Microstructural evolution and hardening effect of 12Cr2W2Mn ferritic/martensitic steel under Au-ions irradiation

The 12Cr2W2Mn ferritic/martensitic(F/M) steel was irradiated by 6 MeV Au ions at room temperature (RT) and 400 degrees C to the peak irradiation doses of 25 dpa and 54 dpa. XRD, nanoindentation and TEM tests were carried out to investigate the microstructural evolution and hardening effect of 12Cr2W2Mn F/M steels. The results demonstrated that a large number of defects such as dislocation walls, dislocation tangles and voids were introduced in 12Cr2W2Mn F/M steels by Au-ions irradiation. The void density increased with the increasing irradiation dose and the void size increased with the increasing irradiation temperature. The void density and average void size were 4.17 x 10(21) m(-3) and 3.92 nm respectively for the sample irradiated at 400 degrees C and 54 dpa. Irradiation hardening was increased obviously with the increasing irradiation dose at RT, meanwhile, the hardening effects decreased with the increasing irradiation dose at 400 degrees C. The hardness of 12Cr2W2Mn F/M steel is found to depend strongly on irradiation temperature, the irradiation hardening recovered partly with the increasing irradiation temperature. Moreover, the amorphization of M23C6 carbides were found in the sample irradiated at 400 degrees C and 25 dpa. (C) 2020 Elsevier B.V. All rights reserved.