What determines the glass-forming ability of metallic alloys?

I will describe our recent computational studies of model bulk metallic glasses to understand the features that differentiate good from poor glass-forming alloys. Good glass-formers possess low critical cooling rates, below which the system crystallizes. In contrast, poor glass-formers possess high critical cooling rates and small critical sample thicknesses. We determine the atomic size ratios, stoichiometries, binding energies, and heats of mixing that maximize the glass-forming ability of model binary Lennard-Jones systems. In addition, using genetic algorithms, we identify the optimal crystal structures for each atomic size ratio and stoichiometry to determine how the packing efficiency difference between the crystal and glass affect the glass-forming ability of each alloy. These studies represent a key first step toward computational design of novel bulk metallic glasses.