Experimental and thermodynamic study of the Mg-Sn-In-Zn quaternary system

Phase equilibria in the Mg-rich region of the Mg-Sn-In (at 415 °C and 330 °C), and Mg-Sn-Zn (at 300 °C) ternary systems were determined by quenching experiments, electron probe micro-analyzer (EPMA), and X-ray diffraction (XRD) techniques. The ternary isoplethal sections with constant 5 In and 10 Sn at.% of Mg-In-Sn system, and 10 Sn at.% of Mg-In-Zn system were determined by differential scanning calorimetry (DSC). No ternary compounds were found in the Mg-Sn-Zn and Mg-Sn-In isothermal sections. Critical evaluation and thermodynamic optimization of the Mg-Sn-In-Zn quaternary system were carried out using CALPHAD (Calculation of Phase Diagrams) technique. The Modified Quasichemical Model in the Pair Approximation (MQMPA) was used for modeling the liquid solution, which exhibits a high degree of short-range ordering behavior. The solid phases were modeled with the Compound Energy Formalism (CEF). All available and reliable experimental data were reproduced within experimental error limits. A self-consistent thermodynamic database was constructed for the Mg-Sn-In-Zn quaternary system, which can be used as a guide for Mg-based alloys development.