"Enhanced Resistance to Irradiation Induced Ferritic Transformation in Nanostructured Austenitic Steels"
Andrew Hoffman, Maalavan Arivu, Haiming Wen, Li He, Kumar Sridharan, Xin Wang, Xiang Liu, Lingfeng He, Yaqiao Wu,
Materialia
Vol. 13
2020
Link
Irradiation induced phase transformation of γ-austenite to α-ferrite has been observed in austenitic steels for the past several decades. This transformation can be detrimental to structural materials in a nuclear reactor environment as the increased fraction of the ferritic phase can increase corrosion and embrittlement and lead to stress corrosion cracking. This transformation is caused by both strain induced martensite transformation as well as radiation induced segregation and precipitation. In this study, two radiation tolerant nanostructured 304L austenitic steels (one ultrafine grained and one nanocrystalline) were manufactured using severe plastic deformation. These nanostructured 304L steels were compared to conventional coarse-grained 304L, after self-ion irradiation at 500°C up to a peak damage of 50 displacements per atom. Phase fraction after irradiation was analyzed using grazing incidence x-ray diffraction, precession electron diffraction, and electron backscatter diffraction. Nanostructured 304L steels showed significant resistance to irradiation induced austenite to ferrite transformation. This resistance was shown to be due to a decrease in defect formation, as well as a reduction in radiation induced segregation and precipitation. |
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"Severe plastic deformation assisted carbide precipitation in Fe-21Cr-5Al alloy" Maalavan Arivu, Andrew Hoffman, Jiaqi Duan, Haiming Wen, Rinat Islamgaliev, Ruslan Valiev, Materials Letters Vol. 253 2019 78-81 Link |
"Enhanced Austenite Stability in Nanostructured Steels During Ion Irradiation" Andrew Hoffman, Haiming Wen, Maalavan Arivu, 2020 TMS Annual Meeting February 23-27, (2020) |
RTE 2nd Call Awards Announced - Projects total approximately $1.6 million These project awards went to principal investigators from 26 U.S. universities, eight national laboratories, two British universities, and one Canadian laboratory. Tuesday, May 14, 2019 - Calls and Awards |
DOE Awards 31 RTE Proposals, Opens FY-20 1st Call - Projects total $1.1 million; Next proposals due 10/31 Awards will go to 22 principal investigators from universities, six from national laboratories, and three from foreign universities. Tuesday, September 17, 2019 - Calls and Awards, Announcement |
"Atom probe tomography of segregation at grain boundaries and gas bubbles in neutron irradiated U-10 wt% Mo fuel" Andrew Hoffman, Mukesh Bachhav, Assel Aitkaliyeva, Yaqiao Wu, Brandon Miller, Dennis Keiser, Jian Gan, Haiming Wen, Maalavan Arivu, [2024] Materials Letters · DOI: 10.1016/j.matlet.2024.136414 | |
"Influence of grain size on α′ Cr precipitation in an isothermally aged Fe-21Cr-5Al alloy" Andrew Hoffman, Jonathan Poplawsky, Ian Spinelli, Cong Dai, Raul B. Rebak, James Cole, Rinat K Islamgaliev, Ruslan Z. Valiev, Haiming Wen, Maalavan Arivu, [2024] Materialia · DOI: 10.1016/j.mtla.2024.102047 | |
"Comparison of the Thermal Stability in Equal‐Channel‐Angular‐Pressed and High‐Pressure‐Torsion‐Processed Fe–21Cr–5Al Alloy"
Andrew Hoffman, Jiaqi Duan, Jonathan Poplawsky, Xinchang Zhang, Frank Liou, Rinat Islamgaliev, Ruslan Valiev, Haiming Wen, Maalavan Arivu,
[2023]
Advanced Engineering Materials
· DOI: 10.1002/adem.202300756
Nanostructured steels are expected to have enhanced irradiation tolerance and improved strength. However, they suffer from poor microstructural stability at elevated temperatures. In this study, Fe–21Cr–5Al–0.026C (wt%) Kanthal D (KD) alloy belonging to a class of (FeCrAl) alloys considered for accident‐tolerant fuel cladding in light‐water reactors is nanostructured using two severe plastic deformation techniques of equal‐channel angular pressing (ECAP) and high‐pressure torsion (HPT), and their thermal stability between 500–700 °C is studied and compared. ECAP KD is found to be thermally stable up to 500 °C, whereas HPT KD is unstable at 500 °C. Microstructural characterization reveals that ECAP KD undergoes recovery at 550 °C and recrystallization above 600 °C, while HPT KD shows continuous grain growth after annealing above 500 °C. Enhanced thermal stability of ECAP KD is from significant fraction (>50%) of low‐angle grain boundaries (GBs) (misorientation angle 2–15°) stabilizing the microstructure due to their low mobility. Small grain sizes, a high fraction (>80%) of high‐angle GBs (misorientation angle >15°) and accordingly a large amount of stored GB energy, serve as the driving force for HPT KD to undergo grain growth instead of recrystallization driven by excess stored strain energy. |
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"Novel effects of grain size and ion implantation on grain boundary segregation in ion irradiated austenitic steel" Yongfeng Zhang, Maalavan Arivu, Li He, Kumar Sridharan, Yaqiao Wu, Rinat K. Islamgaliev, Ruslan Z. Valiev, Haiming Wen, Andrew K. Hoffman, [2023] Acta Materialia · DOI: 10.1016/j.actamat.2023.118714 | |
"Severe Plastic Deformation Assisted Carbide Precipitation In Fe-21Cr-5Al Alloy" Andrew Hoffman, Jiaqi Duan, Haiming Wen, Rinat Islamgaliev, Ruslan Valiev, Maalavan Arivu, [2019] Materials Letters · DOI: 10.1016/j.matlet.2019.05.139 | |
Source: ORCID/CrossRef using DOI |
Correlative Transmission Electron Microscopy and Atom Probe Tomography Study of Radiation Induced Segregation and Precipitation in Nanostructured SS304 - FY 2019 RTE 3rd Call, #19-2880
Alleviating irradiation-induced precipitation in a Fe-21Cr-5Al alloy via nanostructuring. - FY 2019 RTE 2nd Call, #19-1761
The Nuclear Science User Facilities (NSUF) is the U.S. Department of Energy Office of Nuclear Energy's only designated nuclear energy user facility. Through peer-reviewed proposal processes, the NSUF provides researchers access to neutron, ion, and gamma irradiations, post-irradiation examination and beamline capabilities at Idaho National Laboratory and a diverse mix of university, national laboratory and industry partner institutions.
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