Improvement of predictive ability of self-association model to segregation of liquid Zn−Bi alloys

Abstract

The self-association model is an effective theoretical method for determining the thermodynamic parameters of immiscible molten binary alloys. However, two important parameters (the ratios of numbers of two atoms in the cluster n and the interchange energy W) in the model had confusing temperature dependences, which prevented the statistical mechanical model from accurately predicting the physical and chemical properties at various temperatures. The ratios of the two atoms in the cluster and the interchange energy were proposed in this study to be linear with temperature, respectively, to analyze the segregation of liquid Zn–Bi alloys. The hypothesis about two key parameters is helpful to predict the segregating nature of liquid Zn–Bi alloys, as evidenced by the good accordance of the predicted thermophysical properties (activity, free energy of mixing, miscibility gap, entropy of mixing, partial molar entropy, and concentration fluctuation) with the existing experimental data.