Ceramics is easy to break and aluminum is easy to bend — or so many people believe.
But a team at Shanghai Jiao Tong University announced yesterday that after nearly 30 years of research they had blended the two materials together to create a new substance with a strength and rigidity that is even stronger than titanium alloy.
The composite called "alumics‚" is now being tested in C919 jets and Geely automobiles, and is expected to help industries like aviation, automobile and high-speed rail develop into a new era of lighter and more energy-saving products.
Aluminum is one of the most commonly used light metals because of its tenacity and aluminum alloy has been incorporated into handsets and computers to make them light and portable.
But aluminum is easily bent. To make it stiffer, researchers have tried adding ceramics.
"Ceramics is fragile in many people's mind, but its rigidity is actually even better than steel," said Wang Haowei, a professor at Jiao Tong's School of Material Science and Engineering who leads the alumics team.
A method commonly across the world is to make particles or fibers out of ceramics and then add them into the aluminum alloy.
This does add strength and rigidity to the materials, but the particles are large and the blended materials show difficulty in molding, low strength, poor plasticity and unstable quality, which keep them away from industrial application, according to Wang.
"Since it's not a feasible way, we thought up a new method — growing ceramics in aluminum to create a nanometer material," he said.
Their work follows a method initiated 25 years ago by Wu Renjie, founder of the university's State Key Laboratory of Metal Matrix Composites.
"In metal metallurgy, nonmetal things are usually treated as impurities and should be get rid of," said Wang. "But we found in our researches that they can also play favorable roles if we control the sizes, shapes and distribution of these particles by controlling chemical reaction process."
Synthesized by a melt reaction composition, the aluminum-ceramics composites causes the ceramics particles to be reduced to a nanometer level to break through the bottlenecks of poor plasticity and processing difficulty.
The new composites are light, strong, rigid, heat-resistant and anti-corrosive. Their strength and rigidness has proved to be better than titanium alloy.
The new material has been used in military and aerospace industries in recent years.
Wang said the material can help, for example, to reduce the weight of planes, cars, trains and bikes.
The team is cooperating with the Commercial Aircraft Corporation of China and AECC Commercial Aircraft Engine Co to apply alumics on China's domestically made planes, according to Wang.
Wu Guanghui, chief designer of China's self-developed jet C919 and deputy general manager of COMAC, said his company had found effective results in tests of sections made from alumics.
Wu, who helped name the new material, said aviation technology has developed as material development improved.
"Alumics is very suitable in making narrow-body jets like C919, while carbon fiber composites are more suitable for wide-body planes," said Wu.
On Friday, Jiao Tong signed a contract with the government of Huaibei City of Anhui Province, Shanghai Junyao (Group) Co and the Anhui Xiangbang Composite Co to establish an alumics innovation center to promote civil use of the material.