Solidification Using a Baffle in Sealed Ampoules - Effect of Convection on the Columnar-to-Equiaxed Transition in Alloy Solidification

The objective of the proposed investigation is to better understand the columnar-to-equiaxed grain structure transition (CET) in solidification of metal alloys. By performing solidification experiments both on earth and in a microgravity environment, the effects of gravity-driven melt convection and sedimentation/floatation of unattached dendrite fragments and equiaxed crystals on the CET will be examined. The origin of equiaxed grains in non-refined alloys is of particular interest in the proposed experiments. The benchmark data from these experiments can be used to test theoretical models and computer simulations.