Coupling of couette flow and crystal morphologies in directional freezing

Experiment has focused on momentum transport effects on planar interface instability growth and morphologies, the presence of Couette flow and the flow over cells and dendrites in succinonitrille-acetone model alloy during directional solidification. The flow can inhance the planar growth stability strikingly and even induce the transition from cell to planar. The cell or dendrite will modify its arm growth direction without changing its crystallographic orientation and produce asymmetrical growth tips. Based on in-situ observation, plane Couette flow over curved surfaces is used to model the flow near the solid-liquid interface. The results explain qualitatively the experimental phenomena of the interaction between the melt flow and crystal morphologies.