Strain-induced dissolution of CuaMg co-clusters and dynamic recrystallization near a fatigue crack tip of an underaged AlaCuaMg alloy during cyclic loading at ambient temperature

Highlights ao Dissolution of Cu-Mg co-clusters was shown to be connected with the repeated cutting of moving dislocations. ao Room-temperature dynamic recrystallization was confirmed near the crack tip as intense localized straining employed. ao Cyclic deformation around the crack tip should be considered as a severe localized plastic deformation. The microstructure evolution near a fatigue crack tip of an underaged AlaCuaMg alloy indicated that cyclic deformation around the crack tip was a kind of severe localized plastic deformation. It was first revealed that the dissolution of CuaMg co-clusters was directly related to the repeated cutting by moving dislocations as intense localized cyclic straining at the fatigue crack tip was applied. A transition from the dislocation tangles to subgrains, which was associated with room-temperature dynamic recrystallization, was also confirmed.