1. Excellent corrosion resistance
The dullness of titanium depends on the presence of oxide film, and its corrosion resistance is much better in oxidizing medium than in reducing medium, where high rate corrosion can occur.Titanium is protected from corrosion in corrosive media such as seawater, wet chlorine, chlorite and hypochlorite solutions, nitric acid, chromic acid, metallic chlorides, sulfides and organic acids.However, in the media that react with titanium to produce hydrogen, such as hydrochloric acid and sulfuric acid, titanium usually has a higher corrosion rate.But if you add a small amount of oxidizer to the acid, the titanium will form a passivating film.So titanium is corrosion resistant in sulfur-nitric acid or hydrochloric-nitric acid mixtures, and even in hydrochloric acid with free chlorine.Titanium's protective oxide film is often formed when the metal encounters water, even in the presence of small amounts of water or water vapor.If exposed to a strong oxidizing environment with no water at all, titanium can undergo rapid oxidation and produce violent, often spontaneous combustion reactions.Titanium reacts with fuming nitric acid containing excess nitrogen oxide and titanium with dry chlorine gas.To prevent such a reaction, however, a certain amount of water must be present.
2. Good heat resistance
Usually aluminum at 150℃, stainless steel at 310℃ lost the original high mechanical properties, while titanium alloy at 500℃ still maintain good mechanical properties.When the aircraft speed reached 2.7 times of the speed of sound, the surface temperature of the aircraft mechanism reached 230℃, aluminum alloy and magnesium alloy could not be used, while titanium alloy could meet the requirements.Titanium has good heat resistance and is suitable for the turbine disc and blade of the aero-engine compressor and the skin of the rear fuselage of the aircraft.
3. Good low temperature performance
The strength of some titanium alloys (such as ti-5 al-2.5 SnELI) increases with the decrease of temperature, but the plasticity decreases little. It still has good ductility and toughness at low temperature, which is suitable for use at ultra-low temperature.Can be used in liquid hydrogen, liquid oxygen rocket engines, or in the manned spacecraft to make cryogenic containers and tanks.
Titanium is non-magnetic. It is used in submarine shells and does not cause mine explosions.
5. Low anti-damping performance
Clocks of exactly the same shape and size are made of titanium and other metal materials (copper, steel). If you strike each bell with the same force, you will find that the bells made of titanium vibrate for a long time, that is, the energy given to the clock by striking is not easy to disappear.
6. Shape memory function
Ti-50%Ni (atomic fraction) alloy, at a certain temperature, it has the ability to restore its original shape, so it is called titanium shape memory alloy.
When the temperature of NbTi alloy falls to near absolute zero, the wire made of NbTi alloy will lose its resistance and can make arbitrarily large current pass through. The wire will not get hot and there is no energy consumption, so NbTi alloy is called superconducting material.
8. Hydrogen absorption function
Ti-50%Fe(atomic fraction) alloy, capable of absorbing hydrogen in large quantities.This feature of the ti-fe alloy allows hydrogen to be safely stored, that is, hydrogen is not necessarily stored in steel high-pressure cylinders.Under certain conditions, the hydrogen can also be released by the hydrogen storage ti-fe alloy, so it is called the hydrogen storage material.