scholarly journals Enhanced Radiation Tolerance of Tungsten Nanoparticles to He Ion Irradiation

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1052 ◽  
Author(s):  
E. Aradi ◽  
J. Lewis-Fell ◽  
R.W. Harrison ◽  
G. Greaves ◽  
A.H. Mir ◽  
...  
Keyword(s):  
Structural Damage ◽  
Ion Irradiation ◽  
Black Spot ◽  
Volume Ratio ◽  
Potential Effect ◽  
Nanoporous Materials ◽  
Dislocation Loops ◽  
Radiation Induced ◽  
The Individual ◽  
Induced Defects

Materials exposed to plasmas in magnetic confinement nuclear reactors will accumulate radiation-induced defects and energetically implanted gas atoms (from the plasma and transmutations), of which insoluble helium (He) is likely to be the most problematic. The large surface-area-to-volume ratio exhibited by nanoporous materials provides an unsaturable sink with the potential to continuously remove both point defects and He. This property enhances the possibilities for these materials to be tailored for high radiation-damage resistance. In order to explore the potential effect of this on the individual ligaments of nanoporous materials, we present results on the response of tungsten (W) nanoparticles (NPs) to 15 keV He ion irradiation. Tungsten foils and various sizes of NPs were ion irradiated concurrently and imaged in-situ via transmission electron microscopy at 750 °C. Helium bubbles were not observed in NPs with diameters less than 20 nm but did form in larger NPs and the foils. No dislocation loops or black spot damage were observed in any NPs up to 100 nm in diameter but were found to accumulate in the W foils. These results indicate that a nanoporous material, particularly one made up of ligaments with characteristic dimensions of 30 nm or less, is likely to exhibit significant resistance to He accumulation and structural damage and, therefore, be highly tolerant to radiation.

Xenon ion irradiation of superconducting YBa2Cu3O7 thin films

1990 ◽  
Vol 48 (4) ◽  
pp. 92-93
Author(s):  
H. Watanabe ◽  
B. Kabius ◽  
B. Roas ◽  
K. Urban
Keyword(s):  
Defect Formation ◽  
Ion Irradiation ◽  
High Resolution Electron Microscopy ◽  
Structural Disorder ◽  
Flux Lines ◽  
Pinning Effect ◽  
Magnetic Flux Lines ◽  
Resolution Electron ◽  
Radiation Induced ◽  
Induced Defects

Recently it was reported that the critical current density(Jc) of YBa2Cu2O7, in the presence of magnetic field, is enhanced by ion irradiation. The enhancement is thought to be due to the pinning of the magnetic flux lines by radiation-induced defects or by structural disorder. The aim of the present study was to understand the fundamental mechanisms of the defect formation in association with the pinning effect in YBa2Cu3O7 by means of high-resolution electron microscopy(HRTEM).The YBa2Cu3O7 specimens were prepared by laser ablation in an insitu process. During deposition, a substrate temperature and oxygen atmosphere were kept at about 1073 K and 0.4 mbar, respectively. In this way high quality epitaxially films can be obtained with the caxis parallel to the <100 > SrTiO3 substrate normal. The specimens were irradiated at a temperature of 77 K with 173 MeV Xe ions up to a dose of 3.0 × 1016 m−2.

Nucleation and amorphization of radiation-produced phases in a modified austenitic stainless steel during Ni-ion irradiation

1988 ◽  
Vol 3 (5) ◽  
pp. 840-844 ◽  
Author(s):  
E. H. Lee ◽  
E. A. Kenik
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Ion Irradiation ◽  
Amorphous State ◽  
Dislocation Loops ◽  
Nickel Ion ◽  
Carbide Phases ◽  
Direct Formation ◽  
Radiation Induced ◽  
Lower Temperature

The nucleation and amorphization of radiation-induced (G) and radiation-enhanced (η) phases in a silicon- and titanium-modified austenitic stainless steel have been studied under nickel-ion irradiation. These silicon- and nickel-enriched phases form under high-temperature (950 K) irradiation as the result of radiation-induced segregation to radiation-produced interstitial dislocation loops. Availability of carbon promotes the formation of η phase relative to G phase. Under lower temperature (450 K) irradiation, G and η phases are amorphized without significant change in composition of metallic elements. Two carbide phases (MC, M23C6) remain crystalline for the same irradiation conditions. The amorphization of the silicides may result from (1) radiation damage increasing their free energy above that of the amorphous state or (2) direct formation of the amorphous phase in the damage cascade.

scholarly journals MINIMAL VARIATION OF DEFECT STRUCTURE DUE TO THE ORDER OF ROOM TEMPERATURE HYDROGEN ISOTOPE IMPLANTATION AND SELF-ION IRRADIATION IN NICKEL

MRS Advances ◽  
2016 ◽  
Vol 1 (42) ◽  
pp. 2887-2892
Author(s):  
Brittany Muntifering ◽  
Jianmin Qu ◽  
Khalid Hattar
Keyword(s):  
Dislocation Loop ◽  
Hydrogen Isotope ◽  
Room Temperature ◽  
Ion Irradiation ◽  
In Situ Tem ◽  
Loop Formation ◽  
Radiation Induced ◽  
Formation And Evolution ◽  
And Performance ◽  
Induced Defects

ABSTRACTThe formation and stability of radiation-induced defects in structural materials in reactor environments significantly effects their integrity and performance. Hydrogen, which may be present in significant quantities in future reactors, may play an important role in defect evolution. To characterize the effect of hydrogen on cascade damage evolution, in-situ TEM self-ion irradiation and deuterium implantation was performed, both sequentially and concurrently, on nickel. This paper presents preliminary results characterizing dislocation loop formation and evolution during room temperature deuterium implantation and self-ion irradiation and the consequence of the sequence of irradiation. Hydrogen isotope implantation at room temperature appears to have little or no effect on the final dislocation loop structures that result from self-ion irradiation, regardless of the sequence of irradiation. Tilting experiments emphasize the importance of precise two-beam conditions for characterizing defect size and structure.

Atomistic observation of electron irradiation-induced defects in CeO2

2013 ◽  
Vol 1514 ◽  
pp. 93-98 ◽  
Author(s):  
Seiya Takaki ◽  
Tomokazu Yamamoto ◽  
Masanori Kutsuwada ◽  
Kazuhiro Yasuda ◽  
Syo Matsumura
Keyword(s):  
Electron Irradiation ◽  
Imaging Techniques ◽  
Dark Field ◽  
Dislocation Loops ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
Radiation Induced ◽  
Induced Defects ◽  
Irradiation Induced Defects

ABSTRACTWe have investigated the atomistic structure of radiation-induced defects in CeO2 formed under 200 keV electron irradiation. Dislocation loops on {111} habit planes are observed, and they grow accompanying strong strain-field. Atomic resolution scanning transmission electron microscopy (STEM) observations with high angle annular dark-field (HAADF) and annular bright-field (ABF) imaging techniques showed that no additional Ce layers are inserted at the position of the dislocation loop, and that strong distortion and expansion is induced around the dislocation loops. These results are discussed that dislocation loops formed under electron irradiation are non-stoichiometric defects consist of oxygen interstitials.

scholarly journals Interface Effects on He Ion Irradiation in Nanostructured Materials

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2639 ◽  
Author(s):  
Wenfan Yang ◽  
Jingyu Pang ◽  
Shijian Zheng ◽  
Jian Wang ◽  
Xinghang Zhang ◽  
...  
Keyword(s):  
Nanostructured Materials ◽  
Ion Irradiation ◽  
Irradiation Damage ◽  
High Dose ◽  
Research Directions ◽  
Service Lifetime ◽  
Radiation Induced ◽  
Reactor Materials ◽  
Induced Defects ◽  
Interface Effects

In advanced fission and fusion reactors, structural materials suffer from high dose irradiation by energetic particles and are subject to severe microstructure damage. He atoms, as a byproduct of the (n, α) transmutation reaction, could accumulate to form deleterious cavities, which accelerate radiation-induced embrittlement, swelling and surface deterioration, ultimately degrade the service lifetime of reactor materials. Extensive studies have been performed to explore the strategies that can mitigate He ion irradiation damage. Recently, nanostructured materials have received broad attention because they contain abundant interfaces that are efficient sinks for radiation-induced defects. In this review, we summarize and analyze the current understandings on interface effects on He ion irradiation in nanostructured materials. Some key challenges and research directions are highlighted for studying the interface effects on radiation damage in nanostructured materials.

Solute Segregation in Stainless Steel under Irradiation

1977 ◽  
Vol 35 ◽  
pp. 46-47
Author(s):  
Edward A. Kenik
Keyword(s):  
Stainless Steel ◽  
Ion Irradiation ◽  
Three Dimensional ◽  
Void Formation ◽  
Dislocation Loops ◽  
Nickel Ion ◽  
316 Stainless Steel ◽  
Prime Concern ◽  
Radiation Induced ◽  
The Stability

Solute element additions can significantly influence the behavior of an alloy under irradiation. The aggregation of irradiation-induced vacancies into three-dimensional clusters, voids, and the volume expansion, swelling, associated with void formation is of prime concern in the design of nuclear reactors. A modified type 316 stainless steel, LS1A, has been developed which exhibits high resistance to swelling. This alloy, containing ˜1.0 wt % silicon and 0. 15 wt % titanium, swells 30 times less under nickel ion irradiation than a nominal type 316 stainless steel.In addition to the observation of swelling resistance in LS1A, it was observed that the evolution of dislocation portions of the damage structure was modified by the silicon and titanium additions. Specifically, the stability of faulted dislocation loops in LS1A is quite high and the growth of large loops is severely curtailed. At higher doses, radiation-induced precipitates of the same size and shape as the dislocation loops were observed.

scholarly journals New microstructural insights into neutron-irradiated tungsten

2020 ◽  
Author(s):  
Michael Dürrschnabel ◽  
Michael Klimenkov ◽  
Ute Jäntsch ◽  
Michael Rieth ◽  
Hans-Christian Schneider ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Coefficient Of Thermal Expansion ◽  
Fusion Reactors ◽  
Dislocation Loops ◽  
Plasma Facing Components ◽  
Transmission Electron ◽  
Radiation Induced ◽  
Crystallographic Orientation Relationship ◽  
Relationship Of ◽  
Induced Defects

Abstract The development of appropriate materials for fusion reactors that can sustain high neutron fluencies at elevated temperatures remains a great challenge. Tungsten is one of the promising candidate materials for plasma-facing components of future fusion reactors, due to several favorable properties as for example a high melting point, a high sputtering resistivity, and a low coefficient of thermal expansion. The microstructural details of a tungsten sample with a 1.25 dpa (displacements per atom) damage dose after irradiation at 800°C were examined by transmission electron microscopy (TEM). Three types of radiation-induced defects were observed, analyzed and characterized: (i) voids with sizes ranging from 10 nm to 65 nm, (ii) dislocation loops with a size of up to 10 nm and (iii) W-Re-Os containing σ- and χ-type precipitates. The distribution of voids as well as the nature of the occurring dislocation loops were studied in detail. In addition, nano-chemical analyses revealed that the σ- and χ-type precipitates, which are sometimes attached to voids, are surrounded by a solid solution cloud enriched with Re. For the first time the crystallographic orientation relationship of the σ- and χ-phases to the W-matrix was specified. Furthermore, electron energy-loss spectroscopy could not unambiguously verify the presence of He within individual cavities.

Effect of heavy ion irradiation in RbKBrCl quaternary system: EPR study of radiation induced defects

2001 ◽  
Vol 154 (2) ◽  
pp. 141-149 ◽  
Author(s):  
D. Pathinettam Padiyan ◽  
C. Muthukrishnan ◽  
S. John Ethilton ◽  
S. K. Mohanlal ◽  
S. Dhanuskodi ◽  
...  
Keyword(s):  
Quaternary System ◽  
Ion Irradiation ◽  
Heavy Ion ◽  
Heavy Ion Irradiation ◽  
Radiation Induced ◽  
Induced Defects

Effects of Ion Dose and Irradiation Temperature on the Microstructure of Three Spinel Compositions

1994 ◽  
Vol 373 ◽  
Author(s):  
L.M. Wang ◽  
W.L. Gong ◽  
N. Bordes ◽  
R.C. Ewing ◽  
Y. Feit
Keyword(s):  
Spinel Structure ◽  
Room Temperature ◽  
Ion Irradiation ◽  
Structure Type ◽  
Structural Parameter ◽  
Dislocation Loops ◽  
Inverse Spinel ◽  
Oxygen Sublattice ◽  
Radiation Resistant ◽  
Radiation Induced

AbstractThree compositions with the spinel structure (γ-AIVB2VIO4), MgAl2O4, FeCr2O4 and γ-SiFe2O4, have been irradiated with 1.5 MeV Kr+ ions over a temperature range (20 to 873 K). In situ TEM and HRTEM afterwork were conducted to characterize the effects of the ion irradiation on the microstructure. MgAl2O4 was the most “radiation-resistant” among the three materials. After irradiation to lx1016 ions/cm2 at 20 K, the cations were completely disordered among all possible tetrahedral and octahedral sites, but the oxygen sublattice remained intact. At room temperature, a high density of dislocation loops developed after this same dose, but there was no evidence of cation disordering. However, γ-SiFe2O4, a spinel structure type, formed under high pressure (7.0 GPa), was easily amorphized at low ion doses (σ1014 ions/cm 2) below 723 K, even lower than required for radiation-induced amorphization of its olivine polymorph, fayalite (α-SiFe2O4; HCP). At 873 K, the amorphous phase recrystallized to magnetite (Fe2+Fe 3+2O4, an inverse spinel structure) and quartz (SiO2) during continued Kr+ irradiation. Chromite (ideally FeCr2O4) with an actual composition of (Fe0.6Mg0.4)(Cr0.7A10.3)2O4 amorphized at 6x1015 ions/cm2 at 20 K, a dose about 20 times as high as that required to amorphize most other AB2O4 phases under the same irradiation conditions. A structural parameter, which quantifies the deviation from ideal packing in the spinel structure was developed and correlates with themeasured doses required for amorphization among these three spinel compositions.

scholarly journals Desorption of Implanted Deuterium in Heavy Ion-Irradiated Zry-2

2021 ◽  
Vol 5 (2) ◽  
pp. 9
Author(s):  
Hideo Watanabe ◽  
Yoshiki Saita ◽  
Katsuhito Takahashi ◽  
Kazufumi Yasunaga
Keyword(s):  
Electron Microscope ◽  
Defect Formation ◽  
Ion Irradiation ◽  
Spherical Aberration ◽  
Thermal Desorption Spectroscopy ◽  
Heavy Ion ◽  
Dislocation Loops ◽  
Fuel Cladding ◽  
Hydrogen Pickup ◽  
Radiation Induced

To understand the degradation behavior of light water reactor (LWR) fuel-cladding tubes under neutron irradiation, a detailed mechanism of hydrogen pickup related to the point defect formation (i.e., a-component and c-component dislocation loops) and to the dissolution of precipitates must be elucidated. In this study, 3.2 MeV Ni3+ ion irradiation was conducted on Zircaloy-2 samples at room temperature. Thermal desorption spectroscopy is used to evaluate the deuterium desorption with and without Ni3+ ion irradiation. A conventional transmission electron microscope and a spherical aberration-corrected high-resolution analytical electron microscope are used to observe the microstructure. The experimental results indicate that radiation-induced dislocation loops and hydrides form in Zircaloy-2 and act as major trapping sites at lower (400–600 °C) and higher (700–900 °C)-temperature regions, respectively. These results show that the detailed microstructural changes related to the hydrogen pickup at the defect sinks formed by irradiation are necessary for the degradation of LWR fuel-cladding tubes during operation.

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