Effect of particulate reinforcement on the aging behavior of aluminium metal matrix composites - A review

Particulate-reinforced aluminium metal matrix composites (Al-MMCs) have gained renewed attention as promising candidates for aerospace and automotive applications owing to their unique combination of physical and mechanical properties, near-isotropic behavior and cost-effectiveness compared to monolithic alloys. Commercially available Al-MMCs often incorporated with various ceramic particulates, which enhance performance in a range of structural forms. This review examines the influence of particulate reinforcement on the aging behavior of age-hardenable aluminium alloys. The incorporation of ceramic particulates is shown to accelerate the aging kinetics of the matrix, leading to a higher peak hardness. Both increasing the weight fraction and reducing the particle size contribute to greater hardness increments and shorter times to reach peak aging. The underlying mechanisms, including heterogeneous nucleation of precipitates and enhanced dislocation density at particle–matrix interfaces, are discussed to provide a comprehensive understanding of how reinforcement parameters govern aging response in Al-MMCs.