Microstructure of diffusion-bonded Mg-Ag-Al multilayer composite materials

Mg-Al bonded composite materials expand Mg and Al alloys' applications by combining their unique performances together. However, the formation of Mg-Al intermetallic compounds in interface zone of Mg/Al directly-bonded joint seriously obstructs its further development. To solve this problem, Mg-Ag-Al multilayer composite materials have been successfully prepared by diffusion bonding technology. The effect of key process parameter (bonding temperature) on microstructure of this material has been mainly investigated. The results show that Mg and Al were well bonded by using silver interlayer when the bonding temperature exceeded 370°C. But Mg₁₇Al₁₂ and Mg ₂Al₃ compounds were formed in the interface zone at temperatures higher than 420°C. By means of controlling the bonding temperature (380 °C-420 °C), silver interlayer effectively restrained the generation of Mg-Al intermetallic compounds, and Mg-Ag intermetallic compounds (Mg₃Ag, MgAg) were formed in the interface zone instead.