Fatigue of single crystals which were oriented for single slip was studied by using electron channelling contrast imaging in a scanning electron microscope. The technique was used to detect and characterize dislocation structures in bulk specimens. When the incident beam was set at the Bragg condition, changes in the back-scattered electron intensity occurred as the beam was scanned over dislocations which caused local tilting of the diffraction planes. Observations of specimens which were fatigued up to the saturation plateau (at a resolved shear stress of 28MPa) showed that the dislocation sub-structures (mainly ladder structures and elongated cells) were identical to those which were observed during the transmission electron microscopy of thin foils. It was recalled that one of the main advantages of the present technique was that it was possible to monitor all of the stages of formation and evolution of dislocation structures over large areas of a given bulk specimen when fatigue was interrupted at various stages of fatigue life.

Characterizing Dislocation Structures in Bulk Fatigued Copper Single Crystals using Electron Channelling Contrast Imaging J.Ahmed, A.J.Wilkinson, S.G.Roberts: Philosophical Magazine Letters, 1997, 76[4], 237-45