Yong Yang

Profile Information
Name
Yong Yang
Institution
University of Florida
Position
Associate Professor
Affiliation
University of Florida
h-Index
ORCID
0000-0002-0247-6219
Expertise
Radiation Damage
Publications:
"Characterization of microstructure and property evolution in advanced cladding and duct: Materials exposed to high dose and elevated temperature" Todd Allen, Zhijie Jiao, Djamel Kaoumi, Janelle Wharry, cem topbasi, Aaron Kohnert, Leland Barnard, Alicia Certain, Kevin Field, Gary Was, Dane Morgan, Arthur Motta, Brian Wirth, Yong Yang, Journal of Materials Research Vol. 30 2015 1246-1274 Link
Designing materials for performance in high-radiation fields can be accelerated through a carefully chosen combination of advanced multiscale modeling paired with appropriate experimental validation. The studies reported in this work, the combined efforts of six universities working together as the Consortium on Cladding and Structural Materials, use that approach to focus on improving the scientific basis for the response of ferritic–martensitic steels to irradiation. A combination of modern modeling techniques with controlled experimentation has specifically focused on improving the understanding of radiation-induced segregation, precipitate formation and growth under radiation, the stability of oxide nanoclusters, and the development of dislocation networks under radiation. Experimental studies use both model and commercial alloys, irradiated with both ion beams and neutrons. Transmission electron microscopy and atom probe are combined with both first-principles and rate theory approaches to advance the understanding of ferritic–martensitic steels.
"Effects of neutron irradiation and post-irradiation annealing on the microstructure of HT-UPS stainless steel" Chi Xu, Wei-Ying Chen, Xuan Zhang, Meimei Li, Yong Yang, Yaqiao Wu, Journal of Nuclear Materials Vol. 507 2018 188-197 Link
Microstructural changes resulted from neutron irradiation and post-irradiation annealing in a high-temperature ultra-fine precipitate strengthened (HT-UPS) stainless steel were characterized using transmission electron microscopy (TEM) and atom probe tomography (APT). Three HT-UPS samples were neutron-irradiated to 3 dpa at 500?°C, and after irradiation, two of them were annealed for 1?h?at 600?°C and 700?°C, respectively. Frank dislocation loops were the dominant defect structure in both the as-irradiated and 600?°C post-irradiation-annealed (PIAed) samples, and the loop sizes and densities were similar in these two samples. Unfaulted dislocation loops were observed in the 700?°C PIAed sample, and the loop density was greatly reduced in comparison with that in the as-irradiated sample. Nano-sized MX precipitates were observed under TEM in the 700?°C PIAed sample, but not in the 600?°C PIAed or the as-irradiated samples. The titanium-rich clusters were identified in all three samples using APT. The post-irradiation annealing (PIA) caused the growth of the Ti-rich clusters with a stronger effect at 700?°C than at 600?°C. The irradiation caused elemental segregations at the grain boundary and the grain interior, and the grain boundary segregation behavior is consistent with observations in other irradiated austenitic steels. APT results showed that PIA reduced the magnitude of irradiation induced segregations.
"In-situ high-energy X-ray characterization of neutron irradiated HT-UPS stainless steel under tensile deformation" Chi Xu, Xuan Zhang, Yiren Chen, Meimei Li, Jun-Sang Park, Peter Kenesei, Jason Almer, Yong Yang, Acta Materialia Vol. 156 2018 330-341 Link
The tensile deformation behavior of a high-temperature, ultrafine-precipitate strengthened (HT-UPS) stainless steel was characterized in-situ with high-energy X-ray diffraction at 20 and 400?°C. The HT-UPS samples were neutron irradiated to 3 dpa at 400?°C. Significant irradiation hardening and ductility loss were observed at both temperatures. Lattice strain evolutions of the irradiated samples showed a strong linear response up to near the onset of the macroscopic yield, in contrast to the unirradiated HT-UPS which showed a pronounced non-linear behavior well below the macroscopic yield. While the room-temperature diffraction elastic moduli in the longitudinal direction increased after irradiation, the 400?°C moduli were similar before and after irradiation. The evolution of the {200} lattice strain parallel to the loading axis () showed unique characteristics: in the plastic regime, the evolution of after yield is temperature-dependent in the unirradiated specimens but temperature-independent in the irradiated specimens; and the value of at the yield is an irradiation-sensitive, temperature-independent parameter. The evolution of corresponds well with the dislocation density evolution, and is an effective probe of the deformation-induced long-range internal stresses in the HT-UPS steel.
"Irradiaiton Response of the Ferrite Phase in CF3 Cast Stainless Steel" Zhangbo Li, Yong Yang, Transactions of the American Nuclear Society Vol. 116 2017 390-391 Link
"Irradiation response of delta ferrite in as-cast and thermally aged cast stainless steel" Todd Allen, Yiren Chen, Zhangbo Li, Wei-Yang Lo, Janne Pakarinen, Yaqiao Wu, Yong Yang, Journal of Nuclear Materials Vol. 466 2015 201-207 Link
To enable the life extension of Light Water Reactors (LWRs) beyond 60 years, it is critical to gain adequate knowledge for making conclusive predictions to assure the integrity of duplex stainless steel reactor components, e.g. primary pressure boundary and reactor vessel internal. Microstructural changes in the ferrite of thermally aged, neutron irradiated only, and neutron irradiated after being thermally aged cast austenitic stainless steels (CASS) were investigated using atom probe tomography. The thermal aging was performed at 400 °C for 10,000 h and the irradiation was conducted in the Halden reactor at ~315 °C to 0.08 dpa (5.6 × 1019 n/cm2, E > 1 MeV). Low dose neutron irradiation at a dose rate of 5 × 10-9 dpa/s was found to induce spinodal decomposition in the ferrite of as-cast microstructure, and further to enhance the spinodal decomposition in the thermally aged cast alloys. Regarding the G-phase precipitates, the neutron irradiation dramatically increases the precipitate size, and alters the composition of the precipitates with increased, Mn, Ni, Si and Mo and reduced Fe and Cr contents. The results have shown that low dose neutron irradiation can further accelerate the degradation of ferrite in a duplex stainless steel at the LWR relevant condition.
"Micro-mechanical evaluation of SiC-SiC composite interphase properties and debond mechanisms" Mehdi Balooch, Peter Hosemann, Cameron Howard, Yutai Katoh, Takaaki Koyanagi, Yong Yang, Joey Kabel, Kurt Terrani, Composites Part B: Engineering Vol. 131 2017 173-183 Link
SiC-SiC composites exhibit exceptional high temperature strength and oxidation properties making them an advantageous choice for accident tolerant nuclear fuel cladding. In the present work, small scale mechanical testing along with AFM and TEM analysis were employed to evaluate PyC interphase properties that play a key role in the overall mechanical behavior of the composite. The Mohr-Coulomb formulation allowed for the extraction of the internal friction coefficient and debonding shear strength as a function of the PyC layer thickness, an additional parameter. These results have led to re-evaluation of the Mohr-Coulomb failure criterion and adjustment via a new phenomenological equation.SiC-SiC composites exhibit exceptional high temperature strength and oxidation properties making them an advantageous choice for accident tolerant nuclear fuel cladding. In the present work, small scale mechanical testing along with AFM and TEM analysis were employed to evaluate PyC interphase properties that play a key role in the overall mechanical behavior of the composite. The Mohr-Coulomb formulation allowed for the extraction of the internal friction coefficient and debonding shear strength as a function of the PyC layer thickness, an additional parameter. These results have led to re-evaluation of the Mohr-Coulomb failure criterion and adjustment via a new phenomenological equation.
"Microstructural evolution of neutron-irradiated T91 and NF616 to ~4.3 dpa at 469 °C" Kevin Field, Bong Goo Kim, Lizhen Tan, Yong Yang, Sean Gray, Meimei Li, Journal of Nuclear Materials Vol. 493 2017 12-20 Link
Ferritic-martensitic steels such as T91 and NF616 are candidate materials for several nuclear applications. This study evaluates radiation resistance of T91 and NF616 by examining their microstructural evolutions and hardening after the samples were irradiated in the Advanced Test Reactor to ∼4.3 displacements per atom (dpa) at an as-run temperature of 469 °C. In general, this irradiation did not result in significant difference in the radiation-induced microstructures between the two steels. Compared to NF616, T91 had a higher number density of dislocation loops and a lower level of radiation-induced segregation, together with a slightly higher radiation-hardening. Unlike dislocation loops developed in both steels, radiation-induced cavities were only observed in T91 but remained small with sub-10 nm sizes. Other than the relatively stable M23C6, a new phase (likely Sigma phase) was observed in T91 and radiation-enhanced MX → Z phase transformation was identified in NF616. Laves phase was not observed in the samples.
"Microstructural evolution of NF709 (20Cr–25Ni–1.5 MoNbTiN) under neutron irradiation" Bong Goo Kim, Lizhen Tan, Yong Yang, Cheryl Xu, Xuan Zhang, Meimei Li, Journal of Nuclear Materials Vol. 470 2016 229-235 Link
Because of its superior creep and corrosion resistance as compared with general austenitic stainless steels, NF709 has emerged as a candidate structural material for advanced nuclear reactors. To obtain fundamental information about the radiation resistance of this material, this study examined the microstructural evolution of NF709 subjected to neutron irradiation to 3 displacements per atom at 500 °C. Transmission electron microscopy, scanning electron microscopy, and high-energy x-ray diffraction were employed to characterize radiation-induced segregation, Frank loops, voids, as well as the formation and reduction of precipitates. Radiation hardening of ∼76% was estimated by nanoindentation, approximately consistent with the calculation according to the dispersed barrier-hardening model, suggesting Frank loops as the primary hardening source.
"Microstructural evolution of NF709 austenitic stainless steel under in-situ ion irradiations at room temperature, 300, 400, 500 and 600 °C" Chi Xu, Wei-Ying Chen, Yiren Chen, Yong Yang, Journal of Nuclear Materials Vol. 509 2018 644-653 Link
"Microstructure and Fission Product Distribution Examination in the UCO kernel of TRISO Fuel Particles" Isabella van Rooyen, Yong Yang, Terry Holesinger, Mukesh Bachhav, OSTI.gov, Conf Proceedings Vol. 2018 Link
"Using a spherical crystallite model with vacancies to relate local atomic structure to irradiation defects in ZrC and ZrN" Todd Allen, Hasitha Ganegoda, Daniel Olive, Jeff Terry, Yong Yang, Clayton Dickerson, Journal of Nuclear Materials Vol. 475 2016 123-131 Link
Zirconium carbide and zirconium nitride are candidate materials for new fuel applications due to several favorable physicochemical properties. ZrC and ZrN samples were irradiated at the Advanced Test Reactor National Scientific User Facility with neutrons at 800 °C to a dose of 1 dpa. Structural examinations have been made of the ZrC samples using high resolution transmission electron microscopy, and the findings compared with a previous study of ZrC irradiated with protons at 800 °C. The use of X-ray absorption fine structure spectroscopy (XAFS) to characterize the radiation damage was also explored including a model based on spherical crystallites that can be used to relate EXAFS measurements to microscopy observations. A loss of coordination at more distant coordination shells was observed for both ZrC and ZrN, and a model using small spherical crystallites suggested this technique can be used to study dislocation densities in future studies of irradiated materials.
Presentations:
"Effect of Ni on Formatoin of Entermetallic Phases in Highly Irradiated Reactor Pressure Vessel Steels" G. Robert Odette, Nicolas Silva, Peter Wells, Yong Yang, TMS 2014 February 16-20, (2014)
"Irradiation Effects in Aged Cast Duplex Stainless Steels" Janne Pakarinen, Yong Yang, TMS 2014 February 16-20, (2014)
"Irradiation Response of the Ferrite Phase in CF3 Cast Stainless Steel" Zhangbo Li, Yong Yang, 2017 ANS Annual Meeting [unknown]
"Microstructural Evolution of NF709 Steel under In-situ Ion Irradiations at Room Temperature to 600 °C" Yong Yang, 2017 ANS Annual Meeting [unknown]
"Microstructure and Fission Product Distribution Examination in the UCO Kernel of TRISO Fuel Particles" Isabella van Rooyen, Yong Yang, Terry Holesinger, , HTR 2018 October 8-10, (2018)
NSUF Articles:
U.S. DOE Nuclear Science User Facilities Awards 35 Rapid Turnaround Experiment Research Proposals - Awards total approximately $1.3 million These projects will continue to advance the understanding of irradiation effects in nuclear fuels and materials in support of the mission of the DOE Office of Nuclear Energy. Wednesday, September 20, 2017 - Calls and Awards
DOE awards 39 RTE Projects - Projects total approximately $1.3 million Thursday, February 1, 2018 - Calls and Awards
NSUF Researcher Feature: Kumar Sridharan - Learn more about a University of Wisconsin professor who helped kick start NSUF Sridharan's research team put the NSUF's first material samples into the ATR, launching a new era of research into the behaviors of fuels and materials in a nuclear reactor environment. Wednesday, August 28, 2019 - Newsletter, Researcher Highlight
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
Additional Publications:
"Experiments Supporting Effective Thermal Conductivity Calculation of Irradiated U-Zr Fuel" [2023] Transactions of the American Nuclear Society · DOI: 10.13182/t128-42193 · EID: 2-s2.0-85180633342 · ISSN: 0003-018X
"Evolution of δ ferrite in a CF3 cast stainless steel upon neutron irradiation to 3, 5, 10, 20, and 40 dpa" Appajosula Rao, Yiren Chen, Yong Yang, Yu Lu, [2021] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2021.152865 · EID: 2-s2.0-85101074374 · ISSN: 0022-3115
"Microstructural and micro-chemical evolutions in irradiated UCO fuel kernels of AGR-1 and AGR-2 TRISO fuel particles" Yong Yang, Isabella J. Van Rooyen, Subhashish Meher, Boopathy Kombaiah, Zhenyu Fu, [2021] Journal of Physics: Conference Series · DOI: 10.1088/1742-6596/2048/1/012006 · EID: 2-s2.0-85118669359 · ISSN: 1742-6596
Abstract

AGR-1 and AGR-2 tristructural-isotropic (TRISO) fuel particles were fabricated using slightly different fuel kernel chemical compositions, modified fabrication processes, different fuel kernel diameters, and changed 235U enrichments. Extensive microstructural and analytical characterizations were conducted to correlate those differences with the fuel kernels’ responses to neutron irradiations in terms of irradiated fuel microstructure, fission products’ chemical and physical states, and fission gas bubble evolutions. The studies used state-of-the-art transmission electron microscopy (TEM) equipped with energy-dispersive x-ray spectroscopy (EDS) via four silicon solid-state detectors with super sensitivity and rapid speed. The TEM specimens were prepared from selected AGR-1 and AGR-2 irradiated fuel kernels exposed to safety testing after irradiation. The particles were chosen in order to create representative irradiation conditions with fuel burnup in the range of 10.8 to 18.6% fissions per initial metal atom (FIMA) and time-average volume-average temperatures varying from 1070 to 1287°C. The 235U enrichment was 19.74 wt.% and 14.03 wt.% for the AGR-1 and AGR-2 fuel kernels, respectively. The TEM results showed significant microstructural reconstructions in the irradiated fuel kernels from both the AGR-1 and AGR-2 fuels. There are four major phases: fuel matrix of UO2 and UC, U2RuC2, and UMoC2—in the irradiated AGR-2 fuel kernel. Zr and Nd form a solid solution in the UC phase. The UMoC2 phase often features a detectable concentration of Tc. Pd was mainly found to be located in the buffer layer or associated with fission gas bubbles within the UMoC2 phase. EDS maps qualitatively show that rare-earth fission products (Nd et al.) preferentially reside in the UO2 phase. In contrast, in the irradiated AGR-1 fuel kernel, no U2RuC2 or UMoC2 precipitates were positively identified. Instead, there was a high number of rod-shaped precipitates enriched with Ru, Tc, Rh, and Pd observed in the fuel kernel center and edge zone. The differences in irradiated fuel kernel microstructural and micro-chemical evolution when comparing AGR-1 and AGR-2 TRISO fuel particles may result from a combination of irradiation temperature, fuel geometry, and chemical composition. However, irradiation temperature probably plays a more deterministic role. Limited electron energy-loss spectroscopy (EELS) characterizations of the AGR-2 fuel kernel show almost no carbon in the UO2 phase, but a small fraction of oxygen was detected in the UC/UMoC2 phase.

"Computational Investigation of Interface Stresses in Duplex Structure Stainless Steels" Israr Bin M. Ibrahim, P. Prabaharan Graceraj, Yong Yang, Appajosula S. Rao, Ramana M. Pidaparti, [2020] Journal of Materials Engineering and Performance · DOI: 10.1007/s11665-020-04877-9 · EID: 2-s2.0-85087850873 · ISSN: 1544-1024
"In-situ TEM characterization of the tensile deformation of ion-irradiated HT-UPS steel at RT and 400 °C" Yu Lu, Zhenyu Fu, Yong Yang, Chi Xu, [2020] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2019.151911 · EID: 2-s2.0-85075877343 · ISSN: 0022-3115
"Microstructure and fission products in the UCO kernel of an AGR-1 TRISO fuel particle after post irradiation safety testing" Isabella J. van Rooyen, Mukesh Bachhav, Yong Yang, Zhenyu Fu, [2020] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2019.151884 · EID: 2-s2.0-85075860832 · ISSN: 0022-3115
"The role of Ti and TiC nanoprecipitates in radiation resistant austenitic steel: A nanoscale study" Rémi Delville, Erich Stergar, Janne Pakarinen, Marc Verwerft, Yong Yang, Christina Hofer, Ronald Schnitzer, Steffen Lamm, Peter Felfer, Dominique Schryvers, Niels Cautaerts, [2020] Acta Materialia · DOI: 10.1016/j.actamat.2020.07.022 · EID: 2-s2.0-85088626589 · ISSN: 1359-6454
"Effects of thermal aging and low dose neutron irradiation on the ferrite phase in a 308L weld" Y. Chen, A. S. Rao, Y. Yang, Z. Li, [2019] Minerals, Metals and Materials Series · DOI: 10.1007/978-3-030-04639-2_129 · EID: 2-s2.0-85064064268 · ISSN: 2367-1696
"Environmentally assisted cracking and fracture toughness of an irradiated stainless steel weld" [2019] 19th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, EnvDeg 2019 · EID: 2-s2.0-85080091223
"Microstructure and deformation behavior of thermally aged cast austenitic stainless steels" C. Xu, X. Zhang, W.-Y. Chen, J.-S. Park, J. Almer, M. Li, Z. Li, Y. Yang, A. S. Rao, B. Alexandreanu, K. Natesan, Y. Chen, [2019] Minerals, Metals and Materials Series · DOI: 10.1007/978-3-030-04639-2_124 · EID: 2-s2.0-85064061789 · ISSN: 2367-1696
"Effects of neutron irradiation and post-irradiation annealing on the microstructure of HT-UPS stainless steel" Wei-Ying Chen, Xuan Zhang, Yaqiao Wu, Meimei Li, Yong Yang, Chi Xu, [2018] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2018.04.043 · EID: 2-s2.0-85046764331 · ISSN: 0022-3115
"In-situ high-energy X-ray characterization of neutron irradiated HT-UPS stainless steel under tensile deformation" Xuan Zhang, Yiren Chen, Meimei Li, Jun-Sang Park, Peter Kenesei, Jonathan Almer, Yong Yang, Chi Xu, [2018] Acta Materialia · DOI: 10.1016/j.actamat.2018.07.008 · EID: 2-s2.0-85049902022 · ISSN: 1359-6454
"Low temperature CVD coating of vanadium carbide on the F/M cladding steel to minimize fuel cladding chemical interaction" [2018] Transactions of the American Nuclear Society · EID: 2-s2.0-85060850741 · ISSN: 0003-018X
"Microstructural evolution of NF709 austenitic stainless steel under in-situ ion irradiations at room temperature, 300, 400, 500 and 600 °C" Wei-Ying Chen, Yiren Chen, Yong Yang, Chi Xu, [2018] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2018.07.044 · EID: 2-s2.0-85050508910 · ISSN: 0022-3115
"Effect of self-ion irradiation on the microstructural changes of alloy EK-181 in annealed and severely deformed conditions" T. Chen, J.G. Gigax, D. Chen, X. Wang, P.S. Dzhumaev, O.V. Emelyanova, M.G. Ganchenkova, B.A. Kalin, M. Leontiva-Smirnova, R.Z. Valiev, N.A. Enikeev, M.M. Abramova, Y. Wu, W.Y. Lo, Y. Yang, M. Short, S.A. Maloy, F.A. Garner, L. Shao, E. Aydogan, [2017] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2017.02.006 · EID: 2-s2.0-85012202939 · ISSN: 0022-3115
"Fracture toughness and deformation behavior of cast austenitic stainless steels after thermal aging" Wei-Ying Chen, Chi Xu, Xuan Zhang, Zhangbo Li, Yong Yang, Appajosula S. Rao, Bogdan Alexandreanu, Krishnamurti Natesan, Yiren Chen, [2017] American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP · DOI: 10.1115/pvp2017-65768 · EID: 2-s2.0-85034062575 · ISSN: 0277-027X

Cast austenitic stainless steels (CASSs) are used in the cooling system of light water reactors (LWRs) for components with complex shapes, such as pump casings, valve bodies, coolant piping, etc. The CF grades of CASS alloys are the cast equivalents of 300-series stainless steels (SSs) and show excellent mechanical properties and corrosion resistance. In contrast to the fully austenitic microstructure of wrought SSs, CASS alloys consist of a dual-phase microstructure of delta ferrite and austenite and are vulnerable to thermal aging embrittlement. The service performance of CASS alloys is of concern after long-term exposure to high-temperature coolant. In this work, we studied the effects of thermal aging and ferrite content on the fracture resistance of CASS alloys. Crack growth rate and fracture toughness J–R curve tests were performed on aged and unaged CASS alloys in simulated light water reactor environments. The impact of thermal aging on the cracking susceptibility was investigated and the effect of ferrite content was evaluated. Significant embrittlement was observed in the CASS alloys after aging at 400°C. To understand the embrittlement mechanism, microstructural characterizations were performed with transmission electron microscope. The thermal aging produced G-phase precipitates and phase separation in the ferrite, but did not affect the microstructure of austenite. Consequently, the ferrite was hardened considerably after thermal aging while the hardness of austenite phase remained unchanged. The difference in hardness created a high incompatible strain at the interface between ferrite and austenite, leading to fracture at phase boundaries.

"Irradiation response of the ferrite phase in CF3 cast stainless steel" [2017] Transactions of the American Nuclear Society · EID: 2-s2.0-85033473158 · ISSN: 0003-018X
"Microstructural evolution of NF709 steel under in-situ ion irradiations at room temperature to 600 °C" [2017] Transactions of the American Nuclear Society · EID: 2-s2.0-85033481191 · ISSN: 0003-018X
"Vanadium carbide by MOCVD for mitigating the fuel cladding chemical interaction" Wei-Yang Lo, Yong Yang, Shaosong Huang, [2017] Fusion Engineering and Design · DOI: 10.1016/j.fusengdes.2017.04.118 · EID: 2-s2.0-85019010929 · ISSN: 0920-3796
"Fracture resistance of cast austenitic stainless steels" W-Y. Chen, A. S. Rao, Z. Li, Y. Yang, B. Alexandreanu, K. Natesan, Y. Chen, [2016] International Conference on Nuclear Engineering, Proceedings, ICONE · DOI: 10.1115/icone24-60736 · EID: 2-s2.0-84995772573

Cast austenitic stainless steels (CASS) possess excellent corrosion resistance and mechanical properties and are used alongside with wrought stainless steels (SS) in light water reactors for primary pressure boundaries and reactor core internal components. In contrast to the fully austenitic microstructure of wrought SS, CASS alloys consist of a dual-phase microstructure of delta ferrite and austenite. The delta ferrite is critical for the service performance since it improves the strength, weldability, corrosion resistance, and soundness of CASS alloys. On the other hand, the delta ferrite is also vulnerable to embrittlement when exposed to reactor service temperatures and fast neutron irradiations. In this study, the combined effect of thermal aging and neutron irradiation on the degradation of CASS alloys was investigated. Neutron-irradiated CASS specimens with and without prior thermal aging were tested in simulated light water reactor environments for crack growth rate and fracture toughness. Miniature compact-tension specimens of CF-3 and CF-8 alloys were tested to evaluate the extent of embrittlement resulting from thermal aging and neutron irradiation. The materials used are static casts containing more than 23% delta ferrite. Some specimens were thermally aged at 400 °C for 10,000 hours prior to the neutron irradiation to simulate thermal aging embrittlement. Both the unaged and aged specimens were irradiated at ∼320°C to a low displacement damage dose of 0.08 dpa. Crack growth rate and fracture toughness J-integral resistance curve tests were carried out on the irradiated and unirradiated control samples in simulated light water reactor environments with low corrosion potentials. While no elevated crack propagation rates were detected in the test environments, significant reductions in fracture toughness were observed after either thermal aging or neutron irradiation. The loss of fracture toughness due to neutron irradiation seemed more evident in the samples without prior thermal aging. Transmission electron microscope (TEM) examination was carried out on the thermally aged and neutron irradiated specimens. The result showed that both neutron irradiation and thermal aging can induce significant changes in the delta ferrite. A high density of G-phase precipitates was observed with TEM in the thermally aged specimens, consistent with previous results. Similar precipitate microstructures were also observed in the neutron-irradiated specimens with or without prior thermal aging. A more extensive precipitate microstructure can be seen in the samples subjected to both thermal aging and neutron irradiation. The similar precipitate microstructures resulting from thermal aging and neutron irradiation are consistent with the fracture toughness results, suggesting a common microstructural origin of the observed embrittlement after thermal aging and neutron irradiation.

"In-situ high energy x-ray characterization of tensile deformation of advanced austenitic stainless steels" [2016] Transactions of the American Nuclear Society · EID: 2-s2.0-85117897281 · ISSN: 0003-018X
"Microstructural evolution of NF709 (20Cr-25Ni-1.5MoNbTiN) under neutron irradiation" L. Tan, C. Xu, Y. Yang, X. Zhang, M. Li, B.K. Kim, [2016] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2015.12.037 · EID: 2-s2.0-84952683848 · ISSN: 0022-3115
"Using a spherical crystallite model with vacancies to relate local atomic structure to irradiation defects in ZrC and ZrN" Hasitha Ganegoda, Todd Allen, Yong Yang, Clayton Dickerson, Jeff Terry, Daniel T. Olive, [2016] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2016.04.004 · EID: 2-s2.0-84963499976 · ISSN: 0022-3115
"Characterization of microstructure and property evolution in advanced cladding and duct: Materials exposed to high dose and elevated temperature" Djamel Kaoumi, Janelle P. Wharry, Zhijie Jiao, Cem Topbasi, Aaron Kohnert, Leland Barnard, Alicia Certain, Kevin G. Field, Gary S. Was, Dane L. Morgan, Arthur T. Motta, Brian D. Wirth, Y. Yang, Todd R. Allen, [2015] Journal of Materials Research · DOI: 10.1557/jmr.2015.99 · EID: 2-s2.0-84929692498 · ISSN: 2044-5326
"Comparison between thermal aging and low dose neutron irradiation effects on ferrites in a duplex structure stainless steel" [2015] Transactions of the American Nuclear Society · EID: 2-s2.0-85063458190 · ISSN: 0003-018X
"Cracking behavior of thermally aged and irradiated CF-8 cast austenitic stainless steel" B. Alexandreanu, W.-Y. Chen, K. Natesan, Z. Li, Y. Yang, A.S. Rao, Y. Chen, [2015] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2015.08.047 · EID: 2-s2.0-84940985734 · ISSN: 0022-3115
"Effects of Cr on the interdiffusion between Ce and Fe-Cr alloys" Nicolas Silva, Yuedong Wu, Robert Winmann-Smith, Yong Yang, Wei-Yang Lo, [2015] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2014.12.035 · EID: 2-s2.0-84920746900 · ISSN: 0022-3115
"Evaluate the thermal conductivity of off-stoichiometry cerium oxide" [2015] Transactions of the American Nuclear Society · EID: 2-s2.0-85053535465 · ISSN: 0003-018X
"Innovative coating of vanadium carbide on the F/M stainless steel for mitigating fuel cladding chemical interaction" [2015] Transactions of the American Nuclear Society · EID: 2-s2.0-85063538149 · ISSN: 0003-018X
"Irradiation response of delta ferrite in as-cast and thermally aged cast stainless steel" Wei-Yang Lo, Yiren Chen, Janne Pakarinen, Yaqiao Wu, Todd Allen, Yong Yang, Zhangbo Li, [2015] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2015.08.006 · EID: 2-s2.0-84939418850 · ISSN: 0022-3115
"Superior radiation-resistant nanoengineered austenitic 304L stainless steel for applications in extreme radiation environments" S. Zheng, C. C. Wei, Y. Wu, L. Shao, Y. Yang, K. T. Hartwig, S. A. Maloy, S. J. Zinkle, T. R. Allen, H. Wang, X. Zhang, C. Sun, [2015] Scientific Reports · DOI: 10.1038/srep07801 · EID: 2-s2.0-84922637941 · ISSN: 2045-2322
Abstract

Nuclear energy provides more than 10% of electrical power internationally and the increasing engagement of nuclear energy is essential to meet the rapid worldwide increase in energy demand. A paramount challenge in the development of advanced nuclear reactors is the discovery of advanced structural materials that can endure extreme environments, such as severe neutron irradiation damage at high temperatures. It has been known for decades that high dose radiation can introduce significant void swelling accompanied by precipitation in austenitic stainless steel (SS). Here we report, however, that through nanoengineering, ultra-fine grained (UFG) 304L SS with an average grain size of ~100 nm, can withstand Fe ion irradiation at 500°C to 80 displacements-per-atom (dpa) with moderate grain coarsening. Compared to coarse grained (CG) counterparts, swelling resistance of UFG SS is improved by nearly an order of magnitude and swelling rate is reduced by a factor of 5. M23C6 precipitates, abundant in irradiated CG SS, are largely absent in UFG SS. This study provides a nanoengineering approach to design and discover radiation tolerant metallic materials for applications in extreme radiation environments.

"The influence of ion beam rastering on the swelling of self-ion irradiated pure iron at 450 °C" Eda Aydogan, Tianyi Chen, Di Chen, Lin Shao, Y. Wu, W.Y. Lo, Y. Yang, F.A. Garner, Jonathan G. Gigax, [2015] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2015.05.025 · EID: 2-s2.0-84934991209 · ISSN: 0022-3115
"Hydrogen migration, precipitation and re-orientation in nuclear spent fuel cladding in dry storage" [2014] Transactions of the American Nuclear Society · EID: 2-s2.0-84904641163 · ISSN: 0003-018X
"Low-temperature chemical vapor deposition ofvanadium carbide for mitigating the FCCI" [2014] Transactions of the American Nuclear Society · EID: 2-s2.0-84939183419 · ISSN: 0003-018X
"Response of equal channel angular extrusion processed ultrafine-grained T91 steel subjected to high temperature heavy ion irradiation" Y.D. Wu, D. Chen, X.M. Wang, C. Sun, K.Y. Yu, Y. Chen, L. Shao, Y. Yang, K.T. Hartwig, X. Zhang, M. Song, [2014] Acta Materialia · DOI: 10.1016/j.actamat.2014.04.034 · EID: 2-s2.0-84900962530 · ISSN: 1359-6454
"Stoichiometry effect on the irradiation response in the microstructure of zirconium carbides" Wei-Yang Lo, Clayton Dickerson, Todd R. Allen, Yong Yang, [2014] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2014.07.071 · EID: 2-s2.0-84906349006 · ISSN: 0022-3115
"Temperature and grain size dependent plastic instability and strain rate sensitivity of ultrafine grained austenitic Fe-14Cr-16Ni alloy" J. Ma, Y. Yang, K.T. Hartwig, S.A. Maloy, H. Wang, X. Zhang, C. Sun, [2014] Materials Science and Engineering: A · DOI: 10.1016/j.msea.2014.01.003 · EID: 2-s2.0-84893134312 · ISSN: 0921-5093
"Vanadium diffusion coating on HT-9 cladding for mitigating the fuel cladding chemical interactions" Yong Yang, Wei-Yang Lo, [2014] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2014.03.052 · EID: 2-s2.0-84898960897 · ISSN: 0022-3115
"Low temperature creep of used nuclear fuel during long term dry storage" [2013] 14th International High-Level Radioactive Waste Management Conference, IHLRWMC 2013: Integrating Storage, Transportation, and Disposal · EID: 2-s2.0-84886899696
"Defects and microstructural evolution of proton irradiated titanium carbide" Yong Yang, Todd R. Allen, Clayton Dickerson, [2012] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2012.02.005 · EID: 2-s2.0-84860522736 · ISSN: 0022-3115
"Thermal stability and radiation tolerance of ultrafine grained austenitic stainless steel, invited" [2012] Transactions of the American Nuclear Society · EID: 2-s2.0-84876362572 · ISSN: 0003-018X
"Thermal stability of ultrafine grained Fe-Cr-Ni alloy" Y. Yang, Y. Liu, K.T. Hartwig, H. Wang, S.A. Maloy, T.R. Allen, X. Zhang, C. Sun, [2012] Materials Science and Engineering: A · DOI: 10.1016/j.msea.2012.02.033 · EID: 2-s2.0-84862798726 · ISSN: 0921-5093
"Crack growth behavior of irradiated type 316 SS in low dissolved oxygen environment" [2011] 15th International Conference on Environmental Degradation of Materials in Nuclear Power Systems-Water Reactors 2011 · EID: 2-s2.0-84867612292
"Irradiation microstructure of austenitic steels and cast steels irradiated in the BOR-60 reactor at 320°C" [2011] 15th International Conference on Environmental Degradation of Materials in Nuclear Power Systems-Water Reactors 2011 · EID: 2-s2.0-84867587299
"Effect of proton irradiation on ZrC with varied stoichiometry" [2010] Transactions of the American Nuclear Society · EID: 2-s2.0-79551676425 · ISSN: 0003-018X
"Evolution of carbide precipitates in 2.25Cr-1Mo steel during long-term service in a power plant" Yiren Chen, Kumar Sridharan, Todd R. Allen, Yong Yang, [2010] Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science · DOI: 10.1007/s11661-010-0194-6 · EID: 2-s2.0-77952555924 · ISSN: 1073-5623
"Crack growth rates and fracture toughness of neutron irradiated grain-boundary-engineered austenitic stainless steels" [2009] 14th International Conference on Environmental Degradation of Materials in Nuclear Power Systems Water Reactors 2009 · EID: 2-s2.0-78649353407
"Dose dependence of radiation hardening of austenitic steels in bor-60 at PWR-relevant temperatures" [2009] 14th International Conference on Environmental Degradation of Materials in Nuclear Power Systems Water Reactors 2009 · EID: 2-s2.0-78649388816
"Pilot project for irradiation testing of materials at the ATR-national scientific user facility" [2009] Transactions of the American Nuclear Society · EID: 2-s2.0-72749096559 · ISSN: 0003-018X
"Proton irradiation study of GFR candidate ceramics" Yong Yang, Clayton Dickson, Todd Allen, Jian Gan, [2009] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2009.02.021 · EID: 2-s2.0-64649090820 · ISSN: 0022-3115
"Radiation stability of ZrN under 2.6 MeV proton irradiation" Clayton A. Dickerson, Todd R. Allen, Yong Yang, [2009] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2009.03.040 · EID: 2-s2.0-67349129752 · ISSN: 0022-3115
"Radiation stability of proton irradiated zirconium carbide" [2009] International Congress on Advances in Nuclear Power Plants 2009, ICAPP 2009 · EID: 2-s2.0-84907937972
"The stress corrosion cracking behavior of alloys 690 and 152 weld in a PWR environment" [2009] 14th International Conference on Environmental Degradation of Materials in Nuclear Power Systems Water Reactors 2009 · EID: 2-s2.0-78649384439
"Microstructure and mechanical properties of proton irradiated zirconium carbide" Clayton A. Dickerson, Hannah Swoboda, Brandon Miller, Todd R. Allen, Yong Yang, [2008] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2008.06.042 · EID: 2-s2.0-49849096961 · ISSN: 0022-3115
"Proton irradiation induced effects in titanium carbide and titanium nitride" [2008] Transactions of the American Nuclear Society · EID: 2-s2.0-55249083028 · ISSN: 0003-018X
"Radiation stability of proton irradiated ZrC and ZrN" [2008] Transactions of the American Nuclear Society · EID: 2-s2.0-55249124985 · ISSN: 0003-018X
"Microstructural evaluation of stainless alloys irradiated in the bor-60 reactor" [2007] Canadian Nuclear Society - 13th International Conference on Environmental Degradation of Materials in Nuclear Power Systems 2007 · EID: 2-s2.0-51949099772
Source: ORCID/CrossRef using DOI
NSUF Supported Research

Understand the phase transformation of thermal aged and neutron irradiated duplex stainless steels used in LWRs - FY 2016 CINR, #16-10696

Understand the Fission Products Behavior in UCO Fuel Kernels of safety tested AGR2 TRISO Fuel Particles by Using Titan Themis 200 with ChemiSTEM Capability - FY 2019 RTE 3rd Call, #19-2893

Understand the Fission Products Behavior and Irradiation Effects in UCO Fuel Kernels of Irradiated AGR-1 and AGR-2 TRISO Fuel Particles Using Titan Themis 200 with ChemiSTEM Capability - FY 2018 RTE 1st Call, #18-1257

Characterize the Irradiated Microstructure and Understand the Fission Product Behavior in an Irradiated and Safety Tested AGR-1 TRISO Fuel Particle New Proposal - FY 2017 RTE 3rd Call, #17-1091

Low temperature Fe-ion irradiation of 15-15Ti steel in different thermo-mechanical states - FY 2017 RTE 1st Call, #16-864

Evaluate the ferrite decomposition in irradiated duplex cast stainless steels - FY 2016 RTE 2nd Call, #16-655

Characterize Neutron Irradiated NF709 Stainless Steel Using Atom Probe Tomography - FY 2015 RTE 3rd Call, #15-591

Characterization on the Bor-60 neutron irradiated austenitic stainless steels and cast stainless steel - FY 2015 RTE 2nd Call, #15-564

Synergistic Effects of Thermal aging and Neutron Irradiation in 304L Welds - FY 2015 RTE 1st Call, #15-531

Irradiation Effects inAged Cast Duplex Stainless Steels - FY 2013 RTE Solicitation, #13-411

Radiation Stability of Ceramics for Advanced Fuel Applications - FY 2009 Fall Solicitation for User Proposals, #09-152

NSUF Research Collaborations

Understand the Fission Products Behavior and Irradiation Effects in UCO Fuel Kernels of Irradiated AGR-1 and AGR-2 TRISO Fuel Particles by Using Atom Probe Tomography - FY 2020 RTE 2nd Call, #20-4217

Predict the mechanical behavior of irradiated cast stainless steels based on the microstructures and measured properties from nanoindentation - FY 2019 RTE 3rd Call, #19-2895

Understand the atomic positions of the metallic fission product in UCO Fuel Kernels and Determine the exact stoichiometry of UC, UO phase of Irradiated TRISO Fuel Particles by Using Titan Themis 200 with EELS characterization Capability - FY 2019 RTE 2nd Call, #19-1779

Microstructure characterization on neutron irradiated and post-tensile duplex stainless steels - FY 2019 RTE 1st Call, #19-1672

Understand the Fission Products Behavior and Irradiation Effects in UCO Fuel Kernels of Irradiated AGR-1 and AGR-2 TRISO Fuel Particles by Using Atom Probe Tomography - FY 2018 RTE 3rd Call, #18-1593

Fission Product Distribution Comparison in Irradiated and Safety Tested AGR-1 and AGR-2 TRISO Fuel Particles - FY 2018 RTE 1st Call, #18-1256

An in-situ TEM characterization of tensile testing of ion irradiated HT-UPS steel at RT and 400°C - FY 2017 RTE 3rd Call, #17-1098

Characterization of ion irradiated 15-15Ti steel by APT - FY 2017 RTE 2nd Call, #17-930

Irradiation of the vanadium carbide coating on HT-9 steel using protons - FY 2017 RTE 1st Call, #16-863

Effect of Neutron Irradiation on Tensile Deformation of a HT-UPS Stainless Steel - FY 2016 RTE 2nd Call, #16-643

Irradiation Effect in the Heterogeneous Hardening of Cast Austenitic Stainless Steels - FY 2016 RTE 2nd Call, #16-649

Characterize Neutron Irradiated HT-UPS Stainless Steel Using Transmission Electron Microscopy and Atom Probe Tomography - FY 2016 RTE 1st Call, #16-622

Critical evaluation of radiation tolerance of nanocrystalline austenitic stainless steels - FY 2012 RTE Solicitation, #12-353