Critical review of phase equilibria in the Ni-Si-Zn ternary system and its thermodynamic description supported by first-principles calculations

Abstract This paper starts from the critical review of all the phase equilibria of the Ni-Si-Zn ternary system reported in the literature. The discrepancies in the phase equilibria from different sources were comprehensively clarified. After that, the first-principles method was utilized to compute the enthalpies of formation for four Ni-Si-Zn ternary compounds at 0 K. The thermodynamic description for Ni-Si binary system was then updated by means of CALPHAD (CALculation of PHAse Diagram) approach using the 2-sublattice order/disorder transition model. The artificial miscibility gap in the liquid phase existing in all the previous assessments was successfully removed. Subsequently, a thermodynamic assessment of the Ni-Si-Zn system was performed by means of CALPHAD approach based on the critically reviewed literature data and first-principles results together with the updated thermodynamic descriptions for Ni-Si binary system. An optimal set of thermodynamic parameters in ternary Ni-Si-Zn system were obtained, yielding a good agreement with most of the experimental data. Based on the presently obtained thermodynamic parameters, the complete liquidus projection and reaction scheme were finally predicted and presented.