This manuscript explores the influence of atomic structure on glass forming ability and thermal stability in binary metallic glasses. A critical assessment gives literature data for 628 alloys from 175 binary glass systems. The atomic structure is quantified for each alloy using the efficient cluster packing model. Comparison of atomic structure with amorphous thickness and thermal stability gives the following major results. Binary glasses show a strong preference for discrete solute to solvent atomic radius ratios R*, which give efficient local atomic packing. Of 15 possible R* values, only five are common and only four represent the most stable glasses. The most stable binary glasses are also typically solute rich, with enough solute atoms to fill all the solute sites and roughly one-third of the solvent sites. This suggests that antisite defects, where solutes occupy solvent atom sites, are important in the glass forming ability of the most stable glasses. This stabilising effect results from an increase in the number of more stable solute-solvent bonds in solute rich glasses. Solute rich glasses also enable efficient global atomic packing. Together, these structural constraints represent only a narrow range of topologies and thus give a useful predictive tool for the exploration and discovery of new binary bulk metallic glasses (BMGs).

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Metallic glasses demonstrate unique properties, including large elastic limit and high strength, which make them attractive for practical applications. Unlike crystalline alloys, metallic glasses, in general, do not exhibit a strain hardening effect, while plastic deformation at room temperature is localized in narrow shear bands. Room-temperature mechanical properties and deformation behavior of bulk metallic glassy samples and the crystal-glassy composites are reviewed in the present paper.

In the present work we analyze the composition ranges over which bulk metallic glasses (BMGs) are produced in ternary, quaternary, and quinary amorphous alloys. The maximum diameter of the sample over which an amorphous structure can be retained, referred to as the critical diameter, Dc, is consistently large over specific composition ranges. For ternary BMGs, these most stable glasses are centered around the compositions, in decreasing order of accompanying Dc: A44B38C18, A44B43C13, A65B25C10, A56B32C12, A55B28C17, A70B20C10, and A65B20C15. As a general trend, the most stable glasses have the lowest concentrations of solvent atoms. Structural analysis using the efficient cluster packing model suggests that the best ternary glasses are near the isostructural composition, which represents the maximum degree of atomic confusion. Both Dc and ΔTx=Tx−Tg, the difference between the crystallization and glass transition temperatures, are larger in quaternary and quinary systems relative to typical values for ternary BMGs. Glass-forming ability increases with complexity of the alloy, i.e., increasing number of alloying elements. The above results shed some light not only on compositional dependence of the formation of glassy phase but also its relation to the structure of the glasses.