The characterisation of atomic structure and glass-forming ability of the Zr–Cu–Co metallic glasses studied by molecular dynamics simulations

Abstract

In the present work, the glass formation process and structural properties of Zr₅₀Cu_50-xCo_x (0 ≤ x ≤ 50) bulk metallic glasses were investigated by a molecular dynamics simulation with the many body tight-binding potentials. The evolution of structure and glass formation process with temperature were discussed using the coordination number, the radial distribution functions, the volume–temperature curve, icosahedral short-range order, glass transition temperature, Voronoi analysis, Honeycutt–Andersen pair analysis technique and the distribution of bond–angles. Results indicate that adding Co causes similar responses on the nature of the Zr₅₀Cu_50-xCo_x (0 ≤ x ≤ 50) alloys except for higher glass transition temperature and ideal icosahedral type ordered local atomic environment. Also, the differences of the atomic radii play the key role in influencing the atomic structure of these alloys. Both Cu and Co atoms play a significant role in deciding the chemical and topological short-range orders of the Zr₅₀Cu_50-xCo_x ternary liquids and amorphous alloys. The glass-forming ability of these alloys is supported by the experimental observations reported in the literature up to now.

Keywords:

• Bulk metallic alloy
• glass transition temperature
• short-range order
• chemical short-range order
• molecular dynamic simulations
• icosahedra
• Honeycutt–Andersen index

Acknowledgments

The authors would like to thank U. Domekeli, M. Colakogullari and C. Canan (Trakya University) for sharing their experiences on the molecular dynamics and useful discussions.