|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Frontiers in Solidification: An MPMD Symposium in Honor of Michel Rappaz
||Phase-field Simulations of Dendritic Sidebranching in Three Dimensions
||Mathis Plapp, Alain Karma
|On-Site Speaker (Planned)
We report the results of phase-field simulations of equiaxed dendritic growth that focus on the detailed characterization of the sidebranching activity behind the tip. We find that microscopic thermal fluctuations suffice to produce the level of sidebranching activity observed in experiments. Our results show that both the distance from the tip at which sidebranches become visible and their mean spacing decrease with decreasing anisotropy. Both of these trends are qualitatively consistent with what is experimentally observed and predicted by noise-amplification theory. Furthermore, the several orders of magnitude exponential increase of the sidebranch amplitude with distance from the tip is reasonably well predicted quantitatively by this theory. The variation of the mean sidebranch spacing, however, is not : for weak anisotropy, the spacing first decreases with distance from the tip before the increase predicted by theory sets in. Possible limitations of the theory that may explain this discrepancy are discussed.