A thermodynamic description for the ternary Al-Mg-Cu system

A thermodynamic description for the ternary Al-Mg-Cu system was obtained based on the descriptions of its three constituent binaries and ternary phase equilibrium and thermodynamic data available in the literature. All binary intermetallic phases are assumed to have negligible ternary solubility. There are five ternary intermetallic phases; three of them are taken to be line compounds-and two are assumed to be semistoichiometric phases. In view of the extensive experimental data available in the Al-rich corner, particularly for the Al-rich ternary eutectic, the objective of this study was to develop a thermodynamic description that allows us to quantitatively calculate the phase equilibria in the Al-rich corner. The calculated phase equilibria in-the Mg-rich corner may not be as good as those in the Al-rich corner, and those in the Cu-rich corner should be topologically correct and serve as a guide for materials researchers to carry out key experiments in the future to establish the phase equilibria in that portion of the system. Nevertheless, in:the absence bf additional data, the-calculated phase equilibria in-the Cu-rich corner can be used with caution.