Effects of neutron irradiation on vanadium-base alloys

Abstract

Abstract Vanadium-base alloys of the V-Cr-Ti-Si system are attractive candidates for use as structural materials in fusion reactors. The vanadium-base alloys exhibit relatively low long-term activation, irradiation induced afterheat and neutron-induced helium transmutation rates. Because of favorable physical properties these alloys can accommodate higher surface heat fluxes than the steels. The current focus of the U. S. program is on V-(0–10%)Cr-(0–5%)Ti-(0–1%)Si alloys. In this paper we present experimental results on the swelling, microstructure, and mechanical properties of selected alloys after irradiation in fission reactors to displacement damages of up to 125 dpa. Titanium additions of 3–5 wt.% are highly effective in reducing swelling. The effects of Si and nonmetallic elements (O, N and C) on the swelling and microstructure are presented. Two types of irradiation induced precipitates have been identified in alloys containing Ti; Ti2O and Ti5Si3. Swelling is strongly influenced by the precipitat...