Thermodynamic modeling of the RE–Pb (RE=Sc, Dy, Gd) systems

•Rare earth (RE) and Pb alloys or compounds are interesting as magnetic materials.•The phase diagrams and thermodynamic properties of RE–Pb (RE=Sc, Dy, Gd) systems have been assessed.•The CALPHAD method was used with the Redlich–Kister model to optimize the solution phases.•A self-consistent set of thermodynamic parameters has been evaluated.•A good agreement was found between the calculation and experiments. The phase diagrams and thermodynamic properties of RE–Pb (RE=Sc, Dy, Gd) systems have been assessed by means of the CALPHAD method. The solution phases (liquid, fcc, bcc and hcp) were described by the sublattice formalism and the excess term of the Gibbs energy with the Redlich–Kister equation. The stoichiometric intermetallic compounds (Sc5Pb3, Sc6Pb5, Dy5Pb4, DyPb, DyPb2, DyPb3, β-Gd5Pb4, α-Gd5Pb4, Gd11Pb10, Gd6Pb7, GdPb2 and GdPb2) were modeled as line compounds. The non-stoichiometric Dy5Pb3 and Gd5Pb3 phases with a narrow homogeneity range were modeled using a two-sublattice model with substitution. A consistent set of the thermodynamic parameters leading to a reasonable agreement between the calculated results and literature data was obtained.