Steel-Aluminum compound materials were fabricated by inlay casting with un-modification &hot-dip aluminizing（U&H）and surface modification & hot-dip aluminizing（S&H）treated steel as substrates

and the as-cast and T6 heat treatment microstructures and bonding properties of Fe/Al interface were investigated.The U&H casting samples reveal that a variety of gaps exist and metallurgical bonding is absent at the Fe-Al interface.Compared with untreated ones

the interfacial combination of U&H castings is improved

where the bonding force reaches 60.30 kN

increased by 21.23%

and the gap rate is reduced to 10.99%.However

the composite casting samples with S&H treatment reveal the satisfied interface properties with two kinds of interfaces including Fe-Al and Al-Al.The occurrence of"zigzag-shape"transition layer at the Fe-Al interface indicates the existence of metallurgical bonding.Compared with those of U&H castings

the interfacial bonding strength of casting with S&H treatment is improved by more than 13.85%and the gap rate is reduced as low as 2.93%.After T6 heat treatment of S&H modified castings

the thickness of transition layer is increased significantly

especially the"zigzag"whose average length is increased from 31μm to 46μm.And the composition of transition layer is more homogeneous

improving the interfacial force up to 79.71 kN.