Basal slip localization in zinc single crystals. The Considère analyses

Abstract

The tensile and compression tests were performed on zinc single crystals oriented for slip in the basal slip system. During the first stage of the stress–strain curve, the localized necking was typical of strain localization in the tensile specimens. Single or multiple necks were formed along the specimen length. The range of temperatures and the strain rates for single necking of the sample was determined. The formation of such necking depends on strain hardening characteristics and can be predicted by the Considère criterion. On the other hand, propagation of the necked area along the sample length was not predictable by this criterion. Localized sliding and specimen kinking was indicative of the strain localization observed for different specimens compressed under the same conditions, i.e. temperature and strain rate. A decrease in the compression force and in the cross-sectional area with anvil displacements produced localized sliding. On the other hand, a continuous increase in the compression force was representative of tests leading to specimen kinking.

Keywords:

• zinc
• single crystal
• strain localization
• necking
• tension
• compression

Acknowledgements

The financial support of AGH, contracts no 11.11.180.792 and 11.11.180.448, is appreciated. We thank Prof. J. Bonarski from A. Krupkowski Institute of Polish Academy of Sciences for his help during X-ray measurements.