Grain structure, geometrically necessary dislocations and second-phase particles in polycrystals of micro- and mesolevels

The paper considers the influence of size effects on dislocation structure and second-phase particles. Particular attention is given to scalar dislocation density, geometrically necessary dislocation density and parameters of particles formed at grain boundaries. It is found that there exist three critical grain sizes in the range of which the mechanisms of deformation and hardening of polycrystals are changed. Special emphasis is placed on stabilization of the submicropolycrystal grain structure by second-phase particles present at the gain boundaries.