Iron nitride, α″-Fe16N2, around <100> interstitial type dislocation loops in neutron-irradiated iron

T. Yoshiie, K. Inoue, K. Yoshida, T. Toyama, Y. Satoh, Y. Nagai

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Atom probe tomography (APT) and selected area electron diffraction (SAED) by transmission electron microscopy (TEM) were applied to nano-scale precipitates formed in a neutron-irradiated iron (99.99% pure) at high temperatures. In the conventional TEM, we discovered donut-type precipitates on the {100} planes that formed at the dilatational side of interstitial type dislocation loops with the Burgers vector of <100> on the habit planes of {100} in the bcc iron lattice. The precipitates were identified as nitride, bct α″-Fe16N2, by chemical composition and lattice structural analyses using APT and SAED. Image contrasts of the α″-Fe16N2 in a weak beam dark-field electron microscopy study were carefully analysed with the diffraction vector and the sign of deviation parameter from the Bragg condition, and it was concluded to be a selective visualisation of α″-Fe16N2 on one of the {100} planes. These results were in agreement with the crystallographic orientation between the α″-Fe16N2 and matrix iron, thereby bridging a knowledge gap in α″-Fe16N2 formation during neutron irradiation using a sodium-cooled experimental fast reactor, JOYO, or a 14 MeV D-T neutron source, RTNS-II.

Original languageEnglish
Pages (from-to)1202-1213
Number of pages12
JournalPhilosophical Magazine
Issue number10
Publication statusPublished - 2021


  • atom prove tomography
  • interstitial type dislocation loops
  • neutron irradiated iron
  • nitride
  • α″-FeN


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