Fatigue assesment of AA8090 friction stir butt welds after surface finishing treatment

Combining great performances with high standards of safety and efficiency is the challenge for most aircraft manufacturers. Aircraft are subjected to extraordinary loads, repeated for millions of cycles also in extreme environmental conditions, hence every component must be designed and manufactured to maximize its fatigue resistance. Friction Stir Welding of aluminium alloys and surface finishing process es might be a good solution to reach this goal. The high performances reached in this field with the use of this technique could be further increased reducing the welded surface irregularity, which might promote the development of a dangerous fatigue failure mechanism. In this work, the effect of the welded surface finishing treatment on the fatigue behaviour of AA8090 FSW butt joints was assessed. The results obtained from the dynamic tests highlighted the higher fatigue resistance of finished specimens, with respect to the as-welded joints.