Tribological, structural and mechanical characteristics of friction stir processed aluminium-based matrix composites reinforced with stainless steel micro-particles

The efficacy of stainless-steel micro-particles on friction stir processed aluminium-based matrix composite (ABMC) was studied using tribological, mechanical and structural analysis tools. The stainless-steel powder (17-4PH) of average size 45 – 90 µm was used as the reinforcement particle. The parametric values employed during the fabrication of ABMC-AA7075-T651/17-4PH were the rotational speed of 1500 rpm and travel speed of 20 mm/min while the plunge depth and tilt angles used were respectively 0.3 mm and 3 degrees. Tribological study was carried out under the influence of dry sliding condition with varying loads of 20 N and 50 N using tribometer while the scanning electron microscope (SEM) was used to capture the wear track. Structural analysis was examined with the aid of x-ray diffraction (XRD). The tensile strengths of the fabricated ABMC were also tested and the fracture surfaces were studied using SEM analysis. The results from the study revealed that at higher loading of 50 N, the wear performance was significantly improved for the fabricated aluminium composite-AA7075-T651/17-4PH when compare with lower loading of 20 N. The tensile properties for the ABMC were also improved under the influence of the stainless steel microparticles. There was structural improvement in ABMC wherein the value for crystallite size was lowest while micro-strain, dislocation density, as well as full width at half maximum (FWHM), had the highest values over the FSPed AA7075-T651 and the parent material. The examined fractured surface of the fabricated composite was dominated with fine, network and equiaxed dimples with cup and cone attributes confirming superb interfacial bonding and that the failure mode was ductile.