Simulation of dissimilar friction stir welding of AA7075 and AA5083 aluminium alloys using Coupled Eulerian–Lagrangian approach

Abstract

Temperature, strain and material flow during the friction stir welding (FSW) process are factors that determine the quality of the resulting joint. Examining these features by experimental methods is very difficult, so the numerical method is developed. This paper focuses on simulating the FSW of AA5083 to AA7075 aluminium alloys. At first, in order to investigate the materials mixing and also to study the microstructural properties and hardness of the samples, the samples were welded using a milling machine. Then, according to the used parameters, the process was modelled. For this reason, a Coupled Eulerian–Lagrangian (CEL) was employed to estimate thermal, strain and material mixing. Comparing the stir zone (SZ) of the joint produced and predicted by simulation revealed that the CEL approach has well-determined the material mixing in the SZ. The experimental results show that the highest hardness value is 112 HV in the thermo-mechanically affected zone of AA7075 alloy. The numerical results indicate an unequal strain distribution along the weld centre line due to the lower strength of AA5083 and a ‘positive’ interaction between the tool welding and rotational speed on the advancing side.