Stability of the strengthening nanoprecipitates in reduced activation ferritic steels under Fe2+ ion irradiation

L. Tan, Y. Katoh, L. L. Snead

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27 Scopus citations

Abstract

The stability of MX-type precipitates is critical to retain mechanical properties of both reduced activation ferritic-martensitic (RAFM) and conventional FM steels at elevated temperatures. Radiation resistance of TaC, TaN, and VN nanoprecipitates irradiated up to ∼49 dpa at 500 C using Fe 2+ is investigated in this work. Transmission electron microscopy (TEM) utilized in standard and scanning mode (STEM) reveals the non-stoichiometric nature of the nanoprecipitates. Irradiation did not alter their crystalline nature. The radiation resistance of these precipitates, in an order of reduced resistance, is TaC, VN, and TaN. Particle dissolution, growth, and reprecipitation were the modes of irradiation-induced instability. Irradiation also facilitated formation of Fe2W type Laves phase limited to the VN and TaN bearing alloys. This result suggests that nitrogen level should be controlled to a minimal level in alloys to gain greater radiation resistance of the MX-type precipitates at similar temperatures as well as postpone the formation and subsequent coarsening of Laves phase.

Original languageEnglish
Pages (from-to)104-110
Number of pages7
JournalJournal of Nuclear Materials
Volume445
Issue number1-3
DOIs
StatePublished - 2014

Funding

Research supported by the U.S. Department of Energy (DOE), Office of Fusion Energy Sciences under contract DE-AC05-00OR22725 with UT-Battelle, LLC, and through a user project supported by ORNL’s Center for Nanophase Materials Sciences (CNMS) that is sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. DOE. Work also supported by the U.S. DOE, Office of Nuclear Energy under DOE Idaho Operations Office Contract DE-AC07-051D14517, as part of an ATR National Scientific User Facility experiment. Dr. G.S. Was is appreciated for his advice on the Fe 2+ ion irradiation experiment. Mr. O. Toader and Mrs. D.W. Coffey are also appreciated for conducting the Fe 2+ ion irradiation experiment and preparing the FIB specimens, respectively.

FundersFunder number
CNMS
ORNL’s Center for Nanophase Materials Sciences
Office of Basic Energy Sciences
Scientific User Facilities Division
U.S. DOE
U.S. Department of Energy
Office of Nuclear EnergyDE-AC07-051D14517
Fusion Energy SciencesDE-AC05-00OR22725

    Keywords

    • Displacement cascades
    • Dissolution
    • Nanoprecipitates
    • Radiation resistance
    • Reprecipitation

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