Study on the Local Corrosion in Aluminium Composites Reinforced with Titan and Zinc Fabricated by Friction Stir Processing

The effect of titanium- and zinc reinforcing particles in aluminum composites on the development of local corrosion was investigated. Two types of alloy A6061 T6-based composites reinforced with 2, 4, and 6 mass % Ti and Zn respectively, were fabricated by friction stir processing (FSP). The microstructure and the phase content were studied by SEM, EDS, and XRD. Intergranular (IGC) and pitting corrosion (PC) susceptibility tests were performed. IGC corrosion resistance was evaluated by standardized methods and metallographic observations. The results showed that Zn- and Ti reinforced composites were resistant to IGC. The results of cyclic polarization corrosion tests showed that alloy A6061 T6-based composites reinforced with Zn and Ti particles were susceptible to pitting corrosion. The reference alloy A6061 T6 is the most resistant to pitting corrosion and has the lowest corrosion potential Ecorr, compared to Ecorr of the composites reinforced with 2 and 6 mass % Ti. The composite reinforced with 6 mass % Zn is the most susceptible to pitting corrosion.