"In-situ observation of nano-oxide and defect evolution in 14YWT alloys"
Osman El Atwani, Meimei Li, Stuart Maloy, Eda Aydogan,
Materials Characterization
Vol. 170
2020
110686
Link
Nanostructured ferritic alloys (NFAs) are considered as candidates for structural components in advanced nuclear reactors due to their excellent radiation resistance as a result of a high density of nano-oxides (NOs) in the microstructure. Therefore, gaining an understanding on the stability of NOs under irradiation is crucial. In this study, we have investigated the evolution of defects and NOs in 14YWT NFAs under in-situ Kr ion irradiation at room temperature (RT) and 450 °C up to 10 dpa. It has been found that irradiations at 450 °C do not create any changes in the NOs, similar to the bulk irradiations. On the other hand, elemental mapping indicates that NOs dissolve mostly after 10 dpa irradiations at RT. Thus, while defects are both annihilated and pinned by NOs at low doses (before the dissolution of NOs), glissile loops start to escape to the foil surface at high doses (after the dissolution of NOs), justifying the significantly low fraction of <111> loops compared to the literature values. High resolution transmission electron microscopy analysis has shown that the NOs are mostly coherent Y2Ti2O7 particles with pyrochlore crystal structure after both RT and 450 °C irradiations, similar to those observed before irradiation. |
||
"In-situ observation of nano-oxide and defect evolution in 14YWT alloys"
Eda Aydogan,
Materials Characterization
Vol. 170
2020
110686
Nanostructured ferritic alloys (NFAs) are considered as candidates for structural components in advanced nuclear reactors due to their excellent radiation resistance as a result of a high density of nano-oxides (NOs) in the microstructure. Therefore, gaining an understanding on the stability of NOs under irradiation is crucial. In this study, we have investigated the evolution of defects and NOs in 14YWT NFAs under in-situ Kr ion irradiation at room temperature (RT) and 450 °C up to 10 dpa. It has been found that irradiations at 450 °C do not create any changes in the NOs, similar to the bulk irradiations. On the other hand, elemental mapping indicates that NOs dissolve mostly after 10 dpa irradiations at RT. Thus, while defects are both annihilated and pinned by NOs at low doses (before the dissolution of NOs), glissile loops start to escape to the foil surface at high doses (after the dissolution of NOs), justifying the significantly low fraction of <111> loops compared to the literature values. High resolution transmission electron microscopy analysis has shown that the NOs are mostly coherent Y2Ti2O7 particles with pyrochlore crystal structure after both RT and 450 °C irradiations, similar to those observed before irradiation. |
||
"In-situ radiation response of additively manufactured modified Inconel 718 alloys"
Eda Aydogan,
Additive Manufacturing
Vol. 51
2022
102601
In this study, a novel alloy of modified Inconel 718 produced by laser powder bed fusion is studied before and after in-situ Kr irradiation up to 3 dpa at 200 and 450 °C. Before irradiation, the microstructure consists of dislocation cells having a misorientation angle less than 5° and with an average size of ~500 nm. There are also second phase particles of MC type carbides, Laves phase and oxides such as Y-O, Y-(Ti)-Al-O. While the microstructure consists of stacking fault tetrahedra, faulted and perfect loops after irradiation at 200 °C, dislocation loops are the primary defects at 450 °C. With increasing dose, the size of the defects remains similar at 200 °C while it increases at 450 °C. This has been attributed to the existence of vacancy type defects at 200 °C and the different defect transport mechanisms at different temperatures. Moreover, matrix and second phase particle compositions seem to be similar after irradiation. The sink strengths of the structures have been calculated and superior radiation resistance of this alloy has been attributed to the existence of fine cell boundaries stabilized by the second phase particles produced by additive manufacturing. |
||
"In-situ radiation response of additively manufactured modified Inconel 718 alloys"
Eda Aydogan, Osman El Atwani, Begum Erdem, Wei-Ying Chen, Meimei Li, ARUN DEVARAJ, Bahattin Koc, Stuart Maloy,
Additive Manufacturing
Vol. 51
2022
102601
Link
In this study, a novel alloy of modified Inconel 718 produced by laser powder bed fusion is studied before and after in-situ Kr irradiation up to 3 dpa at 200 and 450 °C. Before irradiation, the microstructure consists of dislocation cells having a misorientation angle less than 5° and with an average size of ~500 nm. There are also second phase particles of MC type carbides, Laves phase and oxides such as Y-O, Y-(Ti)-Al-O. While the microstructure consists of stacking fault tetrahedra, faulted and perfect loops after irradiation at 200 °C, dislocation loops are the primary defects at 450 °C. With increasing dose, the size of the defects remains similar at 200 °C while it increases at 450 °C. This has been attributed to the existence of vacancy type defects at 200 °C and the different defect transport mechanisms at different temperatures. Moreover, matrix and second phase particle compositions seem to be similar after irradiation. The sink strengths of the structures have been calculated and superior radiation resistance of this alloy has been attributed to the existence of fine cell boundaries stabilized by the second phase particles produced by additive manufacturing. |
||
"The path towards plasma facing components: A review of state-of-the-art in W-based refractory high-entropy alloys"
Caleb Hatler, Ishtiaque Robin, Hyosim Kim, Nathan Curtis, Bochuan Sun, Eda Aydogan, Saryu Fensin, Adrien Couet, Enrique Martinez, Dan Thoma, Osman El Atwani,
Current Opinion in Solid State and Materials Science
Vol. 34
2025
Link
Developing advanced materials for plasma-facing components (PFCs) in fusion reactors is a crucial aspect for achieving sustained energy production. Tungsten (W) − based refractory high-entropy alloys (RHEAs) have emerged as promising candidates due to their superior radiation tolerance and high-temperature strength. This review paper will focus on recent advancements in W-based RHEA research, with particular emphasis on: predictive modelling with machine learning (ML) to expedite the identification of optimal RHEA compositions; additive manufacturing (AM) techniques, highlighting their advantages for rapid prototyping and high-throughput multi-compositional sample production; mechanical properties relevant to PFC applications, including hardness, high-temperature strength, and ductility; and the radiation tolerance of W-based RHEAs under irradiated conditions. Finally, the key challenges and opportunities for future research, particularly the holistic analysis of candidate compositions as well as the role of radiation activation and oxidation are identified. This review aims to provide a comprehensive overview of W-based RHEAs for fusion applications and their potential to guide the development and validation of advanced refractory high entropy alloys. |
"Post Irradiation Examination of Fast Neutron Irradiated 14YWT Tubes at Nuclear Science User Facilities" Eda Aydogan, Peter Hosemann, David Krumwiede, Stuart Maloy, Tarik Saleh, 2017 ANS Annual Meeting [unknown] |
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 |
"In-situ radiation response of additively manufactured modified Inconel 718 alloys" O. El-Atwani, B. Erdem, W.-Y. Chen, M. Li, A. Devaraj, B. Koc, S.A. Maloy, E. Aydogan, [2022] Additive Manufacturing · DOI: 10.1016/j.addma.2022.102601 · ISSN: 2214-8604 | |
"Selective laser melting of Nano-TiN reinforced 17-4 PH stainless steel: Densification, microstructure and mechanical properties" Eda Aydogan, Arcan F. Dericioglu, Andac Ozsoy, [2022] Materials Science and Engineering: A · DOI: 10.1016/j.msea.2021.142574 · ISSN: 0921-5093 | |
"Enhancement of Nanostructured Ferritic Alloy 14YWT Properties via Heat Treatment for Post-Consolidation Processing" T. A. Saleh, D. T. Hoelzer, B. P. Eftink, E. Aydogan, K. D. Clarke, A. J. Clarke, S. A. Maloy, C. J. Rietema, [2021] Metallurgical and Materials Transactions A · DOI: 10.1007/s11661-021-06275-9 · ISSN: 1073-5623 | |
"Tensile properties and microstructure of additively manufactured Grade 91 steel for nuclear applications" Daniel A. Vega, Osman El Atwani, David J. Sprouster, Yung Suk J. Yoo, Todd E. Steckley, Eda Aydogan, Carl M. Cady, Mohamad Al-Sheikhly, Thomas J. Lienert, Stuart A. Maloy, Benjamin P. Eftink, [2021] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2020.152723 · ISSN: 0022-3115 | |
"In Situ Micro-Pillar Compression to Examine Radiation-Induced Hardening Mechanisms of FeCrAl Alloys" Eda Aydogan, Jonathan G. Gigax, Yongqiang Wang, Amit Misra, Stuart A. Maloy, Nan Li, Yuchi Cui, [2021] Acta Materialia · DOI: 10.1016/j.actamat.2020.10.047 · ISSN: 1359-6454 | |
"Damage relief of ion-irradiated Inconel alloy 718 via annealing" Haley Turman, Aaron French, Matthew Chancey, Jonathan Gigax, Eda Aydogan, Dexin Zhao, Digvijay Yadav, Kelvin Xie, Yongqiang Wang, Mike Borden, Lin Shao, S.A. Maloy, Matt Pharr, Cole D. Fincher, [2020] Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms · DOI: 10.1016/j.nimb.2020.06.038 · EID: 2-s2.0-85087201126 | |
"Effect of high-density nanoparticles on recrystallization and texture evolution in ferritic alloys"
Connor J. Rietema, Ursula Carvajal-Nunez, Sven C. Vogel, Meimei Li, Stuart A. Maloy, Eda Aydogan,
[2019]
Crystals
· DOI: 10.3390/cryst9030172
· EID: 2-s2.0-85064658763
Ferritic alloys are important for nuclear reactor applications due to their microstructural stability, corrosion resistance, and favorable mechanical properties. Nanostructured ferritic alloys having a high density of Y-Ti-O rich nano-oxides (NOs < 5 nm) are found to be extremely stable at high temperatures up to ~1100 °C. This study serves to understand the effect of a high density of nano-particles on texture evolution and recrystallization mechanisms in ferritic alloys of 14YWT (14Cr-3W-0.4Ti-0.21Y-Fe wt %) having a high density of nano-particles and dispersion-free FeCrAl (13Cr-5.2Al-0.05Y-2Mo-0.2Si-1Nb wt %). In order to investigate the recrystallization mechanisms in these alloys, neutron diffraction, electron backscattered diffraction, and in situ and ex situ transmission electron microscopy have been utilized. It has been observed that even though the deformation textures of both the 14YWT and FeCrAl alloys evolved similarly, resulting in either the formation (in FeCrAl alloy) or increase (in 14YWT) in γ-fiber texture, the texture evolution during recrystallization is different. While FeCrAl alloy keeps its γ-fiber texture after recrystallization, 14YWT samples develop a ε-fiber as a result of annealing at 1100 °C, which can be attributed to the existence of NOs. In situ transmission electron microscopy annealing experiments on 14YWT show the combination and growth of the lamellar grains rather than nucleation; however, the recrystallization and growth kinetics are slower due to NOs compared to FeCrAl. |
|
"Impact of composition modification induced by ion beam Coulomb-drag effects on the nanoindentation hardness of HT9" Hyosim Kim, E. Aydogan, L.M. Price, X. Wang, S.A. Maloy, F.A. Garner, L. Shao, Jonathan G. Gigax, [2019] Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms · DOI: 10.1016/j.nimb.2018.12.051 · EID: 2-s2.0-85061537157 | |
"Response of 14YWT alloys under neutron irradiation: A complementary study on microstructure and mechanical properties" J.S. Weaver, U. Carvajal-Nunez, M.M. Schneider, J.G. Gigax, D.L. Krumwiede, P. Hosemann, T.A. Saleh, N.A. Mara, D.T. Hoelzer, B. Hilton, S.A. Maloy, E. Aydogan, [2019] Acta Materialia · DOI: 10.1016/j.actamat.2019.01.041 · EID: 2-s2.0-85061120486 | |
"Unprecedented irradiation resistance of nanocrystalline tungsten with equiaxed nanocrystalline grains to dislocation loop accumulation" E. Esquivel, E. Aydogan, E. Martinez, J.K. Baldwin, M. Li, B.P. Uberuaga, S.A. Maloy, O. El-Atwani, [2019] Acta Materialia · DOI: 10.1016/j.actamat.2018.11.024 · EID: 2-s2.0-85057256708 | |
"α′ formation kinetics and radiation induced segregation in neutron irradiated 14YWT nanostructured ferritic alloys"
E. Martinez, K. March, O. El-Atwani, D. L. Krumwiede, P. Hosemann, T. Saleh, S. A. Maloy, E. Aydogan,
[2019]
Scientific Reports
· DOI: 10.1038/s41598-019-44508-5
· EID: 2-s2.0-85066942625
Nanostructured ferritic alloys are considered as candidates for structural components in advanced nuclear reactors due to a high density of nano-oxides (NOs) and ultrafine grain sizes. However, bimodal grain size distribution results in inhomogeneous NO distribution, or vice versa. Here, we report that density of NOs in small grains (<0.5 µm) is high while there are almost no NOs inside the large grains (>2 µm) before and after irradiation. After 6 dpa neutron irradiation at 385–430 °C, α′ precipitation has been observed in these alloys; however, their size and number densities vary considerably in small and large grains. In this study, we have investigated the precipitation kinetics of α′ particles based on the sink density, using both transmission electron microscopy and kinetic Monte Carlo simulations. It has been found that in the presence of a low sink density, α′ particles form and grow faster due to the existence of a larger defect density in the matrix. On the other hand, while α′ particles form far away from the sink interface when the sink size is small, Cr starts to segregate at the sink interface with the increase in the sink size. Additionally, grain boundary characteristics are found to determine the radiation-induced segregation of Cr. |
|
"Detailed transmission electron microscopy study on the mechanism of dislocation loop rafting in tungsten" E. Aydogan, E. Esquivel, M. Efe, Y.Q. Wang, S.A. Maloy, O. El-Atwani, [2018] Acta Materialia · DOI: 10.1016/j.actamat.2018.01.003 · EID: 2-s2.0-85041467402 | |
"Development of advanced low N ferritic/martensitic steel for reactor applications" [2018] Transactions of the American Nuclear Society · EID: 2-s2.0-85060868062 | |
"High temperature microstructural stability and recrystallization mechanisms in 14YWT alloys" O. El-Atwani, S. Takajo, S.C. Vogel, S.A. Maloy, E. Aydogan, [2018] Acta Materialia · DOI: 10.1016/j.actamat.2018.02.006 · EID: 2-s2.0-85042236934 | |
"Loop and void damage during heavy ion irradiation on nanocrystalline and coarse grained tungsten: Microstructure, effect of dpa rate, temperature, and grain size" E. Esquivel, M. Efe, E. Aydogan, Y.Q. Wang, E. Martinez, S.A. Maloy, O. El-Atwani, [2018] Acta Materialia · DOI: 10.1016/j.actamat.2018.02.035 · EID: 2-s2.0-85042803987 | |
"Microstructure and mechanical properties of FeCrAl alloys under heavy ion irradiations" J.S. Weaver, S.A. Maloy, O. El-Atwani, Y.Q. Wang, N.A. Mara, E. Aydogan, [2018] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2018.03.002 · EID: 2-s2.0-85045754254 | |
"Beam-contamination-induced compositional alteration and its neutron-atypical consequences in ion simulation of neutron-induced void swelling" Hyosim Kim, Eda Aydogan, Frank A. Garner, Stu Maloy, Lin Shao, Jonathan G. Gigax, [2017] Materials Research Letters · DOI: 10.1080/21663831.2017.1323808 · EID: 2-s2.0-85019589187 | |
"Characterization of phase properties and deformation in ferritic-austenitic duplex stainless steels by nanoindentation and finite element method" R. Prakash Kolli, Eda Aydogan, Sarah Mburu, Sreeramamurthy Ankem, Samuel C. Schwarm, [2017] Materials Science and Engineering A · DOI: 10.1016/j.msea.2016.10.116 · EID: 2-s2.0-84998978813 | |
"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 | |
"Effect of tube processing methods on microstructure, mechanical properties and irradiation response of 14YWT nanostructured ferritic alloys" S.A. Maloy, O. Anderoglu, C. Sun, J.G. Gigax, L. Shao, F.A. Garner, I.E. Anderson, J.J. Lewandowski, E. Aydogan, [2017] Acta Materialia · DOI: 10.1016/j.actamat.2017.05.053 · EID: 2-s2.0-85020248611 | |
"Post irradiation examination of fast neutron irradiated 14YWT tubes at nuclear science user facilities" [2017] Transactions of the American Nuclear Society · EID: 2-s2.0-85033440028 | |
"Stability of nanosized oxides in ferrite under extremely high dose self ion irradiations" N. Almirall, G.R. Odette, S.A. Maloy, O. Anderoglu, L. Shao, J.G. Gigax, L. Price, D. Chen, T. Chen, F.A. Garner, Y. Wu, P. Wells, J.J. Lewandowski, D.T. Hoelzer, E. Aydogan, [2017] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2017.01.015 · EID: 2-s2.0-85009821225 | |
"Effect of shock loading on the microstructure, mechanical properties and grain boundary characteristics of HT-9 ferritic/martensitic steels" O. Anderoglu, S.A. Maloy, V. Livescu, G.T. Gray, S. Perez-Bergquist, D.J. Williams, E. Aydogan, [2016] Materials Science and Engineering A · DOI: 10.1016/j.msea.2015.10.102 · EID: 2-s2.0-84946076120 | |
"Effect of tube processing methods on the texture and grain boundary characteristics of 14YWT nanostructured ferritic alloys" S. Pal, O. Anderoglu, S.A. Maloy, S.C. Vogel, G.R. Odette, J.J. Lewandowski, D.T. Hoelzer, I.E. Anderson, J.R. Rieken, E. Aydogan, [2016] Materials Science and Engineering A · DOI: 10.1016/j.msea.2016.02.085 · EID: 2-s2.0-84960393793 | |
"Radiation response of alloy T91 at damage levels up to 1000 peak dpa" T. Chen, Hyosim Kim, J. Wang, L.M. Price, E. Aydogan, S.A. Maloy, D.K. Schreiber, M.B. Toloczko, F.A. Garner, Lin Shao, J.G. Gigax, [2016] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2016.10.003 · EID: 2-s2.0-84993933885 | |
"Temperature dependent dispersoid stability in ion-irradiated ferritic-martensitic dual-phase oxide-dispersion-strengthened alloy: Coherent interfaces vs. incoherent interfaces" Jonathan G. Gigax, Lloyd Price, Di Chen, S. Ukai, Eda Aydogan, S.A. Maloy, F.A. Garner, Lin Shao, Tianyi Chen, [2016] Acta Materialia · DOI: 10.1016/j.actamat.2016.05.042 · EID: 2-s2.0-84975225185 | |
"Microstructural changes and void swelling of a 12Cr ODS ferritic-martensitic alloy after high-dpa self-ion irradiation" Eda Aydogan, Jonathan G. Gigax, Di Chen, Jing Wang, Xuemei Wang, S. Ukai, F.A. Garner, Lin Shao, Tianyi Chen, [2015] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2015.09.016 · EID: 2-s2.0-84941907440 | |
"Surface modification of low activation ferritic-martensitic steel EK-181 (Rusfer) by high temperature pulsed plasma flows" P.S. Dzhumaev, V.L. Yakushin, B.A. Kalin, M.G. Ganchenkova, A.T. Khein, M.V. Leontyeva-Smirnova, R.Z. Valiev, N.A. Enikeev, L. Shao, E. Aydogan, M. Short, F. Garner, O.V. Emelyanova, [2015] Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms · DOI: 10.1016/j.nimb.2015.08.048 · EID: 2-s2.0-84948567546 | |
"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 | |
"Morphology and magnetic properties of barium hexaferrite ceramics synthesized in x wt% NaCl-(100-x) wt% KCL molten salts" Seray Kaya, Arcan F. Dericioglu, Eda Aydogan, [2014] Ceramics International · DOI: 10.1016/j.ceramint.2013.08.002 · EID: 2-s2.0-84888006964 | |
Source: ORCID/CrossRef using DOI |
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.
Privacy and Accessibility · Vulnerability Disclosure Program