Structural features and the microscopic dynamics of the three-component Zr 47 Cu 46 Al 7 system: Equilibrium melt, super
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Structural Features and the Microscopic Dynamics of the Three-Component Zr47Cu46Al7 System: Equilibrium Melt, Supercooled Melt, and Amorphous Alloy R. M. Khusnutdinoffa,b*, A. V. Mokshina,b**, B. A. Klumovb,c,d, R. E. Ryltsevb,e,f, and N. M. Chtchelkatchevb,g,h a
Kazan Federal University, Kazan, 420008 Russia Landau Institute for Theoretical Physics, Russian Academy of Sciences, Chernogolovka, Moscow oblast, 142432 Russia c Aix-Marseille-Université, CNRS, Laboratoire PIIM, UMR 7345 13397, Marseille Cedex 20, France d Joint Institute for High Temperatures, Russian Academy of Sciences, ul. Izhorskaya 13/19, Moscow, 125412 Russia e Institute of Metallurgy, Ural Branch, Russian Academy of Sciences, ul. Amundsena 101, Yekaterinburg, 620016 Russia f El’tsin Ural Federal University, ul. Mira 19, Yekaterinburg, 620002 Russia g Moscow Institute of Physics and Technology, Institutskii per. 9, Dolgoprudnyi, Moscow oblast, 141700 Russia h Institute of High-Pressure Physics, Russian Academy of Sciences, Troitsk, Moscow oblast, 142190 Russia *e-mail: [email protected] **e-mail: [email protected]
b
Received January 22, 2016
Abstract—The structural and dynamic properties of the three-component Zr47Cu46Al7 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 Zr47Cu46Al7 system, which is found to be Tc ≈ 750 K. It is found that the bulk amorphous Zr47Cu46Al7 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 (C L (k, ω)) and transverse (CT (k, ω)) fluxes are calculated in a wide wavenumber range in order to study the mechanisms of formation of atomic collective excitations in the Zr47Cu46Al7 system. It was found that a linear combination of three Gaussian functions is sufficient to reproduce the C L (k, ω) spectra, whereas at least four Gaussian contributions are necessary to exactly describe the CT (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. DOI: 10.1134/S1063776116060042
1. INTRODUCTION Amorphous metallic alloys represent a new class of structural and functional materials with extraordinary properties, which differ from the properties of their crystalline analogs [1–3]. For example, amorphous metallic alloys have a high strength and elasticity and good plasticity during strong deformation [4, 5]. On the whole, this class of materials is characterized by a wide spectrum of un
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