Effect of pre-aging and paint baking processes on precipitation behavior in heat-affected zone of CMT welded Al–Mg–Si–Cu alloy joint
The heat-affected zone (HAZ) of the novel Al–Mg–Si–Cu alloy will undergo serious softening during welding. In this work, pre-aging (PA) and paint-baking (PB) processes are proposed to address this issue. The effects of different PA processes and the synergistic effect of PA and PB on the precipitate...
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Elsevier
2025-03-01
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| Series: | Journal of Materials Research and Technology |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785425004831 |
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| author | Shuncun Luo Yang Tao Zibin Wu Xiaonan Wang Zengrong Hu Hiromi Nagaumi |
| author_facet | Shuncun Luo Yang Tao Zibin Wu Xiaonan Wang Zengrong Hu Hiromi Nagaumi |
| author_sort | Shuncun Luo |
| collection | DOAJ |
| description | The heat-affected zone (HAZ) of the novel Al–Mg–Si–Cu alloy will undergo serious softening during welding. In this work, pre-aging (PA) and paint-baking (PB) processes are proposed to address this issue. The effects of different PA processes and the synergistic effect of PA and PB on the precipitates and properties of Al–Mg–Si–Cu alloy joint are studied. The results show that the degree and mechanism of HAZ softening vary with the distance from the weld center. The most severe softening occurs in HAZ Ⅱ, located 5–7 mm away from the weld center, where coherent β'', QP1/2 and L phases transform into β and Q phases with a weak strengthening effect. The hardness of base metals changes in an S-shaped curve with increasing PA temperature. Compared to the T6 state, the tensile properties of HAZ can only be improved within a PA temperature range of 120–200 °C for 1–4 h. PA inhibits the coarsening of precipitates during welding and promotes the formation of more atomic clusters2 and GP zones in the HAZ, significantly enhancing its tensile properties. Combined with the PA state, the atomic clusters2 and GP zones transform into β'' phases and Cu-containing phases after PB, which further improves the tensile properties of HAZ and significantly increases the hardness of base metals. The joint has the highest bake hardening response when PA is at 140 °C for 1 h. Finally, short-term PA and PB processes are optimized, resulting in a welded joint with a tensile strength of 304.7 MPa and a welding coefficient of 82.2%, demonstrating promising industrial application prospects. |
| format | Article |
| id | doaj-art-80e3ad07330a40c68ce727fdfc8d19c0 |
| institution | OA Journals |
| issn | 2238-7854 |
| language | English |
| publishDate | 2025-03-01 |
| publisher | Elsevier |
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| series | Journal of Materials Research and Technology |
| spelling | doaj-art-80e3ad07330a40c68ce727fdfc8d19c02025-08-20T02:02:02ZengElsevierJournal of Materials Research and Technology2238-78542025-03-01356156616610.1016/j.jmrt.2025.02.236Effect of pre-aging and paint baking processes on precipitation behavior in heat-affected zone of CMT welded Al–Mg–Si–Cu alloy jointShuncun Luo0Yang Tao1Zibin Wu2Xiaonan Wang3Zengrong Hu4Hiromi Nagaumi5School of Iron and Steel, High-Performance Metal Structural Materials Research Institute, Soochow University, Suzhou, Jiangsu, 215021, China; State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle, Changsha, Hunan, 410082, ChinaSchool of Iron and Steel, High-Performance Metal Structural Materials Research Institute, Soochow University, Suzhou, Jiangsu, 215021, ChinaSchool of Iron and Steel, High-Performance Metal Structural Materials Research Institute, Soochow University, Suzhou, Jiangsu, 215021, ChinaSchool of Iron and Steel, High-Performance Metal Structural Materials Research Institute, Soochow University, Suzhou, Jiangsu, 215021, China; Corresponding author.School of Rail Transportation, Soochow University, Suzhou, Jiangsu, 215021, ChinaSchool of Iron and Steel, High-Performance Metal Structural Materials Research Institute, Soochow University, Suzhou, Jiangsu, 215021, China; Corresponding author.The heat-affected zone (HAZ) of the novel Al–Mg–Si–Cu alloy will undergo serious softening during welding. In this work, pre-aging (PA) and paint-baking (PB) processes are proposed to address this issue. The effects of different PA processes and the synergistic effect of PA and PB on the precipitates and properties of Al–Mg–Si–Cu alloy joint are studied. The results show that the degree and mechanism of HAZ softening vary with the distance from the weld center. The most severe softening occurs in HAZ Ⅱ, located 5–7 mm away from the weld center, where coherent β'', QP1/2 and L phases transform into β and Q phases with a weak strengthening effect. The hardness of base metals changes in an S-shaped curve with increasing PA temperature. Compared to the T6 state, the tensile properties of HAZ can only be improved within a PA temperature range of 120–200 °C for 1–4 h. PA inhibits the coarsening of precipitates during welding and promotes the formation of more atomic clusters2 and GP zones in the HAZ, significantly enhancing its tensile properties. Combined with the PA state, the atomic clusters2 and GP zones transform into β'' phases and Cu-containing phases after PB, which further improves the tensile properties of HAZ and significantly increases the hardness of base metals. The joint has the highest bake hardening response when PA is at 140 °C for 1 h. Finally, short-term PA and PB processes are optimized, resulting in a welded joint with a tensile strength of 304.7 MPa and a welding coefficient of 82.2%, demonstrating promising industrial application prospects.http://www.sciencedirect.com/science/article/pii/S2238785425004831Al–Mg–Si–Cu alloyHAZ softeningPre-agingPaint bakingMicrostructureMechanical properties |
| spellingShingle | Shuncun Luo Yang Tao Zibin Wu Xiaonan Wang Zengrong Hu Hiromi Nagaumi Effect of pre-aging and paint baking processes on precipitation behavior in heat-affected zone of CMT welded Al–Mg–Si–Cu alloy joint Journal of Materials Research and Technology Al–Mg–Si–Cu alloy HAZ softening Pre-aging Paint baking Microstructure Mechanical properties |
| title | Effect of pre-aging and paint baking processes on precipitation behavior in heat-affected zone of CMT welded Al–Mg–Si–Cu alloy joint |
| title_full | Effect of pre-aging and paint baking processes on precipitation behavior in heat-affected zone of CMT welded Al–Mg–Si–Cu alloy joint |
| title_fullStr | Effect of pre-aging and paint baking processes on precipitation behavior in heat-affected zone of CMT welded Al–Mg–Si–Cu alloy joint |
| title_full_unstemmed | Effect of pre-aging and paint baking processes on precipitation behavior in heat-affected zone of CMT welded Al–Mg–Si–Cu alloy joint |
| title_short | Effect of pre-aging and paint baking processes on precipitation behavior in heat-affected zone of CMT welded Al–Mg–Si–Cu alloy joint |
| title_sort | effect of pre aging and paint baking processes on precipitation behavior in heat affected zone of cmt welded al mg si cu alloy joint |
| topic | Al–Mg–Si–Cu alloy HAZ softening Pre-aging Paint baking Microstructure Mechanical properties |
| url | http://www.sciencedirect.com/science/article/pii/S2238785425004831 |
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