Mixing behaviour of Au–Cu melt

Abstract

The quasi-chemical expression for weakly interacting binary alloy has been applied to obtain energy parameters and their temperature derivative for AuÀCu liquid alloy at 1550 K. These energy parameters have then been used to calculate thermodynamic functions, such as free energy of mixing, heat of mixing, entropy of mixing, and activity and microscopic functions, such as concentration fluctuation in long wavelength limit and WarrenÀCowely short-range order parameter. The analysis reveals that the energy parameters are temperature-dependent and the AuÀCu liquid alloy at 1550 K is moderately interacting hetero-coordinating system. The observed thermodynamic properties of AuÀCu alloy in molten state have successfully been explained by assuming Au 3 Cu complex on the basis of the quasi-chemical formalism for weakly interacting system.