Nondestructive evaluation of the effect of electrochemical corrosion on anodized aluminum specimens under mechanical cyclic loading

One of the most common methods of surface treatment of the aluminum is anodizing, which improves several metal properties (mechanical, electrical, magnetic, optical, etc.) as well as corrosion resistance. The aim of this work was to investigate the ability of this oxide to protect the tested material from corrosion and its response under the mechanical cyclic loading. In the present study, specimens of Al 1050-H16 were surface anodized at constant voltage using sulfuric acid solution and a layer of aluminum oxide is produced on the surface of the specimen. The anodized specimens were subjected to a corrosive environment simulating the physical exposure to seawater and their subsequent mechanical stress by fatigue method. Two complementary nondestructive evaluation methods, infrared thermography and acoustic emission, were used for predicting the material's fatigue life. The results of the tests of the anodized specimens with and without corrosion were compared with each other, as well as with the corresponding data of the same materials without any treatment. In addition, white light interferometry was used for profiling observation of the aluminum samples in order to characterize the effect of the corrosion process on the specimens' surface.