This metal is indispensable in aviation, aerospace, navigation, medical and other fields, and enjoys the reputation of "future metal" and "space metal".
The American SR-71 Blackbird is famous for its unparalleled altitude and speed. It has set a speed record of 3529.56 kilometers per hour and an altitude record of 25929 meters. But many people do not know that the development and construction of this aircraft has also promoted the progress of human materials science.
When flying at high speed, the surface of the aircraft will rub violently with the air and produce a lot of heat, and the faster the speed, the higher the heat. Aluminum alloy is a commonly used material in the manufacture of aircraft, but it has poor heat resistance and may lose its strength at 150 degrees Celsius. Flying at 3 times the speed of sound, the surface temperature of the aircraft exceeds 300 degrees Celsius, far exceeding the bearing limit of aluminum alloy, seriously affecting flight safety.
Therefore, the creation of "Blackbird" requires new materials with high hardness, high melting point and light weight. After a large number of experiments, a metal came into the eyes of engineers, that is titanium.
In order to meet the performance requirements, the amount of titanium alloy on each Blackbird is fully 30 tons, which exceeds 90% of the total structural weight of the aircraft. So far, no other aircraft has been able to reach this ratio, so some people call "Blackbird" a "pure titanium plane".
In the field of navigation, in the process of "moving towards deep blue", human beings have higher and higher requirements for warship equipment, and traditional metal materials have been unable to fully meet the demand.
At this time, titanium also entered the field of vision of engineers, they found that titanium is not only extremely resistant to seawater corrosion, but also excellent impact resistance. Nowadays, titanium is recognized as a promising metal material in the field of navigation equipment, and it is widely used in surface warships, underwater submarines, deep submersibles, underwater weapons and other fields.
Titanium is widely distributed in the earth's crust and rocks, and also exists in almost all living things and water bodies. Its abundance in the continental upper crust reaches 0.44%, ranking ninth among all elements, much higher than common metals such as zinc and copper.
The reason why titanium is precious mainly lies in the complex smelting process and high processing cost. Titanium is active in nature, easy to react with oxygen at high temperature, and must be smelted in vacuum or in an environment full of inert gas. In addition, titanium smelting needs electrolysis and heating for many times, which will consume a lot of energy.