Thermophysical properties of liquid multicomponent alloys

Kurzfassung

Thermophysical properties of liquid multicomponent alloys J. Brillo, I. Egry Deutsches Zentrum f. Luft- und Raumfahrt, Institute of Space Simulation, D-51170 Koeln, Germany 1. Purpose The study of thermophysical properties of liquid metals is not only important for the simulation of certain industrial manufacturing processes, it also reveils insight into interesting physical processes, such as liquid-liquid phase transitions. Due to the increased reactivity of liquid metals at higher temperatures, pollution of the sample material from the reaction with the container walls is often a problem. Therefore, containerless methods are preferred. 2. Experimental techniques Selected methods for hight temperature measurements of both, caloric quantities, like specific heat, cP, and thermal diffusivity , and thermophysical properties, like density , surface tension , electric conductivity , and viscosity , are listed in the following table1. These techniques include container-based as well as containerless methods. In the containerless techniques image processing plays a key role. For instance, surface tension is obtained from the frequency spectrum of the sample’s oscillations, viscosity from their time decay. 3. Results As a specific example of recent results surface tension and viscosity data are presented for the ternary system Ni-Cu-Fe. The surface tensions are shown in Fig.1 for 1800 K. The data are in good agreement with numerical solutions of the Butler equation. Fig. 2 shows viscosity data for the same system, which have been measured by the oscillating cup method. It turns out that, for this system, surface tension and viscosity are proportional to each other – as predicted by Egry2 and Kaptay3.