Semi-experimental mixing enthalpy of ternary liquid phases as a support of phase-diagrams calculation

There exist about 1250 interesting binary systems but more than 22000 ternary ones. For this reason a good experimental investigation of all ternary phase diagrams cannot be expected in the near future. An approach to many ternary systems can be achieved by a phase diagram optimisation, taking into account various experimental incomplete data. In such an objective the mixing enthalpy of the ternary liquid phase can be selected as a general primary thermodynamic information able to scale the different Gibbs functions of all the phases present in the system. In 1991. we have engaged a program to optimise a general procedure with the goal of rapidly obtaining the mixing enthalpy of any ternary metallic liquid phase with the following restrictive conditions :