THERMODYNAMIC OPTIMIZATION OF THE MG-AL-SI PHASE-DIAGRAM

An optimized phase diagram for the ternary Mg-Al-Si system was constructed using experimental data from the literature. The binary excess terms were represented by Redlich-Kister polynomial expressions. The two binary Mg-Si and Al-Si systems were re-adjusted using newer phase stabilities and experimental results. The ternary system is described, using the Mg-Al system of Saunders by Muggianu's formula and two additional terrnary excess terms for liquid, which were adjusted to experimental values from the literature by the least squares method. A number of vertical and isothermal sections were calculated along with the liquidus surface. The optimized diagram is in acceptable agreement with the experimental data.