Transition from high-entropy to Cu-based (TiZrNbNi)1-xCu x metallic glasses

Abstract

A study of a transition from conventional multicomponent alloys to high-entropy alloys (HEAs) is important both for understanding the formation of HEAs and for proper evaluation of their potential with respect to that of conventional alloys. We report the main result of such a study performed on (TiZrNbNi)1-xCux metallic glasses (MG) over a broad concentration range x ≤ 0.52 encompassing both high-entropy-MGs and Cu-based MGs. A comprehensive study of the composition, homogeneity, thermal stability, atomic structure, electronic structure, and magnetic susceptibility of 11 alloys has been performed. Thermal analysis revealed a rather weak variation of thermal parameters and glass forming ability with x. The study of the atomic structure showed a linear variation of average interatomic distances and atomic volumes close to those predicted by Vegard's law. The coordination numbers and atomic packing fractions were constant throughout the explored concentration range. The electronic density of states (DOS) showed a split-band structure with DOS close to the Fermi level dominated with d-states of Ti, Zr, and Nb. Accordingly, magnetic susceptibility decreased linearly with x and extrapolated to that of Cu. Thus, the studied alloys show ideal solution behavior similar to that of binary Cu-Ti, Zr, and Hf MGs. The results are compared with those for (TiZrNbCu)1-xNix MGs and (CrMnFeCo)1-xNix alloys and their impact on understanding the transition from high-entropy-MGs to conventional MGs with the same composition is briefly discussed.