The effect of friction stir processing (FSP) on the behaviour of wrought alloy 2024 in pulsed laser welding was examined. The results showed that FSP changes the microstructure and that significantly affects the susceptibility of the base metal to liquation cracking. The change in cracking behaviour is proposed to be related to the refinement of the microstructure and redistribution of precipitates along the grain boundaries, increasing the flexibility of the grain network. According to the observations, as a result of FSP, not only liquation cracks but also solidification cracks were reduced, supporting the view that liquation cracks can act as the source of some of the solidification cracks.
