Regensburg 2013 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 15: Poster Session
MM 15.6: Poster
Montag, 11. März 2013, 18:00–20:00, Poster E
Investigation of thermal properties of Si1-xGex melts under microgravity conditions — Bernd Damaschke1, •Yuansu Luo1, Suresh M. Chathoth1, N.V. Abrosimov2, M. Czupalla2, and Korand Samwer1 — 1I. Physikalisches Institut, Georg-August-Universität Göttingen — 2Leibniz Institut für Kristallzüchtung Berlin
Investigation of thermal properties of Si1-xGex melts has been planned on board of the international space station (ISS) under microgravity and electromagnetic levitation (EML) conditions, where the absence of gravity-driven convection and segregation of the components allows precision measurements for the thermal expansion, surface tension and viscosity as function of temperature. The semiconductor alloy crystals for the ISS experiments were prepared by Czochralski growth. For the preparation, parabolic flights (PF), which provided a microgravity condition for ca. 20s, were carried out using the samples Si1-xGex made by arc-melting (x=0, 0.25, 0.5, 0.75 and 1.0). Preliminary data of their density, thermal expansion and surface tension in the melt and undercooled state were obtained. The density shows a non-ideal behavior with x and the highest value occurs at x=0.5, indicating a strong ordering tendency. We report about sample characterization and the status of the project concerning the ISS experiments. The initial results demonstrate that the melts of these alloys can be successfully processed in the MSL-EML facility for precision measurements on board the ISS. We thank DLR and Novespace for the PF campaigns and the MUSC team for the help with experiments. Financial support from DLR project 50WM0541 and 50WM1036 is gratefully acknowledged.