Fellow Engineer, Westinghouse Hanford Company, Richland, Wash.
Pages: 17 Published: Jan 1984
The effect of fast-neutron irradiation on the fracture toughness behavior of Alloy A-286 was characterized at 24 and 427°C using linear-elastic KIc and elastic-plastic JIc fracture mechanics techniques. The fracture toughness was found to decrease continuously with increasing irradiation damage at both test temperatures. In the unirradiated and low fluence conditions, specimens displayed appreciable plasticity prior to fracture, and equivalent KIc-values were determined from JIc fracture toughness results. At high irradiation exposure levels, specimens exhibited a brittle KIc fracture mode. The 427°C fracture toughness fell from 129 MPa√m in the unirradiated condition to 35 MPa√m at an exposure of 16.2 dpa (total fluence of 5.2 × 1022 n/cm2). Room-temperature fracture toughness values were consistently 40 to 60% higher than the 427°C values. Electron fractography revealed that the reduction in fracture resistance was caused by a fracture mechanism transition from ductile microvoid coalescence to channel fracture.
fracture (materials), fracture toughness, J, -integral, neutron irradiation, elevated-temperature tests, fractography, fracture mechanism transition, Alloy A-286
Paper ID: STP32571S