A Theoretical Investigation of Special Aspects of Nonequilibrium Disclinational-Type Boundaries in Crystalline Materials

Resumo

The results of a theoretical analysis of the stress fields and elastic energy distributions of the disclinational grain-boundary structure in nanocrystalline metallic materials as a function of grain size are presented. Considering the superposition of these stresses during screening of the piled-up disclinations it is found out that the maximal values of the principal components of the stress tensors are achieved in the planes of disclination occurrence P = Tr(σ_ij)/3 >  > E/25, while the stress gradients are characterized by the maximum values in the nodal points ∂P/∂x ≈ 0.08 E nm^–1 (Е – Young’s modulus). It is determined that a considerable part of the shear stress components is localized inside the grain. It is shown that the characteristic features of the specific elastic energy distribution in these configurations are the local energy maxima, which could be a reason for the physical broadening of the nanograin boundaries.