Solidification under forced-flow conditions in a shallow cavity

The solidification of an Al-4.5 pct Cu alloy in a shallow cavity under conditions of forced flow was studied both by fluid-dynamics simulations with solidification included and by experiments. The variation in bulk-flow velocity and initial superheat dramatically changes the macro- and microstructure, promoting grain refinement, an equiaxed-to-columnar transition (ECT), the formation of peculiar grain and dendrite morphologies, etc. The solidification parameters during solidification in the shallow cavity under forced-flow conditions have been determined by computer simulations and partially compared with the experimental results. The interaction between flow vortices and the progressing solidification front and its effect on structure evolution have been analyzed. Finally, quantitative correlations between microstructure, solidification, and flow parameters have been established. [PUBLICATION ABSTRACT]