Properties of precipitation hardened steel irradiated at 323 K in the Japan materials testing reactor

A precipitation hardening type 630 stainless steel was irradiated in the Ja pan Materials Testing Reactor (JMTR) in contact with the reactor primary co olant. The temperature of the irradiated specimens was about 330 K,The fast neutron (E > 1 MeV) fluence for the specimens ranged from 10(24) to 10(26) m(-2). Tension tests and fracture toughness tests were carried out at room temperature, while Charpy impact tests were done at temperatures of 273-45 3 It. Tensile strength data showed a peak of 1600 MPa at around 7 x 10(24) m(-2), then gradually decreased to about 1500 MPa at 1.2 x 10(26) m(-2). Th e elongation decreased with irradiation from 12% for unirradiated material to 6% at 1.2 x 10(26) m(-2) The fractography after the tension test reveale d that the fracture was ductile. Fracture toughness decreased to about a ha lf of the value for unirradiated material with irradiation. The cleavage fr acture was dominant on the fractured surface. Charpy impact tests showed an increase of ductile-brittle transition temperature (DBTT) by 60 K with irr adiation. (C) 1999 Elsevier Science B.V. All rights reserved.