Titanium is allotrope

Titanium is allotrope, melting point 1668 ℃, showed a close-packed hexagonal lattice structure, called α titanium at temperatures below 882 ℃; body-centered cubic lattice structure at above 882 ℃ was called β titanium. The use of the different characteristics of the two titanium structures, adding appropriate alloying elements, so that the phase transition temperature and relative content of different tissues obtained by gradually changing the titanium (titanium alloys). At room temperature, there are three titanium matrix organization, titanium will be divided into the following three categories: α alloy, (α + β) alloys and β alloys.
α titanium
It is a single phase alloy consisting of α-phase solid solution, either at ambient temperatures or at higher temperatures the practical application, are the α phase, organizational stability, wear resistance higher than that of pure titanium, high resistance to oxidation. At a temperature of 500 ℃ ~ 600 ℃, and maintains its strength and creep resistance, but can not be heat strengthened, not high temperature strength.
β titanium screws
It is a single-phase alloy consisting of β-phase solid solution, that is not heat-treated after having a high strength, hardening, aging alloy has been further strengthened, the room temperature strength of up to 1372 ~ 1666 MPa; but poor thermal stability, and should not be used at high temperatures .