A novel approach for the production and characterisation of aluminium–alumina hybrid metal matrix composites

Abstract

In this study, aluminium–alumina hybrid metal matrix composites were developed using stir–squeeze casting with ultrasonic stirring. Scrap aluminium alloy wheels (SAAWs) were used as the matrix material, with 1, 2, and 3 wt% of nanosized alumina ((Al2O3)n) particles as well as 4, 5.5, and 7 wt% of microsized alumina ((Al2O3)m) particles as reinforcement components. An experimental study was conducted using the Taguchi method with an L9 orthogonal array, and the multiobjective optimisation based on ratio analysis technique was used for optimisation. The effects of different ratios of nanosized and microsized alumina particles as well as ultrasonic parameters, namely amplitude and pulse time, on the microstructure and mechanical properties were evaluated and compared. Pin-on-disc wear tests were conducted in the dry condition under uniform load to determine the influence of nanosized and microsized alumina on the wear behaviour. The results revealed that SAAWs reinforced with 1 wt% of nanosized alumina particles and 5.5 wt% of microsized alumina particles and having an amplitude of 100% and pulse on-time of 180 s exhibited lower porosity and metal loss (wear) as well as higher hardness, tensile strength, and compressive strength than other composites.