The effect of corrosion on the fatigue life of aluminum alloys

The corrosion behavior of metallic structures is an important factor of material performance. In case of aluminum matrix composites corrosion occurs via electrochemical reactions at the interface between the metallic matrix and the reinforcement. The corrosion rate is determined by equilibrium between two opposing electrochemical reactions, the anodic and the cathodic. When these two reactions are in equilibrium, the flow of electrons from each reaction type is balanced, and no net electron flow occurs. In the present study, aluminum alloy tensile-shape samples are immersed in NaCl solution with an objective to study the effect of the controlled pitting corrosion in a specific area. The rest of the material is completely sealed. In order to investigate the effect of pitting corrosion on the material performance, the specimens were subjected to cyclic loading. The effect of corrosion on the fatigue life was assessed using two complimentary nondestructive methods, infrared thermography and acoustic emission.