Density, molar volume and surface tension of liquid Ti-V-Al and its binary systems measured by electromagnetic levitation

Kurzfassung

Due to their light weight, high strength, increased ductility, large corrosion resistance, and bio-compatibility, Ti-based alloys have raised significant interest in recent years. They are ideal candidates for operation under extreme conditions, such as high temperature or aggressive chemical environment. Thus, Ti-Al alloys are used in a wide range of applications, from turbine blades to medical implants. The addition of vanadium can elevate the thermal as well as the corrosive stability of Ti-Al alloys, especially those of lower aluminum content. The fast-growing interest in these alloys requires precise knowledge of thermophysical properties of the liquid phase as input for process optimization, phase calculation and atomic modelling. However accurate systematic data on density, molar volume and surface tension for liquid Ti-V-Al ternary alloys and its binary sub-systems at high temperature are scarce. The high melting points and the high reactivity at elevated temperatures complicate the measurement of reliable data in the liquid state heavily. The present work uses electromagnetic levitation in order to containerlessly measure density, thermal expansion, and surface tension of Ti-V, Ti-Al as well as Ti-V-Al, as function of both, temperature and composition. First data are presented.