Measurement and calculation of surface tension of undercooled liquid Fe-20 wt.% Cu alloy

Using electromagnetic levitation in combination with the oscillating drop technique, the surface tension of liquid Fe-20 wt.% Cu alloy above and below the liquidus temperature was measured. The containerless state during levitation produces substantial undercooling up to 156 K. In the experimentally covered temperature range, the surface tension of Fe-20 wt.% Cu alloy was determined as 1.658-2.234 × 10^-4 (T-1736) N/m. According to Butler's equation and STCBE software, the surface tension of Fe-20 wt.% Cu alloy was also calculated. A good agreement was found between the calculated and experimentally measured values within the error limits. The different sign of the temperature dependences of the calculated and measured surface tensions is preliminarily discussed.