Phase selection rule of high-entropy metallic glasses with different short-to-medium-range orders

When an equiatomic multi-component alloy is quenched from its molten state down to room temperature, either a solid solution crystalline alloy or a metallic glass is formed. The former is called a high-entropy alloy, whereas the latter is referred as a high-entropy metallic glass (HE-MG). In such multicomponent alloys, thermodynamic parameters, e.g., the mixing entropy, the mixing enthalpy and other parameters such as atomic size mismatch, determine the resulting phases. In this work, we studied the phase selection rule applied to the equiatomic multicomponent Ti₂₀Zr₂₀Hf₂₀Cu₂₀Ni₂₀ HE-MG from a structural perspective, by analyzing the short-to-medium-range orders. It was found that the short-range order in this MG resembles a body-centered cube structure, while the medium-range order is comprised of different orders. The experimental data suggest that different packing schemes, at the medium-range scale, play a critical role in the phase selection rule with regard to an amorphous phase or solid solution.