Alloy compositions of metallic glasses and eutectics from an idealized structural model

Using an idealized atomic packing model for metallic glasses (MGs), we predict the binary alloy compositions structurally favorable for the stability of MGs. Such compositions are proposed to be the likely candidates to obtain MGs. The predicted compositions coincide very well with the experimental glass-forming range for a large number of systems. The relationship between these compositions and the eutectic compositions in the equilibrium phase diagrams is established. Direct correlations are found for symmetric eutectic systems, especially for deep eutectics, whereas off-eutectic MGs are suggested for asymmetric eutectic systems. Rationales from the structural standpoint are also presented to explain the increased frequency of appearance of eutectics at certain composition ratios (the Stockdale/Hume-Rothery puzzle).