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 (S_config.) in defining the H-E alloys and mismatch entropy (Sσ) normalized with Boltzmann constant (k_B), together with mixing enthalpy (λHmix) based on Miedema's empirical model and Delta parameter (δ) as a corresponding parameter to S_σ/k_B. The comparison between λHmix-δ and λHmix- √S_σ/k_Bdiagrams for the ternary amorphous alloys revealed S_σ/k_B ̃ (δ /22)². The zones S, S' and B's where H-E alloys with disordered solid solutions, ordered alloys and BMGs are plotted in the λHmix-δ diagram are correlated with the areas in the λHmix - S_σ/k_B diagram. The results provide mutual understandings among H-E alloys, BMGs and HE-BMGs.