Effect of Cyclic Stress on Corrosion Behavior of 7A09 Aluminum Alloy in Tropical Coastal Atmosphere

In order to simulate the actual service conditions of the structural materials used in the superstructure of marine equipment, the tropical coastal atmosphere was used as the corrosion environment of thin electrolyte layer for 7A09 alloy in this work, and the specifically designed outdoor device was utilized to apply the elastic cyclic stress. Then the corrosion behavior of 7A09 alloy under the combined effects of atmospheric corrosion of thin electrolyte layer and elastic cyclic stress was investigated. The results indicate that the elastic cyclic stress can accelerate the corrosion process of 7A09 alloy significantly under the test conditions, and which contributes more to the increase in the cathodic reaction. The applied stress has a greater effect on the degradation of mechanical properties than on the corrosion morphology. In addition, the interaction mechanism between atmospheric corrosion of thin electrolyte layer and elastic cyclic stress was also discussed.