Submitted for the MAR09 Meeting of The American Physical Society Coupling of Atomistic and Meso-scale Phase-field Modeling of Rapid Solidification1 J. BELAK, P.E.A. TURCHI, M.R. DORR, D.F. RICHARDS, J.-L. FATTEBERT, M.E. WICKETT, F.H. STREITZ, Lawrence Livermore National Laboratory — Recently, phase field models have been introduced to model the crystallography during polycrystal microstructure evolution [1,2]. Here, we assess these models with molecular dynamics and phase field simulations that overlap in time and space. Large parallel computers have enabled MD simulations of sufficient scale to observe the formation of realistic microstructure during pressure driven solidification [3]. We compare the two methods by calculating the phase field order parameter (quaternion) from the atomic coordinates and drive the evolution with the MD. Results will be presented for the solidification of tantalum. [1] R. Kobayashi and J.A. Warren, Physica A, 356, 127-132 (2005). [2] T. Pusztai, G. Bortel and L. Granasy, Europhys. Lett, 71, 131-137 (2005). [3] F. H. Streitz, J. N. Glosli, and M. V. Patel, Phys. Rev. Lett. 96, 225701 (2006). 1This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. James Belak Lawrence Livermore National Laboratory Date submitted: 21 Nov 2008 Electronic form version 1.4