MICROSTRUCTURAL DEVELOPMENT IN IRRADIATED VANADIUM ALLOYS

Three simple vanadium alloys, V-5Al, V-1Ni, and V-2Ti-1Ni have been ex amined to determine the effects of fast neutron irradiation on microst ructural evolution. Specimens were irradiated in EBR II at temperature s in the range 425 to 600 degrees C to doses of 15 and 31 dpa. Each al loy responded very differently to irradiation. All V-5Al specimens wer e generally void-free and contained high densities of coherent precipi tates, and moderate densities of network dislocations. Swelling was mu ch higher in V-1Ni. Voids were uniformly distributed, but with widely varying shape and size. Precipitation of two types also developed. The response in V-2Ti-1Ni was intermediate to that of the other two alloy s. Irradiation produced extensive precipitation of thin rods and a mod erate density of large voids often associated with much larger precipi tate particles. The dislocation structure strongly interacted with the rod precipitate particles.