Understanding the Formation of Metallic GlassCategory: Science & Technology
Posted: April 4, 2013 07:15AM
Glass is one of those terms that has a different meaning in the scientific and non-scientific worlds. In science, glass is not just the stuff of windows but a description of a solid with a disordered internal structure, unlike a well ordered crystal. Researchers at MIT have recently discovered an important mechanism for how metallic glasses form, which can have different and useful properties, compared to their normal crystalline versions.
The discovery was actually an accident as the researchers were working with an alloy that most scientists believe cannot form a glass. The reason for this belief is that copper and niobium, the two elements in the alloy, do not mix, while atoms in known glasses typically do. What the researchers found is that when the alloy was quenched, small domains enriched in one element or the other would form. These domains were so small, that it is not possible for a crystalline structure to form, but it is the boundary between the domains of particular interest. There the atoms arranged themselves into a spongelike structure with pours, similar to the internal structure of gelatin which gives the mostly liquid material strength.
Understanding the glass transition of a material is actually one of the larger mysteries of physics, so this discovery is very important. Better understanding the transition should allow new and better glasses to be made, with special properties such as high strength even compared to its crystalline form.