Corrosion Behaviors of 5A06 Aluminum Alloy Sheet Under Stress Loading in Brine Solution

Based on the problem of corrosion acceleration possibly existing in aluminum alloy sheets under the influence of both loading and brine solution, the corrosion behavior of 5A06 aluminum alloy sheets with the thickness of 1.8mm by the two-point bending method in 3.5% NaCl aqueous solution at 50℃ was discussed.It is found that stress actually can promote the speed of corrosion in these aluminum alloy sheets.Crack morphologies, metallurgical structures and elemental compositions in different corrosion periods of these samples were analyzed.The results show: firstly, large stress will cause severe corrosion, which proves that stress can accelerate the corrosion; secondly, the solid solution strengthening phase in aluminum alloy can cause the anode areas preferentially dissolve, resulting in the formation of corrosion pits.Furthermore, stress can result in tearing of oxide film on the aluminum alloy surface, and facilitate corrosion crack propagation.