A novel weld-bonding hybrid process for joining Mg alloy and Al alloy

A novel weld-bonding hybrid process is carried out to join Mg alloy and Al alloy, and the technology combines a modified metal inert gas (MIG) spot welding process with adhesive bonding. The Mg base metal and the fusion zone are metallurgical connected by an Al–Mg transition layer with the thickness of 30–60 μm. Single nugget of spot welded joint can offer high shear strength of 130 MPa, which reach 81% of that of Mg base metal. The increased strength is due to the intermetallic layer being formed at the region with low stress, so the joint fractures in an Al-rich dendritic region. Superior mechanical properties can be obtained by weld bonded joint, benefiting from the advantages of both welding and adhesive bonding.

► The novel modified MIG spot welding and MIG spot weld bonding have not been reported.
► The modified MIG spot welded joint can offer 130MPa shear strength in welding Mg to Al.
► Intermetallic can be formed at the region with low stress through designing the joint.
► Thickness of the intermetallic layer can be controlled within 30-60μm.
► MIG spot weld bonded joint can offer superior mechanical properties.