scholarly journals Evolution of Dislocation Loops Induced by Different Hydrogen Irradiation Conditions in Reduced-Activation Martensitic Steel

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2276 ◽  
Author(s):  
Weiping Zhang ◽  
Liping Guo ◽  
Zhenyu Shen ◽  
Jingping Xin ◽  
Qunying Huang ◽  
...  
Keyword(s):  
Fast Diffusion ◽  
Hydrogen Ions ◽  
Dislocation Loops ◽  
Damage Level ◽  
Transmission Electron ◽  
Nuclear Systems ◽  
The Mean ◽  
Induced Defects ◽  
Irradiation Induced Defects ◽  
Diffusion Of Hydrogen

Hydrogen can be induced in various ways into reduced-activation ferritic/martensitic (RAFM) steels when they are used as structural materials for advanced nuclear systems. However, because of the fast diffusion of hydrogen in metals, the effect of hydrogen on the evolution of irradiation-induced defects was almost neglected. In the present work, the effect of hydrogen on the evolution of dislocation loops was investigated using a transmission electron microscope. Specimens of reduced-activation ferritic/martensitic (RAFM) steels were irradiated with hydrogen ions to 5 × 1020 H+ • m−2 at 523–823 K, and to 1 × 1020 H+ • m−2 − 5 × 1020 H+ • m−2 at 723 K. The experimental results reveal that there is an optimum temperature for dislocation loop growth, which is ~723 K, and it is greater than the reported values for neutron irradiations. Surprisingly, the sizes of the loops produced by hydrogen ions, namely, 93 nm and 286 nm for the mean and maximum value, respectively, at the peak dose of 0.16 dpa under 723 K, are much larger than that produced by neutrons and heavy ions at the same damage level and temperature. The results indicate that hydrogen could enhance the growth of loops. Moreover, 47.3% 1 2   a0 <111> and 52.7% a0 <100> loops were observed at 523 K, but 1 2   a0 <111> loops disappeared and only a0 <100> loops existed above 623 K. Compared with the neutron and ion irradiations, the presence of hydrogen promoted the formation of a0 <100> loops.

Quantitative TEM Investigations on EUROFER 97 Irradiated up to 32 Dpa

2010 ◽  
Vol 73 ◽  
pp. 118-123 ◽  
Author(s):  
Oliver J. Weiss ◽  
Ermile Gaganidze ◽  
Jarir Aktaa
Keyword(s):  
Quantitative Data ◽  
Dose Dependence ◽  
Volume Density ◽  
Dislocation Loops ◽  
Defect Clusters ◽  
Transmission Electron ◽  
Rafm Steel ◽  
Induced Defects ◽  
Irradiation Induced Defects ◽  
Eurofer 97

The objective of this work is to evaluate the microstructure of the neutron-irradiated reduced activation ferritic/martensitic (RAFM) steel EUROFER 97. For this purpose irradiation induced defects like defect clusters, dislocation loops, voids/bubbles and precipitates are identified by transmission electron microscopy (TEM) and quantified in size and volume density. Emphasis is put on analyzing the influence of the irradiation dose and neutron fluxe on the evolution of size and density of the defects at irradiation temperatures between 300 and 335 °C. A first sample irradiated to a dose of 31.8 dpa was analyzed. The irradiation was carried out in the BOR 60 fast reactor of JSC “SSC RIAR” in Dimitrovgrad, within the framework of the ARBOR-1 irradiation program. To study the dose dependence in a next step the results will be compared to quantitative data on samples irradiated to a dose of 15 dpa. The obtained quantitative data will be used for correlation of the changes in the microstructure to the changes in the mechanical properties and will serve as an input for models describing this correlation.

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.

Transmission Electron Microscopy Observation of 11MEV B5+ Ion Irradiation in Bi2Sr2CaCu2O7-x Single Crystal

1999 ◽  
Vol 5 (S2) ◽  
pp. 758-759
Author(s):  
W.L. Zhou ◽  
Y. Sasaki ◽  
Y. Ikuhara ◽  
C.J.O’Connor
Keyword(s):  
Single Crystal ◽  
Ion Irradiation ◽  
Target Material ◽  
Heavy Ion ◽  
Zone Melting ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Different Types ◽  
Induced Defects ◽  
Irradiation Induced Defects

Artificial defects generated by ion irradiation have been considered an efficient method to enhance the critical current density in superconducting materials. The mechanism of producing defects as flux pining centers is still an important issue since the efficiency of irradiation-induced defects in flux pinning strongly depends on their microstructures. Different types of defects have been found in heavy ion irradiation. However, there are few results that show light ion irradiation due to the target material selected, the type of light ion and energy, and the incident ion angle. Another factor is the difficulty of cross-sectional sample preparation. In this paper, a single crystal Bi2Sr2CaCu2O7-x with 11 MeV B5+ ion irradiation was observed by transmission electron microscope (TEM) from both plan and cross-sectional view.The Bi2Sr2CaCu2O7-x single crystals used for ion irradiation were prepared using the floating-zone melting method. The crystals were cleaved into thin sheets of about 20 μm thickness along the a-b plane and cut to about 2mmx2mm size.

Radiative Recombination in the Cu(In,Ga)Se2 Thin Films Irradiated with Hydrogen Ions

2019 ◽  
Vol 18 (03n04) ◽  
pp. 1940033
Author(s):  
O. Borodavchenko ◽  
V. Zhivulko ◽  
M. Yakushev ◽  
M. Sulimov
Keyword(s):  
Thin Films ◽  
Low Temperature ◽  
Solid Solutions ◽  
Radiative Recombination ◽  
Energy Levels ◽  
Hydrogen Ions ◽  
Photoluminescence Excitation ◽  
Photoluminescence Spectra ◽  
Induced Defects ◽  
Irradiation Induced Defects

The irradiation-induced effects in Cu(In,Ca)Se2 thin films after irradiation with hydrogen ions with dose of [Formula: see text][Formula: see text]cm[Formula: see text] and different energies in the range of 2.5–10[Formula: see text]keV were studied. Irradiated and nonirradiated thin films were investigated by low-temperature (4.2[Formula: see text]K) photoluminescence and photoluminescence excitation methods. The appearance of intense bands at [Formula: see text][Formula: see text]eV and 0.77[Formula: see text]eV in the photoluminescence spectra may be related to radiative recombination on the irradiation-induced defects with deep energy levels in the bandgap of Cu(In,Ca)Se2 solid solutions. A possible nature of these defects and process of radiative recombination are discussed.

Identification of Defects In Ferritic/Martensitic Steels Induced by Low Dose Irradiation

2000 ◽  
Vol 650 ◽  
Author(s):  
R. Schäublin ◽  
M. Victoria
Keyword(s):  
Low Dose ◽  
Fusion Reactor ◽  
Three Dimensional ◽  
Dislocation Loops ◽  
Martensitic Steels ◽  
Weak Beam ◽  
Dose Irradiation ◽  
Diffraction Mode ◽  
Induced Defects ◽  
Irradiation Induced Defects

ABSTRACTThe ferritic/martensitic steels which are candidates for the first wall of the future fusion reactor are investigated in TEM. While the irradiation doses expected in this reactor are in the range of 100 dpa per year, there is still a lack of knowledge on the nature of the irradiation induced defects for the low doses at which hardening is already occuring. This hardening depends strongly on the type of interaction between the moving dislocations and the defects. The early defects, which start to appear as black dots in TEM, are expected to be either three dimensional clusters of interstitials or vacancies, or dislocation loops. The nature and size of these defects is carefully studied in the F82H steel for doses ranging from about 0.5 dpa to 9 dpa and irradiation temperatures ranging from 40°C to 330°C. For that purpose, various weak beam techniques are explored at the limit of resolution of a TEM used in diffraction mode. Results are presented here for the cases of a 1.7 dpa and a 8.8 dpa irradiation.

Microstructure and Nano-Indentation Properties of Ion-Irradiated Fe-9wt%Cr Alloy

2008 ◽  
Vol 135 ◽  
pp. 119-122 ◽  
Author(s):  
Hyung Ha Jin ◽  
Chan Sun Shin ◽  
Wheung Whoe Kim
Keyword(s):  
Indentation Test ◽  
Model Alloy ◽  
Displacement Damage ◽  
Burgers Vector ◽  
Nano Indentation ◽  
Transmission Electron ◽  
Yield Stress Increase ◽  
Hardness Increase ◽  
Induced Defects ◽  
Irradiation Induced Defects

A change of the mechanical property and microstructure of an Fe ion irradiated polycrystalline Fe-9wt%Cr model alloy to 1 dpa was examined using a nano-indentation and transmission electron microscopy. We anticipated that irradiated damage would be formed up to about 2.5μm and a displacement damage peak would be located at around 1.7μm from a surface through a TRIM code calculation. A thick dark band was formed at about 1.5μm from a surface with an actual TEM observation, which is consistent with a displacement damage peak in the TRIM code calculation. TEM observations showed that small defects with a Burgers vector a0<100> and 1/2a0<110> are formed in irradiated Fe-9wt%Cr alloy. In the nano indentation test, the hardness increase due to irradiation induced defects was up to 0.6GPa which can be converted to a yield stress increase of 200MPa.

Cluster Dynamics Study of Neutron Irradiation Induced Defects in Fe-12.5at%Cr Alloy

2011 ◽  
Vol 172-174 ◽  
pp. 449-457 ◽  
Author(s):  
Aleksandr R. Gokhman ◽  
Andreas Ulbricht ◽  
Uwe Birkenheuer ◽  
Frank Bergner
Keyword(s):  
Interstitial Atom ◽  
Volume Fraction ◽  
Size Distributions ◽  
Number Density ◽  
Vacancy Clusters ◽  
Transmission Electron ◽  
Induced Defects ◽  
Irradiation Induced Defects ◽  
Best Fit

Cluster dynamics (CD) is used to study the evolution of the size distributions of vacancy clusters (VC), self-interstitial atom (SIA) clusters(SIAC) and Cr precipitates in neutron irradiated Fe-12.5at%Cr alloys at T = 573 K with irradiation doses up to 12 dpa and a flux of 140 ndpa/s. Transmission electron microscopy (TEM) and small angle neutron scattering (SANS) data on the defect structure of this material irradiated at doses of 0.6 and 1.5 dpa are used to calibrate the model. A saturation behavior was found by CD for the free vacancy and free SIA concentrations as well as for the number density of the SIAC and the volume fraction of the Cr precipitates for neutron exposures above 0.006 dpa. The CD simulations also indicate the presence of VC with radii less than 0.5 nm and a strong SIAC peak with a mean diameter of about 0.5 nm, both invisible in SANS and TEM experiments. A specific surface tension of about 0.028 J/m2 between the a matrix and the Cr-rich a' precipitate was found as best fit value for reproducing the long-term Cr evolution in the irradiated Fe-12.5%Cr alloys observed by SANS.

Direct Evidence of the Si Interstitialicy Injection and Fast diffusion effect in Si During Pulsed Laser Melt Process

1991 ◽  
Vol 230 ◽  
Author(s):  
Yih Chang ◽  
J. Chen ◽  
S. Talwar ◽  
E. Y. Shu ◽  
Thomas. W. Sigmon
Keyword(s):  
High Temperature ◽  
Temperature Gradient ◽  
Pulsed Laser ◽  
Fast Diffusion ◽  
Dislocation Loops ◽  
Diffusion Effect ◽  
High Temperature Gradient ◽  
Transmission Electron ◽  
Before And After ◽  
Dislocation Movement

AbstractHigh temperature gradient induced fast diffusion effect during pulsed laser melt processes is reported for the first time in the Si semiconductor. We use both the oxidationinduced stacking faults and dislocation loops as markers to determine the degree of enhanced diffusion in the unmelted Si substrate by tracing their movement after laser melt. The crosssectional transmission electron microscope is employed to investigate the defect structures before and after laser melt. The expanded dislocation loops exhibit a significant diffusion and climb occurring during the nanosecond-scale processing duration. We also formulate and solve the governed diffusion equation, based on a high temperature gradient induced electric field, to simulate the dislocation movement. The agreement between the experimental and simulated results verifies that the fast diffusion effect indeed occurs in the Si semiconductor during the pulsed laser melt period.

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.

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