Abstract
Intermetallic layer of dissimilar tungsten inert gas welding–brazing butt joint of aluminium alloy/ stainless steel has been studied. A visible unequal thickness intermetallic layer has formed in welded seam/steel interface, and the thickness of the whole layer is <10 μm. The interface with Al–12Si filler metal consists of τ 5-Al8Fe2Si layer in welded seam side and θ-(Al,Si)13Fe4 layer in steel side with the hardness values of 1025 and 835 HV respectively, while the interface with Al–6Cu filler metal consists of θ-Al13(Fe,Cu)4 layer with the hardness of 645 HV. The average tensile strength of the joint with Al–12Si filler metal is 100–120 MPa, and the fracture occurs at θ-(Al,Si)13Fe4 layer, while the joint with Al–6%Cu filler metal presents high crack resistance with tensile strength of 155–175 MPa, which reaches more than 50% of aluminium base metal strength.