Effect of two-steps heat treatments on irradiation hardening in F82H irradiated at 573 K

Ando, Masami; Tanigawa, Hiroyasu; Wakai, Eiichi  ; Stoller, R. E.*

Radiation hardening and embrittlement due to neutron irradiation around 573 K are the important issues on RAF/M steels. It is expected that the improvement of radiation hardening might be one of effective ways to control the mechanical properties after irradiation. The purposes of this study are to find the condition of heat treatment for minimum of radiation hardening in F82H steel using Neutron/Ion-irradiation and to examine a correlation between tensile property and micro-hardness before/after irradiation. Neutron irradiation was performed in HFIR up to 9 dpa. Ion-irradiation at 573 K was carried out at the TIARA facility of JAEA. For the results of tensile test and hardness test of F82H and F82H heat treatment variants neutron-irradiated at 573 K, all specimens caused radiation hardening. The radiation hardening (H) obtained by hardness test is almost same level, however radiation hardening (YS) of F82H heat treatment variants is smaller than that of F82H.