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. C, Fe, W, Hf and Ar 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(15)-1 x 10(18) ions cm-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 mum. 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.