CORROSION AND FATIGUE PERFORMANCE OF FSW JOINTS OF Al ALLOYS

Abstract

The corrosion fatigue behaviour of friction stir welded 2024 aluminum alloy was examined. This aluminum alloy is widely used in aircraft structures, especially wing and - fuselage structures under tension. The fatigue specimens were subjected to completely reversed loads. The specimens were fatigue tested in ambient atmosphere and in different corrosive environment. The results for corrosion fatigue testing data obtained in various corrosive environments were compared to data obtained for the same loading condition in ambient atmosphere. It is believed that the reduction in fatigue life is due to the formation of corrosion pits and a combination of anodic dissolution at crack tip. The optical microscopy and SEM with EDS is carried to study the effect of corrosive environment on the fractured specimen and formation of corrosion pits was observed in the corroded samples. The SEM —EDS analysis revealed the deposition of element like chlorine, oxygen and sodium on the fracture surface of the samples. 111