Glass, by definition, is amorphous; its atoms lack order and are arranged every which way. But when scientists squeezed tiny samples of a metallic glass under high pressure, they got a surprise: The atoms lined up in a regular pattern to form a single crystal. http://venitism.blogspot.com
It's the first time researchers have glimpsed this hidden property in a glass. The discovery offers a new window into the atomic structure and behavior of metallic glasses, which have been used for decades in products such as anti-theft tags and power transformers but are still poorly understood. The more scientists learn about the structure of these commercially important materials, the more effectively they can design new metallic glasses and tinker with old ones to improve their performance.
"Maybe a lot of glasses have this underlying structure, but we just didn't know how to look for it," said Wendy Mao, a mineral physicist of Stanford University. The discovery is a really neat, important finding. Not only will it help researchers design better metallic glasses, but it explains why these materials can be so tough. If each piece of glass is a single crystal at heart, it doesn't have any of the weak spots at the boundaries between crystals where fractures and corrosion tend to start. http://venitism.blogspot.com
Unlike familiar window glass, metallic glasses are alloys made of metals, in this case cerium and aluminum. They resist wear and corrosion and they have useful magnetic properties. If you took apart the plastic antitheft tag on a DVD case, you'd find a thin piece of metallic glass that looks like aluminum foil. When you rent or buy a DVD, the checkout clerk rubs it across a pad to demagnetize the metallic glass so it won't trigger an alarm when you leave.
Scientists have been investigating metallic glasses for half a century, and in 1982 turned up the surprising discovery that these glasses do have some atomic structure, forming patterns over distances spanning just a few atoms. But no long-range patterns were apparent. http://venitism.blogspot.com
