Characterization of high strength aluminium-based surface matrix composite reinforced with low-cost PKSA fabricated by friction stir processing

In the quest to achieving a low cost of production and a cleaner environment has engendered researchers into using agricultural waste that will serve as a potential and promising alternative to metallic powders as reinforcement in metal matrix composites (MMC). On awareness of this search, palm kernel shell ash (PKSA) has been developed in this study as reinforcement particles in friction stir processing (FSP) of high strength, armour grade, AA7075-T651 aluminium matrix composites (AMC). Surface and structural integrity, friction and wear study, corrosion behaviours, tensile properties, and its fractography were investigated. Tribometer, surface roughness tester (SRT), potentiostat/galvanostat, scanning electron microscopy (SEM), Energy dispersive x-ray (EDX), x-ray Fluorescence (XRF), and x-ray Diffraction (XRD) were employed in the analysis. Corrosion behaviour was tested in 3.5% NaCl, two different loads of 20 N and 50 N were applied during wear test. Reinforcing with PKSA has greatly improved and enhanced the friction and wear properties, corrosion behavious, surface and structural integrity in the fabricated AA7075-T651/PKSA except in tensile properties in which base metal, AA7075-T651 has higher tensile strength. The details of XRD structural analysis, the morphology of worn surfaces, corroded surfaces and fractured surfaces are presented in this paper.