DOE develops glass that is stronger than steel
A new type of damage-tolerant metallic glass, demonstrating a strength and toughness beyond that of any known material, has been developed and tested by a collaboration of researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab)and the California Institute of Technology.
The glass flexes if subjected to stress, rather than shattering. This is because it’s no ordinary glass, instead it’s a microalloy with palladium, a metal with a high “bulk-to-shear” stiffness ratio that counteracts the inherent brittleness of glassy materials.
The initial samples of the new metallic glass were microalloys of palladium with phosphorous, silicon and germanium that yielded glass rods approximately one millimeter in diameter. Adding silver to the mix enabled the Cal Tech researchers to expand the thickness of the glass rods to six millimeters. The size of the metallic glass is limited by the need to rapidly cool or “quench” the liquid metals for the final amorphous structure.
“The rule of thumb is that to make a metallic glass we need to have at least five elements so that when we quench the material, it doesn’t know what crystal structure to form and defaults to amorphous,” says Robert Richie, the lead author of “A Damage-Tolerant Glass” just published the research in the journal Nature Materials.
There are many applications within sustainable technology for this material, such as unbreakable solar panels (PV) and evacuated tubes (solar thermal), as well as earthquake-proof greenhouses for local food production.
Ritchie holds joint appointments with Berkeley Lab’s Materials Sciences Division and the University of California (UC) Berkeley’s Materials Science and Engineering Department.
The new metallic glass was fabricated by co-author Demetriou at Cal Tech in the laboratory of co-author Johnson. Characterization and testing was done at Berkeley Lab by Ritchie’s group.