Thermodynamic description of the Al–Cu–Y ternary system

Phase equilibria in the ternary Al–Cu–Y system have been analyzed by coupling the CALPHAD method and first-principles calculations, and a complete thermodynamic description was obtained. The thermodynamic descriptions of its three constituent binary systems were taken from the literature. Most of the binary intermetallic phases, except Al3Y, Al2Y, and Cu2Y, were treated to have zero solubility in the ternary system. Based on experimental data, eight stable ternary intermetallic phases were taken into consideration in the present work. Among them, three phases were treated as line compounds with large homogeneity ranges for Al and Cu. The others were treated as stoichiometric compounds. The calculated phase equilibria were in agreement with available experimental data. ► We thermodynamically evaluated the Al–Cu–Y system using the CALPHAD method. ► Ab initio calculations have been performed to support the evaluation. ► An agreement between the calculated results and experimental data was obtained for the ternary system.