Impact of Galvanic Corrosion Damage and Environmental Spectra on Fatigue Failure of AA7050 - CANCELLED

RIP2025-00090: Dissimilar metal interfaces frequently initiate structural cracks that could lead to mechanically assisted cracking such as corrosion fatigue. The objective of this research is to characterize and understand the effect of various galvanically induced corrosion morphologies and environment loadings on the fatigue behavior and crack growth rate of aluminum alloy (AA) 7050. This study systematically and quantitatively investigates the impact to fatigue crack growth and fatigue life in a corrosive environment with realistic corrosion morphologies resulting from an AA7050 alloy-carbon fiber reinforced plastic (CFRP) couple. In the initial effort, the investigation focused on introducing various corrosion morphologies on the AA7050 surface induced by galvanic corrosion coupled with CFRP. Test coupons were characterized in both ambient and corrosive environments to investigate the effect of a corrosive environment on the fatigue behavior. Results show that any type of corrosion damage or corrosive environment decreases the fatigue life of the 7050 aluminum alloy, as expected. However, fatigue crack growth results indicated a higher threshold stress intensity factor in the corrosive environment. Fractography was performed on a limited number of specimens to understand the environmental effects on fatigue crack initiation and assessment of potential corrosion products influencing the fatigue crack growth behavior. These results were used to validate crack growth and fracture modeling while exposed to a corrosive environment.