Effects of three different post-weld heat treatments on microstructure and properties of 7075/6061 friction stir welded joints
This study examined the effects of three post-weld heat treatment (PWHT) processes: solution treatment (ST), artificial aging (AA), and solution-aging treatment (STA) on the microstructure and mechanical properties of 7075/6061 dissimilar aluminum alloy friction stir welded joints. Compared to untre...
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Elsevier
2025-08-01
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| Series: | Materials & Design |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S0264127525006628 |
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| author | Yongjun Ren Sheng Liu Xinbin Hu Wei Long |
| author_facet | Yongjun Ren Sheng Liu Xinbin Hu Wei Long |
| author_sort | Yongjun Ren |
| collection | DOAJ |
| description | This study examined the effects of three post-weld heat treatment (PWHT) processes: solution treatment (ST), artificial aging (AA), and solution-aging treatment (STA) on the microstructure and mechanical properties of 7075/6061 dissimilar aluminum alloy friction stir welded joints. Compared to untreated joints (UP) with a tensile strength of 207 MPa, STA joint achieved 290 MPa, a 40.10 % improvement. The joint strength coefficient increases from 67 % to 94 %, and elongation increases from 2.49 % to 3.07 %. The ST joint exhibited the highest elongation (5.42 %), while the AA joint had the lowest (1.55 %). Fractures occurred in the HAZ on the 6061 side for all joints. PWHT improved strength and microhardness while eliminating the “onion ring” structure. Grain coarsening occurred in the stir zone (SZ), increasing from 3 μm (UP) to 50 μm (STA). The strength increase of the STA joint was mainly attributed to the high-density precipitation behavior of Mg2Si phase in the 6061. Texture analysis shows that the SZ of the UP and STA joints have higher and lower shear strain microstructures, respectively. The STA treatment significantly improved the uniformity of the microstructure and hardness, thereby significantly reducing the degree of stress concentration and enhancing the joint strength. |
| format | Article |
| id | doaj-art-7c248167b119463fbdcee3e69dad0b3b |
| institution | DOAJ |
| issn | 0264-1275 |
| language | English |
| publishDate | 2025-08-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Materials & Design |
| spelling | doaj-art-7c248167b119463fbdcee3e69dad0b3b2025-08-20T03:22:35ZengElsevierMaterials & Design0264-12752025-08-0125611424210.1016/j.matdes.2025.114242Effects of three different post-weld heat treatments on microstructure and properties of 7075/6061 friction stir welded jointsYongjun Ren0Sheng Liu1Xinbin Hu2Wei Long3School of Materials and Chemical Engineering, Hubei University of Technology, Wuhan 430068, China; Key Laboratory of Green Materials for Light Industry of Hubei Provincial, Wuhan 430068, China; Hubei Engineering Laboratory of Automotive Lightweight Materials and Processing, Wuhan 430068, ChinaSchool of Materials and Chemical Engineering, Hubei University of Technology, Wuhan 430068, China; Key Laboratory of Green Materials for Light Industry of Hubei Provincial, Wuhan 430068, China; Hubei Engineering Laboratory of Automotive Lightweight Materials and Processing, Wuhan 430068, China; Corresponding author at: School of Materials and Chemical Engineering, Hubei University of Technology, Wuhan 430068, China.School of Materials and Chemical Engineering, Hubei University of Technology, Wuhan 430068, China; Key Laboratory of Green Materials for Light Industry of Hubei Provincial, Wuhan 430068, China; Hubei Engineering Laboratory of Automotive Lightweight Materials and Processing, Wuhan 430068, ChinaSchool of Materials and Chemical Engineering, Hubei University of Technology, Wuhan 430068, China; Key Laboratory of Green Materials for Light Industry of Hubei Provincial, Wuhan 430068, China; Hubei Engineering Laboratory of Automotive Lightweight Materials and Processing, Wuhan 430068, ChinaThis study examined the effects of three post-weld heat treatment (PWHT) processes: solution treatment (ST), artificial aging (AA), and solution-aging treatment (STA) on the microstructure and mechanical properties of 7075/6061 dissimilar aluminum alloy friction stir welded joints. Compared to untreated joints (UP) with a tensile strength of 207 MPa, STA joint achieved 290 MPa, a 40.10 % improvement. The joint strength coefficient increases from 67 % to 94 %, and elongation increases from 2.49 % to 3.07 %. The ST joint exhibited the highest elongation (5.42 %), while the AA joint had the lowest (1.55 %). Fractures occurred in the HAZ on the 6061 side for all joints. PWHT improved strength and microhardness while eliminating the “onion ring” structure. Grain coarsening occurred in the stir zone (SZ), increasing from 3 μm (UP) to 50 μm (STA). The strength increase of the STA joint was mainly attributed to the high-density precipitation behavior of Mg2Si phase in the 6061. Texture analysis shows that the SZ of the UP and STA joints have higher and lower shear strain microstructures, respectively. The STA treatment significantly improved the uniformity of the microstructure and hardness, thereby significantly reducing the degree of stress concentration and enhancing the joint strength.http://www.sciencedirect.com/science/article/pii/S02641275250066287075/6061 aluminum alloyFriction stir weldingPost-weld heat treatmentGrain sizePrecipitation |
| spellingShingle | Yongjun Ren Sheng Liu Xinbin Hu Wei Long Effects of three different post-weld heat treatments on microstructure and properties of 7075/6061 friction stir welded joints Materials & Design 7075/6061 aluminum alloy Friction stir welding Post-weld heat treatment Grain size Precipitation |
| title | Effects of three different post-weld heat treatments on microstructure and properties of 7075/6061 friction stir welded joints |
| title_full | Effects of three different post-weld heat treatments on microstructure and properties of 7075/6061 friction stir welded joints |
| title_fullStr | Effects of three different post-weld heat treatments on microstructure and properties of 7075/6061 friction stir welded joints |
| title_full_unstemmed | Effects of three different post-weld heat treatments on microstructure and properties of 7075/6061 friction stir welded joints |
| title_short | Effects of three different post-weld heat treatments on microstructure and properties of 7075/6061 friction stir welded joints |
| title_sort | effects of three different post weld heat treatments on microstructure and properties of 7075 6061 friction stir welded joints |
| topic | 7075/6061 aluminum alloy Friction stir welding Post-weld heat treatment Grain size Precipitation |
| url | http://www.sciencedirect.com/science/article/pii/S0264127525006628 |
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