Investigations on Dissimilar Welded Joints by Magnetic Pulse Method

Abstract

Experimental investigations on magnetic pulse welding of dissimilar materials are carried out in this study. Detailed studies are carried out to assess the mechanical properties, microstructure and interface pattern of lap joint of Aluminium alloy tube and Copper alloy rod by Magnetic Pulse Welding (MPW). The torsion strength values are higher than that of the aluminium tube when the discharge voltage of MPW process is not less than 6 kV. The joint basically comprises of interfaces, non-uniform transition zone and base metals obtained under discharge voltage of 10 kV, the contact angle being 50° and radial gap of 1.2-1.4 mm. It is observed from microstructure examinations that high-density dislocations are present in basic metals along the interfaces. The transition zone appears to have higher hardness as compared to the other classified zones based on the metallurgical configurations. The multidirectional micro-cracks and micro-apertures characterise the transition zone of MPW joint. The mutual diffusion of Cu and Al elements occurs in the transition zone, where content of Al element is higher than Cu element besides a narrow region close to the interface of Cu and Al zone. Through this investigation, the suitability of MPW for joining dissimilar conductive materials is established.