Tensile Properties of 2-1/4Cr-1Mo Steel Irradiated to 23 Dpa at 390 to 550 deg C

摘要

The effect of neutron irradiation on the tensile properties of normalized-and-tempered 2-1/4Cr-1Mo steel was determined for specimens irradiated to 23 dpa in the Experimental Breeder Reactor II (EBR-II) at 390, 450, 500, and 550 deg C. Two types of unirradiated control specimens were tested: as-heat-treated specimens and as-heat-treated specimens thermally aged for 10,000 h at the irradiation temperatures. Aging caused a loss of strength at all four temperatures. Irradiation at 390 deg C increased the strength and decreased the ductility compared to the control specimens. At 500 and 550 deg C, softening occurred relative to the thermally aged specimens, with the amount of softening greatest at 550 deg C. At 450 deg C, the strength of the irradiated specimens was similar to a specimen aged 10,000 h at 450 deg C. The changes in tensile properties result from the displacement damage caused by the irradiation and by irradiation-induced changes in carbide precipitates that occur during elevated-temperature exposure. (ERA citation 10:042402)