High intensity
The density of titanium alloys is generally around 4.51g/cm3, which is only 60% of steel, and some high-strength titanium alloys exceed the strength of many alloy structural steels. Therefore, the specific strength (strength/density) of titanium alloy is much greater than that of other metal structural materials, and parts with high unit strength, good rigidity and light weight can be produced. Titanium alloys are used in the engine components, skeletons, skins, fasteners and landing gear of aircraft.
High thermal intensity
The use temperature is hundreds of degrees higher than that of aluminum alloy, and it can still maintain the required strength at medium temperatures, and can work for a long time at a temperature of 450~500 °C. These two types of titanium alloys still have a high specific strength in the range of 150 °C~500 °C, while the specific strength of aluminum alloy decreases significantly at 150 °C. The operating temperature of titanium alloys can reach 500°C, while aluminum alloys can reach below 200°C.
Good corrosion resistance
Titanium alloy works in humid atmosphere and seawater medium, and its corrosion resistance is much better than that of stainless steel, and its resistance to pitting, acid etching, and stress corrosion is particularly strong, and it has excellent corrosion resistance to alkali, chloride, chlorine organic matter, nitric acid, sulfuric acid, etc. However, titanium has poor corrosion resistance to reducing oxygen and chromium salt media.
Good low-temperature performance
Titanium alloys can still maintain their mechanical properties at low and ultra-low temperatures. Titanium alloys with good low-temperature properties and very low interstitial elements, such as TA7, can maintain a certain plasticity at -253 °C. Therefore, titanium alloy is also an important low-temperature structural material.
Chemically active
Titanium has great chemical activity and produces strong chemical reactions with O2, N2, H2, CO, CO2, water vapor, ammonia, etc. in the atmosphere. When the carbon content is greater than 0.2%, hard TiC will be formed in the titanium alloy, and when the temperature is high, the hard surface layer of TiN will also be formed by the interaction with N, and when the carbon content is above 600°C, titanium will absorb oxygen to form a hardened layer with high hardness, and a brittleness layer will also be formed when the hydrogen content increases. The depth of the hard and brittle surface layer produced by gas absorption can reach 0.1~0.15 mm, and the degree of hardening is 20%~30%. Titanium also has a high chemical affinity, and it is easy to adhere to friction surfaces.