Structural and chemical orders in Ni64.5Zr35.5 metallic glass by molecular dynamics simulation

The atomic structure of $\mathrm{N}{\mathrm{i}}_{64.5}\mathrm{Z}{\mathrm{r}}_{35.5}$ 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 of dominant short-range order (SRO) motifs around Ni atoms in the glass sample of $\mathrm{N}{\mathrm{i}}_{64.5}\mathrm{Z}{\mathrm{r}}_{35.5}$, i.e., mixed-icosahedron(ICO)-cube, intertwined-cube, and icosahedronlike clusters. Furthermore, chemical order and medium-range order (MRO) analysis show that the mixed-ICO-cube and intertwined-cube clusters exhibit the characteristics of the crystalline B2 phase. Our simulation results suggest that the weak glass-forming ability (GFA) of $\mathrm{N}{\mathrm{i}}_{64.5}\mathrm{Z}{\mathrm{r}}_{35.5}$ can be attributed to the competition between the glass forming ICO SRO and the crystalline mixed-ICO-cube and intertwined-cube motifs.