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MM: Fachverband Metall- und Materialphysik
MM 56: Topical Session Growth Kinetics VI
MM 56.3: Talk
Thursday, March 25, 2010, 16:00–16:15, H4
Combined phase-field and MD simulations of diffusion drop and ordering at [NixZr1−x]liquid-Zrcrystal interfaces — •M. Guerdane, F. Wendler, and B. Nestler — Institute of Materials and Processes, Karlsruhe University of applied Sciences, Germany
We combine phase-field (PF) modeling and molecular dynamics (MD) simulations to show that the velocity of the solidification front in a two-phase [NixZr1−x]liquid-Zrcrystal structure is strongly affected by the drop of the liquid diffusion when approaching the solid-liquid interface. The latter is defined through a suitable order parameter that distinguishes between crystalline and liquid atomic environment. The diffusion drop near the interface is attributed to the pronounced short range order inherent to the NixZr1−x melt. The system transforms into a massive lateral ordering in the vicinity of the Zr crystalline wall. Our combined PF-MD analysis points out the shortcoming of the standard interpolation procedure, usually applied in constructing the phase dependent diffusivity, to describe the confinement effect caused by the crystalline wall at low temperatures.