Hardening mechanisms of reduced activation ferritic/martensitic steels irradiated at 300 °C

It has been reported that reduced-activation ferritic/martensitic steels (RAFMs), such as F82H, ORNL9Cr-2WVTa, and JLF-1 showed a variety of changes in ductile-brittle transition temperature and yield stress after irradiation at 300 degrees C up to 5 dpa, and those differences could not be interpreted solely by the difference of dislocation microstructure induced by irradiation. In this paper, various microstructural analyses on low-temperature irradiated RAFMs were summarized with the emphasis on F82H, and a possible mechanism for the irradiation hardening was suggested. The possible contribution of dislocation channeling structure and back stress were indicated. (C) 2009 Elsevier B.V. All rights reserved.