Evaluation of thermodynamic properties from alloy phase diagram with miscibility gap using non-random two-liquid equation

The non-random two-liquid equation has been applied to evaluate the thermodynamic properties of the liquid solution at elevated temperatures in a binary alloy system with a liquid phase miscibility gap. Only upon making use of the phase equilibrium data at the critical and monotectic points of the miscibility gap from a T-X phase diagram and thermochemical data, the parameters needed for the evaluation, i. e., (g12 - g22), g21 - (g11) and a of the non-random two-liquid solution approach, can be determined. The evaluation of thermodynamic properties was carried out numerically for three binary alloy systems, i. e., Al-Pb, Zn-Pb and Ga-Hg systems. The application of the non-random two-liquid equation to these three binary alloy systems shows that the evaluated results are close to the available experimental measurements.