Correlation of viscosity with atomic packing in Cu50Zr50 melt

The viscosities of Cu50Zr50 melt from 1250 K to 1435 K were measured in a containerless electromagnetic levitator under microgravity. The viscosity in the investigated temperature range can be expressed by an Arrhenius temperature dependence η(T) = η0 exp(EA/kBT), with η0 = (0.08 ± 0.02) mPa·s and EA = (0.58 ± 0.03) eV. We find a correlation between the fraction of closer neighboring atoms, f, and viscosity, which is described by η = expn f m, where n = 1.746/Δpec-4.478, m = −0.374/Δpec + 0.440, and Δpec is the excess potential energy, indicating that the temperature dependent viscosity during cooling is controlled by the fraction of closer neighboring atoms.