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Directional Solidification And Convection In Small Diameter Crucibles, Jun Chen, P. K. Sung, D. R. Poirier, H. C. De Groh Iii

Chemical & Biomedical Engineering Faculty Publications

Pb–2.2 wt.% Sb alloy was directionally solidified in 1, 2, 3 and 7 mm diameter crucibles. Pb–Sb alloy presents a solutally unstable case. Under plane–front conditions, the resulting macrosegregation along the solidified length indicates that convection persists even in the 1 mm diameter crucible. Al–2 wt.% Cu alloy was directionally solidified because this alloy was expected to be stable with respect to convection. Nevertheless, the resulting macrosegregation pattern and the microstructure in solidified examples indicated the presence of convection. Simulations performed for both alloys show that convection persists for crucibles as small as 0.6 mm of diameter …