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 (S_s) normalized with Boltzmann constant (k_B), together with mixing enthalpy (DH_mix) based on Miedema’s empirical model and Delta parameter (d) as a corresponding parameter to S_s/k_B. The comparison between DH_mix–d and DH_mix– diagrams for the ternary amorphous alloys revealed S_s/k_B ~ (d /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 DH_mix–d diagram are correlated with the areas in the DH_mix – S_s /k_B diagram. The results provide mutual understandings among H-E alloys, BMGs and HE-BMGs.

FeCoNi(Si_0.6Al_0.2B_0.2) high entropy alloy powders with flaky shapes of 14.7–17.6 μm in mean particle size and 8.2–14.9 in aspect ratio have been prepared by melt-spun and subsequent ball-milling for 10–50 h. The powders possess a mixing structure of BCC nanocrystalline and amorphous phases with average grain sizes of 6–20 nm. The powders exhibit soft magnetic characteristic with saturation magnetization of 78.6–88.1 emu/g. The powders/paraffin (mass ratio = 3:2) composites have high permeability, matchable permittivity, and excellent electromagnetic wave absorption properties in X- and Ku-bands. The composites with thicknesses of 1.2−2.0 mm possess minimum reflection losses (RL) of -38.1 to -44.1 dB with effective absorption bandwidths (RL<10 dB) of 2.5−3.8 GHz.