Berlin 2005 – wissenschaftliches Programm

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M: Metallphysik

M 14: Wachstum

M 14.4: Vortrag

Freitag, 4. März 2005, 15:30–15:45, TU H2038

Growth kinetics of dendrites in Ni and Ni–Zr systems: Simulations and experiments — •Denis Danilov¹, Peter Galenko², and Britta Nestler¹ — ¹Karlsruhe University of Applied Science, Karlsruhe, Germany — ²German Aerospace Center, Cologne, Germany

The morphologies and the kinetics of dendritic microstructures in pure Ni as well as in Ni–Zr alloys are modeled using the phase-field simulations. The simulation results are compared with experimental data on solidified samples processed by electromagnetic levitation facility and with the solutions of a sharp-interface model. In particular, we consider the velocity–undercooling relations for different thermophysical data and for different compositions in 2D and 3D. We use a phase-field model for non-isothermal solidification in multicomponent systems consistent with the formalism of classic irreversible thermodynamics to perform the numerical simulations of the dendritic growth structures. 3D morphology transitions are obtained for variations in surface energy and kinetic anisotropies at different undercoolings. In computations, we investigate the convergence behaviour of a standard phase-field model and of its thin interface extension at different undercoolings and at different ratios between the diffuse interface thickness and the atomistic capillary length. The influence of the grid anisotropy is accurately analyzed for a finite difference method and for an adaptive finite element method in comparison. The work was supported by DFG under contracts No. Ne 882/2 and He 1601/13.