Onset of sidewise instability and cell-dendrite transition in directional solidification

TitleOnset of sidewise instability and cell-dendrite transition in directional solidification
Publication TypeJournal Article
Year of Publication2009
AuthorsTeng J, Liu S, Trivedi R
Journal TitleActa Materialia
Volume57
Pages3497-3508
Date Published07/01
ISBN Number1359-6454
Accession NumberISI:000267527000007
Keywordsarray growth, binary-alloys, cellular growth, dendritic growth, directional solidification, interface dynamics, solidification microstructure, stability
Abstract

The transition from cellular to dendritic microstructure in directional solidification is investigated in succinonitrile (SCN)-camphor alloys. This transition is found not to be sharp, but Occurs locally over a range of velocities or thermal gradients, and the diffuseness of the transition is related to the existence of a range of primary spacing. Within the transition zone, critical cell spacing lambda(cd) is present where a cell just develops sidewise perturbations. An expression for the critical spacing for the onset of sidewise perturbation is obtained, and it is used to establish the conditions for the start and end of the transition. The results of the present study are then synthesized with those in the SCN-acetone system to incorporate the effect of system parameters on the onset of sidewise instability. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

URL<Go to ISI>://000267527000007
DOI10.1016/J.Actamat.2009.04.005