Evaluating the fatigue initiation location in friction stir welded AA2024-T3 joints

This paper presents observations on fatigue initiation in friction stir welded AA2024-T3 joints. Based on these observations, the influence of the weld on the location of initiation is discussed. These locations of initiation are correlated to stress results from numerical analysis. Furthermore, fractography was performed to investigate the role of the microstructure in the weld on the location of initiation. As a result, it has been observed in which cases the residual stress determines the location of initiation and in which cases the microstructure.

Research highlights
► The microstructure in the weld affects the appearance of the fracture surface significantly.
► The location of initiation is determined by the residual stress.
► When no residual stress is present, the fatigue crack has a preference for the TMAZ to initiate.
► The crack path is highly affected by the microstructure of the weld.