Macrostructural and Microstructural Analysis of Bonding of Copper Tubes to Carbon Fiber Composite Tubes by Electromagnetic Joining

Today, an increasing demand for the lightweight materials in automotive, aircraft, railway, and marine industries has led to an increase in utilization of materials such as composites, aluminum alloys, copper, high-strength steel, and magnesium alloys. In this context, new methods called solid-state joining have been developed to join metals effectively. Among these methods, electromagnetic joining stands out for its cost-efficiency and high speed. This research investigates the effect of voltage parameter on mechanical properties, hardness, and microstructure of the composite joints to copper using electromagnetic bonding method. The results indicated that as the voltage increases, the bond between the two tubes becomes stronger, with the joining force reaching 2.3 kN at a voltage of 8 kV. At voltage of 8 kV, due to an increase in the impact velocity, more severe plastic deformation occurs in the specimen, compared to those in the other specimens. This causes an increase in the hardness of the specimen which was about 8% higher than that of the 5 kV specimen. Furthermore, microstructural examination revealed that with an increase in voltage, a continuous joining was created between the two tubes and there was no gap between the two surfaces, resulted in sufficient strength of the joining.