Simulation of the stir casting process

Non-homogeneous particle distribution is one of the greatest problems in casting metal matrix composites (MMCs). To optimise some of the parameters for uniform particle distribution for batch compocasting the present simulation studies were conducted. The simulation involves visualisation experiments. In the visualisation experiments liquid and semisolid aluminium are replaced by other fluids with similar characteristics. SiC reinforcement particulate similar to that used in aluminium MMCs was used in the simulation fluid mixtures. Scaled-up stirring experiments were carried out in a transparent crucible with the percentage of reinforcement material being varied. Optimum conditions for photographing flow patterns were established. The dependence of the photography conditions (shutter speed, aperture control, lighting), particles dispersion and settling times and vortex height on stirrer geometry and speed was found. Results are discussed in terms of their applicability to MMC production.