Decomposition of the γ phase in as-cast and quenched U-Zr alloys

An investigation of the decomposition of the high temperature γ phase in as-cast and quenched U-Zr alloys was conducted. Differential scanning calorimetry data clearly showed δ ⇌ γ transformations in alloys with <10 wt% Zr while XRD data did not contain any peaks which uniquely identify it's presence. Since δ phase forms via ω transformation, a comparison of the theoretical diffraction patterns for ω and δ revealed that the intensities of the peaks which uniquely identify the existence of δ when α-U is present, were either very weak, or were zero in ω, suggesting that the ambiguity can be explained if the phase present in these alloys is ω as opposed to δ. Our data are consistent with the presence of δ and ω in as-cast and quenched U-50Zr alloy, respectively, and (α + ω) in rest of the as-cast and quenched alloys. Based on the experimental data, the transformation sequence from γ phase in U-Zr alloys is proposed.