In recent times, there has been a lot of discussion about the C919 large aircraft and the domestic aviation engine. Especially after some detailed data about the turbofan engine and CJ2000 engine were released, many enthusiasts were very excited. There is no doubt that our development in aviation development is getting faster and faster.
For aero engines, blades are one of the cores, because the blades need to work in the harsh environment of high temperature, high pressure and strong centrifugal force, which means that the blades need to be more stable. The most important thing is that the blades must not only not break when working, but also must not have any misalignment. Therefore, blades generally need to have excellent heat resistance, corrosion resistance, vibration resistance and other characteristics.
The engine is operating at extremely high temperatures, and it can be said that many common metals are difficult to maintain without deformation at this temperature. In the case of the F119 engine, the temperature at the vortex front reaches 1703 degrees Celsius, and the blades need to be made of special metal materials to maintain operation in such high temperatures.
Tungsten has a melting point of 3422 degrees Celsius, which can fully meet this temperature, but basically tungsten alloy is rarely used as engine blade material. In fact, although tungsten has a high melting point, it is easy to undergo a series of reactions with oxygen at high temperatures, resulting in changes in metal properties, and it is also easy to rust and produce various gases.
It is precisely for this reason that tungsten is also used in engine blades, but it is not so widely used, but rhenium with a lower melting point is used as a more commonly used engine blade material.
In fact, rhenium itself is also a high-temperature resistant material, and there is not much difference between its melting point and tungsten, reaching 3186 degrees Celsius, which is actually far more than the temperature of the engine when it is working. The most important thing is that rhenium also has excellent performance in other aspects, such as being able to resist the pull-up of 1172Mpa, and it rarely occurs thermal expansion and contraction. You must know that the temperature of the engine is as high as 1,000 degrees when it is running, but when it stops working, the temperature will gradually cool down until it returns to room temperature.
This also means that there will be a large degree of difference in the temperature of the engine, in which case the general material is prone to deformation in various situations.
After all, many materials will undergo thermal expansion and cold contraction, but the shape will not be completely restored after expansion and contraction. The most important thing is that the service life of the engine is still relatively long, and if the blades often need to be replaced, it is easy to affect the life of the engine.
It is for this reason that although high temperature resistance is important for engine blades, other deformation resistance properties are also very important. If the engine blades deform during use, they may even cause friction against the receiver which can cause a fire and an explosion.
As the core of the aerospace field, the manufacturing threshold of the engine is very high, not only because of the high technical difficulty, but also because of the need for a large number of material technology to support. Some good materials can even make the engine more durable, or have better performance.
It is precisely because of this that there are not many countries in the world that can independently develop and produce aviation engines, and it can even be said that many countries cannot even produce rhenium alloys.
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