Dresden 2003 – scientific programme
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M: Metallphysik
M 16: Symposium: Phasenumwandlungen in Schmelzen VI
M 16.2: Talk
Tuesday, March 25, 2003, 12:00–12:15, IFW A
In-situ Determination of Phase Selection Sequences in Undercooled Ti-Fe-Si-O Melts — •Oliver Heinen1, Dirk Holland-Moritz1, Thomas Volkmann1, Jörn Strohmenger1, Thomas Schenk1,2, Thomas Buslaps2, Sandrine Schlutig1, and Dieter M. Herlach1 — 1DLR, Institut für Raumsimulation, D-51170 Köln — 2European Synchrotron Radiation Facility (ESRF), F-38000 Grenoble Cedex, France
The alloy system Ti-Fe-Si-O forms a great variety of stable and metastable solid phases including structurally complex phases such as quasicrystals and their approximants. The competition of this large number of different phases implies a complicated phase-selection behaviour during solidification, which depends on alloy composition and undercooling.
In this work we present in situ investigations of the phase selection sequences during solidification of undercooled Ti66−68Fe28−26(SiO2)6 melts as a function of composition and undercooling. The liquids were containerlessly processed und undercooled by utilization of the electromagnetic levitation technique which was combined with energy dispersive diffraction of synchrotron radiation at ESRF in order to directly determine the crystal structure of the solid phases formed during solidification with a time resolution of 1-2 seconds. Different solidification pathways were found in these alloys, one starting with the primary formation of the (1/1)-approximant phase, others with the primary formation of α-Ti.
This work was financially supported by DFG under contract No. Ho1942/4 and by ESRF.