Effects of high-pressure torsion on the pitting corrosion resistance of aluminum-iron alloys

Hiroaki Nakano, Hiroto Yamaguchi, Yohei Yamada, Satoshi Oue, In Joon Son, Zenji Horita, Hiroki Koga

Research output: Contribution to journalArticle

Abstract

The effects of reducing the grain size by high-pressure torsion HPT on the pitting corrosion resistance of Al-Fe alloys with Fe contents of 0.5, 2, and 5mass% were investigated by means of polarization curves in solutions containing 0.1 mol-dm-3 Na2SO4 and 8.46 mmol-dm -3 NaCl (300 ppm Cl-) at 298 K and by surface analysis. The potentials for pitting corrosion of the Al-Fe alloys were clearly shifted to the noble direction by HPT, leading to an improvement in pitting corrosion resistance. This improvement was larger in the Al-0.5%Fe and Al-2%Fe alloys and smaller in the Al-5%Fe alloy. The Al-Fe alloys contained precipitates of Al-Fe intermetallic compounds, around which pitting corrosion occurred. The Al-5%Fe alloy, in particular, contained large precipitates tens of micrometers in size, and pitting corrosion was significant around these large precipitates. It is evident from the time-dependence of the corrosion potential and the polarization resistance of the corrosion reaction that the formation rate of AI oxide films increases as a result of HPT. It was therefore concluded that the improvement in pitting corrosion resistance ot the Al-Fe alloys with HPT is causea by increasing the oxidation rate of Al.

Original languageEnglish
Pages (from-to)543-549
Number of pages7
JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
Volume77
Issue number11
DOIs
Publication statusPublished - Nov 1 2013

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

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