The Influence of Helium Co-Implantation on Ion-Induced Hardening of Low Activation Ferritic Steel Evaluated by Mciro-Indentation Technique", in this proceedings

An experimental technique to determine the dual-ion irradiation- induced hardening of solid materials by means of micro- indentation was developed and then applied to evaluate the irradiation response of low activation martensitic steel. Micro-hardness measurements was performed on a low activation Fe-9Cr-2W steel (JLF-1) was obtained following bombardment of 4MeV nickel ions up to 1dpa with simultaneous deposition of helium ions at 0 to 100appm He/dpa in a temperature range of 573 to 873K. The obtained micro-hardness profiles corresponded to the expected hardness profiles. The increasing He/dpa ratio almost monotonically increased the micro-hardness at 673K and higher temperatures. However, the irradiation-induced micro-hardness changes were no more than 10 percent except for very limited cases. Isothermal annealing at temperature above 773K caused softening within a thin surface layer of the specimens and only small amount of helium prohibited the softening. 1