Microstructure and Mechanical Properties of Galvanized Steel/AA6061 Joints by Laser Fusion Brazing Welding

Laser fusion brazing welding was proposed. Galvanized steel/AA6061 lapped joint was obtained by laser fusion brazing welding technique using the laser-induced aluminium molten pool spreading and wetting the solid steel surface. Wide joint interface was formed using the rectangular laser beam coupled with the synchronous powder feeding. The result showed that the tiny structure with the composition of alpha-Al and Al-Si eutectic was formed in the weld close to the Al side. And close to the steel side, a layer of compact Fe-Al-Si intermetallics, including the Al-rich FeAl3, Fe2Al5 phases and Al-Fe-Si tau 1 phase, was generated with the thickness of about 10-20 mu m. Transverse tensile shows the brittle-fractured characteristic along to the seam/steel interface with the maximum yield strength of 152.5 MPa due to the existence of hardening phases tau 1 and Al-Fe intermetallics.