Study of the Uncertainty Heterogeneous Phase Equilibria Areas in the Binary YbTe-SnTe Alloy System

Using the Multipurpose Genetic Algorithm (MGA) the liquidus and solidus regions, binodal and spinodal boundaries of the solid solutions in the system YbTe-SnTe are optimized. The analysis correctly shows that the liquidus and solidus regions in the YbTe-SnTe system cannot be described within the framework of the ideal model of solutions. The use of functions, including the partial molar excess free Gibbs energies of all components, allowed for adequately taking into account deviations from the ideal model of the properties of equilibrium liquid and solid solutions. The analytical relationships between the variables and the phase transition parameters allowed us to estimate the sensitivity of the input data. It is established that the coordinates of the liquidus and solidus curves are insensitive to the melting enthalpy. At the same time, a high sensitivity of the liquidus and solidus coordinates to melting points of the YbTe and SnTe was observed. It was wound that, when melting point changes 10 K, the uncertainty areas for the liquidus and solidus vary in a wide range.