Fatigue crack propagation of aluminium alloy friction stir welds: residual stress effects

摘要

Fatigue crack propagation tests of 4 mm thick friction stir welded (FSW) joints of the aluminum alloys 6013-T6 and 2024-T3 were carried out with compact tension specimens at different mean stress levels (R-ratios) and crack orientations. The da/dN-ΔK curves of the welded specimens are correctly predicted using a simple approach based on the base material da/dN-ΔK{sub}(eff) data and the residual stress intensity factor distribution obtained from the cut compliance technique. It is concluded that the differences in the fatigue crack propagation behavior were almost completely caused by residual stresses and not by the different resistance of base and welding material to fatigue crack propagation.