DENDRITIC SCALING LAWS: APPLICATION TO MICROSTRUCTURE PREDICTION

摘要

Understanding the kinetics of dendritic growth is essential for controlling solidification processes and rnicrostructures, and for improving modeling at small scales. The Isothermal Dendritic Growth Experiments (IDGE) is a series of microgravity experiments designed to study dendrites in ultra-pure materials. Data resulting from these space-flight experiments reveal fundamental aspects of the solidification process: 1) thermal transport occurring at mesoscopic scales, 2) microstructural scaling laws, and 3) dynamic shapes of dendrites. It was found that once convection phenomena in the melt are suppressed adequately, diffusion-limited models become reliable. Scaling laws connecting microstructure length scales and growth rates are found to be robust, and nearly independent of the supercooling, convection state of the melt, and the properties of the melt. This allows applications of these theories to many metallic systems, including alloys. The author and Professor Kurz have collaborated on several of these interesting topics, and it is with considerable pleasure to recount some of this research in his honor.