An initial thermodynamic modeling of the Cu-Ni-Si-Co system was built using CALPHAD approach. The liquid phase and terminal solid solutions were described by substitutional solution model, the nonlinear compounds used sublattice model and the other binary compounds were treated to be stoichiometric compounds. Based on the experimental conditions, the thermodynamic calculations were done to predict the stable precipitates of the alloys and investigated the effect of Co on the phase transitions. The experimental results showed an acceptable agreement with the calculation and verified the reliability of the Cu-Ni-Si-Co thermodynamic modeling.
