Abstract
Investigation of A356-20wt%SiC metal matrix composites was focused in the present research work. A356-20wt%SiC composites were manufactured using two different conditions, namely, mechanical stirring, and mechanical stirring with an ultra-sonic assisted cavitation. For comparison, unreinforced A356 alloy was also cast under the same conditions. The samples were subjected to squeeze at 0, 60, and 120 MPa pressure with mechanical stirring and stirring followed by ultrasonication. Significantly improved physical and mechanical properties with the function of squeeze pressure were obtained in mechanical stirring followed by ultra-sonication due to the uniform distribution of SiC particles over A356 matrix. For instance, a sound A356-20 wt% SiC composite with 99.5% densification was achieved when processed at 120 MPa squeeze pressure using mechanical stirring with an ultrasonication method. In addition, the same composite resulted in 20% increase in hardness and a 12.7% increase in tensile strength by mechanical stirring with ultra-sonication. Furthermore, detailed microstructural evolutions on the fabricated and fractured samples were also explained and reported. From the microstructural evolution, the absence of micro cluster formation of SiC particles over the A356 matrix was achieved through mechanical stirring with ultra-sonication.