Properties of glass-forming metallic liquids: when is there a hard-sphere-like behaviour?

摘要

Chathoth and coworkers (Phys. Rev. Lett. 101, 037801 (2008)) have reported examples of multicomponent glass-forming metallic liquids in which the packing fraction appears to be a dominant parameter. Here, we first summarise, for 15 pure liquid metals, properties of the Ornstein-Zernike direct correlation function c(r) which provide a necessary, though not sufficient, condition for hard-sphere-like (HS) liquid behaviour. Returning to multicomponent melts, NiNb and NiNbSn systems have been studied by Chathoth and coworkers. Pure Ni, according to c(r) data near melting, satisfies the necessary condition for HS behaviour, while Sn certainly does not. But the Sn concentration is low in the metallic glass-forming liquid NiNbSn investigated by Chathoth and coworkers. Suitable experimental diffraction data to obtain c(r) in pure liquid Nb seems not to be available presently. Finally, a brief discussion is given of atomic transport in supercooled multicomponent metallic liquids, the status of the Stokes-Einstein relation being one focus.