Properties of fatigue crack propagation in friction stir welded 2024-T3 aluminum alloy

Abstract

Fatigue crack growth rates in an FSW butt joint panel were obtained in order to evaluate the effect of residual stress on crack growth behavior. Two angles between the weld line and loading direction, and two distances between the weld line and the center of the starter notch were employed to investigate the effect of the residual stress field on the crack growth rate and path, and the effect of the initial distance on crack growth acceleration in tensile residual stress field. The test results indicate that the crack growth rate and path on the weld line are merely affected by the angle between the weld line and the loading direction. Furthermore, the acceleration of crack growth was not affected by the distance between the weld line and the initial notch. Under this test condition, the maximum principle stress is not the primary factor determining the direction of crack growth; rather, the direction of the maximum stress range seems to be the primary factor. © Springer Science+Business Media B.V. 2009.