Structural and Chemical Orders in Ni64.5Zr35.5 Metallic Glass by Molecular Dynamics Simulation

TL;DR

This study uses molecular dynamics simulations to analyze the atomic structure of Ni64.5Zr35.5 metallic glass, revealing dominant short-range orders and their relation to glass-forming ability, aligning well with experimental diffraction data.

Contribution

It introduces a detailed atomic-level analysis of Ni64.5Zr35.5 metallic glass, identifying key structural motifs and their influence on glass-forming ability, using advanced simulation and analysis methods.

Findings

Identification of three dominant SRO motifs: Mixed-ICO-Cube, Twined-Cube, and icosahedron-like clusters.

Demonstration that certain motifs resemble crystalline phases, affecting glass stability.

Weak GFA linked to competition between glassy and crystalline-like motifs.

Abstract

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.