Modelling of thermophysical properties of metallic melts

The understanding of the nature of different metals and how their properties will change due to formation of binary or multicomponent alloys is a key issue for optimization of existing alloy systems or design of new alloys with required properties. There are many studies on solid alloys and their properties, while in the case of liquid alloys, such information are scarce. The determination of the thermodynamic and the thermophysical properties of high melting liquid alloys is hampered by the experimental difficulties related to high temperature measurements, strong reactivity of their components in contact with gaseous species present in the surrounding atmosphere and, in the case of classical experimental methods, reactions between alloy melts and container materials. As a consequence, neither the thermodynamic nor the thermophysical data on many high temperature alloy systems are available. In particular, concerning the data on the surface properties of multicomponent alloys, only the surface tension data of the corresponding pure components can be found in literature. Therefore, it is only possible to estimate the missing property values in terms of theoretical framework. The energetics of mixing and structural arrangement in regular, compound forming and phase separating liquid alloys have been analyzed through the study of surface properties (surface tension and surface segregation), dynamic properties (chemical diffusion, viscosity and electrical resistivity) and microscopic functions (concentration fluctuations in the long-wavelength limit and chemical short-range order parameter) in the framework of classical thermodynamic and quantum statistical models and theories. An overview of different models widely used to predict the thermophysical properties of liquid alloys and the problems related to modelling will be presented.