Tool Rotational and Tool Travel Parameters Influence On Friction Stir Welded Dissimilar Joints Properties

Abstract

Present work is to examine the effects of tool rotational and tool travel parameters on Friction Stir Welded (FSW) dissimilar joints mechanical and microstructural characteristics for 3 mm thick pure copper and 6061 aluminium alloy plates. Welds were made with a cylindrical tapered pin to achieve this goal. The tool rotational speed and tool travel speed are the primary FSW factors considered in this study. Copper plates were kept on the joint's advancing side. Tensile and bending tests are carried out to assess the tensile and bending strength of weld joints in accordance with ASTM standards. Vicker's microhardness tests were carried out in the transverse direction of the weld to check the hardness distribution in weld nuggets. An experimental analysis shows that the best tensile strength 98 MPa and bending stress 16.6 MPa are achieved at tool rotating speeds of 1000 rpm and 62 mm/min, correspondingly. The larger concentration of copper particles in the aluminium region is mostly to blame for this. For 1400 rpm and 62 mm/min, a nugget zone hardness of 190 HV is attained. The presence of more Cu particles on the Al side is evident in SEM pictures, and the higher tensile and bending strength is mostly attributable to the Cu particles covering the Al material in the weld zone. According to X-ray analysis, the synthesis of intermetallic complexes such Al4Cu9, Al2Cu, AlCu, and AlCu4 explains the chemical reaction and phase transformation at the interfaces. The maximum strength values improved because of these intermetallic compounds' proper metallurgical bonding and thinnest thickness. According to fracture analysis, joints with higher strengths have intergranular fracture, while joints with lower strengths experience brittle fracture on both aluminium and copper joints.