thumb|samples of amorphous metal, with millimeter scale an amorphous metal (also known metallic glass or glassy metal) is a solid metallic material, usually an alloy, with a disordered atomic-scale structure. most metals are crystalline in their solid state, which means they have a highly ordered arrangement of atoms. amorphous metals are non-crystalline, and have a glass-like structure. but unlike common glasses, such as window-glass, which are typically insulators, amorphous metals have good electrical conductivity. there are several ways in which amorphous metals can be produced, including extremely rapid cooling, physical vapor deposition, solid-state reaction, ion irradiation, and mechanical alloying.some scientists only consider amorphous metals produced by rapid cooling from a liquid state to be glasses. however, materials scientists commonly consider a glass to be any solid non-crystalline material, regardless of how it is produced. in the past, small batches of amorphous metals have been produced through a variety of quick-cooling methods. for instance, amorphous metal ribbons have been produced by sputtering molten metal onto a spinning metal disk (melt spinning). 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. ==history==  the first reported metallic glass was an alloy (au75si25) produced at caltech by w. klement (jr.), willens and duwez in 1960. this and other early glass-forming alloys had to be cooled extremely rapidly (on the order of one megakelvin per second, 106&nbsp;k/s) to avoid crystallization. an important consequence of this was that metallic glasses could only be produced in a limited number of forms (typically ribbons, foils, or wires) in which one dimension was small so that heat could be extracted quickly enough to achieve the necessary cooling rate. as a result, metallic glass specime
Alloys Amorphous_metals Emerging_technologies Metallurgy