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

The microstructure evolution near a fatigue crack tip of an underaged Al-Cu-Mg 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 Cu-Mg 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. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.