Microbiologically-influenced corrosion of aluminium 6061 and Al_2O_3 particle-reinforced aluminium 6061 composite under anaerobic conditions and elevated temperatures: the effect on the UTS and strain to failure

摘要

MICROBIOLOGICALLY-INFLUENCED corrosion (MIC) of aluminium alloy 6061 and an Al_2O_3 particle-reinforced 6061 matrix composite was performed under continuous termentation conditions of several thermophilic, anaerobic, bacteria. The effect of various types of metabolic reactions, several different reduction/oxidation potentials, pH, and temperatures, were also studied. This information was correlated to the rate of corrosion, ultimate tensile strength (UTS), and strain-to-failure of the unreinforced alloy and composite samples. Exposure to thermophilic bacterial species led to a significant decrease in the strain-to-failure of the unreinforced alloy and composite samples. Decrease in the UTS of the alloy and composite samples was bacterial-species specific. Although the temperature and pH of the media did not correlate with specimen corrosion and decreased mechanical properties, reduction in the mechanical properties occurred concurrently with aluminium extraction, surface pitting, and nicotinamide adenine dinucleotide reduction/oxidation during the corrosion process.