Improving the Mechanical Properties of Hypereutectic Al–14%Si Alloy by Adding Alumina Particles of Different Sizes Using the Taguchi Method

Abstract

This study examines how adding 3 weight percent Al2O3 particles with different particle sizes (25 μm, 50 μm, and 100 μm) using the stir casting technique can improve the mechanical and tribological characteristics of a hypereutectic Al–14%Si alloy. To create the composites, preheated Al2O3 particles were evenly distributed throughout the molten Al–Si alloy and solidified carefully. Vickers hardness and pin-on-disc dry sliding wear tests were used to assess the mechanical performance, whereas optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffraction (XRD) were used to characterise the microstructures. The Taguchi L9 orthogonal array design was used to systematically optimise the experimental parameters, such as the particle size, applied load, and sliding time. The effects of these parameters on the wear behaviour were examined using ANOVA. The finest 25 μm particles achieved the most uniform distribution and the highest hardness of 110 HV, compared to 92 HV for the unreinforced alloy. The results showed that the addition of Al₂O₃ significantly improved the particle–matrix interface and refined the grain structure of the composites. A strong correlation between increased surface hardness and decreased wear rate was confirmed by the wear resistance, which significantly improved as the particle size decreased. According to the statistical analysis, the most important factors influencing the wear rate were particle size, applied load, and sliding time. This study demonstrates how optimising the particle size can improve the performance of Al–Si– Al2O3 composites. High wear resistance and durability are crucial for demanding applications in automotive, aerospace, and industrial components, and these composites show great promise owing to their fine particle reinforcement and optimised processing conditions.