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.