Advantages Of Titanium

Titanium alloy has the following advantages over other metal materials.
① than the strength (tensile strength / density) high (see chart), tensile strength of up to 100 ~ 140kgf/mm2, while the density of only 60% of steel.
② good strength at medium temperature, the use of temperature than the aluminium alloy a few hundred degrees higher, in the middle of the temperature can still maintain the required strength, can be in the temperature of 450 ~ 500 ℃ long-term work.
③ good corrosion resistance, the surface of titanium in the atmosphere immediately form a uniform and dense oxide film, the ability to resist a variety of media erosion. Usually titanium has good corrosion resistance in oxidising and neutral media, and the corrosion resistance in seawater, wet chlorine gas and chloride solution is even better. But in reducing media, such as hydrochloric acid and other solutions, titanium's corrosion resistance is poor.
④ good low-temperature performance, very low gap element titanium alloy, such as TA7, in -253 ℃ can maintain a certain degree of plasticity.
⑤ Low modulus of elasticity, small thermal conductivity, no ferromagnetism.
6. High hardness.
7. Poor stamping, good thermoplasticity.
Heat treatment Titanium alloys can obtain different phase compositions and organisations by adjusting the heat treatment process. It is generally believed that fine isometric organisation has better plasticity, thermal stability and fatigue strength; needle-like organisation has higher endurance strength, creep strength and fracture toughness; isometric and needle-like mixed organisation has better overall performance.

Commonly used heat treatment methods are annealing, solution and aging treatment. Annealing is to eliminate internal stresses, improve plasticity and organisational stability, in order to obtain a better overall performance. Usually α alloy and (α + β) alloy annealing temperature selected in (α + β) - → β phase transition point below 120 ~ 200 ℃; solution and aging treatment is from the high temperature region of the fast cooling, in order to get the martensite α ′ phase and the sub-stable β phase, and then in the medium temperature region to keep warm so that the decomposition of these sub-stable phases, to get the α phase or compounds and other small diffuse second phase of the point, to achieve the purpose of strengthening the alloy. The purpose of strengthening the alloy. Usually, the quenching of (α+β) alloy is carried out at 40～100℃ below the (α+β)-→β phase transition point, and the quenching of sub-stable β alloy is carried out at 40～80℃ above the (α+β)-→β phase transition point. The aging treatment temperature is generally 450～550℃. In addition, in order to meet the special requirements of the workpiece, the industry also uses double annealing, isothermal annealing, β heat treatment, deformation heat treatment and other metal heat treatment processes.