Estimation of The IMC Layer Thickness of Friction-Stir-Welded Aluminum/Copper Lap Joints By Using Temperature Simulation

Abstract

Many studies demonstrated the suitability of Friction Stir Welding (FSW) for joining dissimilar materials. Especially the combination of aluminum and copper is of high interest for many applications. Intermetallic compounds (IMC) forming during FSW due to interdiffusion and the thickness of the IMC layers strongly influence the joint properties, e.g. the joint strength or the thermal and electrical conductivity. Therefore, it is important to predict the IMC layer thickness to tailor the joint properties to the individual application. For this purpose, a thermal-pseudo-mechanical model was built to simulate the temperature field during FSW of aluminum EN AW-1050 and copper CW008A in lap joint configuration. The simulated temperatures as well as the heat inputs corresponded well with experimental data for a wide range of parameter settings. In order to estimate the IMC layer thickness, the simulated temperatures close to the interface of the materials were used. Two approaches for calculating the layer thicknesses were compared. In the first approach, the thickness is calculated based on the peak temperature lasting for several seconds at the interfacial area. This approach was applied for constant feed rates, while the second approach also accounted for the cooling slope and could therefore be used for different feed rates.