Lattice misfit during ageing of a polycrystalline nickel-base superalloy

D. M. Collins*, L. Yan, E. A. Marquis, L. D. Connor, J. J. Ciardiello, A. D. Evans, H. J. Stone

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

44 Citations (Scopus)


The temporal evolution of the lattice parameters and lattice misfit of an advanced polycrystalline nickel-base superalloy have been studied in situ during an ageing heat treatment using synchrotron X-ray diffraction. During ageing, the γ and γ′ lattice parameters were both observed to decrease, a trend that cannot be attributed to a loss of coherency alone. Phase-extracted γ′ replicated this behaviour. Atom probe tomography was used to measure the compositional changes between the start and end of the ageing heat treatment. Using these data, a thermodynamic assessment was made using the software ThermoCalc of the structural change across the interface between γ and γ′. Subsequently, the unconstrained lattice parameters were estimated and were shown to be in good agreement with the X-ray diffraction measurements. Thus, the observed anomalous lattice misfit behaviour was concluded to be dominated by elemental exchange between the γ and γ′ phases during ageing.

Original languageEnglish
Pages (from-to)7791-7804
Number of pages14
JournalActa Materialia
Issue number20
Publication statusPublished - Dec 2013


  • Coarsening
  • Misfit
  • Nickel alloys
  • Synchrotron radiation
  • X-ray diffraction (XRD)

ASJC Scopus subject areas

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


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