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MM: Fachverband Metall- und Materialphysik

MM 35: Topical Session Heterogeneous Nucleation I

MM 35.2: Vortrag

Donnerstag, 17. März 2011, 11:30–11:45, IFW D

Scale-Bridging Simulation on Atomistic and Mesoscopic Length Scales. — •Marco Berghoff¹ and Britta Nestler^1,2 — ¹Institute of Materials and Processes, Hochschule Karlsruhe, Germany — ²Institute for Reliability of Components and Systems, Karlsruhe Institute of Technology (KIT), Germany

In the present analysis we study the process of early stage solidification using molecular dynamics (MD), phase-field crystal (PFC) and the phase-field (PF) methods. While the MD and the PFC methods are mostly in use at the atomistic scale, the PF can make meaningful predictions at the mesoscale. To demonstrate the ability of the PF in applications at the atomistic scale, we conduct a comparative study of growth of pure Ni in the early stage of solidification between MD and PF simulations. For this, the discrete atomic positions from the MD simulations are converted to a continuous field of the PF order parameter differentiating the phases, using the q₆q₆ operation. In addition, we tailor the parameters in the PF model to match those used in the MD model with a temperature dependent specific heat capacity and latent heat. We then compare the volume change of the nucleus as a function of time occurring in both simulation methods. As a substitute to MD simulations, we also used the PFC method for generating data at the atomistic scale, and compared the results with PF simulations. The ultimate goal is to benchmark the atomistic simulations with the PF method at the smaller scale and thereafter conduct PF simulations at the mesoscale, which is outside the realm of atomistic simulation methods.