Nanocluster formation in crystal lattices by plasma treatment

The goal of this paper is to study self-organization processes that cause nanostructural evolution in nonlinear crystal media. The computer simulation has been used to investigate the interaction between low-energy ions and nonlinear crystal lattices. A molecular dynamics method has been applied to calculate the evolution of atom ensembles in lattices of different dimensions using the equations of classical dynamics. Energy transmitted to target atoms was less than the threshold needed to form point defects but sufficient for nonlinear oscillation excitation in ion subsystem of a lattice. The subjects of the experimental investigation were armco-iron, high-speed steel, electrical copper, electrolytic nickel, stainless steel and hard alloy. Low-energy ion impact was carried out in a specially constructed plasma generator, where materials were irradiated by ions of residual gases in vacuum. The ion energy was 1-3 keV. After the low-energy ion treatment, microhardness of the irradiated materials, their fine dislocation structures and electrical resistivity were investigated. We have showed that nonlinear oscillations became excited in the atomic chains of crystal lattices after low-energy ions irradiation and as a result of them the whole atoms became stabilized in new positions, which resulted in the formation and development of new metastable, but long-lived atomic groups (nanoclusters). In fact this provides the volume modification of the investigated materials.