Microkinetics and stabilization of the dynamic fracture in semi-brittle crystals

The problem of stability, stabilization and self-propagation of transcrystalline microcracks in crystals with bcc and hep structures is considered. On the basis of the concept of low-activated stages, considering initiation and propagation of dislocational microcracks by energy consumption, a model of dynamic growth of an isolated crack is suggested, which is simulated by accumulation of cleavage dislocation and is screened by equilibrium distribution of noninteracting lattice dislocations in quasistatic and elastoplastic approximations. Principle possibility of crystal microcrack stabilization by their transfer into safe stage or their stopping by barriers of different nature, grain recrystallization boundaries, disoriented cell boundaries, interface surfaces, for instance, is proved