Dissimilar Joining of Metal/Polymer Using Friction Stir Spot Welding Method

In the joining of aluminum and polyethylene sheets with friction stir spot welding method, various factors affect the strength of joints. In this study, the effect of surface conditions and the dwell time of tool have been investigated. The results indicated the increased shear tension load with the prolonged dwell time due to the higher frictional heating, more molten polyethylene formation and an increased adhesion area. The use of mandrill that created more scratches with smaller dimensions was more effective to increase the strength. The highest shear tension load of joints was 785 N. Macroscopic and microscopic studies revealed that the mechanical interlocking and adhesion of molten polyethylene on the aluminum surface were the main joining mechanisms.