Hardening and elemental segregation of T91 martenstic steel irradiated by 10 MeV Cl ions to doses from 0.06 dpa to 0.83 dpa were investigated with the nanoindentation technique and transmission electron microscopy(TEM).The results demonstrated that the irradiation hardening was closely related with irradiation dose.By increasing the dose,the hardness increased rapidly at first from the initial value of 3.15 GPa before irradiation,and then tended to saturate at a value of 3.58 GPa at the highest dose of 0.83 dpa.Combined with TEM observation,the mechanism of hardening was preliminary attributed to the formation of M(Fe,Cr)_(23)C_6 carbides induced by the high energy Cl-ion irradiation.
