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

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, beta-Gd5Pb4, alpha-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. (C) 2013 Elsevier B. V. All rights reserved.