Microstructure Evolution in a Directional Solidification Process
Models and theories of the microstructure evolution in a directional solidification (DS) process will be firstly addressed. Discrepancies between theories and experiments will be presented. For the thin film sample growth in a temperature gradient stage, the geometrical constraint makes it difficult to compare the experimental primary spacing with theoretical predictions. While for a bulk sample growth, fluid flow always exists in the solidification process despite that the growth interface rejects a lighter or heavier solute. Based on these analyses, the appropriate techniques to conduct DS experiments are proposed that can be used to test models. One is the solidification in a capillary sample where a single cell/dendrite grows. While for array growth in 3 dimensions, long-duration microgravity experiments will be the only viable way to obtain meaningful results.
Z.Y. Zhong, H. Saka, T.H. Kim, E.A. Holm, Y.F. Han and X.S. Xie
S. Liu and R. Trivedi, "Microstructure Evolution in a Directional Solidification Process", Materials Science Forum, Vols. 475-479, pp. 2757-2760, 2005