Acta Metallurgica Sinica (English Letters) ›› 2024, Vol. 37 ›› Issue (8): 1339-1353.DOI: 10.1007/s40195-024-01708-x

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Exfoliation Corrosion of As-Extruded Mg-1Li-1Ca: the Influence of the Superficial Layer

Ze-Song Wei1, Zi-You Ding1, Lei Cai2, Shao-Xia Ma1, Dong-Qing Zhao3, Lan-Yue Cui1, Cheng-Bao Liu1, Yuan-Sheng Yang3,4, Yuan-Ding Huang5, Rong-Chang Zeng1()   

  1. 1Corrosion Laboratory for Light Metals, College of Materials Science and Engineering, Shandong University of Science and Technology, Qingdao, 266590, China
    2Engineering Research Center for Magnesium-Based New Materials, Center for Advancing Materials Performance from the Nanoscale (CAMP-Nano), State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an, 710049, China
    3Shandong Provincial Key Laboratory of High Strength Lightweight Metallic Materials, Advanced Materials Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250014, China
    4Institute of Metals Research, Chinese Academy of Sciences, Shenyang, 110016, China
    5Institute of Metallic Biomaterials, Helmholtz-Zentrum Hereon, Max-Planck-Str. 1, 21502, Geesthacht, Germany
  • Received:2024-01-24 Revised:2024-03-20 Accepted:2024-03-21 Online:2024-08-10 Published:2024-05-06
  • Contact: Rong-Chang Zeng, rczeng@foxmail.com
  • About author:First author contact:

    Ze-Song Wei and Zi-You Ding contributed equally to this work.

Abstract:

Exfoliation corrosion (EFC) has rarely been reported for wrought magnesium alloys. Enhanced EFC of the as-extruded Mg-1Li-1Ca alloy was observed after the removal of outermost fine-grained skins. The microstructure and corrosion products were investigated using optical microscopy, scanning electron microscopy, electron backscattered diffraction, X-ray diffraction, and Fourier transform infrared spectrometry. The corrosion behavior was analyzed using electrochemical polarization, electrochemical impedance spectroscopy, and scanning Kelvin probe techniques. The results indicated that the surface of Mg-1Li-1Ca, with the superficial layer removed, was more susceptible to EFC. A linear correlation between grain boundary density and corrosion resistance was established. Additionally, the influence of factors such as grain size, intermetallic compounds, different alloy surfaces, and corrosion products on EFC were discussed, and the corresponding EFC mechanism was clarified.

Key words: Magnesium alloys, Exfoliation corrosion, Microstructure, Intermetallic compound, Metamorphic skin