Effects of low temperature neutron irradiation on deformation behavior of austenitic stainless steels

Two experiments have been conducted to quantify the effects of neutron irradiation on the deformation and fracture behavior of solution annealed austenitic stainless steels irradiated to doses ranging from 3 to 19 dpa at temperatures from 60 to 400 degrees C. For all alloys, yield strength increases rapidly with dose in the 60-300 degrees C regime. Radiation hardening is accompanied by changes in the flow properties with the appearance of an initial yield drop and a significant reduction in strain hardening capacity. The magnitude of the changes is dependent upon both neutron dose and irradiation temperature, with reductions in strain hardening capacity occurring most rapidly in the range 250-350 degrees C. It is shown that for neutron doses up to about 3 dpa, although the changes in deformation mode reduce the fracture toughness, the toughness remains satisfactorily high.