Thermodynamic calculation of phase equilibria in Cu-Ni-Sn ternary system

On basis of the phase equilibria and thermodynamic properties of the Cu-Ni-Sn ternary system by experiment, the thermodynamic assessment of the Cu-Ni-Sn ternary system was carried out by the CALPHAD (calculation of phase diagrams) method. The Gibbs free energies of liquid and fcc phases were described by the subregular solution model, and Gibbs free energies of the bcc phase were described by the sublattice model in order to predict the order-disorder phase transition in the bcc phase. A set of parameters describing the Gibbs energies of different phases in this system were optimized by experimental data. The calculated results agree well the experimental data. The A2/B2 ordering temperature and miscibility gap of the fcc phase can be predicted. These calculated results provide an effective guide for microstructure design of the new type Cu base practical materials with high strength and high electric conductivity.