Alternative approach for description of the non-equilibrium phenomena arising in solids at a severe external loading is analyzed. The approach is based on the new form of kinetic equations in terms of the internal and modified free energy. It is illustrated by a model example of a solid with vacancies, for which there is a complete statistical ground. The approach is applied to the description of important practical problem - the formation of fine-grained structure of metals during their treatment by methods of severe plastic deformation. In the framework of two-level two-mode effective internal energy potential model the strengthening curves unified for the whole of deformation range and containing the Hall-Petch and linear strengthening sections are calculated.

L. S. Metlov

Thermal field soliton self-organization arising due to absorption of background atoms vibrations is observed in numerical experiment in nonlinear chain with Lennard-Jones potential at high temperature. At some stage intensive space-localized waves are formed and give additional peaks on high-energy tile of energy distribution unlike of Gibbs one.

Leonid S. Metlov

A new mesoscopic non-equilibrium thermodynamic approach is developed. The approach is based on the thermodynamic identity associated the first and second law of thermodynamics. In the framework of the approach different internal dissipative channels of energy are taken in account in an explicit form, namely, the thermal channel and channels of defect subsystems. The identity has a perfect differential form what permits to introduce an extended non-equilibrium state and use the good developed mathematical formalism of equilibrium and non-equilibrium thermodynamics. The evolution of non-equilibrium variables of a physical system are described by a Landau-based equation set expressed through internal or different kinds of free energy connected by means of the Legendre transforms. The accordance between the different kinds of energy is possible owing to introduction of some trends into the equation subset described the defect subsystems and having a nature of structural viscosity. The possibilities of the approach are illustrated on the example of quasibrittle solid damage and failure. Taking into account only one type of defects (viz., microcracks) and mechanical parameters in an expansion of free energy down to third powers in relative to average energy per microcrack, the description of destruction of quasi-brittle solids during long-term loading is considered. The consideration allows to find equilibrium and non-equilibrium values of the free energy. A qualitative behavior of the system on parameters of the theory is analyzed. The destruction of material is described from the uniform positions, both at uniform tension and uniaxial compression. Origins of the high stability of mine workings at small depths and their instability at large depths are explained.

Leonid S. Metlov

The description of the early stage of microfracture growth in a quasibrittle solid with thermodynamic positions is considered. From the most general thermodynamic performances the "principle" of minimization of free energy is received. The account high (down to thirds) degrees in expansion of free energy concerning parameters of a mechanical field and average microcrack energy has allowed to write down the state equation for solids with microcracks, to find equilibrium and nonequilibrium values of their average energy. From positions of a developed formalism the reason of high stability of work developments on small depths and mechanism of loss of their stability on the large depths is explained. From the fact of presence of qualitatively various behaviour of a material on the large depths the additional estimated connection between parameters of the theory is established.

Leonid S. Metlov

It has been first proved the effect of grains merging during drawing deformation. This was done with example of producing a steel wire from rod manufactured by rolling with shear technology and was shown not only grain refinement but its merging as well. The result obtained in current work has fundamental importance; it reveals new mechanism of the "recrystallization" which takes place without diffusion actions owing to the mechanical impact.

Leonid Metlov Anatoliy Zavdoveev Elena Pashinska

Super Li-rich stars form a very small and enigmatic group whose existence cannot be explained in terms of the standard stellar evolution theory. The goal of our study is to check the reality of this group of cool giants based on an independent technique. We have carried out such a check using the K giant HD 77361 (HR 3597), which has previously been assigned to this rare type, as an example. We have redetermined the effective temperature Teff and surface gravity log g for this star. We have applied two different methods, photometric and spectroscopic, to estimate Teff (the accuracy of the Li-abundance determination depends significantly on this parameter). The value of log g has been found from the highly accurate parallax of this nearby star. To apply the photometric method of determining Teff, we have performed UBV observations of the star, which yielded V = 6.18 +/- 0.03, B - V = 1.13 +/- 0.01, and U - B = 1.18+/-0.05. The following parameters of the star have been found: effective temperature Teff = 4370+/- 100 K, surface gravity log g = 2.30 +/- 0.10, iron abundance log e(Fe) = 7.49 +/- 0.14, microturbulence Vt = 1.1 +/- 0.2 km/s, rotational velocity V sin i = 4.5 km/s, and mass M = 1.3 +/- 0.2 Msun. The lithium abundance has been determined from a non-LTE analysis of three Li I lines: the resonance line at 6707.8 ?A and the subordinate lines at 6103.6 and 8126.4 ?A (the latter in a blend with a CN molecular line). We have found a high lithium abundance, log e(Li) = 3.75 +/- 0.11, which exceeds considerably the initial abundance log e(Li) = 3.2 +/- 0.1 for young stars in the solar neighborhood. Thus, we have confirmed that the K giant HD 77361 actually belongs to the type of super Li-rich stars.

L. S. Lyubimkov B. M. Kaminsky V. G Metlov Ya. V. Pavlenko D. B. Poklad T. M. Rachkovskaya

Molecular dynamic simulations are performed to investigate a long-time evolution of different type initial signals in nonlinear acoustic chains with realistic Exp-6 potential and with power ones. Finite number of long-lifetime kink-shaped excitations is observed in the system in thermodynamic equilibrium. Dynamical equilibrium between the processes of their growth and decay is found.

L. S. Metlov Yu. V. Eremeichenkova

A generalized micromagnetic model of hopfions in a helimagnet with a two-dimensional (allowing both radial and azimuthal dependence) profile function is considered. Calculations confirm the elliptical stability of hopfions and the previously obtained analytical expression for the upper critical field of their lattice. Dependencies of the hopfion lattice periods on the magnitude of the applied external magnetic field and the uniaxial anisotropy constant of the material are obtained. It is shown that in an anisotropic helimagnet, the hopfion lattice expands in the direction of the anisotropy axis, and the expansion can be controlled by the external field and the uniaxial anisotropy constant.

Konstantin L. Metlov Artem S. Tarasenko Yulia A. Bezus Maksim M. Gordei

Kinetics of dislocations is studied by means of computer simulation during intensive plastic deformation. The dynamical effect in the form of soliton-like wave of sharply disrupted interparticle bonds is observed. Along with it, micropores similar to steam bubbles at water boiling are formed. After some deformation the solid takes an ideal structure again owing to "emission of the bubbles". The dislocations in this state (with micropore) can form a grain boundary in the case of nano-structural materials. The nanoscopic object of rotational nature is observed at uniaxial intensive deformation. Rotation of some volume of sample which realized with phase transition scenario was observed by intensive shear deformation.

L. S. Metlov

The kinetics of dislocations is studied with computer simulation at loadings of different intensity. It is established that the dislocations have a few different structural states. The dislocations "with the micropore" play important role in the formation of large curved boundaries, and, as a consequence, in the formation of fine grains. Alternation of elastic and inelastic strain stages is established too. At shear loading, in view of special kinetics, the system would have to accumulate the whole set of dislocations leading to the formation of new boundaries and fine grains.

L. S. Metlov