Hamburg 2001 – wissenschaftliches Programm
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M: Metallphysik
M 33: Postersitzung
M 33.8: Poster
Donnerstag, 29. März 2001, 15:15–19:00, Foyer S4, CCH
Rapid directional solidification of undercooled alloy melts — •Zhenhua Zhou1,2 and Hengzhi Fu2 — 1Institut für Raumsimulation, Deutsches Zentrum für Luft- und Raumfahrt, D-51170 Köln — 2State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xian 710072, China
Rapid directional solidification allows the formation of refined and unidirectionally grown dendritic microstructures in alloy melts. Furthermore, it can also be served to study the solidification kinetics in detail. Usually the temperature gradient ahead the solid/liquid interface during directional solidification process is positive, but in the present work, rapid directional solidification of highly undercooled alloy melts, in which the temperature gradient ahead the solid/liquid interface is negative, has been developed. It allows accurate measurement of the crystal growth velocity in undercooled alloy melts. By triggering we have examined the rapid directional solidification process in Ni-Cu alloy melts at various undercoolings. Aligned, refined and continuously grown dendritic microstructures have been obtained. The primary dendritic spacing is refined to a minimum of 25 µm in Cu95Ni5 alloys. The growth process and microstructural characteristics have been discussed within the present dendritic growth theory.