Investigation of Filler Metal on the Mechanical and Metallurgical Properties of Welding- Brazing Hybrid Joining of Aluminium to Ggalvanized Steel

In the present study, 5083 aluminium alloy sheets by tungsten inert gas welding­-­brazing were joined to galvanized steel sheets with 4043 and 4047 filler wires. The amount of the weld heat and filler metal type influence the­ mechanical and microstructural properties of the resultant joint. The results obtained from microstructural observation showed that with equal weld heat input the thickness of brittle intermetallic compound layer for the joint produced with 4047 filler metal was approximately half of that for joint produced with 4043 filler metal. Energy­ dispersive x-­ray spectrometry analysis results­ showed that the IMCs layer formed in interface of steel-weld seam consisted of Fe­(Al, Si)3 phase­ in side of steel and Al7.3Fe1.7 Si phase in side of welded seam. ­It was found that the joint produced with 4047­ filler metal exhibit­ed higher mechanical resistance of 170 MPa than that produced with 4043­ of 120 MPa. The results of­ x-ray diffraction analysis conducted on the fracture plane showed the presence of Al0.5Fe3Si0.5 phase. Moreover, for joints produced with 4047 filler metal, the FeSi2 phase­­ created from enriching of Si atoms in IMCs layer was seen.