Journal of South China University of Technology(Natural Science Edition) ›› 2018, Vol. 46 ›› Issue (11): 68-75.doi: 10.3969/j.issn.1000-565X.2018.11.010

• Materials Science & Technology • Previous Articles     Next Articles

Influence of Si and heat treatment on microstructures and corrosion behavior of Al–Zn–Mg–Cu alloys

JIAO Huibin1 CHEN Kanghua1， 2 YANG Zhen1 CHEN Songyi1 WANG Huiping3 MA Yunlong3   

  1. 1． Light Alloy Ｒesearch Institute，Central South University，Changsha 410083，Hunan，China;
    2． Collaborative Innovation Center of Advance Nonferrous Structural Materials and Manufacturing，Central South University，Changsha 410083， Hunan，China;
    3． Beijing Institute of Astronautical Systems Engineering，Beijing 100076，China
  • Received:2018-04-13 Revised:2018-07-10 Online:2018-11-25 Published:2018-10-02
  • Contact: 陈康华(1962) ，男，博士，教授，主要从事铝合金研究 E-mail:khchen@csu.edu.cn
  • About author:焦慧彬(1988) ，女，博士生，从事7xxx 系铝合金研究
  • Supported by:
    The National Key Ｒesearch and Development Program of China( 2016YFB0300801) and the Major Ｒesearch Equipment Development Projects of National Natural Science Foundation of China( 51327902) 

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Abstract: Stress corrosion cracking (SCC) behavior of Al-Zn-Mg-Cu alloys with different Si contents and heat treatments was studied using slow strain rate test. Grain boundary microstructures were identified by transmission electron microscopy (TEM) and statistical analysis. It was found that the SCC resistance of alloys is improved by increasing Si contents and aging degree. Grain boundary precipitates (GBPs) area fraction was found to be an important parameter to evaluate the SCC susceptibility. The results reveal that for Al-Zn-Mg-Cu-0.16Zr-0.04Si(wt%) alloy with different aging degrees, hydrogen induced cracking dominates the SCC when the area fraction of GBPs is relatively low. For peak-aged Al-Zn-Mg-Cu alloy and Al-Zn-Mg-Cu-0.16Zr-0.02Si(wt%) alloy, anodic dissolution dominates the SCC when the area fraction of GBPs is sufficiently high.

Key words: aluminum alloy, stress corrosion cracking, grain boundary, corrosion behavior

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