Thermodynamic assessments of the U–Nb–Mo and U–Nb–Cr ternary systems

Abstract

The thermodynamic assessments of the U–Nb–Mo and U–Nb–Cr systems have been performed by using the CALPHAD (Calculation of Phase Diagrams) method on the basis of critical evaluation of phase diagram data reported in literature. The reported individual solution phases, i.e. liquid, (αU), (βU), γ, δ and two intermetallic compounds, i.e. MoU2 and NbCr2, have been modeled. The modeling covers the whole composition range and a wide temperature range. By utilizing the available thermodynamic parameters of the sub-binary systems, the U–Nb–Mo and U–Nb–Cr systems have been thermodynamically assessed and a series of self-consistent parameters have been obtained for the first time, which can reproduce most of the phase diagram and thermodynamic data to provide guidance for the design of nuclear fuels.