Compression and corrosion characterization of Al-B4C-TiO 2 hybrid composites for marine superstructure applications

This study reports the combined influence of Boron carbide (B4C) and Titanium dioxide (TiO2) reinforcements on the compressive and corrosion characteristics of pure aluminium (Al)-based composites fabricated by powder metallurgy (P/M), specifically for marine superstructure applications. The powders were ball-milled, compacted in a cylindrical die to form pellets, and then sintered in a muffle furnace. Compression tests and salt-spray corrosion tests were conducted on the fabricated composites. Microstructural investigation of the samples was carried out using Scanning Electron Microscopy (SEM) to compare morphological changes following the corrosion test. The addition of ceramics, both as single and hybrid reinforcements, enhanced the compressive strength (CS) and compressive modulus (CM) of the aluminium composites. The composites with10 wt% B4C and TiO2 single reinforcements had strengths 251% and 159% higher than that of pure aluminium, respectively. However, the hybrid composites demonstrated a maximum CS enhancement of 98% compared to the pure aluminium composite. Among the composites, the monolithic metal had better corrosion resistance than the reinforced composites. Al monolithic metal has the lowest corrosion rate of 0.049 mm/year, whereas Al + 10 wt% B4C has the highest corrosion rate of 4.91 mm/year due to the galvanic corrosion of the B4C reinforcement.