(1. School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, China) (2. Engineering Department, Bohai University, Jinzhou 121013, China)
Al-10Si alloy powder and pure Al powder (with a ratio of 1∶1) were mixed as the intermediate layer, and the diffusionbonded Mg/Al joints with the interlayer have been investigated. Scanning electron microscopy (SEM) and electron probe (EPMA) were used to analyze the microstructure and element distribution in the interface region. The results show that elemental diffusion occurs between the mixed powder layer and the bases, forming a gradient structure reaction layer. Al3Mg2, Al12Mg17, Sirich phase and Al12Mg17 + Mg eutectic layers are observed in the interface from Al side to Mg side. The thickness of the Sirich phase layer is greater than that of the other three layers. The hardness test results show that the average hardness value of aluminum and magnesium bases are 242 and 478 MPa, respectively. The Al3Mg2 intermetallic compound layer near the Al side has the highest hardness, which reaches 2520 MPa. Meanwhile, the average hardness value of the Al12Mg17 + Mg eutectic and the Sirich phase layers are 2100 and 1980 MPa, respectively. Tensileshear test results show that the bonding strength of Al/Mg joint with the interlayer is 23 MPa. The XRD analysis shows that the fracture site is located in the Al3Mg2 layer. The fractures exhibit typical brittle fracture characteristics.