摘要
Sn-Ag-Zn alloys are promising Pb-free solders. In this study, the Sn-Ag-Zn liquidus projection was determined, and the Sn-Ag-Zn thermodynamic modeling was developed. Various Sn-Ag-Zn alloys were prepared. Their as-cast microstructures and primary solidification phases were examined. The invariant reaction temperatures of the ternary Sn-Ag-Zn system were determined. The liquidus projection of the Sn-Ag-Zn ternary system was constructed. It was found that the Sn-Ag-Zn ternary system has eight primary solidification phases: ε 2 -AgZn 3 , γ-Ag 5 Zn 8 , β-AgZn, ζ-Ag 4 Sn, (Ag), ε 1 -Ag 3 Sn, β-(Sn) and (Zn) phases. There are eight ternary invariant reactions, and the liquid + (Ag) = β-AgZn + ζ-Ag 4 Sn reaction is of the highest temperature at 935.5 K. Thermodynamic modeling of the ternary Sn-Ag-Zn system was also carried out in this study based on the thermodynamic models of the three constituent binary systems and the experimentally determined liquidus projection. The liquidus projection and the isothermal sections are calculated. The calculated and experimentally determined liquidus projections are in good agreement.