Behaviour of Friction Stir Welded Joints Made out of Two Aluminium Alloys under Cyclic Loading Conditions

The friction stir welding (FSW) is a dynamically developing version of the pressure welding processes. Nowadays, the knowing of the properties and the behaviour of the welded joints is an important direction of the investigations, especially under cyclic loading. The research work aimed (i) to demonstrate the behaviour of the friction stir welded joints under cyclic loading conditions; (ii) to determine fatigue limit or design curves for aluminium alloys and their welded joints made by FSW process. Experiments were performed on 5754-H22 and 6082-T6 aluminium alloys and their welded joints. Both high cycle fatigue (HCF) and fatigue crack propagation (FCG) tests were executed on both base materials and their welded joints. Statistical behaviour of the base materials and welded joints was represented by the cutting of the specimens and the using of different crack paths. HCF limit curves were determined based on staircase method. FCG limit curves can be determined by own developed six step method. The investigations and their results were compared with each other and with the results can be found in the literature.