Berlin 2008 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 46: Interfaces
MM 46.3: Talk
Thursday, February 28, 2008, 17:00–17:15, H 0111
Simulation of partial melts with a phase-field model — Jens Becker1, Britta Nestler2, and •Frank Wendler2 — 1Institute of Geoscience, University of Tübingen, Sigwartstr. 10, 72076 Tübingen, Germany — 2Institute of Computational Engineering, University of Applied Sciences Karlsruhe, Moltkestr. 30, 76133 Karlsruhe, Germany
Partially molten grain systems are of great interest in engineering (thixoforming, rheocasting) as well as in geology, as they appear in the rock forming layers of the deeper earth's crust. Particularly properties like the growth rate of isolated grains as well as coarsening in grain ensembles are substantially modified after partial melting. We present recent results found by applying our formerly introduced multi phase-field model (a diffuse interface method based on the formulation of a Ginzburg-Landau free energy functional) to partial melts. First, details on the phase-field model and the numerical aspects necessary to treat the enormous computational effort for a large grain system are presented. Secondly, a comparison of normal grain growth in 2D with grain growth in partial molten systems is given. The parabolic growth law and the validity of the von Neumann-Mullins relation for isolated grains are found to hold very well in the case of normal grain growth simulations. Partial melts in contrast show a strongly reduced growth rate. The dependancy on wetting angles, liquid fraction and permeability of the grain structure is highlighted using results in from 2D and 3D simulations. Additionally, the evolution of 'wet' triple points including an orientational dependancy of the surface energy are shown as a first step to clarify the role of anisotropy in partial melts.