Nanostructure Development of Al-Fe Eutectic Alloy

The effects of cooling rates on the microstructure development of an Al-Fe eutectic alloy were studied. Two different cooling rates of 0.03 and 61.00 °C/s were applied to the solidifying alloys. To unfold the characteristics of phase changes and the microstructure evolution taking place during solidification, the recorded cooling curves based on temperature measurements were analyzed by thermal analyses, in which the first and second differences of the cooling curves were derived. The slow cooling resulted in the formation of only the eutectic Al phase and the eutectic Al-Fe phase in the microstructure identified by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). With the cooling rate increasing to 61.00 °C/s, the primary Al phase appeared, as the solidification became strongly non-equilibrium. A large quantity of the nanosized eutectic Al-Fe particles were detected. Overall, the microstructure refined substantially.