Molecular dynamics simulation on glass formation, microstructural evolution, and transport properties of Cu54Hf46 alloy during rapid solidification

The rapid solidification process of the Cu54Hf46 alloy has been simulated by molecular dynamics simulations using tight-binding potential. In detail, we consider the potential energy, partial pair distribution functions [gijr], structure factor [S(q)], coordination numbers, glass transition temperature (Tg), linear thermal expansion coefficients, chemical short-range order parameters, specific heat, mean square displacements, bond angle distribution functions (BADs), and Voronoi tessellation analyses. The Tg value has been determined using five different methods. The calculated S(q) [or gijr] curves are in good agreement with the experimental (or other) results reported in the literature. We have investigated the positions, heights, and widths of the first peak and valley of gijr/g(r), as well as the positions of the two sub-peaks of the second peak. The results showed that the main cause of the splitting of the second peaks of the g(r) curves is the icosahedral-like clusters and their linkage types. High fractions of Cu-centered full icosahedra (⟨0, 0, 12, 0⟩) and Cu- and Hf-centered icosahedral-like clusters has been observed in supercooled liquids and glasses. The BAD analysis revealed that Cu-centered clusters have been more likely to form icosahedral or similar motifs than Hf-centered clusters. These findings will contribute positively to understanding the microstructural evolution and glass formation process of the Cu54Hf46 alloy during rapid solidification and will motivate researchers to discover new Cu-Hf metallic glasses under different conditions in the future.