Measurement of the heat of fusion of Fe–Ni alloys using a closed-type aerodynamic levitator

Abstract Despite its essential importance for heat transfer at the liquid–solid interface and for applications such as casting and welding, the heat of fusion of Fe–Ni alloys has been difficult to measure because of reactions with containers and oxidation. In this study, we conducted fully containerless and contact-free measurements of the heat of fusion for Fe–Ni binary alloys using a closed-type aerodynamic levitation method, which effectively eliminates container interactions and suppresses oxidation. The measurements, based on the determination of the hypercooling limit, revealed that the heat of fusion of the Fe–Ni alloys is lower than that predicted by the ideal solution model. The compositional dependence of the heat of fusion was well reproduced using a quadratic fitting with an excess parameter of − 8.8 kJ mol 1 for compositions with x Ni > 0.4. A larger negative deviation was observed for Fe80Ni20, indicating increased nonideality in the Fe-rich compositions. These results suggest that the heat of fusion may be influenced by local structural features of the melt near the melting temperature.