Numerical and experimental analysis on friction stir welding of the dissimilar materials 6061-T6 AA and pure copper

Abstract

The paper presents the numerical and experimental model of friction stir welding of 6061-T6 Aluminium alloy (AA) and pure Copper (Cu). The heat transfer model coupled with the fluid flow model is established and computed in COMSOL Multiphysics V5.3a software. In the experiment, the 6061-T6 AA (soft material) plate is placed on the advancing side (AS), and a pure Cu (hard material) plate is placed on the retreating side (RS). The thermograph results were plotted using an infrared thermal imager (IR camera). The mechanical analysis of the weld specimen revealed that the hardness of the aluminium-copper weld joint was around 224HV0.2, and the tensile strength of the specimen was recorded at around 190 MPa and 175 MPa in the transverse and longitudinal direction of the weld joint line direction, respectively. The microstructural observation of the weld specimen revealed that the softer material (6061-T6AA) deformed and easily flowed towards the harder material side (Copper). However, the harder material (Copper) fragments were available on the 6061-T6 AA side. The high-pressure zone was created on the tool leading zone, and the rotating tool drags the plasticized material towards the 6061-T6 AA side (AS).