Effect of Sm additions on the microstructure and corrosion behavior of magnesium alloy AZ91

Z. Hu, R. L. Liu, S. K. Kairy, X. Li, H. Yan, N. Birbilis

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Of the alloying additions to magnesium to date, samarium (Sm) has not been widely studied. Herein, the effect of Sm on the microstructure and corrosion of AZ91 (Mg-9Al-1Zn-0.4 Mn in wt.%) were investigated using scanning and transmission electron microscopy, electrochemical measurements, mass loss, and hydrogen collection. Results reveal preferential segregation of Sm with aluminium, leading to the formation of Al 2 Sm. Formation of Al 2 Sm in AZ91 resulted in a morphology change of β-Mg 17 Al 12 phase, from a coarse, mesh structure, to a fine short rod structure – reducing the overall β-Mg 17 Al 12 phase area fraction. Microelectrochemical tests were also employed to rationalise the corrosion observed.

Original languageEnglish
Pages (from-to)144-152
Number of pages9
JournalCorrosion Science
Publication statusPublished - Apr 2019


  • Alkaline corrosion
  • Intermetallics
  • Magnesium
  • Polarisation
  • SEM
  • TEM

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