Influence of welding processes on mechanical properties of aluminum alloy 2219

Both types of welds, friction stir welds of aluminum alloy 2219 and variable polarity gas tungsten arc welds of the same alloy were made and mechanical properties were evaluated by tensile testing. It is shown that the FSW welds had better performances than VPTIG welds, although both welding processes decreased the mechanical properties of aluminum alloy 2219 base metal plates. The weld metals and base metals were characterized by scanning electron microscopy and optical microscopy. According to fractography and microstructures analysis, the weld nugget zone (WN), where the dynamic recrystallization occurred, consisted of refined and equiaxed grains structure and FSW tensile specimens fractured at the retreating side. Variable polarity TIG specimens are liable to produce defects such as a high concentration of gas porosity and fusion zone is the weakness.