By altering metal alloy at a nanoscale level, researchers at the Graduate Institute of Ferrous Technology (GIFT) at Pohang University of Science and Technology in South Korea have created a new material that has the strength of steel and the lightness of titanium alloy. Made from an amalgam of steel, aluminum, carbon, manganese, and nickel, the new alloy promises to be low-cost and readily available due to its mix of common minerals.
Previous research into lightweight steel has focused on mixing in aluminum in varying proportions to attempt to reduce the density, and therefore the weight. Unfortunately, upping the aluminum content in steel also badly affects its ductility (the way that a material behaves under tensile stress) which results in its increasing vulnerability to fracture.
In an attempt to rectify this major impediment to producing a practical lightweight steel, the research team at GIFT uniformly distributed nanometer-sized B2 intermetallic compounds (an amalgam of two metals with equal numbers of atoms) in and around the steel grain structure. though incorporating B2 into steel has been tried in the past, it has ordinarily been harmful to the structure. However, by adding nickel to the admixture, the team was able to take advantage of the addition of B2, while also helping to increase the ductility of the steel alloy.
As a result of this research, sturdier, lightweight and more ductile steel compounds may be developed, promising to alleviate the age old problem of brittle intermetallic compound alloys. In this vein, the researchers intend to collaborate with POSCO (formerly the Pohang Iron and Steel Company) to trial forge its new alloy later on this year.
It is still early days in this research, and no plans have been announced as to whether this will go beyond a trial commercial process level. But the concept of producing a lightweight version of steel using an abundant mineral such as iron – the base component of steel – could open up a raft of possibilities. Not the least of which may be a new era of high-strength, lightweight steels that may one day usurp aluminum in the production of fuel efficient vehicles and other construction systems.
Source: Pohang University