The atomic structure of aluminum based metallic glasses and universal criterion for glass formation

It recently became recognized that several phenomena related to the formation of glass or liquid for metallic alloy systems can be explained in terms of a universal criterion for glass formation. These include the composition limit for glass formation by rapid cooling of a liquid alloy, that for solid state amorphization by radiation, thermal or mechanical alloying, and the conditions for glass transition and melting of a crystalline alloy. The aluminum-based metallic glasses, however, appear to be an exception for this rule. It is shown that, by modifying the rule to allow for the interstitial site occupation, the composition range of glass formation for aluminum-based glasses can also be explained by the same principle of local topological instability.