Microstructural investigation of as-cast uranium rich U-Zr alloys

The present study evaluates the microstructure in as-cast uranium rich U-Zr alloys, an important subsystem of U-Pu-Zr ternary metallic nuclear reactor fuel, as a function of the Zr content, from 2wt.% to 15wt.%Zr. It has been previously suggested that the unique intermetallic compound δ phase in U-Zr alloys is only present in as-cast U-Zr alloys with a Zr content exceeding 10wt.%Zr. However, our analysis of transmission electron microscopy (TEM) data shows that the δ phase is common to all as-cast alloys studied in this work. Furthermore, specific coherent orientation relationship is found between the α and δ phases, consistent with previous findings, and a third variant is discovered in this paper.