Effects of heavy-ion irradiation on microstructure of V-4Cr-4Ti alloy at moderate temperatures

V-4Cr-4Ti is promising for first-wall and structural applications in magnetic fusion reactors. Fast neutron sources were used to evaluate postirradiation properties of fusion candidate materials, but FFTF and EBR-II have been shutdown. Under these circumstances, heavy-ion irradiation is an attractive alternative. We used 3-MeV V+ and 4.5-MeV Ni2+ ions to investigate effects of irradiation on microstructure of V-4Cr-4Ti at 200-420 C. This paper report results of ion irradiation experiments and compare with fast-neutron irradiation data. From TEM, the dominant feature of postirradiation microstructure was a high density of dislocation loops and point- defect clusters. Density and defect size depend on irradiation dose and temperature. Precipitates and voids/bubbles were not observed, even in specimens simultaneous injected with he and exposed to heavy ions. Increased transport of point defects to internal interfaces was observed, as manifested by defect denuded zones along grain boundaries. Defect denuded zones along grain boundaries could lead to segregation of impurities and solutes and formation of precipitates on grain boundaries