Researchers at Pohang University of Science and Technology, South Korea, report that they have developed a lightweight steel by uniformly dispersing nanometer-size intermetallic compounds between and within the steel’s grains. By adding nickel and heat treating an alloy of iron, aluminum, manganese, and carbon, they induced nanoparticles to form evenly throughout the steel. The photo shows that six specimens of the new steel weigh less than five specimens of conventional steel.
With this innovative approach, stronger and more ductile lightweight steels have been created, solving the longstanding problem of poor ductility caused by the formation of large brittle intermetallic compound particles. Besides being lightweight, this new steel possesses an excellent combination of strength and ductility.
The team plans to work with POSCO to produce its new product later this year, ushering in a new era of high-specific-strength steels that will be lightweight and strong enough to produce fuel-efficient vehicles and other transportation systems.
In the 5 February issue of Nature, materials scientist Sang-Heon Kim and colleagues at Pohang describe improving lightweight steel by altering how metal compounds are arrayed in an alloy. They report that the microstructure of their material is stronger and more ductile than titanium alloys.
The researchers think that their work could be useful for industrial steel making. But “even if it takes a long time before this can become a part of production, the novelty of the microstructure that forms could be very useful for thinking about how to construct new alloys,” says Suveen Mathaudhu, a materials engineer at the University of California, Riverside.
