Effects of cooling rate on the atomic structure and glass formation process of Co₉₀ Zr₁₀ metallic glass investigated by molecular dynamics simulations

Authors: MURAT ÇELTEK, SEDAT ŞENGÜL

Abstract: In this study, the atomic structure and the glass formation process of Co₉₀ Zr₁₀ metallic glass alloy were studied by molecular dynamic simulation based on the embedded atom method using four different cooling rates. The average atomic volume and the potential energy of the system were observed to be strongly dependent on the cooling rate during rapid solidification, and the glass transition temperature decreased with decreasing cooling rate. The radial distribution functions and the structure factors derived from molecular dynamics simulations at 300 K agreed well with the experimental and other molecular dynamics results. The coordination numbers calculated at 300 K were consistent with the experimental results in the literature. The local structural atomic orders of the system have been characterized by Honeycutt-Andersen indices and the Voronoi tessellation method. We realized that the FCC and icosahedral shortrange order increases with decreasing cooling rate, the icosahedral clusters are predominant in the Co₉₀ Zr₁₀ metallic glass, and the fraction of the icosahedral polyhedra increases with decreasing cooling rate and temperature. We have seen that Co-centered Voronoi polyhedrals such as <0,2,8,2> , <0,0,12,0> , and <0,1,10,2> play a dominant role in the development of the icosahedral order of the Co₉₀ Zr₁₀ alloy.

Keywords: Metallic glassy, glass transition temperature, short-range order, molecular dynamic simulations, icosahedral, Honeycutt-Andersen index, Voronoi tessellation

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