Effect of post-welding aging on the microstructure and mechanical properties of high-strength Al-6.7Zn-1.8Mg-0.2Cu aluminum alloy joints prepared by friction stir welding
Friction stir welding (FSW) is used to weld Al-6.7Zn-1.8Mg-0.2Cu aluminum alloy sheet with 3.2 mm thickness, and the welded joint is subjected to post-welding aging heat treatment, and that is artificial ageing (AA) 120 ℃ × 24 h. The welded and aged joints are studied by scanning electron microscopy...
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Editorial Office of Transactions of the China Welding Institution, Welding Journals Publishing House
2025-01-01
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| Series: | Hanjie xuebao |
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| Online Access: | https://doi.org/10.12073/j.hjxb.20231029001 |
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| author | Shasha HU Cheng QIU Datong ZHANG |
| author_facet | Shasha HU Cheng QIU Datong ZHANG |
| author_sort | Shasha HU |
| collection | DOAJ |
| description | Friction stir welding (FSW) is used to weld Al-6.7Zn-1.8Mg-0.2Cu aluminum alloy sheet with 3.2 mm thickness, and the welded joint is subjected to post-welding aging heat treatment, and that is artificial ageing (AA) 120 ℃ × 24 h. The welded and aged joints are studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), hardness test and tensile test. The results show that the tensile strength of the joint is 470 MPa, the welding coefficient is 80.0%, and the elongation is 10.1%. AA could effectively improve the tensile strength of the joint, which is 525 MPa, 89.6% of the base material (BM). Compared to as-welded joint increases 11.8%. And the elongation is 8.5%. In the FSW process, the precipitated phases in thermo-mechanically affected zone (TMAZ) and nugget zone (NZ) are dissolved and then precipitated after cooling, in which the precipitated phase is mainly η' phase, and the dissolution of GP zone (Guinier-Preston zone) and coarsening of η' phase mainly occurred in the heat-affected zone (HAZ) , and the precipitated phase gradually changed from dissolution to coarsening under different heat input. After welding ageing, GP zone precipitates and GP zone transforms to η' phase, and the existing η' phase at HAZ transforms into coarse η phase. The hardness curve of the joint is obviously W-shaped, the fracture of the FSW joint is in the NZ, and the fracture of the post-welding aging joint is in the HAZ. |
| format | Article |
| id | doaj-art-d088c9dc9cd942d6a9d8a8b8981ecc1b |
| institution | DOAJ |
| issn | 0253-360X |
| language | zho |
| publishDate | 2025-01-01 |
| publisher | Editorial Office of Transactions of the China Welding Institution, Welding Journals Publishing House |
| record_format | Article |
| series | Hanjie xuebao |
| spelling | doaj-art-d088c9dc9cd942d6a9d8a8b8981ecc1b2025-08-20T02:43:20ZzhoEditorial Office of Transactions of the China Welding Institution, Welding Journals Publishing HouseHanjie xuebao0253-360X2025-01-01461414710.12073/j.hjxb.20231029001hjxb-46-1-hushashaEffect of post-welding aging on the microstructure and mechanical properties of high-strength Al-6.7Zn-1.8Mg-0.2Cu aluminum alloy joints prepared by friction stir weldingShasha HU0Cheng QIU1Datong ZHANG2National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials, South China University of Technology, Guangzhou 510641, ChinaNational Engineering Research Center of Near-Net-Shape Forming for Metallic Materials, South China University of Technology, Guangzhou 510641, ChinaNational Engineering Research Center of Near-Net-Shape Forming for Metallic Materials, South China University of Technology, Guangzhou 510641, ChinaFriction stir welding (FSW) is used to weld Al-6.7Zn-1.8Mg-0.2Cu aluminum alloy sheet with 3.2 mm thickness, and the welded joint is subjected to post-welding aging heat treatment, and that is artificial ageing (AA) 120 ℃ × 24 h. The welded and aged joints are studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), hardness test and tensile test. The results show that the tensile strength of the joint is 470 MPa, the welding coefficient is 80.0%, and the elongation is 10.1%. AA could effectively improve the tensile strength of the joint, which is 525 MPa, 89.6% of the base material (BM). Compared to as-welded joint increases 11.8%. And the elongation is 8.5%. In the FSW process, the precipitated phases in thermo-mechanically affected zone (TMAZ) and nugget zone (NZ) are dissolved and then precipitated after cooling, in which the precipitated phase is mainly η' phase, and the dissolution of GP zone (Guinier-Preston zone) and coarsening of η' phase mainly occurred in the heat-affected zone (HAZ) , and the precipitated phase gradually changed from dissolution to coarsening under different heat input. After welding ageing, GP zone precipitates and GP zone transforms to η' phase, and the existing η' phase at HAZ transforms into coarse η phase. The hardness curve of the joint is obviously W-shaped, the fracture of the FSW joint is in the NZ, and the fracture of the post-welding aging joint is in the HAZ.https://doi.org/10.12073/j.hjxb.20231029001friction stir weldingal-6.7zn-1.8mg-0.2cu aluminum alloypost-welding heat treatmentmicrostructuremechanical property |
| spellingShingle | Shasha HU Cheng QIU Datong ZHANG Effect of post-welding aging on the microstructure and mechanical properties of high-strength Al-6.7Zn-1.8Mg-0.2Cu aluminum alloy joints prepared by friction stir welding Hanjie xuebao friction stir welding al-6.7zn-1.8mg-0.2cu aluminum alloy post-welding heat treatment microstructure mechanical property |
| title | Effect of post-welding aging on the microstructure and mechanical properties of high-strength Al-6.7Zn-1.8Mg-0.2Cu aluminum alloy joints prepared by friction stir welding |
| title_full | Effect of post-welding aging on the microstructure and mechanical properties of high-strength Al-6.7Zn-1.8Mg-0.2Cu aluminum alloy joints prepared by friction stir welding |
| title_fullStr | Effect of post-welding aging on the microstructure and mechanical properties of high-strength Al-6.7Zn-1.8Mg-0.2Cu aluminum alloy joints prepared by friction stir welding |
| title_full_unstemmed | Effect of post-welding aging on the microstructure and mechanical properties of high-strength Al-6.7Zn-1.8Mg-0.2Cu aluminum alloy joints prepared by friction stir welding |
| title_short | Effect of post-welding aging on the microstructure and mechanical properties of high-strength Al-6.7Zn-1.8Mg-0.2Cu aluminum alloy joints prepared by friction stir welding |
| title_sort | effect of post welding aging on the microstructure and mechanical properties of high strength al 6 7zn 1 8mg 0 2cu aluminum alloy joints prepared by friction stir welding |
| topic | friction stir welding al-6.7zn-1.8mg-0.2cu aluminum alloy post-welding heat treatment microstructure mechanical property |
| url | https://doi.org/10.12073/j.hjxb.20231029001 |
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