DIFFUSION IN THE SEMISOLID REGION DURING DENDRITIC GROWTH

Diffusion in the liquid during the later stages of cellular and dendritic solidification is described. A simple model is constructed, incorporating adaptations of the earlier treatments by Bower, Brody, and Flemings1,2 and Rohatgi and Adams:3 the apparent conflict between these treatments is discussed. Behind the growth front, the diffusion fields of neighboring primary arms spread laterally, meet and merge in an initial transient. This can take up a significant fraction of the solidification time, especially at high growth rates. After the initial transient has been completed, the supercooling of the interdendritic liquid is reduced, but concentration gradients in the liquid persist throughout solidification. © 1979 The Metallurgical of Society of AIME.