SiC/A356 composites were prepared by mechanical stirring and by ultrasonic stirring method

and processing parameters of mechanical stirring and ultrasonic stirring were presented. Microstructure

hardness and wear resistance of the SiC/A356 composite prepared by mechanical stirring and by ultrasonic stirring were investigated by SEM （scanning electron microscopy） and Brinell’s machine and friction and wear test machine. The results indicate that there exists slight interface reaction in the composites prepared by mechanical stirring

while the uniform fine and compact structure can be observed in one prepared by ultrasonic stirring. With SiC size in 2

3

μm

compared to those of one prepared by mechanical stirring

the hardness and wear resistance of SiC/A356 composites are improved by 22% and by 56%

respectively.