Fracture toughness and tensile behavior of ferritic-martensitic steels irradiated at low temperatures

Disk compact tension and sheet tensile specimens of the ferritic-martensitic steels F82H and Sandvik HT-9 were irradiated in the High Flux Isotope Reactor (HFIR) at 90 degrees C and 250 degrees C to neutron doses of 1.5-2.5 dpa. For both steels, radiation hardening was accompanied by a reduction in strain hardening capacity (SHC). When combined with other literature data it is apparent that severe loss of SHC occurs in F82H for irradiation temperatures below similar to 400 degrees C and in HT-9 for irradiation temperatures below similar to 250 degrees C. For both alloys, severe loss of SHC does not correlate with brittle behavior during fracture toughness testing. (C) 1998 Elsevier Science B.V. All rights reserved.