Equiaxed dendritic solidification in supercooled melts

The growth of equiaxed dendrites from a pure supercooled melt is examined. We propose modifications to the classical Ivantsov theory that allow for consideration of multiple interacting dendrites. The modified theory reveals the existence of a steady-state dendritic solidification mode in a frame of reference moving with the dendrite tip. This regime should be valid from the onset of nucleation to the commencement of time-dependent coarsening when the mass of the solid becomes comparable to the liquid mass in the solidification chamber. This regime is characterized by a reduced (relative to the single dendrite case) heat flux leading to slower solidification rates, but with the same level of supercooling. We study the effects of the relative proximity and number of interacting dendrites through a numerical example of solidification of succinonitrile, a common material used in many experiments. The data show that the model predicts a new steady growth regime that is different than the steady growth law of a single dendrite as described by Ivantsov theory. ( 1999 Published by Elsevier Science B.V. All rights reserved. PACS: 68.70.#w; 61.50.Cj