Fatigue Behaviour of Friction Stir Spot Welded Joints with Re-filled Probe Hole in Al-Mg-Si Alloy

摘要

In this study, fatigue behaviour of FSSW (friction stir spot welding) joints of Al-Mg-Si aluminium alloy was investigated. FSSW was performed using specially designed double-acting tool, which could re-fill probe hole of the joints. Fatigue tests were conducted using lap-shear specimens with probe hole and re-filled one at a stress ratio of R = 0.1. The refilling process was beneficial to tensile strength, while detrimental to the fatigue strength at high applied loads. The dependence of fracture mechanism on FSSW tool geometry was discussed based on the macroscopic and microscopic structures near the weld zone.