Application of Method of Molecular Dynamics (MMD) for Modeling the Process of Dislocation of Hardening of Surface Zone

Abstract

This article analyzes the modeling process of hardening using a molecular dynamics method with the example of formation and subsequent cleavage of edge dislocations at the superficial zone of carbonitriding heat-resistant steel during sliding friction using industrial grease. Previously obtained experimental data of the surface area of friction reflect the processes of structure formation in a continual approximation and thus, allow to identify its main characteristics. In particular, setting higher diffusion coefficients and lowering temperature ranges during phase transitions reveal that the cause of the anomalous behavior of the diffusion processes is thermal shock leading to the occurrence of highly pressurized area of “compression–expansion” in the surface layer of the hardened metal. However, using the methods of continual approximation, a high speed of diffusion processes does not allow us to establish a number of features of these processes, which affect both the formation of secondary structures and their tribotechnical properties. This is a quantitative assessment of the process of prediffusion excitation of atoms in the form of: appearance of vacancy clusters, intrinsic interstitial clusters, and dislocation loops, i.e., about the damage to the surface layer at this stage.