National Synchrotron Light Source Seminar
"A metallic glass that grows from the melt like a crystal"
Presented by Gabrielle Long, ANL
Wednesday, February 5, 2014, 2 pm
NSLS-II, Building 743, Room 177
Hosted by: Wah-Keat Lee
When a molten material is cooled, it typically grows into orderly crystals. But if the cooling rate is too fast for the entire melt to crystallize, the remaining material ends up in a non-crystalline state known as a glass. This talk is about the discovery and characterization of a unique metallic glass that, during rapid cooling, forms a solid by means of nucleation followed by growth normal to a moving interface between the solid and melt, with partitioning of the chemical elements. We were able to show experimentally that this is not a polycrystalline composite with nanometer-sized grains, and conclude that this may be a new kind of structure: an atomically ordered, isotropic, non-crystalline solid, possessing no long-range translational symmetry. This novel structure‚Ä"isotropic with infinite rotational symmetry and no translational symmetry‚Ä"had been considered theoretically possible, but has never before been observed.