'Super steel' with high strength, ductility developed

In a breakthrough, scientists have developed a steel with a high level of both strength and ductility that may have a wide range of industrial applications. The material cost of the steel is just one-fifth of that used in the current aerospace and defence applications, researchers said. The steel belongs to the group of medium manganese steel that contains 10 per cent manganese, 0.47 per cent carbon, 2 per cent aluminium and 0.7 per cent vanadium, they said.

Strength and ductility - when a solid material stretches under stress - are desirable properties of metallic materials for wide-ranging applications. However, increasing strength often leads to the decrease in ductility, researchers said. To address the problem, the team led by Huang Mingxin from the University of Hong Kong used a new manufacturing technique called deformed and partitioned (D&P).

In a study published in the journal Science, researchers noted that it is very difficult to further improve the ductility of metallic materials when their yield strength is beyond two Gigapascal (GPa), Xinhua news agency reported. 

They made "a successful attempt in realising the dream" as the newly developed method yields a "breakthrough steel" that has the "unprecedented" yield strength of 2.2 GPa and uniform elongation of 16 per cent. "The D&P steel demonstrated the best combination of yield strength and uniform elongation among all existing high- strength metallic materials," researchers, including those from University of Science and Technology Beijing, said.

The uniform elongation of the new steel is much higher than that of metallic materials with yield strength beyond 2.0 GPa, they said.