A new engine for hypersonic weaponsbuilt using technology the military didn’t think would work, has successfully completed its first test flights in China, the team behind said.
Scientists think it will help China accelerates large-scale production of hypersonic weapons at relatively low cost while maintaining high quality and performance.
They said a new method of manufacturing allowed them to make titanium alloy components that lab and real-world testing found far better than those made using traditional methods, enabling them to pass straight from the oven to the engine assembly line with no additional processing.
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The breakthrough will also pave the way for the development of more advanced components for hypersonic flight, Yin Zhongwei and colleagues from the Aerospace Research Institute of Materials and Processing Technology in Beijing wrote in a paper published in the Chinese language. Propulsion Technology Journal Last week.
The ramjet built by the team allows a missile or aircraft to travel at least five times the speed of sound.
The air intake, which is designed to protect the engine from turbulence that could extinguish burning fuel, is one of the largest and most important components, but it is difficult to manufacture.
The meter-long component has an irregular shape and many complex and delicate structures that must remain strong in an extreme environment. At the same time, it must be light and to achieve this, its walls are no thicker than two credit cards.
Previously, entrances were constructed from separate parts which were welded together and reprocessed, but this method is time consuming and expensive and the results vary widely in quality.
Yin and his colleagues took another approach known as near-net shaping hot isostatic pressing to produce the input, as well as other critical components.
The process involves placing a fine powder of titanium and rare earth elements into a steel mold from which air is pumped before being placed in a furnace filled with inert gas.
When heated, the gas expands and compresses the mold, pressing the titanium particles together and forcing them to crystallize and fuse together.
It takes about three hours of pressing to achieve a full entry using this technique, according to the team.
They also said it does not require additional processing because the surface is already smooth, adding that the method is four times more accurate than previous techniques.
The hot pressing method was first adopted in the United States in the 1950s to manufacture certain structural components of fighters such as the F-14.
A US Air Force report in 1989 concluded that hot isostatic pressing had potential for use in the production of hypersonic weapons and suggested that the government fund more investigation into the technology, but it did not. there have been no reports that it has been successfully used to build hypersonic weapons since then. .
China has used the method in aircraft and rocket production since the 1990s, but the military didn’t initially believe it could meet the extreme demands of hypersonic flight, the researchers say, because unexpected shortcomings, gas bubbles or polluting elements could occur during the process and weaken the product.
“There is a lack of confidence in components made with titanium powders,” Yin’s team complained in a separate paper published in the national journal Materials Reports in 2019, when an inlet was built but not flight tested.
A major challenge was to produce perfectly round grains of titanium powder of different sizes with rare earth elements, so that they could bond perfectly to each other.
Another problem was mold. Under high pressure, the steel canister can pass harmful elements into the component inside or leave scratches on the surface.
But Yin and his colleagues say those issues have largely been resolved, and they are now making improvements to allow the technology to be used for civilian purposes.
For example, the process used to make titanium frames for commercial passenger planes can waste up to 80 percent of the metal, but researchers believe technology can reduce that percentage to almost zero.
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