Effect of Ti addition on microstructural evolution of V-Cr-Ti alloys to balance irradiation hardening with swelling suppression

Transmission electron microscopy studies and nano-indenter tests were used to examine model alloys of V-4Cr-xTi (where x is less than 1 wt.%) that were irradiated in a nuclear reactor with neutrons and irradiated in an ion accelerator with He ions. Void formation resulted in V-4Cr-0.1Ti and 0.3Ti from 400 °C to 600 °C with a damage level of 21 dpa in neutron irradiation. No void formation was visible in V-4Cr-1Ti. A threshold concentration of void formation and Ti(CON) precipitate formation occurred for x = 0.3 wt.% to 1 wt.% in the V-4Cr-xTi alloy. Void formation and Ti(CON) precipitation competed in neutron irradiation as caused by vacancy migration depending on the concentration of the added Ti in the V-4Cr-xTi alloy. A study of the He-ion irradiation indicated the same competitive process of void formation and Ti(CON) precipitate formation depending on the added Ti concentration.