Thermal–solutal flows and segregation and their control by angular vibration in vertical Bridgman crystal growth

Thermal–solutal flows and their induced segregation and supercooling are important in the growth of an alloy crystal. For the vertical Bridgman crystal growth having a stabilized thermal profile, in addition to the thermal convection induced by radial thermal gradients, solute gradients can either induce or suppress the flow depending on the solute density. Such thermal–solutal flows significantly affect the segregation behavior, constitutional supercooling, and thus the morphological instability of the solidification front. A transparent Bridgman growth of succinonitrile containing a lighter (acetone) or heavier (salol) solute was investigated. The evolution of the interface shape as well as morphological instability was visualized and was interpreted through computer simulation. To further control the flow and segregation, angular vibration was applied and its effects on the thermal–solutal flows and morphological instability were investigated.