Fatigue crack growth rate in friction stir welded joint of AA6082 alloy

Fatigue crack growth rates（ FCWR） at different locations in FSWed joint of A6082 alloy were investigated. The microstructures and fatigue fracture morphology were analyzed. The results showed that the highest FCWR appears in the nugget zone. At lower ΔK range,the FCPR in heat affected zone is lower than that in base metal. At higher ΔK range,the FCPR in the heat affected zone increases,which is higher than that in base metal. The fatigue fracture showed that fatigue crack propagates in the nugget zone in the form of brittle quasi-cleavage mode,the resistance of fatigue crack propagation was reduced. While the typical plastic fatigue striation was the fracture mode of crack propagated in the heat affected zone and base metal.