Molecular Dynamics Simulations of Glass Formation and Crystallization in Binary Liquid Metals
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The glass formation of binary liquid metals is studied using molecular dynamics simulations, where the atomic interactions are modeled with a Sutton-Chen many-body potential. We use model binary alloy systems (Cu*50Cu**50), which differ in their atomic radii and/or cohesive energies between Cu* and Cu**. First, when we change the atomic size ratio (1.0) only, we find that there are three regimes defined by the magnitude of upon cooling. When is close to 1.0, crystallization occurs. Glass formation occurs at moderate values. When the is small, the alloy phase separates into pure phases. Second, when we vary and the cohesive energy ratio (?1.0) along the line in constant energy density space (/3=constant), glass formation occurs at moderate values, but phase separation is not observed at any . Therefore, we find that the energy density is the dominant parameter in controlling the phase separation behavior of metallic alloys. From the studies of structural properties, we find that the fivefold symmetry becomes prominent in glasses and shows a maximum at =0.85 in both cases. Finally, when we only vary , while keeping constant, the system shows a very limited glass forming regime (<0.3), indicating that the atomic size ratio is more crucial to frustrate the crystallization.
Journal of Metastable and Nanocrystalline Materials
author list (cited authors)
Lee, H. J., Cagin, T., Goddard III, W. A., & Johnson, W. L.