Influences of ruthenium and crystallographic orientation on creep behavior of aluminized nickel-base single crystal superalloys

F. H. Latief, K. Kakehi, H. An-Chou Yeh, Hideyuki Murakami

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The influences of ruthenium and surface orientation on creep behavior of aluminized Ni-base single crystal superalloys were investigated by comparing two different types of NKH superalloys. The aluminized coated specimens were then subjected to creep rupture tests at a temperature of 900. °C and a stress of 392. MPa. The coating treatment resulted in a significant decrease in creep rupture lives for both superalloys. The diffusion zones between the coating and substrate led to changes in microstructure, which diminished the creep behavior of the aluminized superalloys. Because of the interdiffusion of Ru, Al and Ni, the solubility of some of the refractory elements, such as W, Re. Mo, Co and Cr decreased in the diffusion zone; the precipitation of topologically close-packed (TCP) phases was thus inevitable. In the present study, the addition of Ru increased the degree of Re and Cr supersaturation in the γ matrix. Consequently, the addition of Ru indirectly promoted the precipitation of TCP phases in aluminized Ni-base single crystal superalloys. Furthermore, the growth of TCP precipitates was greatly influenced by the specific surface orientations of the Ni-base single crystal superalloys. In conclusion, the {110} specimens showed shorter creep rupture life than the {100} specimens, this was due to the difference in the crystallographic geometry of {111}〈101〉 slip system and TCP precipitates between the two side-surface orientations of the specimens.

Original languageEnglish
Pages (from-to)143-152
Number of pages10
JournalMaterials Science and Engineering A
Volume592
DOIs
Publication statusPublished - 2014 Jan 13
Externally publishedYes

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Keywords

  • Aluminide coating
  • Creep
  • Crystallographic orientation
  • Ni-base superalloy
  • Ruthenium

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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