Thermodynamic reassessment of the neodymium-gold binary system

Phase relationships in Nd-Au binary system have been thermodynamically assessed by means of the CALPHAD technique through Thermo-Calc software package based on the experiment information of phase equilibria and thermodynamic properties from the published literature data. The excess Gibbs energy functions of the solution phases including liquid, fcc_A1, bcc_A2, and dhcp were formulated with Redlich-Kister polynomial functions. The two-sublattice energy model was employed to describe the Nd14Au51 phase which exhibits a homogeneity range. The intermetallic compounds Nd2Au, NdAu, Nd3Au4, Nd17Au36, and NdAu6 were treated as stoichiometric phases. A set of self-consistent thermodynamic parameters formulating the Gibbs energy of various phases in the Nd-Au binary system were then obtained. A much better agreement was achieved between the calculated results and the reported experimental data.