Role of Third Material (Interlayer) on Mechanical Properties of the AA2024-Copper Joints Carried out by Friction Stir Welding (FSW)

The work focused on improving the mechanical properties of AA2024-Cu joints by introducing a third material in the form of interlayer. The interlayer chosen for this purpose was Zn based on the resultant intermetallic phases that could have formed with matrix. Experiment was carried between AA2024 and copper plates with Zn strip. It included the optimization of tool-offset positions. The welds were characterized by scanning electron microscope (SEM) equipped with electron probe micro-analyser (EPMA) and X-ray diffraction (XRD) techniques. The results showed that the Zn strip diffused well into the AA2024 matrix at the optimum tool-offset position and it had formed more than two intermetallic phases in the processed region, which had improved the strength and ductility of the welds significantly. It concluded that it was possible to enhance the properties by altering the composition and kind of intermetallics by using an appropriate filler metal in the form of interlayer.