A titanium alloy contains vanadium, from 10 to 20% by weight; aluminum,
from 0.2 to 10% by weight; and a balance essentially titanium, and the
alloy has a microstructure including a martensite phase. Alternatively,
the titanium alloy contains vanadium, from 10 to 20% by weight; aluminum,
from 0.2 to 10% by weight; and a balance essentially titanium, and the
alloy has a microstructure including a .beta. phase capable of
transforming into a martensite phase by cold working or cooling under a
room temperature.