TIG welding-brazing for Al/Cu dissimilar metals using filler material

5052 aluminum alloy and H62 brass dissimilar metals were lap welded by TIG welding-brazing with Al-12%Si flux-cored wire as filler material. Microstructure and mechanical properties of the joint were studied.High-quality welded-brazed joint is difficult to be obtained due to the poor wettability of molten Al-12Si filler material on the surface of brass. Larger size strips of AlCu IMCs are formed in the transition zone at brass side due to the high Al content in the filler material and which reacted with the partially melted and dissolved brass base metal.The formation of Cu₉Al₄ IMC strips severely weak the mechanical properties of joint.The interface layer at brass side consists of two kinds of IMCs layers, which are Cu₉Al₄ and CuZn from the weld to the brass base metal, respectively.Tensile test indicated that the joint fractures at the transition zone or interface layer of the brass side with cleavage fracture surface.