Thermophysical properties of multicomponent liquid alloys and their measurement at elevated temperature

Kurzfassung

Economic-, cultural- and social- evolution goes hand in hand with the development and continuous improvement of new materials. The casting of metals, their optimization and the advancement of their production processes is especially crucial in this context. The liquid phase plays a key role in this context, as the vast majority of materials is made directly from the melt or under its direct involvement. For any process of materials development, the properties of the liquid metal need to be known precisely. As liquid metals are generally highly reactive at elevated temperature, the use of levitation methods is inevitable. In addition, technical alloys are generally multicomponent materials. This makes the investigation of the concentration dependence of their properties especially important. The present talk will describe electromagnetic levitation and corresponding diagnostic methods in order to contactlessly determine thermophysical properties such as density, surface tension, specific heat and several others. The concentration dependence of these properties will be discussed systematically. Three distinct classes of materials can be identified where the members of each class exhibit qualitatively the same behavior with respect to the mixing rules and applicable solution models. Furthermore, the effect of oxygen on the surface tension of liquid metals will be discussed using the Butler equation.