Segregation of silicon carbide by settling and particle pushing in cast aluminum-silicon-carbide particle composite

Abstract

Some effects of remelting and isothermal holding, unidirectional solidification, multidirectional solidification and rapid solidification on particle segregation and the dendritic structure of an A1357-15vol.%SiC particle composite were studied. Significant segregation of silicon carbide particles occurred owing to settling of the silicon carbide during isothermal hold; countergravity unidirectional solidification led to the SiC particles being pushed by the growing dendrites against gravity. Owing to the pushing of the silicon carbide partciles by the growing dendrites, the final distribution of silicon carbide was influenced by the rate of solidification; the best distribution was obtained under fast cooling rates during multidirectional cooling.