When alloys solidify in a gravitational field there are complex interactions between solidification and natural, buoyancy-driven convection that can alter the composition and impair the structure of the solid product. The particular focus of this project has been the compositional convection within mushy layers that occurs in situations where the lighter component of the alloy is rejected into the melt during solidification by cooling from below. The linear stability of such a situation was described at the 2nd Microgravity Fluid Physics Conference and has been further elucidated in a number of published articles. Here we describe some recent developments in the study of the nonlinear evolution of convection in mushy layers.
Worster, M.G., Schulze, T.P., Anderson, D.M, Nonlinear Convection in Mushy Layers, 3rd Microgravity Fluid Physics Conference, NASA Lewis Research Center, Cleveland, OH, CP 3338, pp. 369-376, June 13, 1996.