Regensburg 2007 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 30: Phase transitions III
MM 30.3: Vortrag
Donnerstag, 29. März 2007, 10:45–11:00, H4
Molecular dynamics simulations for calibrating a phase-field model of solidification in Ni-Zr alloys — •Britta Nestler1, Denis Danilov1, Hamid Guerdane2, and Helmar Teichler2 — 1Institute for Computational Engineering, Karlsruhe University of Applied Sciences, Karlsruhe, Germany — 2Institut für Materialphysik, Universität Göttingen
Atomic-scale simulations of crystal-melt interfaces in Ni-Zr alloys are performed to determine the energy densities and material parameters for phase-field modelling of solidification microstructures. To set up the phase-field (PF) model, quantities such as the free energy density functions related to the liquidus and solidus lines of the phase diagram, the diffusion coefficients and the interface thickness are calculated from molecular dynamics (MD) simulation data. The kinetic coefficient is approximated by comparing interfacial positions of MD and PF simulations. Direct comparison of PF and MD simulations show a disagreement in the dynamics of the interface motion. To match PF and MD results the diffusion coefficients of the solid and liquid phases in the PF model have been calibrated using a two-sided analytical sharp interface solution. Results of simulated solid-liquid interfaces are presented showing a comparison of concentration profiles across the crystal-melt interface and of the growth dynamics obtained from MD and PF simulations.