Thermodynamic assessment of the Mg-Zn-Sr system

The phase equilibria and thermodynamic properties of the Mg-Sr-Zn system were analyzed in this work for the first time and a thermodynamic description of the system was obtained using a computerized optimization procedure. The available thermodynamic and phase diagram data were critically assessed for the Mg-Sr, Mg-Zn and Sr-Zn binary systems. Optimized thermodynamic properties of the binary systems were then used to construct a database and calculate the ternary phase diagram. The excess terms of the liquid phase in the binary Gibbs energy equation, for all binaries, were described by the Redlich-Kister polynomial equation. The established database predicted 4 saddle points, 11 ternary quasi-peritectics, 1 ternary peritectic and 3 ternary eutectics. Lack of ternary experimental data led to the following assumptions: no ternary solid solution and/or compounds are present in the system and no ternary terms were added to the model parameters for the thermodynamic properties of the liquid. The calculated ternary phase diagram can be improved by the addition of new experimental data and can help in establishing Mg multi-component database.