Low-amplitude fatigue of copper and copper-5 at. % aluminium single crystals

Abstract The surface structures and interior dislocation structures of fatigued copper and copper-5 at. % aluminium crystals have been studied using replicas and scanning and transmission electron microscopy techniques. A very regular structure of walls of dislocations has been found; these walls consist of primary edge dipoles held together by a mesh of secondary dislocations. It is suggested that the wall structure is the ‘ideal structure’ to which other structures tend as the fatigue process progresses, and that this regular structure is found in the persistent slip bands.