Microstructural characteristics of the microphase Y-Ti2SC in nickel-based superalloys

Xiaobing Hu, Y. B. Xue, S. J. Zheng, Y. L. Zhu, D. Chen, X. L. Ma*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


The microstructural characteristics of microphase Y-Ti2SC in Ni-based superalloys have been studied by means of analytical transmission electron microscopy (TEM). In the standard heat treated samples, the Y phase always exhibits slab morphology forming either the sandwiched plate in MC or the side-by-side structure with MC. Moreover, the Y phase also maintains an definite crystallographic orientation relationship of [12̄10]Y// [11̄0]MC and (0 0 0 1)Y//(1 1 1)MC with the MC-type carbide. Stacking fault which results from the insertion of two Ti-C layers has been identified in the Y-Ti2SC phase. Combined with high resolution TEM (HRTEM) and first-principles calculations, we also determine the most stable interfacial structure between Y phase and MC carbide. Additionally, we find that Y-Ti2SC phase can solutionize amounts of beneficial elements Hf and Zr from the matrix during long-term annealing process, which leads to its lattice expansion. This solution phenomenon is detrimental for superalloys due to the consumption of the beneficial elements.

Original languageEnglish (US)
Pages (from-to)104-110
Number of pages7
JournalJournal of Alloys and Compounds
StatePublished - Oct 25 2014


  • Interface
  • MC-type carbide
  • Ni-based superalloys
  • Transmission electron microscopy

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry


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