The wettability and metallurgical bonding between molten Mg and Al substrates can be improved by using the brazing flux QJ207 to remove the oxide film on the surface of Al substrates. The as-prepared Mg-Al bimetallic samples with varied Si contents can be produced via adjusting the Si contents in Al substrates. The microstructure and mechanical properties of the AM60/Al Si alloy were investigated by SEM

EDS

XRD and tensile testing. The results reveal that Mg

2

Si can be generated in the transition layer with the increase of Si content in Al substrate. When the Si content reaches 5. 5%

the Mg

2

Si particles are connected with each other to form a Mg

2

Si layer

and Mg

2

Si layer is tended to the interface with Si content increase. With Si content of 12. 5%

the Mg

2

Si layer is transfered to the interfacial surface to inhibit the generation of the intermetallics and the brittle phases in the transition layer effectively

so mechanical properties of the composites prepared are improved.