Lattice Misorientation and Displaced Volume for Microhardness Indentations in MgO Crystals

Diamond pyramid indentations on (001) surfaces were studied by X‐ray diffraction microscopy and scanning electron microscopy. These methods reveal the patterns of internal strains and external surface relief, respectively, which accompany various deformation (and cracking) processes at the indentation sites. These processes are controlled by the formation of sessile 〈110〉 dislocations which prevent additional straining of the crystals along [001]. The results provide evidence that the local crystal work‐hardening behavior is important in determining the microhardness values.