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

Highlights: → 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. -- Abstract: 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.