Thermodynamic and dynamical properties and structural evolution of binary Zr80Pt20 metallic liquids and glasses: Molecular dynamics simulations

Abstract

The structural evolutions and thermodynamic and dynamical properties of binary Zr80Pt20 metallic liquid and glass have been studied by classical molecular dynamics simulations. The calculated pair distribution functions at different temperatures agree well with the theoretical and the experimental results. The local atomic ordered structures of liquids and glasses have been characterized by the Honeycutt-Andersen index and Voronoi tessellation. High fractions of Pt-centered full icosahedra clusters (Z12) and Zr-centered icosahedra-like clusters (Z13-Z15) have been detected in both supercooled liquids and glasses, which are likely to be responsible for glass formation in Zr80Pt20 systems. Most of the Pt-centered clusters in the system are icosahedra, suggesting that the presence of Pt promotes the glass-forming ability. The critical temperature of the liquid Zr-Pt system is similar to 1025.42 K from the transport properties using mode coupling theory. At temperatures near the critical value, there is a dynamic crossover. These results show that the molecular dynamics results provide a powerful approach to obtain detailed chemical and topological ordering of metallic glasses and liquids when compared with experimental and theoretical results in the literature.