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Compositional convection in the solidification of binary alloys

Published online by Cambridge University Press:  26 April 2006

P. W. Emms  and
A. C. Fowler
P. W. Emms
Affiliation:
Mathematical Institute, Oxford University, 24–29 St. Giles’, Oxford OX1 3LB, UK
A. C. Fowler
Affiliation:
Mathematical Institute, Oxford University, 24–29 St. Giles’, Oxford OX1 3LB, UK
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Abstract

When a binary alloy is directionally solidified, a two-phase mushy dendritic zone is often formed. Interdendritic convection of the melt may occur, and is coupled with compositional convection of the residual melt. If fluid flow velocities are high enough, local melt-back of the dendrites may occur, leading to channel formation, and thus preferred flow paths. In order to predict the onset of convection, a coupled liquid/mush model is proposed, which includes most of the known physics. An elaborate scaling procedure leads to certain conclusions concerning the nature of convection, and points to a much simplified model, which can essentially be solved analytically. Predictions of the theory are compared quantitatively with experiments.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 262 , 3 October 1994 , pp. 111 - 139
Copyright
© 1994 Cambridge University Press

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