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

According to the vacancy formation energy (Δ H h) in binary alloys, an easy approach for the computation of multi-component alloys is suggested. And the calculated Δ H h values have linear correlation with the crystallization temperature ( T x) in Ca–Mg–Cu, Mg–Cu–Gd, Zr–Ni–Al and Cu–Zr–Ti alloying systems. Based on the relationship between Gibbs free energy (Δ G) and the liquidus temperature ( T l) and the glass-forming ability (GFA) indicator α (= T x/ T l), a new expression containing Δ H h, mixing entropy (Δ H mix) and configurational enthalpy ( S config) for estimation of GFA is defined as Δ H hΔ H mix S config. 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 Δ H hΔ H mix S config 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 Δ H hΔ H mix S config values.