Directional solidification and melting of eutectic GaIn

Eutectic gallium-indium is studied in a horizontal Bridgman furnace geometr y. Differential temperature gradients are applied to solidify and melt the alloy while observing in-situ the interface morphology and the chemical seg regation in the melt and in the solid as well. Upon cooling, a wedge-type i ndium-rich mushy zone develops at the cold wall. The melt is initially stir red by convective flow. After solidification starts the roll cell recedes t o be replaced by a chemically layered conductive melt that eventually solid ifies with rather uniform eutectic structure. Upon re-melting, the morpholo gy of the interface adopts a profile that is predetermined by the original solid structure. Those patterns, as well as the flow, are different from si ngle element solid melting experiments and have yet to be modeled. Under hi gh thermal gradient the convective flow mixes the binary melt and the visua lized density pattern eventually becomes that of a homogeneous melt.