Structure and properties of undercooled liquid metals

Abstract

Electromagnetic levitation is a useful tool to process high-temperature and highly reactive melts without a container. It provides a pure environment and contamination of the melt is reduced to a minimum. With the application of non-contact measurement techniques, structures and properties of pure samples can be investigated. One major advantage of this approach is that it allows one access to the metastable state of the undercooled melt. This paper reports on measurements of thermophysical properties of undercooled liquid metals and recent investigations of their structure. We have performed measurements of the surface tension, electrical conductivity, density and thermal expansion of a number of pure metals and alloys. Some experiments were performed under microgravity conditions which reduce the strength of the required electromagnetic fields by orders of magnitude and lead to a much higher precision. We have recently used electromagnetic levitation in combination with synchrotron radiation to obtain EXAFS spectra of an undercooled Co - Pd alloy.