2010 Volume 4 Issue 6 Pages 840-848
The behavior of fatigue cracks which propagated at some representative areas in the friction stir welded joint of aluminum alloy, AA6063-T5, was studied at both room temperature (RT) and 200°C. The experimental results showed that the fatigue crack propagation (FCP) rates were significantly different depending on the crack propagating area. The test temperature also affected the FCP rates remarkably. In all cases, the FCP rates in the weldment were higher than those in the parent metal. The difference could not be reasonably interpreted only from mechanical point of view in which the crack closure behavior was taken into account. Furthermore, the non-uniform distribution of hardness had insignificant effect on FCP rates. This study found that the microstructural inhomogeneity played more essential role in FCP behavior of FSW.
