Investigation of the initial transient in directional solidification of binary AlCu alloys

For the understanding of the formation of microstructures the initial transient, i.e. the very beginning of solidification, is of major relevance. At this stage a complex interaction between the velocity of the solidification front, the concentration pile-up and the temperature gradient takes place. In a Bridgman-Stockbarger furnace directional solidification experiments with binary AlCu 1.3 wt.% were performed allowing solidification with a planar solid-liquid interface. The velocity and temperature profile were measured during the experiments, concentration profiles afterwards. In this paper we present experimental results. Parallel to the experimental work numerical simulations based on the model of Coriell et al. were performed and first results are compared to the experiments.