Formation of the internal structure of solids under severe load

Abstract

An alternative form of kinetic equations, involving the internal and free energies symmetrically, has been derived in the framework of the theory of vacancies. Dynamical nature of irreversible phenomena during formation and motion of defects (dislocations) has been analyzed by a computer experiment. Results of this simulation are then extended into a thermodynamic identity, involving the law of conservation of energy at interaction with an environment (the first law of thermodynamics) and the law of energy transformation in the internal degrees of freedom (relaxation). This identity is compared to the analogous Jarzynski identity. The approach is illustrated by simulation of processes during severe plastic deformation; the Rybin kinetic equation for this case has been derived.

Mechanical properties of icosahedral boron carbide explained from first principles

“…As pointed out recently, the generation and motion of structural defects in a solid under severe external action is a complicated process, whose theory is still in its infancy. 11,12 In the following, vacancies are shown to be located in the C-B-C chains and to be boron vacancies only, C-V-C (Fig. 1).…”

Nonlinear thermodynamic model of boundary friction

“…The liquid state is commonly interpreted as the region of plastic flow on the loading diagram and char acterized by the defects present in the lubricant [15]. In this paper the authors use an approach based on the Landau theory of phase transitions [36][37][38][39] to describe strongly nonequilibrium processes occurring during the sliding of two solids separated by a lubricant layer.…”

Thermodynamics and kinetics of solids fragmentation at severe plastic deformation

“…The steady-state density of grain boundaries h g is fixed by the extremum condition of the potential (12), since at ∂V /∂h g = 0 according to equation (10) ∂h g /∂t = 0. Besides, the minima of the potential correspond to the unstable states, but its maxima meet the stable states [14][15][16]25].…”

“…It can be investigated in the most general form independently of the specific deformation mechanism. The general theory of the SPD processes was offered in the studies of the author [14][15][16], which is based on the nonequilibrium evolution thermodynamics. The formation of a limiting structure within the framework of this theory is related to a minimum or a maximum of the thermodynamic potential and is analogically described by the theory of phase transitions based on the general kinetic Landau-Khalatnikov-type equation [14][15][16].…”

“…The general theory of the SPD processes was offered in the studies of the author [14][15][16], which is based on the nonequilibrium evolution thermodynamics. The formation of a limiting structure within the framework of this theory is related to a minimum or a maximum of the thermodynamic potential and is analogically described by the theory of phase transitions based on the general kinetic Landau-Khalatnikov-type equation [14][15][16]. The main feature of this approach is that the defect structure is taken into account by an obvious introduction of the corresponding terms in the basic thermodynamic relationships which is similar to mesoscopic thermodynamics [17,18], while the ordinary thermodynamics is an unstructured theory.…”