Thermodynamic assessments of the Bi–U and Bi–Mn systems

Abstract

The Bi–U and Bi–Mn binary systems have been critically assessed by using the CALPHAD (Calculation of Phase Diagrams) technique on the basis of the experimental data including thermodynamic properties and phase equilibria. The Gibbs free energies of the solution phases (liquid, bcc, fcc, αU, βU, αMn, (Bi), and βMn) were modeled by a sub-regular solution model with the Redlich–Kister equation, and those of the intermetallic compounds (UBi, U 3Bi 4, UBi 2, αBiMn and βBiMn) in these two binary systems were described by a two-sublattice model. A proper set of thermodynamic parameters has been derived for describing the Gibbs free energies of each phase in the Bi–U and Bi–Mn systems. An agreement between the calculated results and experimental data is obtained.