Highly collective atomic transport mechanism in high-entropy glass-forming metallic liquids

Quasielastic neutron scattering (QENS) has been used to study the atomic relaxation process and microscopic transport mechanism in high-entropy glass-forming metallic (HE-GFM) liquids. Self-intermediate scattering functions obtained from the QENS data show unusually large stretching, which indicates highly heterogeneous atomic dynamics in HE-GFM liquids. In these liquids, a group of atoms over a length scale of about 21 Å diffuses collectively even well above the melting temperature. However, the temperature dependence of the diffusion process in one of the HE-GFM liquid is Arrhenius, but in the other HE-GFM liquid is non-Arrhenius. Although the glass-forming ability of these HE-GFM liquids is very poor, the diffusion coefficients obtained from the QENS data indicate the long-range atomic transport process is much slower than that of the best metallic glass-forming liquids at their melting temperatures.