A thermodynamic description of the Al-Ca-Zn ternary system

A comprehensive thermodynamic database of the Al-Ca-Zn ternary system is presented for the first time. Critical assessment of the experimental data and re-optimization of the binary Al-Zn and Al-Ca systems have been performed. The optimized model parameters of the third binary system, Ca-Zn, are taken from the previous assessment of the Mg-Ca-Zn system by the same authors. All available as well as reliable experimental data both for the thermodynamic properties and phase boundaries are reproduced within experimental error limits. In the present assessment, the modified quasichemical model in the pair approximation is used for the liquid phase and Al_FCC phase of the Al-Zn system to account for the presence of the short-range ordering properly. Two ternary compounds reported by most of the research works are considered in the present calculation. The liquidus projections and vertical sections of the ternary systems are also calculated, and the invariant reaction points are predicted using the constructed database.