Flux-free laser joining of aluminum and galvanized steel

Joints between aluminum and galvanized steel pose a challenge for current manufacturing technologies. A hybrid joining method, which combines a pulsed and a continuous laser beam in a single process, has been identified as a potential solution for this challenge. The feasibility of this approach is verified by joining different base material alloys using zinc- and aluminum-based consumables. It is shown that the double beam method can be applied to different joint geometries by joining both double-flanged joints and lap joints. An analysis of the joint microstructure using metallographic cross-sections and transmission electron microscopy shows that intermetallic compounds can be limited to non-critical amounts. Tensile tests show that joint strengths in excess of 150 MPa can be achieved for both types of joint geometries. When shear loads are applied, the use of aluminum-based consumables leads to superior strength.