Predicting alloy compositions of bulk metallic glasses with high glass-forming ability

According to the vacancy formation energy (ΔHh) in binary alloys, an easy approach for the computation of multi-component alloys is suggested. And the calculated ΔHh values have linear correlation with the crystallization temperature (Tx) in Ca–Mg–Cu, Mg–Cu–Gd, Zr–Ni–Al and Cu–Zr–Ti alloying systems. Based on the relationship between Gibbs free energy (ΔG) and the liquidus temperature (Tl) and the glass-forming ability (GFA) indicator α (=Tx/Tl), a new expression containing ΔHh, mixing entropy (ΔHmix) and configurational enthalpy (Sconfig) for estimation of GFA is defined as ΔHhΔHmixSconfig. The predicted composition lines derived with this expression are all very near the reported BMGs in La–Al–Co, Zr–Cu–Be, Ca–Mg–Zn and Cu–Zr–Ti alloying systems, respectively. Moreover, values of ΔHhΔHmixSconfig is found to have a strong correlation with the critical diameters in La–Ce–Al–Co quarternary alloying system. Finally, three BMGs with Cu-rich compositions in Cu–Zr–Al alloying system are prepared and the experimental result about GFA is consistent with the computational ΔHhΔHmixSconfig values.