Effect of welding parameters on the microstructure and mechanical properties of the friction-welded dissimilar joints of AA6063 alloy and faying surface-tapered AISI304L alloy

Mechanical bonding between dissimilar metals is challenged due to the differences in their properties. In this paper, the influence of tapering in friction welding (FW) between AA6063 and AISI304L and the effect of welding parameters are investigated to obtain quality joints. Different experiments were carried out for this study with main influencing parameters such as upset pressure (UP), friction time (FT) and friction pressure (FP). Tensile test, impact test and microhardness distribution along weld zone, heat affected zone (HAZ), parent zone of welded joint were evaluated and the results were compared. Microstructure study observed by scanning electron microscopy (SEM) revealed the bonding between two dissimilar metals. Fractography analysis showed the dimple rupture. Tensile strength and peak load increased with increasing friction pressure. The formation of intermetallic compounds at the weld interface was confirmed with the EDX spectrum. The tapering on faying surface of SS304L specimen reduced the friction time needed for sound weld joints and increases the properties of joint. Since no appreciable researches have been done on the joining between AA6063 and AISI304L with minimum working pressure through FW, special attention was given to this work with a taper on faying portion. The minimum parameters required for the joining were also understood through this investigation.