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 the 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. This paper suggests that when the double tungsten electrode TIG welding is used, a stable arc has been formed with a good bead appearance. The heat dissipated by the arc generates several zones (molten zone (WZ), bonding zones (LZ), heat-affected zones (HAZ)) with different microstructures or precipitates of the type θ (Al2 Cu), S (Al2 Cu, Mg) and η (Mg Zn2), S (Al2 Cu Mg) are formed in the heat-affected zone (HAZ) of base metals 2024 and 7075 respectively. The microhardness is lower in the molten zone and higher in the heat-affected zone of 7075 T6 alloy, which cried out an embrittlement and a 44% and 37% drop in the tensile strength of 7075 T6 and 2024 T3 base metals respectively.
Highlights
Today, the search for new designs that allow either to fulfill a new functions or to lighten existing structures [1]
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)
We have found that this process thins the weld bead and reduces the size of the heat affected zone (HAZ) of the welded joint
Summary
The search for new designs that allow either to fulfill a new functions or to lighten existing structures [1]. Aluminum and its alloys are some of the most widely used materials in the industry, especially in the aeronautics and aerospace industry. The structural hardening alloys of the 7xxx and 2xxx series are the most widely used alloys; they are characterized by high mechanical strength and high corrosion resistance [2]. The assembly of these materials by welding is a challenge [3] for manufacturers and technologists, especially for heterogeneous assemblies. The high thermal conductivity generates lime cracks and deformations during welding ... [4, 5, 6] For this reason, research has been carried out to study the feasibility of heterogeneous joining of aluminum alloys using TIG, MIG, high energy LASER beam and lately FSW
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