Formation and Structure of Pd--Zr Metallic Glasses Studied by Molecular Dynamics Simulations

For the Pd--Zr system, a long-range potential was constructed under the newly proposed empirical framework. Applying the constructed potential, molecular dynamics simulations were carried out to compare the relative stability of crystalline solid solution versus its disordered counterpart. Simulations reveal that the origin of metallic glass formation is the crystalline lattice collapsing while the solute concentrations exceed critical values, and further determine a composition range, within which the metallic glass formation is energetically favored. Moreover, the energy differences between the crystalline solid solutions and the disordered states, which are considered as the driving force for amorphization are computed. Thermodynamics calculations show that the glass-forming range of the Pd--Zr system is 10--90 at. % Pd, and the largest driving force exist around 50 at. % Pd. In addition, the coordinate numbers and atomic volumes of the Pd--Zr alloys were analyzed by the Voronoi tessellation method, showing that atomic configurations would vary greatly with amorphous-crystal phase transformation.