Prediction of favored and optimized compositions for Cu-Zr-Ni metallic glasses by interatomic potential.

For the Cu-Zr-Ni system, an interatomic potential was constructed under the newly proposed formulism named smoothed and long-range second-moment approximation of tight-binding. Applying the constructed potential, molecular dynamics simulations were carried out to compare the relative stability of crystalline solid solution versus its disordered counterpart. Simulations not only reveal that the origin of metallic glass formation is the crystalline lattice collapsing while the solute concentrations exceed critical values, but also determine a quadrilateral region, within which the metallic glass formation is energetically favored. Moreover, the energy differences between the crystalline solid solutions and the disordered states were considered as the driving force for amorphization and were computed by molecular static calculations. The calculation results located an optimized composition area with the driving force much greater than those outside. In addition, the alloys around the composition of Cu(16)Zr(60)Ni(24) were identified to have maximum driving force, and the atomic configurations were also analyzed by the Voronoi tessellation method.