Systematization of the thermodynamic model of changes in the structure of metals and alloys under mechanical action

Abstract

Recently, the construction of theoretical models that allow us to qualitatively describe the accompanied processes of fragmentation (grinding) of the crystal structure of a material during processing by IPD methods has acquired significant importance. A thermodynamic model is presented that uniquely establishes the course of highly nonequilibrium processes and allows us to describe the specifics of the formation of the limiting (stationary) granular structure of the material during IPD. Defect densities, entropy, and components of the elastic strain tensor are considered as independent thermodynamic variables of the model. In the future, the presented ideas are used as a basis for solving specific problems. The purpose of the article is to generalize the thermodynamic model describing the fragmentation of metals or alloys at IPD, and to study the features and conditions of the formation of limit (stationary) structures of various types. Thus, in the approximation of a two-defect model, taking into account the dislocation density and GB, PD is constructed, which establishes the conditions for the formation of limit (stationary) structures of various types. In addition, the article examines in detail the evolution of the main structural defects and their interaction during the implementation of the stationary regime, and also establishes the dependence of the type of limit structure formed on the values of landslide deformation and the initial state of the material. It was found that the change in the states of the system has the character of SPT. It follows from the description methods that the limiting (stationary) structure is not immutable, but represents a dynamic equilibrium of the processes of generation and annihilation of structural defects.