Comparison of MIG welding and laser -MIG welding of high strength aluminum alloy

The 20 mm thick 2519-T87 high strength aluminum plates were welded by MIG welding and CO₂ laser -MIG hybrid welding process.And the welding efficiency, microstructure and mechanical properties of welded joint were compared.Results indicarte that the efficiency of laser-MIG hybrid welding is 5 times of that of MIG welding, and the tensile strength of the joints has been improved, reaching 70% of the tensile strength of base material, while the tensile strength of MIG welded joints is only 60% of that of the base material.Because of the low heat input of laster -MIG hybrid welding, the condition of the fluid flow and temperature gradient are different from that of MIG welding, resulting in the finer microstructure in weld center, and the equiaxed zone near the bond line which often occurs in MIG welding disappears.