Observation of Deep Dislocation Structures and "Long-Range Effect" in Ion-Implanted alpha -Fe

The results of experimental investigations of "long-range effect" by ion implantation into alpha -Fe are presented. Carbon, iron, tungsten, hafnium and argon ions were implanted into alpha -Fe in continuous and pulse-periodic regimes. The ion energy varied in the range 40-150 keV and the irradiation dose varied in the range 1 x 10 exp 15 -1 x 10 exp 18 ions cm exp --2 . It has been established that dislocation structures are formed in the near-surface layer of pure metals by ion implantation. The thickness of the near-surface layers with the dislocation structure induced by ion implantation is in the range 20-100 mu m. Stress measurements and calculations in the near-surface layers by ion implantation show that the stresses are considerably greater than the yield strength. The stresses result in the plastic deformation of the near-surface layers of the irradiated materials. The plastic deformation is the main reason for the dislocation structure development.