Study of viscosity of Fe-Cr melts containing 2 to 40 at % of chromium

The temperature, time, and concentration dependences of viscosity ν of Fe-Cr melts containing 2 to 40 at % of chromium are studied. It is shown that the observed anomalies in viscosity polytherms in the first heating mode and the hysteresis of ν in subsequent cooling are due to the slow setting of thermodynamic and chemical equilibrium in the system of crucible-melt-atmosphere, which is shifted to higher temperatures with increasing oxygen content in the alloy. The minimum and maximum of viscosity are observed at 5 and 12 at % of Cr, respectively; they are caused by a concentration change in the binding energy between the atoms, which is determined by the geometric and compositional short-range order. The nonequilibrium state of the melts has no significant effect on the nature of their viscosity isotherms.