Titanium alloy is a new important structural material used in the aerospace industry. Its specific gravity, strength and working temperature are between aluminum and steel, but its strength is higher than aluminum and steel, and it has excellent seawater corrosion resistance and ultra-low temperature performance. In 1950, the United States first used the f-84 fighter bomber as the rear fuselage heat shield, wind shield, tail cover and other non-bearing components. Since the 1960s, the use of titanium alloys has shifted from the rear fuselage to the mid-fuselage, partially replacing structural steel to make heat-insulating frames, beams, flap slide rails and other important bearing components.
The use of titanium alloys in military aircraft is rapidly increasing, reaching 20% to 25% of the weight of the aircraft structure. Since the 1970s, civil aircraft began to use a large amount of titanium alloys, such as the Boeing 747 with more than 3640 kg of titanium alloys. Aircraft with a Mach number greater than 2.5 mainly use titanium instead of steel to reduce structural weight, such as the US SR-71 high-altitude high-speed reconnaissance aircraft (Flying Mach 3 at an altitude of Mach 3,212), titanium accounts for 93% of the weight of the aircraft’s structure and is called an “all-titanium” aircraft. The proportion of aero engines has increased from 4~6 to 8~10, and the compressor outlet temperature has increased from 200~300°C to 500~600°C.
Therefore, titanium alloy must be used instead of aluminum low-pressure compressor discs and blades, or use Titanium alloy replaces stainless steel to make high-pressure compressor discs and blades to reduce structural weight.
In the 1970s, the content of titanium alloy in aero engines usually accounted for 20% to 30% of the total structural weight, and was mainly used to manufacture compressor parts, such as forging Titanium fans, compressor discs and blades, cast titanium compressor casings, intermediate casings, bearing boxes, etc.
Titanium alloy plates with high specific strength, corrosion resistance and low temperature resistance are used to manufacture various pressure vessels, fuel tanks, fasteners, instrument belts, frames and rockets. Titanium alloy plates are also used for welding satellites, lunar modules, manned spacecraft and space shuttles.