Enhancing mechanical properties of friction stir welded joints of Al-Si-Mg alloy through post weld heat treatments

In the present research, three different post weld heat treatments were carried out on friction stir welded joints of precipitation hardening Al-Si-Mg alloys to explore their effect on microstructure and mechanical properties. In general, applied post weld heat treatments significantly affected the microstructure and morphology of a aluminium grains and strengthening precipitates in all the zones of friction stir weld joints. Post weld heat treatments homogenized the morphology of strengthening precipitates. Artificial aging resulted in better combination of tensile properties than other post weld heat treated weld joints. Solution treatment with artificial aging can be used to improve tensile strength at the expense of % elongation while solution treatment is not viable option to improve joint performance. Post weld heat treatments also affected the mode of fracture during tensile test. (C) 2017 Elsevier Ltd. All rights reserved.