Berlin 2008 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 49: Phase Transitions VI

MM 49.1: Vortrag

Freitag, 29. Februar 2008, 11:45–12:00, H 0107

Comparative investigation of nucleation undercooling of Zirconium using the electromagnetic and electrostatic levitation technique — •Stefan Klein^1,2 and Dieter M. Herlach¹ — ¹Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt, 51170 Köln, Germany — ²Institut für Festkörperphysik, Ruhr-Universität Bochum, 44780 Bochum, Germany

Containerless processing techniques are applied to deeply undercool metallic melts by avoidance of heterogeneous nucleation on container walls. In this work we investigate the nucleation undercooling of Zirconium processed by the electromagnetic and the electrostatic levitation. While in the first case the samples are processed within ultra high purity inert gas atmosphere, the electrostatic levitation allows to process the melts in ultra high vacuum.

We achieved large melt undercoolings of up to 400 K. A statistical analysis of the maximum undercooling observed within a modified model by Skripov gives information about the nucleation mechanism.

The project was funded by Deutsche Forschungsgemeinschaft, under contract No. HE 1601/21.