Atomic-scale simulation to study the dynamical properties and local structure of Cu-Zr and Ni-Zr metallic glass-forming alloys

• Published in: Physical chemistry chemical physics : PCCP Vol. 18; no. 1; pp. 7169 - 7183
• Main Authors: Yang, M. H, Li, Y, Li, J. H, Liu, B. X
• Format: Journal Article
• Language: English
• Published: England 14.03.2016
• Subjects: Amorphous materials; Binary systems; Copper; Dynamical systems; Dynamics; Glass formation; Metallic glasses; Nickel; Polyhedrons
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c5cp07676e

Molecular dynamics simulation with well-developed EAM potentials was carried out to investigate the transport properties and local atomic structure of Cu-Zr and Ni-Zr metallic glasses and supercooled liquids. It is found that Cu or Ni atoms have much faster dynamics than Zr atoms in relaxation timescales, while Zr atoms display faster dynamics in the Cu-Zr system than in the Ni-Zr system. A dynamical crossover phenomenon from Arrhenius to super-Arrhenius behavior in the transport properties was observed for the Cu 65 Zr 35 system at T x 1250 K and the Ni 65 Zr 35 system at T x 1500 K, respectively. Further structural analysis suggests that the dominant interconnected clusters in Cu 65 Zr 35 and Ni 65 Zr 35 systems are 〈0, 0, 12, 0〉, 〈0, 1, 10, 2〉, 〈0, 2, 8, 2〉 and 〈0, 3, 6, 4〉. To directly characterize and visualize the correlated dynamics, we regard the full icosahedra as the microscopic origin responsible for the formation of metallic glasses in the Cu 65 Zr 35 system, while the metallic glass formation in the Ni 65 Zr 35 system can be attributed to the slow dynamics of 〈0, 3, 6, 4〉, 〈0, 2, 8, 2〉 and 〈0, 1, 10, 2〉 Ni-centered Voronoi polyhedra. The local atomic order and dynamics for Cu 65 Zr 35 and Ni 65 Zr 35 systems are remarkably different, and these differences are presumed to hinder crystal nucleation and growth, hence promoting the largely different bulk glass-forming ability. Molecular dynamics simulation with well-developed EAM potentials was carried out to investigate the transport properties and local atomic structure of Cu-Zr and Ni-Zr metallic glasses and supercooled liquids.