Sedimentation during Liquid Processing of Metal Matrix Composites

Abstract

During the incorporation of ceramic particles into metallic alloy melts for the production of metal matrix composites, the particles tend to float or sink, depending on their density. In order to study the sedimentation patterns, a novel electrical resistance technique has been developed. A current is passed between two electrodes, and the potential over a fixed distance is measured with two other electrodes. Experiments were carried out in an aluminum foundry alloy(A356) containing up to 30 volume percent 88 μm silicon carbide particles. The particles’ behaviour was compared with sedimentation patterns in aqueous systems. The implications for fabrication and remelting of metal matrix composite material are discussed.