MOLECULAR DYNAMICS SIMULATION OF A REDUCTION IN THE POROSITY OF THE SURFACE LAYER OF A BCC CRYSTAL CAUSED BY THE INFLUENCE OF LASER PULSES

10.25712/ASTU.1811-1416.2023.02.003

Abstract

A more complete understanding of the processes of interaction of laser radiation with matter can contribute to the development of technologies for laser synthesis of materials with unique properties, nanostructuring of surfaces of treated solids, and so on. Difficulties associated with direct observations of various fast processes contribute to the development of the use of computer simulation methods for their study. This paper presents the results of modeling the processes of reducing the porosity of the surface layers of iron, which was formed as a result of laser pulsed exposure. The study was carried out using the potential calculated within the embedded atom method. The model under study was subjected to structural analysis using proven algorithms, which makes it possible to quantify the surface area of voids in the bulk of the crystal. We considered computational cells containing voids in the amorphous region, which remain stable when the model is cooled, which corresponds to the process of natural cooling of a solid in the environment, which is described by a mathematical expression. An obvious approach to get rid of defects is to anneal the solid. It is shown that pores are preserved after annealing at a temperature not exceeding half of the melting temperature. Taking into account that the main mechanisms for reducing porosity are the diffusion-viscous flow of matter into voids, and the fact that diffusion in the amorphous phase is more intense than in the crystalline one, it was necessary to create conditions in the model when the crystallization process slows down at a given temperature. Similar conditions were achieved by deforming the computational cell. As a result, it is shown that both under compression and under tension, a decrease in voids is observed.