Formation energetics/dynamics of icosahedral clusters in supercooled metallic liquids in the dynamic equilibrium regime: Gibbs free energy, entropy, enthalpy, and connection to coordination shells

Abstract

AbstractIcosahedral (ICO) clusters are known to exist in many supercooled metallic liquids and believed to play an important role in stabilizing the liquid before it transitions into a glassy, crystalline or quasicrystalline solid. However, a detailed understanding of their formation energetics/dynamics is currently lacking and a set of key questions regarding these clusters remains to be answered. Here, we report our study on the formation energetics/dynamics of ICO clusters in liquid Cu64Zr36 and Ta by combining MD simulations with statistical and theoretical analysis. We present the formation Gibbs free energy, entropy, enthalpy of ICO clusters in the two liquids in the dynamic equilibrium regime (T > 0.75 Tm), determine the size of the spatial domain (number of coordination shells) surrounding the clusters from which the formation enthalpy is originated, and discuss the results in connection with liquid composition, degree of randomness, potential energy landscape, and glass transition. Graphical abstract