Theoretical Study of Plastic Deformation Features in Nonequilibrium Nanostructural States of Metallic Materials with a High Lattice Curvature

Within the continuum theory of defects, a model of a disclination defect continuously distributed in space is presented. On the basis of this model and the results of an electron microscopic study, the features of nanostructural states with a high curvature of the crystal lattice in niobium are analyzed. The spatial distributions of stress fields and energies of such states at the nanoscale structural level are constructed. It is found that the energy distribution is characterized by highly localized extrema, in which the maximum energy per atom is multiple (more than 2 times) higher than the activation energy of self-diffusion processes. An energy criterion for a high-energy state is proposed, which consists in the fact that the energy of such states normalized to an atom is comparable to or exceeds the activation energy of various processes of structural-phase transformation.

Automated summary

By presenting a model of a continuously distributed disclination defect and analyzing the features of nanostructural states with high lattice curvature in niobium, the spatial distributions of stress fields and energies at the nanoscale level are constructed. It is found that the energy distribution exhibits highly localized extrema and an energy criterion for high-energy states is proposed.