Phase equilibria and solidification of Mg-rich Mg–Al–Zn alloys

Phase equilibria in Mg-rich corner of Mg–Al–Zn system are analyzed in detail. Thermodynamic calculations are compared with literature data and own key experimental results by means of DSC and DTA measurements. The detailed comparison strongly supports the reliability of the selected thermodynamic description. Furthermore, our focus is placed on proper interpretation of experimental results obtained by thermal analysis. Based on thermodynamic calculation, it is clarified that a signal observed in thermal analysis, which was interpreted as end of solidification in the literature, is related to the start of the monovariant eutectic reaction L + (Mg) + γ-Mg17Al12 under non-equilibrium condition and the solidification process ends at lower temperature. This fact is supported by our microstructural observation.