Dissimilar welding of aluminum alloys 2024 T3 and 7075 T6 by TIG process with double tungsten electrodes

Abstract The aim of this work is to study the metallurgical and mechanical properties of dissimilar assemblies of 2024 T3 and 7075 T6 structural hardening aluminum alloy by TIG twine electrode arc welding process. It will include a weld performed according to optimized welding parameters followed by a study of the macroscopic and microscopic evolution of the dissimilar assembly (2024–7075) using optical and scanning electron microscopy (SEM); In addition, the phase compositions were analyzed with an energy dispersive spectrometer (EDS). Tensile and microhardness tests were performed. The tensile fracture was observed by SEM. We have found that this process thins the weld bead and reduces the size of the heat affected zone (HAZ) of the welded joint. The microhardness is lower in the melted area and higher on the side of the area affected by the heat especially for 7075 alloy, resulting in brittle strength and a sudden drop in breaking strength.