Determination of the Enthalpy of Mixing of Liquid Aluminium - Copper - Nickel Ternary Alloys

Abstract

The enthalpy of mixing, ΔH, of liquid Al-Cu-Ni ternary alloys at 1700 K, was measured using a high-temperature mixing calorimeter. Results for eight sections with constant concentration ratios of two components are given. Within the range of experimental accuracy, the measured ΔH values are most accurate regarding the self-consistency of a single series and the points of intersection. An association model is used to calculate the thermodynamic mixing functions of the ternary alloys, based on the enthalpy of mixing of the binary bordering systems. The calculated enthalpy of mixing shows small deviations from the experimental data. The existence of the ternary τ and β phases shows that these deviations are caused by additional ternary interactions in the liquid state