Understanding the relationship between atomic structures and transport properties in (Cu0.5Zr0.5)100-xAlx (≤10) glass forming liquids: Molecular dynamics simulations

We have performed a systematic investigation on the atomic structures, thermal and transport properties of (Cu0.5Zr0.5)(100-x)Al-x (x <= 10) glass forming liquids using MD simulations, aiming to underpin the understanding of the relationship between atomic structures and the experimentally observed glass forming ability in the system. A good correlation between the atomic structures and the transport properties has been revealed. Macroscopically, it is found that the composition with x = 7 has the highest viscosity and the lowest diffusivity near the glass transition, which are responsible for the best glass forming around x = 7 or 8 observed experimentally. At the atomic scale, the short range order of both glass forming liquids and the resultant glasses shows a strong dependence on Al additions. By a careful analysis of the chemical environment of the icosahedra and icosahedra-like clusters, we categorize the sub-types of these clusters into three groups according to their behaviors upon Al additions. The sub-types in group III show an excellent correlation between the transport properties and the glass forming ability. We propose that such clusters can govern the transport properties and glass forming ability in (Cu0.5Zr0.5)(100-x)Al-x glass-forming liquids within the studied composition range. (C) 2011 Elsevier B.V. All rights reserved.