Studies on Pitting Corrosion of Al-Cu-Li Alloys Part I: Effect of Li Addition by Microstructural, Electrochemical, In-situ, and Pit Depth Analysis

Xiaowei Lei; Alireza Saatchi; Elmira Ghanbari; Runze Dang; Wenzhe Li; Nan Wang; Digby D Macdonald

doi:10.3390/ma12101600

Studies on Pitting Corrosion of Al-Cu-Li Alloys Part I: Effect of Li Addition by Microstructural, Electrochemical, In-situ, and Pit Depth Analysis

Materials (Basel). 2019 May 16;12(10):1600. doi: 10.3390/ma12101600.

Authors

Xiaowei Lei^{1

2}, Alireza Saatchi³, Elmira Ghanbari⁴, Runze Dang⁵, Wenzhe Li⁶, Nan Wang⁷, Digby D Macdonald⁸

Affiliations

¹ MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions, School of Natural and Applied Sciences, Northwestern Polytechnical University, Xi'an 710072, China. xiaowei_lei@nwpu.edu.cn.
² Department of Materials Science and Engineering, University of California at Berkeley, Berkeley, CA 94720, USA. xiaowei_lei@nwpu.edu.cn.
³ Department of Materials Science and Engineering, University of California at Berkeley, Berkeley, CA 94720, USA. alireza.saatchi@berkeley.edu.
⁴ Department of Materials Science and Engineering, University of California at Berkeley, Berkeley, CA 94720, USA. elmira.ghanbari@berkeley.edu.
⁵ MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions, School of Natural and Applied Sciences, Northwestern Polytechnical University, Xi'an 710072, China. dangrunze@mail.nwpu.edu.cn.
⁶ MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions, School of Natural and Applied Sciences, Northwestern Polytechnical University, Xi'an 710072, China. lwz913157048@163.com.
⁷ MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions, School of Natural and Applied Sciences, Northwestern Polytechnical University, Xi'an 710072, China. nan.wang@nwpu.edu.cn.
⁸ Department of Materials Science and Engineering, University of California at Berkeley, Berkeley, CA 94720, USA. macdonald@berkeley.edu.

Abstract

To analyze the effect of lithium and microstructure on the pitting corrosion behavior of aluminum alloys, three types of aluminum alloys were studied via scanning electron microscopy, transmission electron microscopy, electrochemical polarization, and by immersion tests coupled with in-situ observation of pitting and statistical analysis of pit depths measured by surface profilometry. It was found that, with increasing lithium content, the resistance to pitting corrosion was enhanced and the passive range was enlarged. In-situ observation revealed that the development of pitting corrosion exhibited three stages, including an initial slow nucleation stage (Stage I), a fast development stage (Stage II), and a stabilized growth stage (Stage III). Higher lithium content contributed to shorter time periods of Stages I and II, resulting in faster pitting evolution and a higher number of pits. However, the pits were generally shallower for the specimen with the highest lithium content, which is in agreement with the results of the electrochemical analysis.

Keywords: Al-Cu-Li alloys; TEM; microstructure; pitting corrosion; polarization.

Abstract

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