Finite Element Simulation and Experimental Verification of HAZ Softening during Welding of Aluminum alloy 7075

the one-of-a-kind properties of series 7xxx aluminum alloys such as high strength, relatively low density, good formability, and good resistance to stress corrosion cracking have made this class of materials a good choice for aerospace, automobile, and marine industries. Watertight, low weight, and fast procedure are the reason why welding is used in many industries. The heat that welding produce causes many problems like softening in the heat-affected zone. In this research with the use of a 3-D finite element model, the heat transfer of the Al-7075-T6 is investigated and verified by comparing them with the experimental model and the reduction of hardness in the heat-affected zone of the aluminum was predicted with good precision. In the next step, the softening of HAZ due to welding was measured with microhardness. With the use of the FEM model kinetic of over-aging was measured. The results show hardness of the alloy has two sources i.e. age-hardening and work-hardening. It seems welding eliminates the effects of age-hardening but has no effect on the hardness that comes from work hardening. Also, the decrease in the hardness of the solution-annealed area can be recovered through proper heat treatment. However, it is unrecoverable in the over-aged area.