Regensburg 2010 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 60: Phase Transitions II

MM 60.4: Vortrag

Donnerstag, 25. März 2010, 16:15–16:30, H5

Bulk liquid undercooling and nucleation in Nickel — •Joachim Bokeloh, Anna Moros, and Gerhard Wilde — Institut für Materialphysik, Westfälische Wilhelms-Universität Münster

While classical nucleation theory is widely accepted textbook knowledge, it is somewhat lacking with regard to the atomistic details of the nucleation and growth mechanisms. Right now, there are many efforts in exploring these details with computational methods. However, only few experimental methods that can corroborate these results are available. The best known of these experimental methods are containerless processing in levitation melting and the investigation of fine droplet dispersions.

We present here data on the liquid undercooling behaviour of Ni obtained by repeated melting and crystallization in a DTA. This method allows to acquire a statistically meaningful data set under clean and reproducible conditions, while still allowing reasonable sample sizes, thus combining several advantages of the two methods mentioned above. Ni was chosen as a model system because it shows good levels of undercooling and because it is well suited for computer simulations due to its relatively low number of electrons.