Viscous Flow of Glass-forming Liquids: A Cluster Approach

ABSTRACTAn accurate description of the structure of a glass-forming liquid has eluded investigators, partly due to the dynamic behaviour that is inherent to liquids. The free volume concept provides a useful descriptor of a structural parameter that can be applied to glass-forming liquids. In previous work, we developed a cluster model to account for the viscous flow of glass-forming liquids (G. J. Fan and H. J. Fecht, J. Chem. Phys. 116, 5002 (2002)). In this work, we found that the kinetic fragility of a glass-forming liquid is quantitatively connected with its entropy of fusion Sf, the value of its melting point Tm, and the structures of interfaces between clusters. We will demonstrate that the proposed cluster model is consistent with an energy landscape model of the glass transition. On the basis of this suggestion, glass-forming liquids, consisting of nanometer-sized clusters, may be responsible for the observed similarity in the mechanical properties between metallic glasses and nanostructured metals.

Viscous Flow of Glass-forming Liquids: A Cluster Approach Academic Article