RESEARCH PAPER |
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Effects of Post-weld Aging Treatment on Friction Stir Welding Joint of 6082-T6 Aluminum Alloy |
WANG Xijing, WEI Xueling, ZHANG Liangliang
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State Key Laboratory of Gansu Advanced Nonferrous Metal Materials, School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050 |
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Abstract Microstructure evolution and mechanical properties of friction stir welded 6082-T6 aluminum alloy during post-weld natural and artificial aging treatment were investigated by means of transmission electron microscope(TEM), scanning electron microscope (SEM), tensile test machine and Vickers hardness tester. The results show that microhardness of the joint after artificial aging treatment was about 10-25HV higher than welded and naturally aged alloy. Artificial aging was superior to natural aging on improving the microhardness of the nugget zone and heat affected zone. After post-weld natural aging or artificial aging treatment, the mechanical properties of welded joint was improved to certain extents.The tensile strength increased by 12% and elongation decreased by 9% after artificial aging, compared to natural aging. Artificial aging was more effective for tensile strength improvement. After artificial aging, the microstructure of the nugget had significant changes. NZ was mainly GP zone and the microhardness increased with the increase of the cluster size and the GP region after artificial aging treatment. HAZ was mainly coarse β′, but microhardness had little change after artificial aging treatment.It is found that the shape of precipitates can be determined by the interface energy and strain energy via microstructure analysis.
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Published: 25 April 2017
Online: 2018-05-02
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