Calculation Assisted Composition Design of Fe-Based Amorphous Alloys

Combining calculation to accelerate the composition design of Fe-based amorphous alloys is of paramount importance for diversifying the alloy systems and applications. In this study, the constituent elements in Fe-based amorphous alloys and the parameters affecting glass-forming ability (GFA) were statistically analyzed. Taking a simple FePC bulk amorphous alloy system as the model material, the ternary phase diagram and the atomic mismatch factor (λ), mixing enthalpy (ΔHmix), mixing entropy (ΔSmix), electronegativity (Δχ), atomic size difference (δ), electron concentration (e/a) were carefully calculated. Accordingly, a series of FePC alloys with high GFA were determined and casted into rod samples to experimentally verify the GFA. The optimal FePC alloys with a critical diameter (dc) of 1.5 mm are in the composition range of 78 ≤ Fe ≤ 80 at.% and 11 ≤ P ≤ 13 at.%, which is quite consistent with the calculated compositions with a low melting point, a large negative ΔHmix and a fixed e/a value of around 1.67. This calculation assisted composition design method was further evaluated in a FeCoNiPC alloy system. With the introduction of a small amount of Co, Ni elements, the optimal Fe72-76Co3-6Ni1-4P13C7 (at.%) alloys exhibit an improved dc of 2 mm. These criteria are quite effective in accelerating the composition design of Fe-based amorphous alloys, and can be also extended to other multi-component alloy systems to discover high GFA amorphous alloys.