Predicted atomic arrangement of Mg₆₇Zn₂₈Ca₅ and Ca₅₀Zn₃₀Mg₂₀ bulk metallic glasses by atomic simulation

The microstructures of Mg-based Mg₆₇Zn₂₈Ca₅ and Ca-based Ca₅₀Zn₃₀Mg₂₀ bulk metallic glasses are predicted by the simulated-annealing basin-hopping method with the tight-binding potential function. The parameters of Mg, Zn, and Ca, and the cross-element pairs of the TB potential are first fitted by the force-matching method with the reference data from experimental results and the density functional theory calculation. The structures from the SABH methods reveal that the average bond lengths of different atomic pairs are almost the same for these two BMGs. However, the microstructures found by the Honeycutt-Anderson pair analysis are very different. For Mg₆₇Zn₂₈Ca₅, the perfect icosahedral local structure occupies the highest fraction, while for Ca₅₀Zn₃₀Mg₂₀ the distorted icosahedral local structures are predominant.