Atomistic modeling to optimize composition and characterize structure of Ni–Zr–Mo metallic glasses

Abstract

An interatomic potential was constructed for the Ni-Zr-Mo ternary metal system with the newly proposed long-range empirical formulism, which has been verified to be applicable for fcc, hcp and bcc transition metals and their alloys. Applying the constructed potential, molecular dynamics simulations predict a hexagonal composition region within which metallic glass formation is energetically favored. Based on the simulation results, the driving force for amorphous phase formation is derived, and thus an optimized composition is pinpointed to Ni45Zr40Mo15, of which the metallic glass could be most stable or easiest to obtain. Further structural analysis indicates that the dominant interconnected clusters for Ni64Zr36-xMox MGs are 〈0, 0, 12, 0〉, 〈0, 1, 10, 2〉, 〈0, 2, 8, 2〉 and 〈0, 3, 6, 4〉. In addition, it is found that the appropriate addition of Mo content could not only make a more ordered structure with a higher atomic packing density and a lower energy state, but also improve the glass formation ability of Ni-Zr-Mo alloys. Moreover, inherent hierarchical atomic configurations for ternary Ni-Zr-Mo metallic glasses are clarified via the short-range, medium-range and further in the extended scale of the icosahedral network.

Atomistic Simulations to Predict Favored Glass-Formation Composition and Ion-Beam-Mixing of Nano-Multiple-Metal-Layers to Produce Ternary Amorphous Films

“…Within the red dot region, the Ni45Zr40Mo15 alloy symbolized by the black pentagram is shown as the composition with the maximum ADF. Additionally, the composition of Ni45Zr40Mo15 obtained from the atomistic simulation is close to that of Ni48Zr48Mo4 obtained from thermodynamic calculation [56]. Therefore, the Ni45Zr40Mo15 alloy and the nearby compositions can be considered energetically favored for metallic glass formation.…”

“…For the Ni-Zr side, the mechanical alloying (MA) [76] experiments reveal a glass formation range of 24-83 at.% Zr. Besides, XRD diffractograms of Zr x Ni 100−x thin film MGs produced by magnetron sputtering method [39] [56]. The XRD data [73] for Ni64Zr36 MGs are also presented and marked as olive dots.…”

“…Furthermore, the potential parameters of the Ni-Zr-Mo (fcc-hcp-bcc) system [56] constituted by three major different crystalline structures are presented in Table 2. Tables 3 and 4 present the lattice constants, cohesive energies, and bulk moduli of B2 and L1 2 compounds in the Ni-Nb-Mo and Ni-Zr-Mo systems computed from the constructed interatomic potentials.…”

“…Therefore, the Ni45Zr40Mo15 alloy and the nearby compositions can be considered energetically favored for metallic glass formation. [56], and (b) Ni-Nb-Mo system [55]. The quantitative energy scale for dots with different colors are presented for the respective systems.…”

“…Based on the long-range empirical potential [55,56], the potential energy E i of atom i can be calculated as follows:…”