Mechanism for Z-phase formation in 11CrMoVNbN martensitic heat-resistant steel

Myung Yeon Kim, Sung Min Hong, Kyu Ho Lee, Woo Sang Jung, Young Su Lee, Young Kook Lee, Jae Hyeok Shim

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11 Citations (Scopus)


The mechanism for the formation of Z-phase was investigated for samples of an 11CrMoVNbN steel aged at 593 °C for up to 50,000 h. X-ray diffraction indicates that Z-phase appears after 5000 h of aging, and its amount gradually increases up to 50,000 h aging at the expense of mainly Cr2N. Transmission electron microscopy shows that Z-phase nucleates in the V-enriched rim region of Cr2N precipitates, which forms due to the diffusion of V into the precipitates from the matrix. Nucleated Z-phase tends to grow relatively rapidly compared with the preexisting precipitates such as Nb(C,N) and M23C6. Z-phase seems to consume Cr2N by the nucleation and growth mechanism rather than the transformation mechanism. The main difference in the aged samples is that the Nb content of Z-phase is lower and that Z-phase does not replace Cr2N completely, compared to the results of the crept samples.

Original languageEnglish
Pages (from-to)40-45
Number of pages6
JournalMaterials Characterization
Publication statusPublished - 2017 Jul 1

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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