Metallic Glass is just Wonderful stuff


New research into super speed pulse mould technology will allow a new type of glass that has the properties of being strong, tough, and cheap

Metallic glasses were first discovered at Caltech in the 1960s, since then industry has been able to produce metallic glass. It is a metal alloy, but one with the disordered structure of glass, not formed into crystals the way most metals are.

The crystalline structure of metal is a disadvantage, making it week. Unfortunately ordinary glasses are strong and rigid, but generally crack and shatter easily.

If you can make a metallic glass that has a non-crystalline structure like window glass; then this won’t crack or fracture, but will be stronger than an equivalent object made of ordinary metal.

At the moment, metallic glass parts are made by melting and then further heating up metal above 1,000°C, this breaks down the crystalline structure. This is then poured into a mould, and cools down in the desired shape to solidify before crystals can form. The problem is that moulds need to be replaced often and this makes the process expensive.

But a new process refined at Caltech uses an extremely rapid “ohmic heating” system. A brief but extremely powerful jolt of electric current is passed through the 2cm metallic glass billet. For a sub-millisecond the billet gets heated up at a rate of a million degrees per second and then moulding it into any shape in just a few milliseconds

This process uniformly heats the glass at least a thousand times faster than has ever been done before in such attempts.

The metalic glass is heated up, moulded and cooled to solid again before crystals can form.

This means that an inexpensive, high-performance; precision parts made in the same way plastic parts, yet the parts are 20 times stronger and stiffer than plastic.

“We’ve redefined how you process metals, this is a paradigm shift in metallurgy.” says William Johnson, the Ruben F. and Donna Mettler Professor of Engineering and Applied Science.

Be sure to read “Strong, Tough, and Now Cheap: Caltech Researchers Have New Way to Process Metallic Glass “ at Caltech, its link is: http://media.caltech.edu/press_releases/13415