Effect of alloying on the oxidation behaviour of Co-Al-W superalloys

H. Y. Yan, V. A. Vorontsov, D. Dye

Research output: Contribution to journalArticle

72 Citations (Scopus)

Abstract

The 800°C isothermal and cyclic oxidation of alloys based on Co-7Al-7W (at.%) was examined. Cr, Fe and Si additions were beneficial. Repeated oxide bilayers formed during cycling of non-Cr alloys, which were not protective (>100μm thick). In these layers, the outer was Co3O4 and the inner, a porous Co3O4 and Al2O3 mixture. 10at.% Cr substitution for Co was sufficient to produce a protective, ~1μm thick scale which contained an outer layer of Al2CoO4, a very thin (100nm) middle layer of Cr2O3 and an inner layer of Al2O3. Therefore protective oxide scales are possible in γ/γ', Co-Co3(Al,W) superalloys.

Original languageEnglish
Pages (from-to)382-395
Number of pages14
JournalCorrosion Science
Volume83
DOIs
Publication statusPublished - 1 Jan 2014

Keywords

  • superalloys
  • STEM
  • thermal cycling
  • oxidation
  • oxidation behaviour
  • Co–Al–W superalloys

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