On the formation of irregular-shaped gamma prime and serrated grain boundaries in a nickel-based superalloy during continuous cooling

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Interrupted cooling tests have been carried out in order to study the microstructural evolution of a high γ´ fraction nickel-based superalloy during continuous cooling from above γ´ solvus. It was found that the formation of irregular-shaped γ΄ during slow cooling is the result of coarsening and coalescing of γ΄ precipitates which involved dissolution of adjacent even finer precipitates and solute flux from them. The formation of serrated grain boundaries was found to be associated with the presence of large γ´ precipitates at the grain boundaries which may have pinned grain boundaries during their migration.


Original languageEnglish
Pages (from-to)28-34
Number of pages7
JournalMaterials Characterization
Early online date5 Dec 2012
Publication statusPublished - Feb 2013


  • Nickel-based superalloy, gamma prime, continuous cooling, microstructural evolution, serrated grain boundaries