Structural features and the microscopic dynamics of the three-component Zr47Cu46Al7 system: Equilibrium melt, supercooled melt, and amorphous alloy

• Published in: Journal of experimental and theoretical physics 2016-08, Vol.123 (2), p.265-276
• Main Authors: Khusnutdinoff, R. M., Mokshin, A. V., Klumov, B. A., Ryltsev, R. E., Chtchelkatchev, N. M.
• Format: Article
• Language: English
• Subjects: Alloys; Aluminum base alloys; Amorphous alloys; Amorphous structure; Atomic excitations; Bulk density; Classical and Quantum Gravitation; Cluster analysis; Copper; Distribution functions; Dynamic characteristics; Elementary Particles; Excitation spectra; Glass transition temperature; Metallic glasses; Molecular dynamics; Order parameters; Particle and Nuclear Physics; Physics; Physics and Astronomy; Quantum Field Theory; Radial distribution; Relativity Theory; Solid State Physics; Solids and Liquids; Wavelengths
• ISSN: 1063-7761; 1090-6509
• DOI: 10.1134/S1063776116060042

The structural and dynamic properties of the three-component Zr 47 Cu 46 Al 7 system are subjected to a molecular dynamics simulation in the temperature range T = 250–3000 K at a pressure p = 1.0 bar. The temperature dependences of the Wendt–Abraham parameter and the translation order parameter are used to determine the glass transition temperature in the Zr 47 Cu 46 Al 7 system, which is found to be T c ≈ 750 K. It is found that the bulk amorphous Zr 47 Cu 46 Al 7 alloy contains localized regions with an ordered atomic structures. Cluster analysis of configuration simulation data reveals the existence of quasi-icosahedral clusters in amorphous metallic Zr–Cu–Al alloys. The spectral densities of time radial distribution functions of the longitudinal ( C̃ L ( k , ω)) and transverse ( C̃ T ( k , ω)) fluxes are calculated in a wide wavenumber range in order to study the mechanisms of formation of atomic collective excitations in the Zr 47 Cu 46 Al 7 system. It was found that a linear combination of three Gaussian functions is sufficient to reproduce the ( C̃ L ( k , ω)) spectra, whereas at least four Gaussian contributions are necessary to exactly describe the ( C̃ T ( k , ω)) spectra of the supercooled melt and the amorphous metallic alloy. It is shown that the collective atomic excitations in the equilibrium melt at T = 3000 K and in the amorphous metallic alloy at T = 250 K are characterized by two dispersion acoustic-like branches related with longitudinal and transverse polarizations.