Abstract
Oxide dispersion strengthened (ODS) FeCrAl alloys are promising candidate materials for advanced nuclear reactor applications requiring high-temperature strength, corrosion resistance, and irradiation tolerance. As these alloys have increased in compositional complexity through attempts to use highly reactive elements such as Zr to refine particle sizes and optimize nanoprecipitate dispersion characteristics, much debate has ensued as to the effects of these alloying element additions on alloy properties. In an attempt to reconcile differences in nanoprecipitate distributions reported in the literature over the past decade, a detailed investigation of a recently developed ODS FeCrAl alloy with nominal composition Fe–10Cr-6.1Al-0.3Zr+0.3Y2O3 is presented using a combination of atom probe tomography (APT), scanning/transmission electron microscopy (S/TEM), and computational thermodynamics modeling. It is illustrated that based on the amount of Zr available in the lattice, Zr competes with Al and Cr to form carbides and nitrides as opposed to oxygen-rich precipitates. This alloy system has a high number density (>1023 m−3) of ∼2–4 nm diameter (Y,Al,O)-rich nanoprecipitates, but it is shown that due to the compositional spread and unknown partitioning of Al between the matrix and precipitates, significant challenges still exist for quantifying the exact compositions of these precipitates using APT. However, the noted compositional spread is supported by identified complex oxides yttrium aluminum monoclinic (YAM) and yttrium aluminum garnet (YAG) using S/TEM. As a result of these findings, researchers developing ODS FeCrAl with reactive element additions must pay careful attention to C and N impurities when optimizing reactive element additions.
| Original language | English |
|---|---|
| Article number | 152105 |
| Journal | Journal of Nuclear Materials |
| Volume | 533 |
| DOIs | |
| State | Published - May 2020 |
Funding
The work presented in this paper was supported primarily by the Advanced Fuels Campaign of the Nuclear Technology R&D program in the Office of Nuclear Energy, US Department of Energy. This work was also funded in part by the Office of Fusion Energy Sciences. This manuscript has been authored by Oak Ridge National Laboratory, managed by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. A portion of this work was conducted using the FEI Talos F200X S/TEM tool provided by US DOE, Office of Nuclear Energy, Fuel Cycle R&D Program and the Nuclear Science User Facilities. Microscopy performed as part of a user project at the Center for Nanophase Materials Sciences (CNMS), which is sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. D. W. Coffey assisted with the experimental work. The authors would like to thank Tom Geer for metallographic sample preparation and to Gregory Cox for extruding the powder material. Finally, we would like to thank and acknowledge Karren More for her insight and critical review of our manuscript during its preparation. The work presented in this paper was supported primarily by the Advanced Fuels Campaign of the Nuclear Technology R&D program in the Office of Nuclear Energy , US Department of Energy . This work was also funded in part by the Office of Fusion Energy Sciences . This manuscript has been authored by Oak Ridge National Laboratory, managed by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. A portion of this work was conducted using the FEI Talos F200X S/TEM tool provided by US DOE, Office of Nuclear Energy, Fuel Cycle R&D Program and the Nuclear Science User Facilities. Microscopy performed as part of a user project at the Center for Nanophase Materials Sciences (CNMS), which is sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy . D. W. Coffey assisted with the experimental work. The authors would like to thank Tom Geer for metallographic sample preparation and to Gregory Cox for extruding the powder material. Finally, we would like to thank and acknowledge Karren More for her insight and critical review of our manuscript during its preparation. This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ).
Keywords
- Atom probe tomography
- Electron microscopy
- Oxide dispersion strengthened (ODS) alloy
- Precipitation