Computer-aided study of surface influence on behaviour of solids under deformation

In the paper the influence of a surface layer in development of process of deformation of solid at nanoscale level in conditions of dynamic loading is investigated. Researches are carried out on the basis of computer modeling by a method of molecular dynamics. Processes at the initial stage of loading and the processes taking place directly at the moment of formation and development of plastic flow are considered. It is shown, that near to surface in the loaded solid formation of dynamic vortical structures not only at stage of active loading of material, but also at a stage of relaxation of pressure is possible. Atomic displacement in this case can form the coordinated system of vortical strings. It was established, that time of life of such dynamic defects can reach tens picoseconds, and their characteristic sizes make nanometers. It is shown, that such system of vortical strings, can change a sign on angular speed in such manner that observable on different intervals of time atomic displacement practically compensate each other. In the paper it is marked, that formation of similar dynamic vortex-like structures are observed also at an active stage of loading of material, but in this case it does not have a periodic character. In the paper also it is shown, that the beginning of process of localization of deformation is directly connected with loss of structural stability in surface layers, formation of zones of localization of deformation on surface and distribution of this zones to depth of material. The obtained results are coordinated with known experimental data and evidently confirm a special influence of surface layer in formation and development of deformation of materials.