NSUF 19-1744: Correlation of In-situ TEM Characterization and Ex-situ Microchemistry Analysis of Radiation Damage in Metal/Oxide Multilayers

Cross-sectional TEM specimens of Fe/Fe2O3 and (Fe-18%Ni)/Fe2O3 multilayers will be prepared using a Focused Ion Beam (FIB) instrument at the Analytical Instrument Facility (AIF), at North Carolina State University (NCSU). In-situ ion irradiation experiments will be carried out at the IVEM at ANL, at 25 and 500ºC using 1 MeV Kr2+ ions with the ion beam incident at 30º from the electron beam and typically ~13-16º from the specimen normal. During irradiation, the flux will be kept at 6.25×1015 ions.m-2.s-1 and measured to an accuracy of ±10% using an annular Faraday cup. The irradiation dose rate in displacement per atom per second (dpa.s-1) is estimated using the software package SRIM-2008 under the “Kinchin-Pease calculation” mode (a.k.a. “quick damage calculation” mode). The default density of 7.86×103 kg.m-3 and displacement energy of 40 eV/atom for iron are used. The damage profile based on srim simulations is relatively uniform through the first 100 nm of the total range of 500 nm, resulting in an irradiation dose rate of ~1.03×10-3 dpa.s-1 in the first 100 nm depth (corresponding to the thickness of the TEM samples). Final irradiation doses are expected to be 10 dpa. The microstructure evolution under irradiation will be followed and characterized at successive doses, using bright field and (g, 3g) weak beam dark field TEM imaging methods. Brief pauses during irradiation will be conducted to allow for taking TEM images at specific dose levels. Furthermore, videos will be recorded throughout irradiation for subsequent frame-by-frame analysis (15 frames/s). The study focuses on the identification of dislocation loop nature (interstitial vs. vacancy), Burgers vectors, size distribution and density as a function of dose since the irradiations are done IN-SITU. Radiation-enhanced diffusion effects and potential phase transformations (at 500C) if any will be characterized by analyzing the Diffraction Patterns (DPs) recorded during the experiments, and using the FEI Titan S/TEM at the NCSU (post-experiment). The microscope is equipped with high-brightness field emission electron source (X-FEG) and four Bruker© energy dispersive X-ray spectroscopy detectors. Such configuration, a.k.a the “ChemiSTEM” method, enables qualitative mapping of the elemental distribution. The ChemiSTEM mapping will be carried out at interfaces of metal/oxide multilayers to identify if any radiation-enhanced diffusion occurs.

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Поле	Стойност
Abstract	Cross-sectional TEM specimens of Fe/Fe2O3 and (Fe-18%Ni)/Fe2O3 multilayers will be prepared using a Focused Ion Beam (FIB) instrument at the Analytical Instrument Facility (AIF), at North Carolina State University (NCSU). In-situ ion irradiation experiments will be carried out at the IVEM at ANL, at 25 and 500ºC using 1 MeV Kr2+ ions with the ion beam incident at 30º from the electron beam and typically ~13-16º from the specimen normal. During irradiation, the flux will be kept at 6.25×1015 ions.m-2.s-1 and measured to an accuracy of ±10% using an annular Faraday cup. The irradiation dose rate in displacement per atom per second (dpa.s-1) is estimated using the software package SRIM-2008 under the “Kinchin-Pease calculation” mode (a.k.a. “quick damage calculation” mode). The default density of 7.86×103 kg.m-3 and displacement energy of 40 eV/atom for iron are used. The damage profile based on srim simulations is relatively uniform through the first 100 nm of the total range of 500 nm, resulting in an irradiation dose rate of ~1.03×10-3 dpa.s-1 in the first 100 nm depth (corresponding to the thickness of the TEM samples). Final irradiation doses are expected to be 10 dpa. The microstructure evolution under irradiation will be followed and characterized at successive doses, using bright field and (g, 3g) weak beam dark field TEM imaging methods. Brief pauses during irradiation will be conducted to allow for taking TEM images at specific dose levels. Furthermore, videos will be recorded throughout irradiation for subsequent frame-by-frame analysis (15 frames/s). The study focuses on the identification of dislocation loop nature (interstitial vs. vacancy), Burgers vectors, size distribution and density as a function of dose since the irradiations are done IN-SITU. Radiation-enhanced diffusion effects and potential phase transformations (at 500C) if any will be characterized by analyzing the Diffraction Patterns (DPs) recorded during the experiments, and using the FEI Titan S/TEM at the NCSU (post-experiment). The microscope is equipped with high-brightness field emission electron source (X-FEG) and four Bruker© energy dispersive X-ray spectroscopy detectors. Such configuration, a.k.a the “ChemiSTEM” method, enables qualitative mapping of the elemental distribution. The ChemiSTEM mapping will be carried out at interfaces of metal/oxide multilayers to identify if any radiation-enhanced diffusion occurs.
Award Announced Date	2019-05-14T15:56:21.32
Awarded Institution	None
Facility	None
Facility Tech Lead	Wei-Ying Chen
Irradiation Facility	Intermediate Voltage Electron Microscopy (IVEM)-Tandem Facility
PI	Djamel Kaoumi
PI Email	[email protected]
Project Type	RTE
RTE Number	1744