Unexpected Universality in the Viscosity of Metallic Liquids

TL;DR

This paper demonstrates a universal behavior in the viscosity of metallic liquids, showing it follows a common function related to temperature and cooperative motion, with implications for understanding the glass transition.

Contribution

It reveals a universal relationship between viscosity and temperature in metallic liquids, linking viscosity to the onset of cooperative motion and the glass transition.

Findings

Viscosity follows a universal function of Tcoop/T.

Extrapolated infinite temperature viscosity is approximately nh.

Universal relation connects viscosity to glass transition temperature.

Abstract

The range of the magnitude of the liquid viscosity as a function of the temperature (T) is one of the most impressive of any physical property, changing by approximately 17 orders of magnitude from its extrapolated value at infinite temperature to that at the glass transition. We present experimental measurements of containerlessly processed metallic liquids that reveal that the ratio of the viscosity to its extrapolated infinite temperature value follows a universal function of Tcoop/T. The temperature Tcoop corresponds to the onset of cooperative motion and is strongly correlated with the glass transition temperature. On average the extrapolated infinite temperature viscosity is found to be nh, where h is Planck's constant and n is the particle number density. A surprising universality in the viscosity of metallic liquids and its relation to the glass transition is demonstrated.