Localized microstructures induced by fluid flow in directional solidification - art. no. 166105

The dynamical process of microstructure localization by multiscale interact ion between instabilities is uncovered in directional solidification of tra nsparent alloy. As predicted by Chen and Davis, morphological instability o f the interface is observed at inward flow-stagnation regions of the cellul ar convective field. Depending on the driving force of fluid flow, focus-ty pe and honeycomb-type localized patterns form in the initial transient of s olidification, that then evolves with time. In the case of solute-driven fl ow, the analysis of the onset of thermosolutal convection in initial transi ent of solidification enables a complete understanding of the dynamics and of the localization of morphological instability.