Abstract
Dissimilar metal joining techniques are necessary for the manufacturing of a number of structures and parts in the industries. Aluminium and copper are widely used in engineering structures, due to their unique performances, such as higher electrical conductivity, heat conductivity, corrosion resistance and mechanical properties even if they have considerable differences in their melting points. Among the aims for future years in the automotive industry is the development and implementation of new technologies, including a broad application of friction stir spot welding (FSSW) of similar and dissimilar materials.
Friction stir spot welding (FSSW) is a variant of friction stir welding (FSW) for spot welding applications. Joining aluminium and copper to meet the requirements from the electrical industry have been conducted by using different joining techniques, such as ultrasonic welding, friction welding and laser welding. However, the major challenge with these techniques is the occurrence of brittle intermetallic compounds in the joint zone. FSSW has been successfully used to join aluminium and copper by a few researchers; but more research is needed to investigate the evolving properties of FSSW between copper and aluminium.
The current research project joined 3 mm thick AA1060 and C11000, by using friction stir spot welding (FSSW), and by using different tool geometries namely a flat pin/flat shoulder and a conical pin/concave shoulder and different process parameters, in order to fill the gap in the literature in this field of study. Limited research results exist on friction stir spot welding between aluminium and copper. However, the successful joining of these two materials has the potential for many applications in the industry. The spot welds were produced and characterised through optical microscopy, and by scanning electron microscopy for the microstructural evolution; while the chemical and phase identification were analysed using energy dispersive spectroscopy and X-ray diffraction, respectively.
Furthermore, tensile testing, microhardness profiling, residual stress analysis, electrical resistivity and statistical analysis were also conducted. This was done to investigate the relationship between the process parameters, the tool geometry and the produced welds. The real time forces acting during the welding process were monitored and analysed. It was observed that the maximum forge...
D.Phil. (Mechanical Engineering Science)