  The atomic structure of Ni64.5Zr35.5 metallic glass has been investigated by
molecular dynamics (MD) simulations. The calculated structure factors from the
MD glassy sample at room temperature agree well with the X-ray diffraction
(XRD) and neutron diffraction (ND) experimental data. Using the pairwise
cluster alignment and clique analysis methods, we show that there are three
types dominant short-range order (SRO) motifs around Ni atoms in the glass
sample of Ni64.5Zr35.5, i.e., Mixed-Icosahedron(ICO)-Cube, Twined-Cube and
icosahedron-like clusters. Furthermore, chemical order and medium-range order
(MRO) analysis show that the Mixed-ICO-Cube and Twined-Cube clusters exhibit
the characteristics of the crystalline B2 phase. Our simulation results suggest
that the weak glass-forming ability (GFA) of Ni64.5Zr35.5 can be attributed to
the competition between the glass forming ICO SRO and the crystalline
Mixed-ICO-Cube and Twined-Cube motifs.
