Deformation of KCl Single Crystal by Spherical and Pyramidal Indentors

In order to elucidate the mechnism of friction and wear, it is necessary to have a knowledge on deformation in materials produced by invasion of sharp projections or wear particles. In this study, the cleaved faces of KCl single crystal were indented with a steel ball or a Vickers diamond indentor. The deformation and hardness around the indentation were examined from macroscopic viewpoints, and the dislocation patterns were observed from microscopic one. The results obtained are as follows: (1) The indents formed on the indented surfaces with a ball or a pyramid were not perfectly circular nor square in shape due to the crystal anisotropy. (2) The appearances of the pile-up and sink-in around indents were clarified. (3) The strain hardening around the indent was more active in the ‹110› direction than in the ‹100›. (4) The deformed area on {100} face with a ball or pyramidal indentor consisted of a high dislocation density range and a wing shaped area of comparatively low density extended along the ‹110› and ‹100› directions. (5) The hardness and the dislocation density were related each other. (6) The etch pit patterns in the cleaved cross section were observed on {110}45 faces.