Precipitation behavior in V–6W–4Ti, V–4Ti and V–4Cr–4Ti alloys

The cold rolled V–6W–4Ti, V–4Ti and V–4Cr–4Ti alloys were annealed at 900 and 1100 °C for recrystallization and solid solution, respectively. Large precipitates were found in the 900 °C annealed ones with main difference in the number density among the alloys. Followed the heat treatments, the alloys were annealed again at 400–900 °C for 1 h or aged at 600–800 °C for durations up to 50 h. Precipitation hardening was found in solid solution treated alloys after the annealing below 900 °C and after the aging at 600 °C. The precipitates are Ti and C-rich ones, without the enrichment of W in the V–6W–4Ti alloy. Results showed that the growth of the precipitates was controlled by the diffusion of interstitial solutes of C, N and O. V–4Cr–4Ti showed much stronger precipitation hardening than the others due to Cr addition.