Synthesis and wear behaviour analysis of SiC- and rice husk ash-based aluminium metal matrix composites

Research efforts seek to develop aluminium alloy composites to enhance the poor tribological performance of aluminium alloy base matrix. In this research, a hybrid metal matrix composite (HMMC) was developed by reinforcing an aluminium alloy (AA8011) with SiC and rice husk ash (RHA) using a stir casting technique. RHA was prepared by the cracking of rice husk, which is abundantly available in the Indian subcontinent. The samples were cast by keeping the amount of RHA constant at 2.5 wt.% and varying the amount of SiC from 0.0 wt.% to 8 wt.%. The samples were machined to manufacture pins for wear tests (at ambient temperature, 100 ◦C, and 200 ◦C) and hardness measurement. The microstructures of the cast samples were analysed using an X-ray diffractometer (XRD) and a scanning electron microscope (SEM), along with energy-dispersive X-ray spectroscopy (EDS). It was observed that the composites with greater reinforcement of SiC exhibited improved hardness and wear resistance, but the coefficient of friction increased with the addition of RHA and SiC, and the wear performance deteriorated with an increase in the operating temperature. The contribution of RHA alone to the improvement in wear performance was marginal compared to the pure alloy. It was also confirmed that the reinforced composites could be a better option for automotive applications to replace aluminium alloys.