-9 steel at 700 °C and 730 °C was investigated. The Zr-rich layer near the interface between two alloys was formed mainly due to the decomposition of the δ-UZr2 phase in U–Zr alloy, and acted to interrupt the interdiffusion of the alloying elements. Considerable interdiffusion was observed only when the Zr-rich layer was destroyed locally. As a result, the diffusion–reaction layer was mainly composed of a U-rich, (U,Zr)(Fe,Cr)2 compound, Zr-rich and Zr-depleted layers. Fe elements which had diffused from HT-9 were mainly observed in the boundaries of the Zr-rich particles in the U–Zr alloy.