Thermodynamics of liquid Al–Fe alloys

Abstract

We have used a complex formation model to study chemical short range order due to atomic level interactions in liquid Al–Fe alloys. Assuming the existence of a complex of the form FeAl3, we use the model to deduce information on thermodynamic properties of the alloy such as the Gibbs free energy of mixing, the thermodynamic activity and the enthalpy of mixing. In our approach, we first model the Gibbs free energy in terms of interaction parameters. Subsequently, we use the parameters to describe properties such as the concentration– concentration fluctuations in the long wavelength limit, the Warren-Cowley short range order parameter and the chemical diffusion. Underlying the present calculations is the fact that for Al–Fe liquid alloys, a reasonable degree of chemical short range order although of a weak nature persists throughout the whole concentration range.