Experiments on Dendrite Branch Detachment in the Succinonitrile-Camphor Alloy

Detachment of secondary dendrite arms has been observed in succinonitrile-camphor alloys under the microscope. The dendrites have been grown under a positive temperature gradient (columnar growth). After the tip has reached the thermocouple the displacement of the specimen was inversed and the remelting behaviour observed. It is found that detachment of arms is more frequent in concentrated alloys, when the growth rate is high and the melting rate low.