Metallic Glass: A small review

An amorphous metal is a metallic material with a disordered atomic-scale structure. In contrast to most metals, which are crystalline and therefore have a highly ordered arrangement of atoms, amorphous alloys are non-crystalline. Materials in which such a disordered structure is produced directly from the liquid state during cooling are called "glasses", and so amorphous metals are commonly referred to as "metallic glasses" or "glassy metals". However, there are several other ways in which amorphous metals can be produced, including physical vapor deposition, solid-state reaction, ion irradiation, melt spinning, and mechanical alloying. Amorphous metals produced by these techniques are, strictly speaking, not glasses; however, materials scientists commonly consider amorphous alloys to be a single class of materials, regardless of how they are prepared.In the past, small batches of amorphous metals have been produced through a variety of quick-cooling methods. For instance, amorphous metal wires have been produced by sputtering molten metal onto a spinning metal disk. The rapid cooling, on the order of millions of degrees a second, is too fast for crystals to form and the material is "locked in" a glassy state. More recently a number of alloys with critical cooling rates low enough to allow formation of amorphous structure in thick layers (over 1 millimeter) had been produced, these are known as bulk metallic glasses (BMG). Liquidmetal sells a number of titanium-based BMGs, developed in studies originally carried out at Caltech. More recently, batches of amorphous steel have been produced that demonstrate strengths much greater than conventional steel alloys.[....]

Recent Developments on Metallic Glass:

• Solving The Mysteries Of Metallic Glass: Researchers have made significant progress in understanding a class of materials that has resisted analysis for decades. Their findings could lead to the rapid discovery of a variety of useful new kinds of glass made of metallic alloys with potentially significant mechanical, chemical and magnetic applications.[1]
• Metallic Glass: Material Of The Future?: Say "glass" and most people think of window panes. But metals can also form glasses, materials that can be useful in electric transformers, golf clubs and many other products. A Johns Hopkins researcher is developing new metallic glasses with superior strength, elasticity and magnetic properties.[2]
• Mystery Of Metallic Glass Is Cracked By Johns Hopkins Engineers: Johns Hopkins researchers have discovered how atoms pack themselves in unusual materials known as metallic glasses. Their findings should help scientists better understand the atomic scale structure of this material, which is used to make sports equipment, cell phone cases, armor-piercing projectiles and other products.[3]
• Sparks Fly As Novel Metallic Glass Throws Off Fireworks: Many materials can heat up somewhat when they are bent or broken, but few throw off showers of sparks as hot as those emitted when a new kind of metallic glass is shattered. For the first time, a team of researchers in Lawrence Berkeley National Laboratory's Materials Sciences Divison has measured the extremely high temperature of particles ejected when this unusual amorphous metal is fractured. [4]