Superelasticity in Ti–10V–2Fe–3Al alloys with nitrogen addition

Metastable β titanium alloy Ti–10V–2Fe–3Al is known to exhibit a shape memory effect due to a stress-induced α″ martensitic transformation at room temperature. In the present study, nitrogen (N) was added to this alloy to strengthen the β matrix. The effect on the deformation behavior of β phase was studied. Thermally induced martensite is formed in the N-free alloy by quenching after β solutionizing but it is not observed in the alloys containing nitrogen of more than 0.1 mass%. Superelasticity due to stress-induced formation of α″ martensite was observed in the 0.1 and 0.2N alloys. N addition is moreover effective in increasing a true elastic strain up to 1% by strengthening of the β matrix.