Density-functional study of Zr-based actinide alloys

Density-functional formalism is applied to study the phase equilibria in the U–Zr system. The obtained ground-state properties of the γ (bcc) and δ (C32) phases are in good agreement with experimental data. The decomposition curve for the γ-based U–Zr solutions is calculated. We argue that stabilization of the δ-UZr2 phase relative to the α-Zr (hcp) structure is due to an increase of the Zr d-band occupancy that occurs when U is alloyed with Zr.