ELECTRON-MICROSCOPE STUDIES OF LOCALIZED CHANGES IN DISLOCATION CONFIGURATIONS DURING FATIGUE

A method has been developed which allows for the study of localized changes in dislocation arrangements, using transmission electron microscopy, at different stages of cyclic deformation. The method is illustrated in studies of the cyclic deformation of pure aluminium at a constant total strain amplitude of 6 × 10-4. Two experiments are described which involve temperature changes from 163 to 223 K and show the effect of the detailed dislocation arrangements formed at the low temperature on the later (higher temperature) arrangements. A third experiment is a study of changes within a single cell, formed by room temperature cyclic deformation, when the direction of the stress is changed by 90°. © 1990.