Metals are one of the most-used materials in the modern built world, found in everything from buildings to aircraft to smartphones. While most metals are mined from the earth, scientists have recently created a new generation of metals in the lab. These so-called bulk metallic glasses have unique properties. They’re stronger and harder than conventional metals, but can be formed like plastics. This sounds astonishing. What’s behind their special characteristics?
To the naked eye, these lab-made materials look like regular metals, but are smoother and very shiny. The secret behind their unusual properties has to do with their structure on an atomic level. My colleagues (at Universität des Saarlandes in Germany and Oregon State University) and I undertook new research using high-energy X-ray light to unravel some of their mysteries. We have identified the relationship between bulk metallic glasses’ atomic-scale structure and their visible-scale viscous flow—essentially what allows them to flow like thick honey or thin water.
Super Strong and Can Also Flow
Bulk metallic glasses are made of multiple components, including zirconium, copper, nickel, aluminum, gold, and platinum. They exhibit very high strength. If you tear, bend or press a piece of one of these metals, it is so strong that deforming it permanently is very difficult. It can store much more deformation energy than any other metals, making it an ideal spring material.
But what makes bulk metallic glasses unique is that their great strength is combined with the ability to flow like a thick liquid when in a special supercooled liquid state that regular metals cannot reach. When heated to a certain temperature range, they flow like viscous liquid. This makes it possible to mold these special metals by hot-forming processing typically used for traditional glasses and plastics. In principle, you can even blow the metals as you would with bottle glasses.
