Corrosion Science and Technology

The Corrosion Science Society of Korea (한국부식방식학회)
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Atmospheric Corrosion of 7B04 Aluminum Alloy in Marine Environments

  • Zhang, Xiaoyun (Beijing Institute of Aeronautical Materials) ;
  • Liu, Ming (Beijing Institute of Aeronautical Materials) ;
  • Lu, Feng (Beijing Institute of Aeronautical Materials) ;
  • Liu, Minghui (Beijing Institute of Aeronautical Materials) ;
  • Sun, Zhihua (Beijing Institute of Aeronautical Materials) ;
  • Tang, Zhihui (Beijing Institute of Aeronautical Materials)
  • Received : 2017.08.17
  • Accepted : 2018.02.21
  • Published : 2018.02.28
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Abstract

Outdoor exposure tests using of 7B04 aluminium alloy samples including plate, tensile and various SCC samples were carried out in Tuandao station, Shandong province (East of China) and Wanning station, Hainan province (South of China). Corrosion characteristics including weight loss, microstructure, tensile strength and SCC susceptibility were investigated. The corrosion rates in Tuandao and Wanning showed high to low and the corrosion rates changed to the following equation of $w=at^b$ (b<1). The corrosion of 7B04 aluminium alloy in Wanning was more serious than that in Tuandao. Pitting appeared at early stage of expose test, and it can be changed to general corrosion with test time extension. The 7B04 aluminium alloy of which specimen shapes are forging and thick plate also showed SCC (Stress corrosion cracking) in the marine atmosphere. The higher SCC sensitivity was observed in Wanning station than in Tuandao station. The 7B04 aluminium alloy with a high stress level was more sensitive to SCC. Intergranular and transgranular or a mixed mode of cracking can be observed in different marine exposure.

Keywords

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Fig. 1 Relation between 7B04 corrosion weight loss and exposuretime in Tuandao and Wanning station.

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Fig. 2 Morphology of 7B04 aluminum alloy exposed in Wanning and Tuandao.

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Fig. 3 SEM of 7B04 aluminum alloy specimens exposed in (a)Wanning/1y，surface(160×) ; (b)Wanning/5y，cross section (1500×)；(c)Tuandao /1y，surface(160×)； (d)Tuandao/1y，cross section(160×).

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Fig. 5 The curves between cracking expanding speed and stress intensity factor 7B04 in Tuandao ; (b) 7B04 in Wanning.

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Fig. 6 Microstructure of cross-section after failure of pre-cracking specimens exposed in (a)7B04/Wanning；(b)7B04/Tuandao.

Table 1 The chemical compositions of 7B04 alloy (mass fraction, %)

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Table 2 Mechanical properties of 7B04 alloy

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Table 3 Environmental parameters in Tuandao and Wanning station

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Table 4 Mass loss-time regression result of outdoor exposure tests

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Table 6 Results of pre-crack sample exposed in wanning and tuandao

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References

  1. Du Hongzeng, Guild for Aircraft Structure Repair, Beijing University of Aeronautics and Astronautics Press, Beijing (1993).
  2. S. Q. Sun,Q. F. Zheng, D. Li, S. Hu, and J Wen, Corros. Sci., 53, 2527 (2011). https://doi.org/10.1016/j.corsci.2011.04.010
  3. S. Hu, S. Sun, A. Guo, X. Jia, and Y. Geng, Corrosion, 67, 106002-1 (2011). https://doi.org/10.5006/1.3651017
  4. Z. Y. Cui, X. G. Li, K. Xiao, C. F. Dong, L. W. Wang, D. W. Zhang, and Z. Y. Liu, J. Mater. Eng. Perform., 24, 297 (2015).
  5. T. Zhang, Y. He, R. Cui, and T. An, J. Mater. Eng. Perform., 24, 2764 (2015). https://doi.org/10.1007/s11665-015-1541-y
  6. Z. Y. Cui, X. G. Li, C. Man, K. Xiao, C. F. Dong, X. Wang, and Z. Y. Liu, J. Mater. Eng. Perform., 24, 2885 (2015). https://doi.org/10.1007/s11665-015-1571-5
  7. X. K. Yang, L. W. Zhang, S. Y. Zhang, M. Liu, K. Zhou, and X. L. Mu, Mater. Corros., 68, 529 (2017). https://doi.org/10.1002/maco.201609201
  8. S. Q. Sun, C. L. Li, Q. F. Zheng, X. M. Wang, and S. Q. Hu, Mater. Corros., 68, 450 (2017). https://doi.org/10.1002/maco.201609149
  9. Editorial Committee of China Aeronautical Materials Handbook, China Aeronautical Materials Handbook, vol. 2, China Standard Press, Beijing (2002).
  10. S. Yan, X. Yong, S. Hong, and S. Chang, Corros. Sci. Pro. Technolo., 24, 458 (2012).
  11. M. Gao, Z.-H. Sun, M. Liu, W. Yan, and Z.-H. Tang, Equip. Environ. Eng., 13, 160 (2016).
  12. C. Wang, Y. Chen, Y. Zhang, and G. Bian, J. Aeronaut. Mater., 37, 59 (2017).
  13. F. Qi, J. Aeronaut. Mater., 20, 73 (2000).
  14. F. Qi, J. Li, and M. Liu, J. Mater. Pro., 34, 35 (2001).