Thermophysical Properties of Undercooled Refractory Alloys Measured by Electrostatic Levitation

Haipeng Wang1*, Chenhui Zheng, Liang Hu and Bingbo Wei

School of Physical Science and Technology, Northwestern Polytechnical University,
Xi'an, 710072, China

EXTENDED ABSTRACT: The thermophysical properties of liquid alloys are essential for fundamental research studies and engineering applications. However, the accurate thermophysical properties data of liquid alloys, especially for the refractory alloys, are still scarce in the literature. Due to the high temperature and reactivity, the liquid refractory alloys are prone to react and contaminated with the container, making it difficult to accurately measure with traditional methods. The electrostatic levitation containerless method, which has several advantages such as steady levitation without stirring effects, spacious observation fields, heating separated from levitation, wide heating temperature, a wide range of applicable materials, provide an alternative way for thermophysical property measurements of liquid refractory alloys. Moreover, due to the contact between the liquid alloy and the container is avoided, it make the liquid alloys can be maintained at an undercooled state. The thermophysical properties, such as density, surface tension, viscosity, isobaric specific heat, of various refractory alloys including Nb-based, Zr-based and W-based alloys have been measured by electrostatic levitation method over a wide temperature range from overheated to undercooled states. Especially for binary Zr-V and Zr-Fe alloys, the obtained thermophysical properties covering the whole composition range, and which make a complete understanding of the thermophysical properties change tendency for these two binary alloy systems. For Nb-Si, W-Hf, W-Ta alloys, the accurate thermophysical properties data could promote the precise simulation on the solidification research. Besides, the the皿ophysical peoperties of refractory Nb-Si and Zr-V alloys has also been measured by the electrostatic levitation devices, which is on board Chinese Space Station. The results measured from the ground and the space environments have also been compared, which is benefit for the comprehening the influence of the gravity on the thermophyscial properties.

Keywords: Thermophysical property; undercooled liquid; refractory alloys; electrostatic levitation 

Brief Introduction of Speaker
Haipeng Wang

Professor Haipeng Wang is a Ph. D Supervisor from Northwestern Polytechnical University. He is the Director of the Space Materials Science and Technology Branch of CMRS. He is supported by National Science Fund for Excellent Young Scholars, Young Leading Talents in Innovation of The Ministry of Science and Technology, and so on. He has published more than 100 papers in reputed journals like Acta Materialia, Physical Review E, Metallurgical and Materials Transactions A/B, and has been serving as an editorial board member of repute journals such as Applied Physics Letter, Journal of Physics D, Nanotechnology, etc.