Simple model for the structure and thermodynamics of liquid alloys with strong chemical interactions. II. Chemical order and packing constraints

Ordering effects in disordered systems: the Au-Si system

We have characterized the short-range order in the liquid and undercooled states of Au-Si alloy at the eutectic composition using molecular dynamics simulations. The interactions are described via a modified embedded-atom model refined to take into account the liquid properties. For the eutectic liquid, the local structure is characterized by a strong Au-Si affinity, namely a well-pronounced chemical short-range order which leads to the slowing down of the formation of icosahedral local motifs in the undercooled regime. Moreover we discuss the influence of this peculiar local structure on the dynamic and thermodynamic properties of the liquid phase and compare our results with available experimental data.

Entropy of mixing for Ag(x)In(1-x) and Ag(x)Sn(1-x) liquid binary alloys

The entropy of mixing for Ag(x)In(1-x) and Ag(x)Sn(1-x) liquid binary alloys has been systematically investigated by using the perturbation theory. The interionic interactions as one of the basic ingredients are described by a local model pseudopotential. Since the metals forming the concerned alloys are less simple in nature the effect of the sp-d hybridization is appropriately taken into account through the interionic interactions. Results of our calculations across the full range of Ag concentrations are found to be good in agreement with the available experimental data.