Compositional pathways and capillary effects during isothermal precipitation in a nondilute Ni-Al-Cr alloy

Chantal K. Sudbrack, Ronald D. Noebe, David N. Seidman*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

68 Scopus citations

Abstract

For a Ni-5.2Al-14.2Cr at.% alloy with moderate solute supersaturations, the compositional pathways, as measured with atom-probe tomography, during early to later stage γ′(L12)-precipitation (R = 0.45-10 nm), aged at 873 K, are discussed in light of a multi-component coarsening model. Employing nondilute thermodynamics, detailed model analyses during quasi-stationary coarsening of the experimental data establish that the γ/γ′ interfacial free-energy is 22-23 ± 7 mJ m-2. Additionally, solute diffusivities are significantly slower than model estimates. Strong quantitative evidence indicates that an observed γ′-supersaturation of Al results from the Gibbs-Thomson effect, providing the first experimental verification of this phenomenon. The Gibbs-Thomson relationship for a ternary system, as well as differences in measured phase equilibria with CALPHAD assessments, are considered in great detail.

Original languageEnglish (US)
Pages (from-to)119-130
Number of pages12
JournalActa Materialia
Volume55
Issue number1
DOIs
StatePublished - Jan 2007

Keywords

  • Atom-probe tomography
  • Capillary phenomena
  • Coarsening
  • Nanostructure
  • Ni-Al-Cr alloys

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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