Stress-Strain Curves and Slip Bands of KCl Whiskers

Abstract

Tensile tests were made, at room temperature, on KCl whiskers grown on outer surfaces of thin cellophane bags containing saturated aqueous solution. It was found that their stress-strain curves consist of four deformation stages. Slip bands were straight in the early stage of deformation, but rumpled surfaces were observed in the later stages under an optical microscope. Deformed specimen showed several Lüders bands where the slip was single. From etch pit study, it was deduced that most of dislocations generated during deformation slipped out from surfaces. In thicker specimens the hardening rate was larger and the strain value for the beginning of each stage was smaller as compared with those of thinner specimens. Cross-slip seems to play important role for development and increasing of slip bands, and also for work hardening and size effect.