Why Do We Have To Use Titanium Alloys For Aerospace Materials?
Titanium alloy is mainly used in aircraft and engine manufacturing materials, such as forging titanium fans, compressor disks and blades, engine hoods, exhaust equipment and the Kaifeng frame and other structural components of aircraft. The high specific strength, corrosion resistance and low temperature resistance of titanium alloy are used to manufacture various pressure vessels, fuel tanks, fasteners, instrument straps, frames and rocket shells. Titanium plate welds are also used in artificial earth satellites, lunar modules, manned spacecraft and space shuttles.
In 1950, the F-84 fighter-bomber was first used titanium alloy to make a rear body heat shield, wind shield, tail cover and other non-load-bearing components. Since the 1960s, titanium alloy has been used to replace structural steel in some important load-bearing components, such as diaphragm, beam and flap slide rail, from the rear fuselage to the middle fuselage. Since the 1970s, titanium alloys have been widely used in civil aircraft, such as Boeing 747 aircraft, which use more than 3,640 kg of titanium, accounting for 28% of their weight. With the development of processing technology, a lot of titanium alloys are used in rockets, satellites and spaceships.
The more advanced the aircraft, the more titanium is used. The titanium alloy used in the F-14A fighter accounts for about 25% of the weight of the aircraft, the F-15a fighter accounts for 25.8% , the fourth-generation fighter uses 41% titanium, and the F-119 engine uses 39% titanium, is currently the highest amount of titanium used in the aircraft.
The top speed of modern aircraft is more than 2.7 times the speed of sound. Such a fast supersonic flight will cause the aircraft and air friction and produce a lot of heat. When the speed of flight reaches 2.2 times the speed of sound, the aluminum alloy can not stand, and high temperature resistant titanium alloy must be used. When the thrust-weight ratio of the aero-engine increases from 4-6 to 8-10, the outlet temperature of the compressor correspondingly increases from 200-300 ° C to 500-600 ° C, the low-pressure compressor disks and blades made of aluminum have to be made of titanium alloy.
In recent years, new progress has been made in the study of the properties of titanium alloys. The maximum working temperature of the original TI-AL-V alloy is 550 ° C ~ 600 ° C, while that of the newly developed TiAl alloy has been increased to 1040 ° C. High-pressure compressor disks and blades made of titanium alloy instead of stainless steel can reduce structural weight. For every 10% weight loss, the aircraft can save 4% of fuel. For a rocket, every 1kg of weight lost adds 15km of range.
