Formation and evolution of Al/steel interface structure in composite casting

Al/steel composite materials were prepared using liquid-solid composite casting method, with aluminum as the liquid and 45 steel rods as the solid. The key factors affecting the formation and evolution of intermetallic compounds at the Al/steel reaction interface were studied. Results show that the defects present in the intermetallic compounds prepared at a liquid temperature of 900 °C and a holding time of 20 s are the least. The average hardness of Fe2Al5 phase is 3 times higher than that of 45 steel and more than 7 times higher than that of pure aluminum. The average shear strength of the sample obtained through air cooling is higher than that of water cooling, and Fe2Al5 phase is the main reason for the brittle fracture of the sample. The activation energy calculation of intermetallic compounds reveals that Fe2Al5 is easy to grow up than FeAl3 phase under air cooling conditions, and FeAl3 is easy to grow up than Fe2Al5 phase under water cooling conditions. This work offers assistance in studying the formation of intermetallic compounds during composite casting processes.