Macrosegregation during plane front directional solidification of Csl-1 wt. percent Tll alloy

摘要

Macrosegregation produced during vertical Bridgeman directional solidification of Csl-1 wt. pct. Tll in crucibles of varying diameter, from 0.5 to 2.0 cm, was examined. Gravity driven convection is present in the melt even in the smallest crucible diameter of 0.5 cm. Observed solutal profiles are in agreement with the analytical boundary layer model of Favier which describes macrosegregation in the presence of convection. The scintillation efficiency of Csl decreases along the specimen length as the thallium iodide content of the alloy increases.