Effect of aging on the microstructure and stress corrosion resistance of Al–Zn?Mg alloy

YE Ling-ying; YANG Wen-qing; TANG Jian-guo; LIU Sheng-dan; DENG Yun-lai; ZHANG Xin-ming

doi:10.13374/j.issn2095-9389.2018.12.28.005

Volume 41 Issue 12

Dec. 2019

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Article Navigation > Chinese Journal of Engineering > 2019 > 41(12): 1575-1582

YE Ling-ying, YANG Wen-qing, TANG Jian-guo, LIU Sheng-dan, DENG Yun-lai, ZHANG Xin-ming. Effect of aging on the microstructure and stress corrosion resistance of Al–Zn?Mg alloy[J]. Chinese Journal of Engineering, 2019, 41(12): 1575-1582. doi: 10.13374/j.issn2095-9389.2018.12.28.005

Citation:

YE Ling-ying, YANG Wen-qing, TANG Jian-guo, LIU Sheng-dan, DENG Yun-lai, ZHANG Xin-ming. Effect of aging on the microstructure and stress corrosion resistance of Al–Zn?Mg alloy[J]. Chinese Journal of Engineering, 2019, 41(12): 1575-1582. doi: 10.13374/j.issn2095-9389.2018.12.28.005

Citation:

YE Ling-ying, YANG Wen-qing, TANG Jian-guo, LIU Sheng-dan, DENG Yun-lai, ZHANG Xin-ming. Effect of aging on the microstructure and stress corrosion resistance of Al–Zn?Mg alloy[J]. Chinese Journal of Engineering, 2019, 41(12): 1575-1582. doi: 10.13374/j.issn2095-9389.2018.12.28.005

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Effect of aging on the microstructure and stress corrosion resistance of Al–Zn?Mg alloy

doi: 10.13374/j.issn2095-9389.2018.12.28.005

YE Ling-ying^{1, 2, 3},
YANG Wen-qing^{1, 2, 3},
TANG Jian-guo^{1, 2, 3
,
,},
LIU Sheng-dan^{1, 2, 3},
DENG Yun-lai^{1, 2, 3},
ZHANG Xin-ming^{1, 2, 3}

1.
School of Materials Science and Engineering, Central South University, Changsha 410083, China
2.
Key Laboratory of Nonferrous Metal Materials Science and Engineering (Ministry of Education), Central South University, Changsha 410083, China
3.
Nonferrous Metal Oriented Advanced Structural Materials and Manufacturing Cooperative Innovation Center, Central South University, Changsha 410083, China

More Information

Corresponding author: E-mail: jgtang@csu.edu.cn
Received Date: 2018-12-27
Publish Date: 2019-12-01

Abstract

Abstract

Controlling the balance between mechanical properties and stress corrosion resistance of Al–Zn?Mg alloys by aging tempers has long been an active focal point of research. Traditional peak-age can improve the mechanical properties, but the continuous precipitate at the grain boundary reduces the stress corrosion resistance of the alloy. While alloys in over-aged (T73) condition show good resistance to stress corrosion, their mechanical properties will drop significantly. In this paper, tensile properties, resistances to stress corrosion, and microstructures of the Al–Zn?Mg alloy, in interrupted aged (T5I4, T5I6) and traditional (T5, T73) tempers, were studied using a tensile test, a slow strain rate tensile test, and transmission electron microscopy. Results reveal that the tensile strength of T5I4 temper is 400.0 MPa, higher than that of T5,T73 tempers, while the stress corrosion resistance is clearly compromised, with index of slow strain rate testing, I_SSRT, of 5.7%, significantly larger than that of the other three aging treatments. The tensile strength of the T5I6 temper increases to 408.5 MPa, and the stress corrosion resistance is also improved, to I_SSRT=3.2%, significantly lower than that of T5 and T5I4 tempers. Volume fraction (8.8%) and average particle diameter (2.0 nm) of intragranular precipitates of T5I4 temper has the minimum value among the four aging treatments, and there are large numbers of fine precipitates distributed continuously at grain boundaries. In the T5I6 temper, the number of intragranular precipitates increase significantly, and the volume fraction of intragranular precipitates is 24.6%, larger than that of the other three aging treatments. In addition, the average particle diameter (4.1 nm) of the intragranular precipitates of the T5I6 temper is larger than that of the T5I4 temper, but is still smaller than that of the T5 and T73 tempers. Precipitates at the grain boundaries of the T5I6 temper are unevenly distributed, and significantly larger than those of the T5I4 temper.
- Al–Zn?Mg alloy,
- interrupted aging,
- stress corrosion resistance,
- microstructure,
- tensile property

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References(22)

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