Microstructures Evolution in Refill Friction Stir Spot Welding of Al-Zn-Mg-Cu Alloy
Abstract
:1. Introduction
2. Material and Experiment
3. Results and Discussions
3.1. Microstructural Characteristics
3.1.1. Base Material Zone
3.1.2. Stir Zone
3.1.3. Thermo-Mechanically Affected Zone
3.1.4. Heat-Affected Zone
3.2. Microhardness Distribution
4. Conclusions
- In the SZ, CDRX occurs under the intense plastic deformation. All the original GP (II) zones and η’ precipitates dissolved into the aluminum matrix under the welding heat input, and the stable η and E precipitates are remained. The η and E precipitates can inhibit the dislocation migration and grains growth.
- In the TMAZ, high-density dislocations and subgrains boundaries can be observed. The CDRX was not activated and only dynamic recovery occurs. Sub-boundaries and high-density dislocations in this zone can be observed. In this zone, the η precipitates are coarsened and dissolution is the main evolution mechanism for the GP (II) zones and η’ precipitates.
- In the HAZ, no dislocation was induced and all the initial precipitates were coarsened under the welding heat input.
- The HAZ, the TMAZ, and the SZ constitute a soft region in the RFSSW joint. The distribution curve of the hardness values presented an asymmetric “W” shape, and the minimum value located at the interface between the HAZ and the TMAZ.”
Author Contributions
Funding
Conflicts of Interest
References
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Chemical Compositions, wt.% | |||||||||
---|---|---|---|---|---|---|---|---|---|
Zn | Mg | Cu | Mn | Fe | Cr | Si | Ni | Ti | Al |
5.86 | 2.51 | 1.62 | 0.34 | 0.18 | 0.15 | 0.07 | 0.05 | 0.03 | Bal. |
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Zhao, Y.; Dong, C.; Wang, C.; Miao, S.; Tan, J.; Yi, Y. Microstructures Evolution in Refill Friction Stir Spot Welding of Al-Zn-Mg-Cu Alloy. Metals 2020, 10, 145. https://doi.org/10.3390/met10010145
Zhao Y, Dong C, Wang C, Miao S, Tan J, Yi Y. Microstructures Evolution in Refill Friction Stir Spot Welding of Al-Zn-Mg-Cu Alloy. Metals. 2020; 10(1):145. https://doi.org/10.3390/met10010145
Chicago/Turabian StyleZhao, Yunqiang, Chunlin Dong, Chungui Wang, Shu Miao, Jinhong Tan, and Yaoyong Yi. 2020. "Microstructures Evolution in Refill Friction Stir Spot Welding of Al-Zn-Mg-Cu Alloy" Metals 10, no. 1: 145. https://doi.org/10.3390/met10010145