Bulk and surface properties of liquid Al–Mg, Au–Sn, and Mg–Tl compound forming alloys

We have used phenomenological models based on statistical mechanics to study the bulk and surface properties of Au–Sn, Al–Mg, and Mg–Tl binary liquid alloys. Our study reveals that the three alloys are weakly ordered systems with the most stable intermetallic complexes at temperatures of 823 K, 1073 K and 923 K been AuSn, Al3Mg2 and Mg4Tl, respectively. An analysis of Warren–Cowley short-range order parameter indicates that the weakest intermetallic compound is Al–Mg while Au–Sn is observed to be more chemically ordered than Mg–Tl. Furthermore, our surface properties calculations shows that Mg-atom and Sn-atom segregate to the surface over the whole concentration range of Al–Mg and Au–Sn alloys, respectively. In Mg–Tl, there is a competing effect between Tl-atom being drawn into the bulk and at the same time Tl-atom wanting to segregate to the surface over the whole concentration range.