Чувствительность дислокационных розеток к форме индентора Берковича на кристаллах LiF и MgO

Abstract

A peculiar effect, namely, the sensitivity of the shape of dislocation rosettes to the indenter type under indentation of the (001) face of LiF and MgO single crystals has been revealed. It was shown that the dislocation rosettes forming around the Vickers indenter are symmetrical, while the rosettes around the Berkovich one are asymmetric, the edge beams of the dislocation rosettes vary in length, and the screw ones do not show such asymmetry. An orientation effect was found during the penetration of the Berkovich indenter: the shape of the dislocation rosettes and the length of the edge beams change with a change in the orientation of the indenter relative to the crystallographic directions of the sample. It was also shown that the asymmetry of dislocation rosettes is more visible on harder crystals and increases with load growth on the indenter. The factors responsible for the anomaly in the development of dislocation rosettes under indentation in nano and micro scale by the Berkovich indenter of the (001) plane of cubic crystals are established