The microscopic deformation mechanism of KCl single crystals under the indentation with a steel ball was studied under the load range of 0.5N-5.0N in the temperature range 20°C-300°C. Indentations were made on the {100} plane, and using the etch pit detecting technique the dislocation structures were investigated on the indented surface and its cross section.
The results obtained are as follows:
(1) The dislocation structure formed on a {100} plane at room temperature consists of a high-dislocation-density range and a wing-shaped area of comparatively low density extending along the ‹110› and ‹100› directions.
(2) Dislocation activities on the {110}
90 and {110}
45 planes are more active under the testing temperature at 100°C and 200°C than at room temperature. At these testing temperatures, the deformation is mainly caused by the slip on the {110}
90 plane under comparatively high loads, while the deformation under the lower loads is caused in the pattern that the slips on the {110}
90 and {110}
45 planes have almost equal effect on the formation of the dislocation structure.
(3) At 300°C, the slip activities on the slip system besides the {110} ‹110› are observed. Dislocation structures with a pattern of circle in the neighborhood of indent, and with a wing-shaped pattern along the ‹110› direction in the outer range, are observed.
(4) On the cross section, dislocation activities on the {110}
45 plane are detected at all testing temperatures. It is confirmed that the secondary slip activities occur on the {100} plane at 300°C.
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