Analytical investigation of dislocations ensemble self-consistent dynamics in the elastic fields of initial mesodefects (junction disclination, planar groups of dislocations and disclination dipole) generating in boundaries and junctions of grains during plastic deformation is made. It is shown that these mesodefects lead to stratification of the initially homogeneous dislocation flow and generate regions of increased dislocation charge density. Such re-distribution of dislocations effectively screens elastic fields of mesodefect, essentially decreases the system energy and preconditions the formation of the secondary mesodefects, such as broken dislocation boundaries providing misorientations of crystall lattice regions and dividing initial grains to sub-grains.
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