Surface segregation and surface tension in liquid Fe-Cu alloys

A simple statistical mechanics model has been used to study the temperature dependence of the surface properties of Fe-Cu liquid alloys. The calculated values for the composition dependence of surface segregation indicates that Cu atoms segregate to the surface and, in addition, that the surface tension in Fe-Cu alloys decreases with increasing copper content. Furthermore, our formalism is able to predict the temperature dependence of the surface properties for the liquid alloy based only on knowledge of the results at the melting point. This illustrates that the model used provides a simple recipe to extract information in the under-cooled region about the dependence of surface properties in liquid binary alloys. In addition, close to the decomposition temperature, the surface concentration of Cu increases sharply in the undercooled region.