Entropies in Alloy Design for High-Entropy and Bulk Glassy Alloys

High-entropy (H-E) alloys, bulk metallic glasses (BMGs) and high-entropy BMGs (HE-BMGs) were statistically analyzed with the help of a database of ternary amorphous alloys. Thermodynamic quantities corresponding to heat of mixing and atomic size differences were calculated as a function of composition of the multicomponent alloys. Actual calculations were performed for configurational entropy (Sconfig.) in defining the H-E alloys and mismatch entropy (S) normalized with Boltzmann constant (kB), together with mixing enthalpy (Hmix) based on Miedema’s empirical model and Delta parameter () as a corresponding parameter to S/kB. The comparison between Hmix– and Hmix– σ B S k diagrams for the ternary amorphous alloys revealed S/kB ~ ( /22). The zones S, S′ and B’s where H-E alloys with disordered solid solutions, ordered alloys and BMGs are plotted in the Hmix– diagram are correlated with the areas in the Hmix – S/kB diagram. The results provide mutual understandings among H-E alloys, BMGs and HE-BMGs.