An impact-resistant amorphous steel alloy

A team of engineers from several California colleges has developed and tested a type of steel with a record-breaking ability to withstand impacts without permanent deformation. The new alloy, named SAM2X5-630, could be used in applications from drills to body armor to meteor-resistant casings for satellites. The material is an amorphous steel alloy, a subclass of steel alloys made of arrangements of atoms that deviate from steel’s classical crystal-like structure, where iron atoms occupy specific locations.

Transmission electron microscopy images show different levels of crystallinity embedded in the amorphous matrix of the SAM2X5-630 steel alloy. Image courtesy Jacobs School of Engineering, UC San Diego.

Researchers are increasingly looking to amorphous steel as a source of new materials that are affordable to manufacture and incredibly hard, yet resilient. SAM2X5-630 has the highest recorded elastic limit for any steel alloy, according to the researchers. The alloy can withstand pressure and stress of up to 12.5 gigapascals, or about 125,000 atmospheres, without suffering permanent deformation.

The researchers, from the University of California, San Diego, the University of Southern California and the California Institute of Technology, described the material’s fabrication and testing in a recent issue of Nature Scientific Reports.