In order to improve the bonding strength of the steel/aluminum composite interface

the steel matrix with a large number of convex structures was utilized

which was prepared by sand casting after different pretreatments of plating aid

plating aid + hot dip on the surface of steel substrate. The effects of different surface pretreatment on the microstructure and mechanical properties of steel/aluminum composite interface were investigated. The results indicate that there are a lot of crevices at the interface between steel and aluminum without hot-dip treatment. The interface bonding mode is characterized by mechanical bonding with the poor bonding effect

and the interface shear strength is 9.6 MPa. After the hot-dip treatment of steel matrix

metallurgical bonding occurs at the interface between steel and aluminum

forming intermetallic compound layer composed of Fe

2

Al

5

phase

Al

8

Fe

2

Si phase and Al

4.5

FeSi phase. The thickness of intermetallic compound layer at the convex and the straight interface of steel matrix is 35.3 μm and 29.4 μm

respectively

and the interfacial shear strength reaches 48.7 MPa.