Formation of nanostructures in metals by low-energy ion irradiation

Abstract

The purpose of this paper is the study of nanostructure formation in metals by low-energy ion irradiation and computer simulation of nonlinear effects in crystal lattices on an atomic scale. Polycrystalline armco-iron and instrumental steel samples were irradiated by low-energy ions of residual gas in discharge plasma. The fine structure of the samples was studied by transmission electron microscopy. Computer simulations of the self-organizing processes induced by interaction of the low-energy ions with the crystal lattice surface were performed by means of a molecular dynamics method. We show that the process of low-energy irradiation results in the formation of complex multilayer structures in the near-surface region. There are layers with amorphous, microcrystalline and nanocrystalline structures. The formation of atomic clusters with nanometrical dimensions, running autosolitons, long-lived undamped oscillations in local areas were observed. Such modifications in materials can be understood by the concept of active self-organizing processes in crystal lattices, where the energy transition from a vibrational mode to a translational mode takes place. Low-energy ion irradiation results in a change in the physical and mechanical properties of the irradiated materials.