Interface microstructure and mechanical property of CMT welding-brazed joint between aluminum and galvanized steel sheet

Welding-brazing experiment of aluminum and galvanized steel was conducted with cold metal transfer method. The interface microstructure and mechanical property of the joint were analyzed by SEM, EDAX and transverse tensile test. The results indicate that good lap joint between aluminum and galvanized steel sheet can be made in appropriate parameters. The interface turns to be thin from middle to the edge with the components changing from FeAl₃ intermetallics to a compound of α solid solution and FeAl₃ intermetallics. Meanwhile, a rich-zinc zone composed of α solid solution and aluminum at the edge of weld metal exists. In the tensile test, fracture appears in the heat affected zone of aluminum base metal, and its tensile-strength is 72.09 MPa.