Abstract
We have studied the concentration dependence of the free energy of mixing, concentration–concentration fluctuations in the long-wavelength limit, the chemical short-range order parameter, the enthalpy and entropy of mixing of Ga–Zn, Ga–Mg and Al–Ga binary alloys at different temperatures using a quasi-chemical approximation for compound forming binary alloys and that for simple regular alloys. From the study of the thermodynamic quantities, we observed that thermodynamic properties of Ga–Zn and Al–Ga exhibit positive deviations from Raoultian behaviour, while Ga–Mg exhibits negative deviation. Hence, this study reveals that both Ga–Zn and Al–Ga are segregating systems, while chemical order exists in Ga–Mg alloy in the whole concentration range. Furthermore, our investigation indicate that Al–Ga binary alloy have a tendency to exhibit ideal mixture behaviour in the concentration range
0
⩽
c
Al
⩽
0.30
and
0.7
⩽
c
Al
⩽
1
.