Atomic modeling to design favored compositions for the ternary Ni–Nb–Zr metallic glass formation

Abstract

An interatomic potential is constructed for the Ni–Nb–Zr ternary metal system under the newly proposed long-range empirical formulism, which has been verified to be applicable for face-centered cubic, body-centered cubic and hexagonal close-packed transition metals and their alloys. Applying the constructed potential, Monte Carlo simulations were performed to study the alloy compositions favored for Ni–Nb–Zr metallic glass formation. Simulations reveal that the underlying physics of metallic glass formation is the collapse of the crystalline lattice when the solute concentration exceeds a critical value. An intrinsic glass formation region for the Ni–Nb–Zr system can then be predicted, reflecting the possible composition region energetically favored for metallic glass formation. Furthermore, an optimal composition sub-region was pinpointed within which the driving forces for the crystalline-to-amorphous transition are larger than those outside the sub-region. The Ni–Nb–Zr amorphous alloys with the optimal compositions are expected to be more stable or easier to be produced in practice. Moreover, Voronoi tessellation analysis reveals that the atomic structure of the Ni–Nb–Zr ternary metallic glass is obviously influenced by the alloy composition, the size difference and chemical interactions of constituent metals. Ni- (or Nb-centered) icosahedral clusters are inferred as the basic local structural feature in the Ni–Nb–Zr metallic glass.