Ternary interdiffusion in L12-Ni3Al with Ir alloying addition

M. Ode, N. Garimella, M. Ikeda, H. Murakami, Y. H. Sohn

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Average ternary interdiffusion coefficients in Ni3Al with Ir additions have been determined using solid-to-solid diffusion couples annealed at 1200°C for 5 hours. Disc shaped alloy specimens were prepared by the vacuum arc melting at compositions of Ni-24Al, Ni-25Al, Ni-26Al, Ni-23.5Al-1Ir, Ni-24.5Al-1Ir, Ni-23Al-2Ir, Ni-23Al-2Ir, Ni-24Al-2Ir, Ni-23Al-3Ir (at.%). Surfaces of alloys were polished down to 1200 grit and diffusion couples were assembled in Si3N4 jig for initial bonding heat treatment at 1200°C for 0.5 hours. Additional diffusion anneal was carried out at 1200°C for 4.5 hours outside of Si3N4 jig so that diffusion couples can be water quenched. Concentration profiles of individual components were measured by electron probe microanalysis using pure standard of Ni, Al and Ir. Interdiffusion flux of individual component was determined directly from the experimental concentration profiles, and the moments of interdiffusion flux were examined to calculate the average ternary interdiffusion coefficients, D̃̄ijk either with Al or Ni as dependent component. Calculated interdiffusion coefficients suggest that Ir-alloyed Al2O3-forming oxidation resistant coatings would be beneficial to reduce the interdiffusion flux of Ni from superalloy substrates to the coating, and reduce the interdiffusion flux of Al from the coating to the superalloy substrate.

Original languageEnglish
Pages (from-to)637-642
Number of pages6
JournalDefect and Diffusion Forum
Volume273-276
DOIs
Publication statusPublished - 2008 Jan 1
Externally publishedYes

Keywords

  • High temperature alloys
  • Intermetallics
  • Ir
  • L1
  • NiAl
  • Ternary interdiffusion

ASJC Scopus subject areas

  • Radiation
  • Materials Science(all)
  • Condensed Matter Physics

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