Properties of titanium----High strength: 1.3 times of aluminum alloy, 1.6 times of magnesium alloy, 3.5 times of stainless steel, the champion of metal materials.
High thermal strength: the use temperature is several hundred degrees higher than aluminum alloy, and it can work for a long time at a temperature of 450 ~ 500°C.
Good corrosion resistance: acid resistance, alkali resistance, atmospheric corrosion resistance, pitting corrosion, stress corrosion resistance is particularly strong.
Good low temperature performance: Titanium alloy TA7 with very low gap elements can maintain a certain plasticity at -253°C.
High chemical activity: high chemical activity at high temperature, easily react with gas impurities such as hydrogen and oxygen in the air to generate a hardened layer.
The thermal conductivity is small, the elastic modulus is small: the thermal conductivity is about 1/4 of nickel, 1/5 of iron, 1/14 of aluminum, and the thermal conductivity of various titanium alloys is about 50% lower than the thermal conductivity of titanium. The elastic modulus of titanium alloy is about 1/2 that of steel.
Titanium alloys can be divided into: heat-resistant alloys, high-strength alloys, corrosion resistant alloys (titanium-molybdenum, titanium-palladium alloys, etc.), low-temperature alloys and special functional alloys (titanium-iron hydrogen storage materials, titanium-nickel memory alloys). Although the history of titanium and its alloys is not long, it has won a number of honorable titles because of its extraordinary properties. First won the title is "space metal", it is light weight, specific strength and high temperature resistance, especially suitable for the manufacture of aircraft and various spacecraft. At present, about three-quarters of the world's production of titanium and titanium alloys are used in the aerospace industry. Many parts originally made of aluminum alloy have been converted to titanium alloy.
Titanium alloy is mainly used in aircraft and engine manufacturing materials, such as forged titanium fans, compressor discs and blades, engine covers, exhaust devices and other parts of the aircraft girder frame and other structural frame. The spacecraft mainly uses the high specific strength, corrosion resistance and low temperature resistance of titanium alloy to manufacture various pressure vessels, fuel tanks, fasteners, instrument straps, frames and rocket shells. Artificial Earth satellites, lunar modules, manned spacecraft and space shuttles also use titanium alloy plate welds.
