Energy absorption and X-ray studies of kink formation in zinc single crystals

Abstract

Kink formation in single crystals of zinc was studied dynamically and statically in such a manner that it was possible to measure the energy absorbed during the process. The experiments reveal that two consecutive stages are involved. 1. (a) A uniform bending of the crystal takes place accompanied by an absorption of energy. For the crystals with the pole of the basal plane at about 75° from the specimen axis the energy absorbed was 2.6 × 10 5 ergs; for 83° crystals the energy absorbed was 4.0 × 10 5 ergs. Laue patterns taken after the bending had occurred show asterism and a slight rotation of the basal plane. 2. (b) With an absorption of additional energy a sharp kink is produced. For the 75° crystals the additional energy was .7 × 10 5 ergs; for the 83° crystals the additional energy was 1.2 × 10 5 ergs. After the kink was formed the sections on either side of the kink became straight and relatively parallel. Asterism from these sections decreased in going from stage ( a) to stage ( b). Severe asterism was obtained from the kink. X-ray studies show, in agreement with Hess and Barrett, that the basal plane in the kink is rotated relative to the basal plane in the rest of the specimen, about an axis within the basal plane which is perpendicular to the active slip direction. In addition, the plane has bent about this axis. Finally, a qualitative dislocation model is presented which also is quite similar to that of Hess and Barrett.