Defect microstructure and deformation behavior of V–Ti–Cr–Si–Al–Y alloy irradiated in ATR

Low-temperature irradiation performance of vanadium alloys, especially after neutron irradiation below 400°C, is a major concern. Defect microstructures and deformation behavior of V–Ti–Cr type alloys containing small amounts of Si, Al and Y after neutron irradiation below 400°C were studied. Neutron irradiation was conducted in the advanced test reactor (ATR) to fluences of 0.7–4.7 displacements per atom (dpa) at temperatures from 141°C to 293°C. A large amount of hardening was observed in the specimens irradiated at 290°C or below, which corresponded to a high density of small dislocation loops. The density and the size of loops depended on the irradiation temperature and the pre-irradiation annealing temperature. The loops in the specimen annealed at 900°C had a lower density and a larger size than those annealed at 1000°C and 1100°C. The specimen annealed at 900°C showed very small hardening and retained good work-hardening capability after irradiation at 290°C.