Effect of adhesive on laser-arc hybrid welding of aluminum alloy to high-strength steel joint

Aluminum alloy 6061 and high-strength steel Q460 were joined by laser-arc-adhesive hybrid welding technology successfully. A Cu alloy interlayer was added between Al alloy and high-strength steel. The effect of the adhesive on laser-arc-adhesive hybrid welding of Al alloy to high-strength steel was discussed. The optical microscope, scanning electron microscope and electron probe micro-analysis were applied to observe the microstructural evolution and phase transition at Al–Fe interface of laser-arc-adhesive hybrid welded joints. The results showed the maximum tensile shear strength of the joint without adhesive was 256 MPa. After adding adhesive, the maximum tensile shear strength reached 282 MPa. The combination of the mechanical bonding and the metallurgical effect could improve the mechanical performances. The shape of the joint in Al alloy changed into a canine-like morphology. There was no porosity in welds because the molten pool of Al alloy and the special keyhole phenomenon of laser welding provided a channel for the decomposed gas to escape from fusion zone.