Molecular-dynamics simulations of glass formation and crystallization in binary liquid metals: Cu-Ag and Cu-Ni

We used molecular dynamics (MD) to obtain an atomistic description of the melting, glass formation, and crystallization processes in metal alloys. These studies use the quantum Sutton-Chen many-body potentials for Cu, Ni, and Ag to examine the Cu₄Ag₆ and CuNi alloys. Using cooling rates in the range of 2×10¹² to 4×10¹⁴K/s, we find that CuNi and pure Cu always form a face-centered-cubic (fcc) crystal while Cu₄Ag₆ always forms a glass (with Tg decreasing as the quench rate increases). The crystal formers have radius ratios of 1.025 (CuNi) and 1.00 (Cu) while the glass former (CuAg) has a ratio of 1.13, confirming the role of size mismatch in biasing toward glass formation.