Production of Al-Si-SiC_p Cast Composites by Injection of Low-Energy Ball-Milled Al-SiC_p Powder into the Melt

摘要

Al-7wt%Si-10wt%SiC_p composite with uniformly distributed reinforcement particles with the average size of about 3 microns was produced by a special compocasting method in which the reinforcement was injected into the melt in the form of particulate Al-SiC_p composite powder instead of SiC_p. The effects of the reinforcement addition form, the solid fraction of primary alpha-aluminum particles at pouring, and stirring speed on the incorporation of reinforcement particles into the matrix were investigated. Injection of particulate Al-SiC_p composite led to improved incorporation and dispersion and reduced size of SiC_p. Casting from the semisolid state significantly improved the incorporation of SiC_p into the matrix. The optimal solid fraction of primary alpha-aluminum particles to achieve a reasonable combination of reinforcement incorporation and fluidity of the composite slurry was recognized to be about 0.1. The incorporation of SiC_p was improved by increasing the stirring speed up to 500 rpm and then gradually decreased.