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Enhancing surface integrity of AA5052 aluminium alloy is vital for load-bearing and tribological applications. This study investigates single-pass friction stir processing to develop hybrid surface nanocomposites with Si3N4 and BN nanoparticles (70/30, 60/40, and 50/50 wt. %). This approach combines groove loading and pre-sealing for uniform powder retention and defect-free consolidation. Microstructural analyses showed significant grain refinement versus base alloy, with 60/40 hybrid exhibiting finest equiaxed morphology (≈3.2 µm) due to particle pinning and lubrication-assisted flow. XRD confirmed phase stability of Si3N4 and BN without formation of AlN or Al – B intermetallics. Mechanical characterisation showed 44% improvement in hardness (124 ± 3 HV vs. 85 ± 2 HV) and 50% increase in ultimate tensile strength (255 ± 5 MPa vs. 217 ± 4 MPa). Tribological performance improved with 60–65% reduction in wear rate and 25–35% decrease in friction coefficient, attributed to Si3N4 load-bearing capacity and BN solid-lubricant behaviour. The 60/40 hybrid showed optimal performance, demonstrating superior balance between reinforcement dispersion, grain refinement, mechanical strength, and wear resistance. These results highlight FSP hybridisation effectiveness in enhancing AA5052 components for marine fittings and automotive brackets requiring improved strength, ductility, and surface durability.
Navaneethasanthakumar et al. (Wed,) studied this question.