Berlin 2005 – wissenschaftliches Programm
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M: Metallphysik
M 23: Phasenumwandlung III
M 23.6: Vortrag
Samstag, 5. März 2005, 16:00–16:15, TU H1058
Solidification of Undercooled Si, Si-Co and Si-Ge Melts — •C. Panofen1, R.P. Liu2, and D.M. Herlach1 — 1DLR Köln, Institut für Raumsimulation — 2Yanshan University, Qinhuangdao, China
We undercooled and solidified pure Si, dilute Si-Co and Si-Ge melts in a high purity environment containerlessly by electromagnetic and electrostatic levitation techniques. Without surrounding crucible walls and thus reducing heterogeneous nucleation sites we achieved large melt undercoolings of up to 330K.
Crystallization at the desired undercooling was initiated by triggering with a silicon wafer. The velocity of the solidification front as a function of undercooling was directly determined with a high speed camera.
We analyzed the growth behavior within current theories of crystal growth in undercooled melts. Special emphasis was placed to a microstructure transition from faceted to dendritic growth. The results of the growth measurements were correlated to microstructure formation upon undercooling prior to solidification.
This work is funded by the Sino-German Science Center, Beijing, and DFG under contract number HE-1601/16-1