Researchers in South Korea say they may have found a way to improve lightweight steel by altering how metal compounds are arranged in an alloy.

The findings, published in the journal Nature, report that the microstructure of the material is stronger and more pliable than even titanium alloys. The final product is 13% less dense than normal steel and has almost the same strength-to-weight ratio when compared to titanium alloys.

The key to creating this material was overcoming a challenge that had dogged materials scientists for decades. In the 1970's, Soviet researchers discovered that adding aluminum to the steelmaking process can make a strong and lightweight metal but one that also is brittle. That's because during the process of creating the aluminum-steel alloy, metallurgists occasionally fused atoms of aluminum and iron together to form tough, crystalline structures called B2.

Sang-Heon Kim, a materials scientist from the Pohang University of Science and Technology, and colleagues devised a method of heat-treating and then thinly rolling their steel to control when and where B2 crystals were formed. They also found that adding a small percentage of nickel offered the steel more control over B2 formation. That's because nickel made the crystals formed at a much higher temperature.

One further challenge, however, still must be overcome. Steelmakers currently use a silicate layer to cover and protect mass-produced steel from oxidation with the air and contamination. This silicate can't be used for Kim's steel because it has a tendency to react with the cooling aluminum, compromising the final product.

The academic research team plans to work with South Korean steel manufacturer POSCO in an effort to scale up their methods.

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