Abstract
Deformed single crystals of copper are sectioned on the primary slip plane. The sections are studied by transmission electron microscopy and the natures of dislocation dipoles are determined on the basis of the kinematical theory of electron diffraction. It is found that both vacancy and interstitial dipoles are present. Dislocation configurations associated with open dipoles are analysed. It is suggested that open dipoles which originate at sessile long jogs in a particular screw dislocation are ended-off by glissile long jogs in the same screw dislocation to form closed dipoles.