Deformation Mechanism of KCl Single Crystal by Spherical Indentor

I. Indentation with Steel Ball

Abstract

The indentation test is probably the simplest method of estimating the strength of material under the frictional condition that the asperity tips are pressed into other body and that wear debris are scratched between two bodies. With the advancement of techniques of revealing dislocations in crystals, it has been thought possible to obtain a right understanding of the deformation in the material with a single crystalline structure caused by indentation.
In the present study, KCl single crystal was indented with a steel ball to examine the dislocation structures associated with indentation at various loads. The slip systems and the range of deformed area were investigated in detail on the indented surface and on its cross section by using a dislocation etching technique.
The results obtained are as follows:
(1) The deformed area on the indented surface consists of a circular high dislocation density area and the area of comparatively low dislocation density shaped like wings and extended in the ‹110› and ‹100› directions.
(2) Dislocation patterns on the indented surface and on its cross section consist of etch pit rows that belong to the {110}₉₀ and {110}₄₅ planes, respectively.
(3) The plastic deformation range is affected by the diameter of indentor under comparatively high loads, but not under exceedingly low loads.