| 1. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Fu, Le, et al.
(författare)
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Structural integrity and damage of glass-ceramics after He ion irradiation : Insights from ZrO2-SiO2 nanocrystalline glass-ceramics
- 2023
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Ingår i: Journal of the European Ceramic Society. - : Elsevier. - 0955-2219 .- 1873-619X. ; 43:6, s. 2624-2633
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Tidskriftsartikel (refereegranskat)abstract
- Developing new radiation-resistant materials and understanding the structural damages caused by radiation are persistent goals of material scientists. Here, we report on the structural integrity and damage to ZrO2-SiO2 nanocrystalline glass-ceramics after radiation with 1.4 MeV He ions at three different fluences: 1.0 x 1016 ions/ cm2 (low), 5.0 x 1016 ions/cm2 (moderate), and 1.0 x 1017 ions/cm2 (high) at 500 degrees C. Grazing incident X-ray diffraction shows the tetragonal-ZrO2 to monoclinic-ZrO2 phase transformation induced by microstrain from the irradiation. The addition of yttrium indicated tetragonal-ZrO2 stabilization effect during irradiation. The irra-diated glass-ceramics show a Raman signal-enhancement effect probably related to the electronic structure changes of the amorphous SiO2 component in the glass-ceramics. The formation of microcracks and lattice de-fects within ZrO2 nanocrystallites is the main structural damage caused by irradiation. There was no observable amorphization of ZrO2 nanocrystallites due to irradiation. No obvious He bubbles were detected, either. The formation of microcracks results in a decrease of in the nanohardness of the glass-ceramics. The results provide fundamental experimental data to understand the structural integrity and damage caused by radiation, which could be useful to design radiation-resistant nanocrystalline glass-ceramics for extremely radioactive environments.
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| 3. |
- Gangaprasad Rao, Smita, et al.
(författare)
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Mechanical properties of Xe-ion-irradiated high-entropy-alloy-based multilayers
- 2024
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 124:6
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Tidskriftsartikel (refereegranskat)abstract
- In this Letter, we investigate the mechanical stability of HEA-based multilayers after Xe-ion irradiation. CrFeCoNi/TiNbZrTa metallic and nitride thin films with a bilayer thickness of 30 nm were grown by reactive dc-magnetron sputtering on Al2O3(0001) substrates for irradiation studies and on Si(100) substrates for other characterizations. The films were subjected to 3-MeV Xe-ion irradiation at room temperature (RT) and at 500 degrees C. The crystal structure and mechanical properties of the films before and after irradiation were studied by x-ray diffraction and nanoindentation. Before irradiation, both the metallic and nitride multilayers displayed a lower hardness (7 and 20 GPa, respectively). Annealing at 500 degrees C for 150 min increased the hardness of the multilayer samples, but it also induced intermixing of elements between the sublayers of the metallic multilayer. Irradiation hardening was observed only in the metallic multilayer at room temperature. When comparing the effects of irradiation damage vs the effects of annealing on the mechanical properties, it was observed that annealing the multilayers had a more pronounced effect.
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| 4. |
- Wang, Ji, et al.
(författare)
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Microstructural evolution of epitaxial Ti3AlC2 film on sapphire under ion irradiation and nanoindentation-induced deformation
- 2018
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Ingår i: Journal of Nuclear Materials. - : ELSEVIER SCIENCE BV. - 0022-3115 .- 1873-4820. ; 509, s. 181-187
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Tidskriftsartikel (refereegranskat)abstract
- Feasibility of Ti3AlC2 phase as the protective coatings of accident tolerant fuels (ATFs) was investigated by means of ions irradiation, nanoindentation and transmission electron microscopy. Au ions irradiation was carried out on thin Ti3AlC2 film to simulate the high displacement damage induced by the energetic particles in the nuclear reactors. Nanoindentation on the Ti3AlC2 film was followed subsequently as a source of external stress to simulate the high pressure applied on the cladding in nuclear reactor cores of pressurized water reactors (PWRs). TEM was used to characterize the microstructural evolution of Ti3AlC2 film after irradiation and nanoindentation. TEM analysis shows that Ti3AlC2 film remains pristine layered structure and no amorphization was detected after irradiation to similar to 14 dpa. The combined nanoindentation and TEM show that no rupture and exfoliation of the Au-irradiated Ti3AlC2 film occur even the extern stress and total elongation induced by nanoindentation reach to 16.6 GPa and similar to 5%, respectively. The above results show good irradiation resistance and good ductility as well as excellent adhesion of the Ti3AlC2 coating on the substrate after high dose irradiation and under high external stress. This indicates the good feasibility of Ti3AlC2 thin films as the coatings of ATF claddings. (C) 2018 Elsevier B.V. All rights reserved.
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| 5. |
- Wang, Ji, et al.
(författare)
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Microstructure investigations of Fe50Mn30Co10Cr10 dual-phase high-entropy alloy under Fe ions irradiation
- 2021
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Ingår i: Journal of Nuclear Materials. - : ELSEVIER. - 0022-3115 .- 1873-4820. ; 552
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Tidskriftsartikel (refereegranskat)abstract
- An Fe50Mn30Co10Cr10 dual-phase high-entropy alloy (DP-HEA) was irradiated at room temperature with 3 MeV Fe ions to a dose of 50 displacement per atom (dpa). Potentials of special elemental designed DP-HEAs with low stacking fault energy (SFE) as promising candidate materials for future nuclear energy systems are evaluated. Transmission electron microscopy (TEM) analysis finds that FCC gamma-gamma, HCP epsilon-epsilon twinning structures and FCC gamma-HCP epsilon co-existed structures of the DP-HEA, which correlate with the combined high strength and high ductility featured by this alloy, remain stable under a displacement damage of 50 dpa. No elemental segregation after irradiation was detected by energy dispersive spectroscopy. The results indicate that TWIP and TRIP mechanisms, owned by many other DP-HEAs, may still work effectively, and the materials still possess the merits of combined high strength and ductility brought by TWIP and TRIP mechanisms under irradiation conditions. Defects free channels (DFCs) and abundant Lomer-Cottrell (L-C) locks are observed in the irradiated samples after tensile deformation. The immobile L-C locks restrict DFCs growth, prevent the pile-up of dislocation along grain boundaries, thus sustaining dislocations in the grain interior. This study provides a new strategy to improve simultaneously the irradiation resistance and mechanical properties of structural materials by introducing the TWIP and TRIP mechanisms. (C) 2021 Elsevier B.V. All rights reserved.
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| 6. |
- Wang, Ji, et al.
(författare)
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Structural stability under Xe-ion irradiation of TiZrNbTaV-based high-entropy alloy and nitride films
- 2023
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Ingår i: Surface & Coatings Technology. - : ELSEVIER SCIENCE SA. - 0257-8972 .- 1879-3347. ; 454
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Tidskriftsartikel (refereegranskat)abstract
- Refractory high-entropy protective coatings are of interest for nuclear fuel cladding applications due to their corrosion resistant properties and irradiation resistance at elevated temperature. Here, TiZrNbTaV metallic and (TiZrNbTaV)N films were deposited by magnetron co-sputtering. The metal elemental contents of both films were nearly equiatomic. These films were irradiated by Xe ions at room temperature and 500 degrees C, and examined by X-ray diffraction and transmission electron microscopy. The as-deposited (TiZrNbTaV)N film showed a single NaCl-type fcc phase and a pronounced columnar growth structure, which could remain intact after irradiation treatments. In contrast, the as-deposited TiZrNbTaV film exhibited an amorphous structure and formed a bcc phase structure after irradiation at 500 degrees C. The TiZrNbTaV film after irradiation at 500 degrees C composed of depth -dependent size of grains. This distribution of grain size is consistent with simulated displacement damage. The stable structure of (TiZrNbTaV)N film under high temperature irradiation indicates that these materials have potential for use as protective coatings for nuclear fuel claddings.
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| 7. |
- Wang, Ji, et al.
(författare)
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Xe-ion-irradiation-induced structural transitions and elemental diffusion in high-entropy alloy and nitride thin-film multilayers
- 2022
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Ingår i: Materials & design. - : Elsevier Science Ltd. - 0264-1275 .- 1873-4197. ; 219
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Tidskriftsartikel (refereegranskat)abstract
- The study aims to understand the irradiation behavior of multilayer coatings composed of high-entropy materials. Here, we report the structural stability and elemental segregation of high-entropy TiNbZrTa/CrFeCoNi metallic and nitride multilayer coatings under 3-MeV Xe20+ ion-irradiation at room temperature and 500 degrees C, respectively. Transmission electron microscopy analysis shows that the microstructure of nanocrystalline CrFeCoNi high-entropy-alloy sublayers are not stable and readily transforms into amorphous state at 500 degrees C and/or under irradiation conditions. The elemental distribution, acquired by energy-dispersive X-ray spectroscopy under scanning transmission electron microscopy mode, shows preferential diffusion of Co and Ni into TiNbZrTa sublayers, while Fe and Cr preferentially remain within the previous CrFeCoNi sublayers. TiNbZrTaN/CrFeCoNiNx nitride multilayers exhibit a higher crystallinity and structural stability as well as resistance to diffusion at high-temperature and/or irradiation conditions than their TiNbZrTa/CrFeCoNi metallic multilayer counterparts. These findings are explained by atomic size differences, the difference in Gibbs free energy of the mixing system, and interstitial-solute-induced chemical heterogeneity. Our findings thus provide a design strategy of high entropy nitride for nuclear fuel cladding. (C) 2022 The Author(s). Published by Elsevier Ltd.
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