Sharath, B.N.Mahesh, V.Mahesh, V.Kattimani, S.Harursampath, D.2026-02-032025Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications, 2025, , , pp. -14644207https://doi.org/10.1177/14644207251315872https://idr.nitk.ac.in/handle/123456789/20492This study investigates the synergistic influence of boron nitride (BN) tertiary ceramic additives and age-hardening treatment on the microhardness and wear resistance of Al2090-based hybrid composites, fabricated using the stir casting method. X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM) studies are carried out to assess the phases present, microstructure, and surface properties, respectively. The metallurgical investigations confirm a relatively superior uniformity in the distribution of particles and the ageing of precipitation at 150°C, vis-à-vis the other temperatures explored in this study. The experimental examinations conducted as per ASTM (E8 and G99) standards revealed a significant improvement in both the hardness and the primary tribological properties, when micron-sized boron carbide, graphite, and boron nitride were used as reinforcements. Age-hardened samples, especially the hybrid composite HS-2 with 5 wt.% each of boron carbide, graphite, and boron nitride, demonstrated an enhanced hardness of 25.23% and lower surface roughness (44.3 nm) compared to Al2090 (AS), due to the presence of load-bearing ceramic reinforcements. Increasing the applied load led to higher wear rates and coefficients of friction for Al2090. However, heat-treated hybrid metal matrix composites (HMMCs) exhibited a contrary behaviour, suggesting enhanced durability. The investigation highlighted the better wear resistance of heat-treated and near-optimally reinforced HMMCs, indicating their potential candidature for wear-resistant aerospace applications. © IMechE 2025.Age hardeningAluminum compoundsAluminum graphite compositesBoron carbideBoron nitrideBrinell HardnessCeramic materialsCeramic matrix compositesMicrohardnessNitridesWear of materialsWear resistanceAtomic forceAtomic force microscopeCeramic additivesCeramic compositesD surfacesHardening treatmentHybrid compositesHybrid metal matrix compositesSurface characterizationTribological performanceReinforcement