Microstructure and Mechanical Behaviour of Stir Casting Al/SiCp/Mg/Cu Composite with Varying Pouring Temperatures

The effect of pouring temperature while preparing Aluminium SiC metal matrix composites, with additional benefits of magnesium and copper through stir casting technique was investigated. The composites were fabricated by mixing 12 wt% of SiC reinforcements, 4 wt% magnesium, and 2 wt% copper into 6061 aluminum alloy melt at different pouring temperatures (630ºC, 670ºC, and 710ºC). The addition of magnesium will enhance the wettability of the SiC particles with the Al matrix. The inclusion of copper has considerable improvement in the strength and hardness of the composite. The microstructure and mechanical properties (tensile strength and hardness) of the Al MMC are evaluated with the corresponding processing parameter, specifically the pouring temperature of the cast composites. The metallurgical characterization utilizing optical and scanning electron microscope were observed for the prepared composites. The coarse microstructure and homogenous distribution of SiC particles appeared within the dendrite structures of the composites. The SiC particles have effectively distributed, and higher tensile strength and maximum hardness have occurred in composite at a pouring temperature of 670ºC as compared to other composites. The mechanical properties were lower in composites prepared using lesser pouring temperature (630ºC) and significantly decreased for higher pouring temperature (710ºC) of the composites.