Thermodynamic description of the Pb–Yb binary system

Thermodynamic modelling of the Pb–Yb binary system was carried out with the help of the CALPHAD method. The liquid phase has been described with the association solution model with ‘ Pb1Y b2’ as an associated complex. The solution phases BCC_A2 and FCC_A1 were modelled with the sublattice formalism. The α PbYb_LT and β PbYb_HT Pb sub-stoichiometric intermetallic compounds, which have a homogeneity range, were treated with the formula (Pb,Y b)0.5(Y b)0.5 by a two-sublattice model with Pb and Yb on the first sublattice and Yb on the second one. Pb3Y b, Pb3Y b5 and PbY b2 have been treated as stoichiometric compounds. The calculations based on the thermodynamic modelling are in good agreement with the phase diagram data and experimental thermodynamic values.