At Mach 5 (3,836 mph), a hypersonic vehicle enters a dense atmospheric layer, the ambient gas undergoes not only density change, but also a significant temperature increase. This physical-chemical reaction is associated with the flight speed is converted into heat and chemical energy, which is a considerable heat barrier that had researchers around the world scrambling for new materials that could withstand temperatures far higher than the melting point of metal.
It seems that researchers in central China, studying hypersonic heat transfer, a subdivision of aerodynamics that studies gas motion laws, have developed a non-carbon-based heat-resistance material for hypersonic flight, according to the Global Times.
The lead scientist, Fan Jinglian from Central South University in Central China's Hunan Province, developed a composite of ceramics and refractory metals that can endure hypersonic flight at Mach 5-20 within the atmosphere for several hours, or temperatures of about 5,400 Fahrenheit.
Jinglian said the composite of ceramics and refractory metals makes the new material far more superior to Western technologies that use "traditional refractory metals and carbon-carbon materials."
She said the composite is like concrete cobble.
"Think of the ceramics as the cobblestones, or the pellets, and the refractory metals are like the concrete. In high temperatures, the ceramics will act as pellets that pin the refractory metals, so they will not soften and deform."
As a result, the material has a melting point higher than metal, but also important characteristics such as low density and high malleability, according to the Hunan Television report.
As of March, the composite has been used in aviation, space exploration, shipbuilding, and national defense products, Hunan Television said.
Over the past two decades, China has made enormous progress in upgrading its military capabilities. China launched its hypersonic program in 2009, and by 2014, began testing an experimental hypersonic glide vehicle - that could be operational by 2020.
We reported last month that Xiamen University, a public university in Xiamen, Fujian on China's southeast coast, successfully tested a hypersonic missile in Northwestern China.
Unlike American hypersonic rockets such as Boeing's X-51 Waverider, which rides on a hot layer of gas known as a "shock wave," the Jiageng-1 No.1 rides on two layers of shock waves, one underneath the rocket and the other in the air intake of its ramjet engine.
The Jiageng-1 No.1 has several innovative advantages over Western hypersonic rockets: it can transition from supersonic to hypersonic speeds with ease, and the design produces more lift allowing it to travel further with more efficient fuel consumption.
Zhu Chengxiang, an assistant professor at the university's School of Aerospace Engineering and part of the hypersonic launch, said the Pentagon is deeply disturbed by China's rapid development of hypersonic vehicles and had tried to severe Chinese scientists' collaboration efforts with Western researchers.
A Weibo post by Xiamen University shows the hypersonic rocket in flight. The rocket flies throughout the Stratosphere with a maximum altitude of about 90,000 feet. During the test, the rocket performed as planned after making some maneuvers to "reproduce real flight conditions and conduct aerodynamic tests," then glided down and deployed a parachute to land safely on the ground.
Xiamen University Aerospace Academy with Beijing Lingkong Tianxing Technology Co., Ltd. successfully launched and recovered the reusable winged suborbital JiaGeng-1 technology tester rocket. (max alt 26.2Km)— LaunchStuff (@LaunchStuff) April 23, 2019
US Air Force Lt. Gen. Samuel Greaves, director of the Missile Defense Agency, said last year that he supports Undersecretary of Defense for Research and Engineering Michael Griffin's push to develop space-based sensors that would defend the nation from hypersonic attacks by America's adversaries [China and Russia].
"The hypersonic threat is real, it is not imagination," Lt. Gen. Greaves explained last summer at the Capitol Hill Club.
Griffin warned that the US could be falling behind in hypersonic arms race.
"In the last year, China has tested more hypersonic weapons than we have in a decade. We've got to fix that."
The new, groundbreaking composite material and the latest hypersonic missile test in China - exposes just how far the US is behind the curve.