Prediction of wear outcomes and mechanical characterization of innovative SiO2 incorporated aluminium matrix composites

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.