Effects of Post Weld Aging on the Mechanical Properties and Microstructure of TIG and MIG Welded AA 7075

Abstract In this study, the effect of post-weld artificial aging has been investigated on Tungsten Inert Gas (TIG) and Metal Inert Gas (MIG) welds of Aluminum Alloy 7075 (AA 7075). Artificial aging has been carried out for several durations at a temperature of 125 °C. In order to study the effect of post-weld aging, microstructural examination, hardness measurements and room temperature tensile tests have been carried out. The results show that TIG and MIG welding caused an increase in grain size in the HAZ and the weld metal as compared to the base material. After post-weld aging, it turned out that the mechanical properties of MIG welds increased while those of TIG welds decreased for the same aging conditions, compared to as-welded joints, while the grain sizes are not significantly affected from the aging process.