Interface behavior of diffusion bonding AZ31 magnesium alloy to 3003 aluminum alloy using silver-based interlayer

In order to connect magnesium to aluminum reliably, the AZ31 magnesium alloy/3003 aluminum alloy was diffusion bonded with the silver copper zinc alloy under argon atmosphere. The microstructure, composition, and mechanical properties of the joints have been studied. The results showed that a complete metallurgical bond was formed at the 420 ℃ for 120 min, and obvious diffusion layers were formed at the interfaces between the base metals and the interlayer. The thickness of the diffusion layer on the aluminum side was greater than that on the magnesium side, aluminum diffused to a farther position than magnesium. The distribution of aluminum in the interlayer was in a gradient from outside to inside. The hardness of the diffusion layer near aluminum is 194 HV, and that near magnesium is 111 HV, both of which are significantly higher than the adjacent base metal. The hardness distribution of the joint is V-shaped. The maximum tensile shear strength of the joint is 71 MPa, and the tensile shear fracture morphology of the joint is cleavage fracture. The formation mechanism and structural characteristics of AZ31/AgCuZn/3003 diffusion joints have been revealed, which can provide novel ideas and evidences of interlayer components and interface behavior for the subsequent research work on Mg/Al dissimilar metal bonging.