Diffraction contrast study of the defect structure of polyethylene single crystals

Dark-field electron microscopy was used to characterize the defects present in polyethylene single crystals. The effect of radiation damage on dark-field images was examined, and the optimum working conditions for employing an image intensifier to observe nearly undamaged crystals were determined. Two new defects associated with microsectors, jogs and screw dislocation dipoles at the termination of microsectors, are shown to be present. Some previously reported contrast observations of slip traces are re-examined in terms of the present results.