Microstructural evaluation of U-rich U–Zr alloys under near-equilibrium condition

Reaction kinetics in U-rich U–Zr alloys is known to be very sluggish in nature; which renders difficulty in obtaining the equilibrium microstructures in these alloys. As a result, perhaps, no data is available in open literature pertaining to the microstructural description of these alloys under equilibrium condition. The present study evaluates the near-equilibrium microstructure and phase constituents in uranium rich U–Zr alloys; i.e. uranium alloys containing 7 wt% and 35 wt% zirconium; using SEM, EDS, XRD and dilatometric analyses. Thermodynamic analysis provided here explains the apparent discrepancies between the earlier results and the equilibrium phase diagram. A simple quasi-3D geometrical model is proposed here that helps understanding the particle coarsening process; which is relevant in the present system but otherwise general in nature.