Effect of post-weld aging on stress corrosion sensitivity of 7020 aluminum alloy

doi:10.13251/j.issn.0254-6051.2023.06.014

Abstract

Abstract: Welded joints of 7020 aluminum alloy are often cracked due to stress corrosion. In order to address the above problems, sample of the same welding process were treated by post-weld heat treatment processes of natural aging, one-step aging, two-step over-aging, retrogression and re-aging (RRA). By analyzing the surface micromorphology, microstructure, slow strain rate tensile stress corrosion test results and fracture of the specimens undergone different post-treatments, the effect of different post-weld aging treatment on the stress corrosion cracking resistance of the 7020 welded joints were studied. The results show that after the regression re-aging treatment, the number of pores is decreased, the precipitates free zone is widened, the grain boundary precipitates disappear, and the grain precipitates are refined, by which the welded joints of the 7020 aluminum alloy obtains the lowest stress corrosion tendency.

Key words: 7020 aluminum alloy, welded joint, post-weld heat treatment, retrogression and re-aging, stress corrosion

CLC Number:

TG166.3

Zhou Yongdong, Gong Lanfang, Liu Ziyi. Effect of post-weld aging on stress corrosion sensitivity of 7020 aluminum alloy[J]. Heat Treatment of Metals, 2023, 48(6): 80-84.

References

[1] 刘兵, 彭超群, 王日初, 等. 大飞机用铝合金的研究现状及展望[J]. 中国有色金属学报, 2010, 20(9): 1705-1715.
Liu Bing, Peng Chaoqun, Wang Richu, et al. Recent development and prospects for giant plane aluminum alloys[J]. The Chinese Journal of Nonferrous Metals, 2010, 20(9): 1705-1715.
[2]顾恺迪, 高志良, 李世江, 等. 7系铝合金在上海轨道交通车辆的应用现状及适用性分析[J]. 城市轨道交通研究, 2022, 25(9): 141-145.
Gu Kaidi, Gao Zhiliang, Li Shijiang, et al. Application status and adaptability analysis of 7 series aluminum alloy in shanghai rail transit vehicle[J]. Urban Mass Transit, 2022, 25(9): 141-145.
[3]杨守杰, 戴圣龙. 航空铝合金的发展回顾与展望[J]. 材料导报, 2005, 19(2): 76-80.
Yang Shoujie, Dai Shenglong. A glimpse at the development and application of aluminum alloys in aviation industry[J]. Materials Reports, 2005, 19(2): 76-80.
[4]陈小明, 宋仁国. 7000系铝合金应力腐蚀开裂的研究进展[J]. 腐蚀科学与防护技术, 2010, 22(2): 120-123.
Chen Xiaoming, Song Renguo. Progress in research on stress corrosion cracking of 7000 series aluminum alloys[J]. Corrosion Science and Protection Technology, 2010, 22(2): 120-123.
[5]谭思治, 罗兵辉, 柏振海, 等. 7N01铝合金应力腐蚀行为研究[J]. 稀有金属, 2021, 45(10): 1162-1170.
Tan Sizhi, Luo Binghui, Bo Zhenhai, et al. Stress corrosion behavior of 7N01 aluminum alloy[J]. Chinese Journal of Rare Metals, 2021, 45(10): 1162-1170.
[6] Han Junsoo, Ogle Kevin. The anodic and cathodic dissolution of α-phase Zn-68Al in alkaline media[J]. Corrosion Science, 2019, 148: 1-11.
[7] Shimizu Kazuyuki, Toda Hiroyuki, Fujihara Hiro, et al. Hydrogen partitioning behavior and related hydrogen embrittlement in Al-Zn-Mg alloys[J]. Engineering Fracture Mechanics, 2019, 216: 1-13.
[8]Su Hang, Toda Hiroyuki, Shimizu Kazuyuki, et al. Assessment of hydrogen embrittlement via image-based techniques in Al-Zn-Mg-Cu aluminum alloys[J]. Acta Materialia, 2019, 176: 96-108.
[9]Xie Peng, Chen Songyi, Chen Kanghua, et al. Enhancing the stress corrosion cracking resistance of a low-Cu containing Al-Zn-Mg-Cu aluminum alloy by step-quench and aging heat treatment[J]. Corrosion Science, 2019, 161: 108184.
[10]金骥戎, 宋仁国, 代春丽, 等. 时效、阴极极化对7050铝合金应力腐蚀敏感性的影响[J]. 材料热处理学报, 2015, 36(3): 90-95.
Jin Jirong, Song Renguo, Dai Chunli, et al. Effects of aging and cathodic polarization on susceptibility to SCC of 7050 aluminum alloy[J]. Transactions of Materials and Heat Treatment, 2015, 36(3): 90-95.
[11]梁帅. 回归再时效对7150合金组织和腐蚀性能的影响[D]. 哈尔滨: 哈尔滨工业大学, 2017.
[12]中国机械工程学会热处理学会. 热处理手册[M]. 北京: 机械工业出版社, 2008.
[13]刘继华, 李荻, 刘培英, 等. 时效和回归处理对7075铝合金力学及腐蚀性能的影响[J]. 材料热处理学报, 2002, 23(1): 50-53, 76.
Liu Jihua, Li Di, Liu Peiying, et al. Effect of ageing and retrogression treatments on mechanical and corrosion properties of 7075 aluminum alloy[J]. Transactions of Materials and Heat Treatment, 2002, 23(1): 50-53, 76.
[14] Xu Yongqian, Zhan Lihua. Effect of creep aging process on microstructures and properties of the retrogressed Al-Zn-Mg-Cu alloy[J]. Metals, 2016, 6(8): 189.
[15] Pan Yanlin, Zhang Di, Liu Haoran, et al. Precipitation hardening and intergranular corrosion behavior of novel Al-Mg-Zn(-Cu) alloys[J]. Journal of Alloys and Compounds, 2021, 853: 157199.