Structural changes in the Kh20N45M4B nickel alloys and the Kh16N15M3B steel due to helium ion bombardment

Abstract

Using transmission electron microscopy, x-ray structural analysis, and the thermal desorption techniques, the authors carried out a detailed study of the structural and phase changes, defect formation, and helium accumulation in the He/sup +/-bombarded 16-15 austenitic steels and 20-45 nickel alloys. Microstructure of the bombarded specimens was studied using the methods of transmission electron microscopy of thin foils in the EVM-100, and EM-301G electron microscopes. Results of x-ray studies on the bombarded specimens are presented. The conducted studies show that bombardment of structural materials with light ions can lead to significant structural damages and changes in the chemical and phase composition of the surface layer. The possible mechanisms of the changes in the chemical and phase composition include selective sputtering and radiation-induced accelerated diffusion of elements in the field of internal lateral stresses developing during the He/sup +/ implantation process.