Effect of surface treatment and crystal orientation on microstructural changes in aluminized Ni-based single-crystal superalloy

Kazuki Kasai, Hideyuki Murakami, Seiji Kuroda, Hachiro Imai

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The effect of pre-surface treatment and crystal orientation on microstructural changes in the aluminized 4th generation Nibased single-crystal superalloy TMS-138 was investigated. The substrate superalloy was cut along the {100} and {110} planes on which three kinds of surface finishing, such as grit-blasting, mechanically polishing and electro-polishing were conducted prior to the conventional high-activity aluminizing process. A thermal cycling test at 1373 K revealed that heavy deformation of substrate surface by grit blasting gave rise to the formation of a secondary reaction zone (SRZ) in the vicinity of interdiffusion zone/substrate interfaces. While when the surfaces were finished by electro-polishing, voids were formed in the vicinity of interdiffusion zone/substrate interfaces. It is also found that accelerated formation of SRZ and voids was observed along <110> directions rather than <100> directions during the thermal cycling test. The difference in morphological changes of substrates can be related to the residual stress introduced by the surface finishing.

Original languageEnglish
Pages (from-to)19-23
Number of pages5
JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
Volume74
Issue number1
DOIs
Publication statusPublished - 2010 Jan 1
Externally publishedYes

Keywords

  • Aluminizing
  • Nickel-based single crystal superalloys
  • Secondary Reaction Zone (SRZ)
  • Thermal Barrier Coatings (TBC)

ASJC Scopus subject areas

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

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