Yu. V. Grinyaev

Spectrum of excited states and the rotational mechanical field in a deformed crystal

The authors discuss, from the standpoint of quantum gauge theory, the plastic deformation of crystals as a process of their structural transformation in regions of strongly excited states and their relaxation by the emission of defects as elements of a new structure. Plastic deformation is considered on the basis of the behavior of inhomogeneous highly nonequilibrium systems which undergo local structural transformations and move toward equilibrium through the motion of elements of new structures in the fields of stress gradients.

Stress state in elastically loaded polycrystal

The stress state of a polycrystal is considered by means of contact-problem theory. It is shown that this approach is able to account for the great inhomogeneity of the stress state at the junctions between several grains.

Relationship of a gauge model of an elasto-plastic medium to the Mindlin theory

We examine the relationship between the simplest gauge model of a material with the Mindlin theory that takes into account microstructure in linear elasticity. We establish a connection between the dynamical equations for the two models. The connection allows us to relate an unknown material constant in the gauge Lagrangian to the inertial properties of the structural elements. We obtain an estimate of the unknown constant and the corresponding characteristic frequency for the dimensions of elements with different structural levels of deformation.

Excitation spectrum of anisotropic non-dissipative elastic-plastic medium

The simplest gauge theory of an elastic-plastic medium is considered in this paper that takes account of just translational plasticity. The equations of motion for such a model turn out to be linear and permit the normal modes spectrum of a medium to be obtained. Taking account of plasticity results in a cardinal transformation of the elastic branches of the spectrum and the appearance of a group of “plasma oscillations” of a dislocation gas.

Mechanics of deformation of structurally nonuniform media

It is shown theoretically and experimentally that the complete deformation of structurally nonuniform media consists of two components: macrodeformation, which is determined by the relative displacement of the elements in the structure (grains, subgrains, phases, and so on) as a whole, and microdeformations, which represent the deformations of these elements themselves.

A study of mechanical twinning inα-solid solutions of the system Cu-Ge

Electron and optical microscopy have been used to study the structure and distribution of mechanical twins in polycrystalline Cu-Ge alloys containing up to 9.5 at.% Ge which had been deformed at room temperature. The probability of twinning occurring increases continuously with rise in concentration of the alloy up to the solubility limit. A reduction in the grain size of a polycrystalline aggregate impedes the development of twinning. It is shown that the twins have an imperfect structure even in the initial stage of growth.