Formation of vacancy-helium complexes at low-energy irradiation of tungsten

Abstract

The structure of subsurface area of tungsten after low-energy irradiation by helium ions was investigated by the method of field-ion microscopy. The emerging of the compact groups of interstitial atoms to the surface was registered. It was found the depleted zones consisted with vacancy–helium clusters, which arise as the result of crowding out own lattice atoms by helium. The depleted zones spatial configuration was investigated as a function of the dose. The processes of forming of vacancy–helium complexes and depleted zones in subsurface area at the high concentration of the implanted helium atoms were analyzed. The correlation between the size of depleted zones and the range of image forces was shown.