Thermodynamic assessments of the Ag–Tb and Ag–Ho systems

The phase diagrams and thermodynamic properties in the Ag–Tb and Ag–Ho binary systems have been assessed by using the CALPHAD (Calculation of Phase Diagrams) method on the basis of the experimental data including the thermodynamic properties and phase equilibria. The Gibbs free energies of the liquid, bcc, fcc and hcp phases were described by the substitution solution model with excess energy expressed by Redlich–Kister polynomial, and those of intermetallic compounds (Ag2Tb, AgTb, Ag2Ho and AgHo phases) were treated as stoichiometric compounds, and Ag51 Tb14 and Ag51 Ho14 phases were modeled by the sublattice model in these two binary systems. The thermodynamic parameters of each phase in the Ag–Tb and Ag–Ho binary systems were obtained, and an agreement between the calculated results and experimental data was obtained in each binary system.