Mechanical and corrosion behavior of SiC/Graphite/ZrO2 hybrid reinforced aluminum-based composites for marine environment

Abstract

Abstract Marine conditions are highly contentious for most materials manifested by the decayed condition of old ships and wrecks (made up of steel/wood). This work investigates the mechanical and corrosion behavior of aluminum-based composites reinforced with 3, 6, and 9 wt% of hybrid reinforcements (SiC, graphite, and ZrO2). It was observed that 3 wt% reinforcement composite had the optimum mechanical properties along with minimum corrosion rate. This composition had the least void contents, and its micro-hardness increased by 27.5% (42.6 VHN) in comparison to that of the unreinforced Al (33.3 VHN). Impact strength of the composite increased by 27.2% for 6 wt% hybrid reinforcement (247.1 J) and then started decreasing, whereas tensile strength of the composite increased by 8% for 9 wt% hybrid reinforcement (124.0 MPa) with respect to that of pure Al. The flexural strength of the pure Al reduced with the addition of hard reinforcing particles. The corrosion behavior of the composite was analyzed in 3.5% NaCl solution (simulating the seawater condition) at room temperature with the help of Tafel polarization curve and scanning electron microscopy (SEM) micrographs. It revealed that the 3% reinforced composite had the minimum corrosion current density (0.4 μA) and corrosion rate (0.23 mpy) compared to those of pure Al. The surface morphology of corrosion tested samples indicated the pitting corrosion mechanism.