Straining Apparatus for Dynamic Observation by X-Ray Topography

Abstract

In order to carry out the dynamic observation of dislocation behaviour by X-ray topography, two kinds of straining apparatus have been developed; one for room-temperature deformation and the other for high temperatures. By using these apparatuses and a TV-VTR system for X-ray topography, continuous video recording of the dynamic behaviour of dislocations in a stressed crystal can be made in the temperature range from room temperature to 1173 K. In-situ deformation experiments of Cu-4 at.%Al single crystals showed that the first slip initiates at a stress level of about two-thirds of the yield stress and that the propagation speed of the slip line at this stress level is about 1 mm·s^-1. It was also shown in high-temperature deformation of silicon single crystals that the deformation proceeds by the propagation of plastic zones developed from strain centers existing in the surface layer of the specimens.