Hybrid laser-Metal Inert Gas welding of Al–Mg–Si alloy joints: Microstructure and mechanical properties

• Microstructure and mechanical properties of the welded joint have been investigated.
• Reasons for the strength loss of the welded joint have been discussed.
• The distribution of strengthening elements has been obtained using synchroton radiation X-rays.

Hybrid fiber laser-Metal Inert Gas (MIG) welding is an advanced joining technology that is increasingly employed in the modern industry. In this paper, hybrid fiber laser-MIG welding was applied to join 5 mm thick AA6005-T5 alloy used in the carbody of high-speed railway vehicles. The mechanical properties of the hybrid welded joints were investigated. The results showed that the hybrid welded joints have more excellent mechanical properties than that of the MIG joints. However, there is still strength loss in the hybrid welded joins comparing with the base metal. The reason for the loss of the strength was studied from the aspects of microstructure and vaporization of strengthening elements.