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

Highlights: • 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. • Following neutron irradiation, void formation was visible in V4Cr0.1Ti and 0.3Ti from 400 to 600°C with a damage level of 21 dpa. No void formation was visible in V4Cr1Ti. In the V4Cr1Ti alloys, Ti(CON) precipitate formation was dominant under all experimental conditions • A threshold concentration of void formation in Ti(CON) precipitate formation exists for x = 0.3 wt.% to 1.0 wt.% in the V–4Cr–xTi alloy. - Abstract: 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.