Tensile properties of the NLF reduced activation ferritic/martensitic steels after irradiation in a fast reactor spectrum to a maximum dose of 67 dpa

The NLF series of steels are reduced activation ferritic-martensitic (RAFM) steels that are a part of the Japanese program to produce a suitable reduced activation ferritic-martensitic steel for the ITER project. Published reports on the NLF steels after about 35 dpa at 400 degrees C by Kurishita et al., indicate that these steels have similar strength and better ductility than other RAFM steels such as the JLF steels and F82H irradiated at 400 degrees C to similar doses. The tensile properties of NLF steels irradiated at similar to 400 degrees C to doses as high as 67 dpa are presented here. Tensile tests were conducted at a strain rate of 5 x 10(-4) s(-1) at 25, 400 degrees C, and 500 degrees C. Variations in irradiation temperature in the range of 390-430 degrees C had a relatively small, but definite effect on the tensile properties for tests conducted at 25, 400, and 500 degrees C. The strongest hardening is observed for specimens irradiated at 390 degrees C, and very little hardening is observed for specimens irradiated at 430 degrees C. Strain rate jump tests were performed on NLF-0 and NLF-1 at 400 degrees C after irradiation to 52 dpa. The rate sensitivity, m, is quite low, 0.003-0.005 and does not appear to be affected by irradiation at 52 dpa for an irradiation temperature of 430 degrees C. (c) 2005 Published by Elsevier B.V.