Effects of Sustained Tensile Stress on Localized Corrosion Evolution of 5A06 Aluminum Alloy in Natural Seawater

In marine engineering structures, components made of 5A06 aluminum alloy are often subjected simultaneously to sustained tensile stress and corrosion in natural seawater; their initial surface condition may further influence the initiation and propagation of localized corrosion. In this study, in situ potentiodynamic polarisation under constant load was combined with scanning electron microscopy and quantitative pit‐depth measurements to investigate the localized corrosion behavior of 5A06 aluminum alloy in natural seawater. Changes in corrosion morphology and local composition suggested that, with increasing exposure time, local disruption of the surface film or corrosion‐product layer re‐exposed the substrate, allowing pits to spread laterally and deepen. The combined effects of exposure time and tensile stress markedly aggravated localized corrosion damage, indicating that prolonged immersion and high tensile stress are key factors accelerating corrosion‐induced degradation of 5A06 aluminum alloy.