CORROSION INVESTIGATION OF Al/Al₂O₃ COMPOSITES MANUFACTURED VIA COMBINED STIR CASTING AND ARB PROCESS

This study investigates the corrosion behavior of Al/Al2O3 composites fabricated via a novel combination of stir casting and accumulative roll bonding (ARB) processes. The composites were produced using fully annealed AA1100 aluminum bars and alumina particles with 99% purity. The stir casting process ensured uniform dispersion and bonding between the matrix and reinforcement, while the ARB process induced severe plastic deformation (SPD), leading to ultrafine-grained (UFG) structures. Corrosion properties were analyzed in a 3.5[Formula: see text]wt.% NaCl solution through potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests. Key findings indicate that higher ARB cycles enhanced corrosion resistance by reducing grain size and dislocation density, achieving a uniform microstructure and oxide layer formation. Samples subjected to six ARB cycles exhibited the lowest corrosion current density ([Formula: see text] and the highest polarization resistance ([Formula: see text], compared to annealed aluminum. SEM analysis revealed the evolution of pit morphology with increased ARB cycles, showing higher pit density and uniformity. The cathodic reaction rate decreased significantly due to the strengthened passive oxide layer, while the anodic potential shifted positively, demonstrating improved corrosion stability. These results highlight the synergy between stir casting and ARB processes in enhancing the microstructural and corrosion-resistant properties of Al/Al2O3 composites. Future research may explore bi-metal bulk composites fabricated using similar methods to optimize corrosion resistance further.