Researchers at Brown University have developed a new way to make super-hard metals. The team made nanoparticle “building blocks” that could be fused together under moderate pressure, thanks to a chemical treatment.
A material’s hardness specifically describes how well it resists being scratched or bent out of shape by force or pressure. In the case of metals, it’s usually determined by the size of the microscopic grains that make it up – the smaller the grain, the harder the metal.
Normally a metal is made harder using macroscopic manufacturing methods like hammering, bending or twisting. But in the new study, the team started from the “bottom up,” resulting in much harder metals.
“Hammering and other hardening methods are all top-down ways of altering grain structure, and it’s very hard to control the grain size you end up with,” says Ou Chen, corresponding author of the study. “What we’ve done is create nanoparticle building blocks that fuse together when you squeeze them. This way we can have uniform grain sizes that can be precisely tuned for enhanced properties.”