materialsscienceandengineering: Amorphous metal, metallic...

Samples of amorphous metal, with millimeter scale.


Metallic glass - shiny, easy to mould and with a high strength-to-weight ratio.


A time-temperature-transformation diagram for the primary crystallization of V1.


The relations between mechanical properties of typical BMGs.


A sample of a fractured amorphous metal alloy.

materialsscienceandengineering:

Amorphous metal, metallic glass

In nature they prefer to form crystal structures but if liquid metals are cooled down fast enough then, just like glass, the atoms will arrange into a disordered amorphous structure. These amorphous metals, also called metallic glasses, don’t exist naturally because the cooling rates required can be on the order of millions of degrees a second. Methods of forming these materials include extremely rapid cooling, physical vapor deposition, solid-state reaction, ion irradiation, and mechanical alloying.

Metallic glasses are materials of interest because of the properties that can result. They typically have extremely high strength to weight ratios (higher than aluminium and titanium alloys) and are tougher and less brittle than oxide glasses and ceramics. Like crystalline metallic alloys, the properties of these materials also depends upon the composition. Alloys of boron, silicon, phosphorus, and other glass formers with magnetic metals have high magnetic susceptibility and electrical resistance. The fact that amorphous metals are true glasses also allows for easy processing because they soften and flow upon heating. Not all properties are favorable however, metallic glasses also typically have lower ductilities and fatigue strengths. 

Bulk metallic glasses, or BMGs, are alloys with critical cooling rates low enough to allow formation of the desired amorphous structure in thick layers (over 1 millimeter). They are made from alloys with typically three to five metallic components that have a large atomic-size mismatch and a composition close to a deep eutectic. Some examples include Vitreloy 1 (41.2% Zr, 13.8% Ti, 12.5% Cu, 10% Ni, and 22.5% Be), Ti₄₀Cu₃₆Pd₁₄Zr₁₀, and Mg₆₀Zn₃₅Ca₅.

Sources: (1, top left) (2, top right) (3, middle left) (4, middle right) (5, bottom)

Not all glasses are Glass, the clear compound made from silica used in windows and such. A glass is a kind of compound.

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