Effect of tool profile on wear and mechanical behaviors of CeO₂ and ZrO₂-reinforced hybrid magnesium matrix composite developed via FSP technique

A dual/double eccentric-pin tool was used for the reinforcement of the CeO₂ and ZrO₂ particles into a 5 mm thick AZ31B magnesium alloy through the application of the friction stir processing route to develop a composite with improved properties. A comparison of the developed composite's properties with that of the single pin-processed counterpart was carried out to ascertain the improvement recorded. The structure, hardness, shear punching strength, tensile, corrosion, and wear properties of the hybrid AZ31B/(ZrO₂ + CeO₂)_p composite were investigated. The findings show that the dual/double eccentric pin tool widened the stir zone at the shoulder area, eliminated flow-related voids, and improved the flow of material and the particle distributions within the composite. The extra pin-induced plastic shearing/straining and dynamic recrystallization of the tool meaningfully refined the grain structure (5.6–3.35 μm) and the particle size (6.4–4.8 μm) of the composite while aiding even dislocation spread across the stir zone. In relation to the singular probe tool, the dual/double eccentric-pin tool also enhanced the hardness (102–141 HV), the shear punching strength (148–219 MPa), the tensile strength (175–225 MPa), the wear properties (coefficient of friction, rate, and loss), and the corrosion behavior of the hybrid AZ31B/(ZrO₂ + CeO₂)_p composite due to the uniform and fine particle dispersion-strengthening and the elimination of stress raiser. The dual/double eccentric pin tool is thus recommended as a better tool for improving the performances of Mg-based composites.