Dresden 2009 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 23: Topical Session Heterogeneous Nucleation and Initial Evolution of Microstructure - Poster
MM 23.5: Poster
Dienstag, 24. März 2009, 14:45–16:30, P4
Heterogeneous nucleation undercooling and kinetics analysis — •Charuayporn Santhaweesuk1, John H. Perepezko1, Joachim Bokeloh2, and Gerhard Wilde2 — 1University of Wisconsin-Madison, Department of Materials Science and Engineering, Madison, USA — 2University of Münster, Institute of Materials Physics, 48149 Münster, Germany
For large liquid volumes it is essential to remove or to deactivate heterogeneous nucleation sites in order to achieve large undercooling values. An effective method of melt conditioning for nucleant removal is based upon flux treatments, but the mechanism that is responsible for the large undercooling is not properly understood. Recent experiments and analyses of the undercooling behavior in flux treated pure Cu have provided new results as well as confirmation for a model of nucleant refining that accounts for the undercooling behavior including initial conditioning, atmosphere effects and saturation in a self-consistent manner. Moreover, the statistical analysis of the undercooling data that has been developed during the initial work on pure Au can yield nucleation rates that are independent of the choice of a specific nucleation kinetics model. These results are also discussed in comparison with a description based on classical nucleation theory.