This study investigates the effect of SiO2 (silicon dioxide) powder as a reinforcement material in AA8011 aluminium matrix composites fabricated using the stir casting technique. The composites were produced with varying SiO2 contents of 0, 3, 6, and 9 wt% to evaluate their mechanical and tribological performance. The incorporation of SiO2 particles resulted in significant improvements in mechanical properties and wear resistance while maintaining a lightweight structure. The ultimate tensile strength increased from 156 MPa for the unreinforced alloy to 210 MPa for the composite containing 9 wt% SiO2, indicating substantial strengthening due to effective load transfer and grain refinement. Similarly, microhardness showed a noticeable improvement with increasing reinforcement content. However, the impact strength decreased by 11.42%, 22.85%, and 34.28% for composites containing 3 wt%, 6 wt%, and 9 wt% SiO2, respectively, compared with the base alloy. Wear tests conducted using a pin-on-disc apparatus demonstrated a considerable reduction in wear rate with increasing SiO2 reinforcement, particularly under higher loading conditions, due to the load-bearing capability and hardness of SiO2 particles. Microstructural analysis confirmed a relatively uniform distribution of reinforcement within the aluminium matrix, although minor particle agglomeration was observed at higher reinforcement levels. Overall, the results indicate that SiO2-reinforced AA8011 composites fabricated through stir casting offer improved mechanical strength and enhanced wear resistance, making them suitable for lightweight structural and tribological applications in automotive, aerospace, and engineering sectors.
Bhowmik et al. (Mon,) studied this question.