Friction stir-induced brazing of Al/Mg lap joints with and without Zn interlayer

The interfacial structure and mechanical properties of Al/Mg joints with and without Zn interlayer by friction stir-induced brazing bond have been investigated. The results revealed that the formation of brittle Al-Mg intermetallics could be effectively suppressed by the addition of Zn interlayer and using appropriate welding parameters, which were replaced by (Mg)+Mg-Zn and Al-Mg-Zn intermetallic. When rotation speed was further increased, Al-Mg intermetallics were formed again at the interface. The shear strength of Al/Mg joints with Zn interlayer was improved by up to similar to 25% in comparison with those of the joints without Zn interlayer. A mixture of ductility and cleavage fracture occurred on fracture surfaces of Zn-added joints which was different from the cleavage fracture feature of the direct joints.