Dendritic growth into undercooled alloy metals

Free dendrites growing in a liquid alloy reject both heat and (for k0 < 1) solute. A growth equation has been developed both by coupling their diffusion fields for a parabolic tip and by applying a stability criterion. This relationship indicates that (1) the dendrite tip radius passes through a minimum with increasing solute concentration and (2) at a given undercooling the growth velocity should increase with increasing solute concentration and then decrease as higher solute levels are reached. These findings are shown to correspond to experimental results obtained using succinonitrile-acetone alloys.