Investigation of structural and mechanical properties of magnetic pulse welded dissimilar aluminum alloys

The present study aimed to join AA4014 to AA7075 by using magnetic pulse welding (MPW). In addition, acceptable joints were achieved by selecting welding parameters such as collision angle and discharge energy appropriately. Changing collision angle and discharge energy can influence the velocity, leading to the formation of three different types of welding interfaces with wavy, molten wavy and porous morphologies. The formation of these various morphologies is mainly associated with different collision angle parameters. The hardness of the welding interface with molten layer was significantly higher than that of the base metals due to the grain refinement phenomenon occurring through the rapid melting and solidification during MPW process. The formation of porous welding interface is related to gas entrapment and the base metal vaporization. Further, the sample welded with the collision angle of 6 degrees and discharge energy of 7.35 kJ could exhibit the highest rupture force about 13.8 kN among all samples which is related to the wavy welding interface of this sample leading to an adequate bonding between two metals. The lower rupture force of the samples welded with higher collision angle and/or discharge energy can be attributed to microstructural defects such as micro cracks induced by huge plastic deformation.