Mechanical and corrosion behavior of SiC/Graphite/ZrO₂hybrid reinforced aluminum-based composites for marine environment

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.

AZ31-Mg metal matrix composite in metallurgical and testing approaches

“…Therefore, it exhibits modern fracture mechanism, that is, it shows both brittle and ductile fractures as the same phenomenon was reported in AZ31 alloys reinforced with vanadium MMCs. 16 In this study, the wear morphology of MMMCs are also studied after conducting wear test in pin on disc apparatus. The worn surface of the composite tested under 30 N using SEM.…”

Corrosion Properties of Aluminum Alloy Reinforced with Wood Particles

“…Figure 3 shows the open circuit potential (OCP) plot, which is the potential in the composite material when no current is applied in the system [24,25]. From the plot, each sample shows variations in potential with respect to exposure time, which could result from pores and inhomogeneity, as explained by Yadav et al [26]. It could further be attributed to simultaneous corrosion product formation and breakdown, described by Alaneme and Olubambi [19].…”

“…The formation of pits on the surface of the samples further shows that the passive film (Al 2 O 3 ) formed against corrosion attack was not enough to sustain the effect of the halide ions (Cl − ) [21,23,30]. It could also be due to inclusions and intermetallic formed within the composites [18,26]. From the EDS charts, the presence of oxygen (O), chlorine, sodium, and carbon in the composites suggested the formation of aluminum carbide, which Alaneme et al [31] explained is for the adverse effect of corrosion in aluminum composites.…”

“…In Table 4, the unreinforced sample shows improved corrosion resistance as the current density (I corr ) values are lower than the reinforced aluminum composites. According to Faraday's law, corrosion current density has a linear relationship with the corrosion rate [26], which results in the unreinforced composites having a lower corrosion rate, that is, the higher current density value tends to be more susceptible to pitting corrosion. The increase in current density as the percentage of wood particles increases in the composite could be due to impurities and inclusions such as silicon, and carbon, which results from the addition of wood particles.…”

Investigating the Microstructure, Tensile Strength, and Acidic Corrosion Behaviour of Liquid Metal Stir Casted Aluminium-Silicon Carbide Composite

“…Once the rigid oxide liner is removed, the chloride ions spread into the fabricated aluminium composite through the available circumference microcracks and create aluminium chloride with the elimination of hydrogen bubbles. Tis action initiates the generation of pitting corrosion [23,24]. However, nitric and sulfuric acidic solutions showed less amount of corrosion rate than a hydrochloric acidic solution due to the availability of a strong aluminium oxide layer on the circumference surface of the composite.…”