Multiple Cracking Development at the Prefructure Stage of Ion Crystals

By means of physical mesomechanics three scale levels of plastic flow localization in LiF single crystals under compression were revealed: fine slip at micrometer range, kink bands at a millimeter range and localization of macroshear-bands accompanied by extremely pronounced effects of shear — bending — torsion. In a zone of macro shear-bands localization a crack of longitudinal delaminating nucleates whose development is completed by specimen fracture. Scale levels of shear stability loss of ionic LiF crystals under compression are qualitatively similar to those under tension of metal materials. It testifies the universality of a principle of the physical mesomechanics that the plastic deformation and fracture of solid is related to its shear stability loss at micro-, meso- and macroscale levels.