HRTEM Study of the Role of Nanoparticles in ODS Ferritic Steel under Dual-Ion Irradiation

2011 ◽  
Vol 1296 ◽  
Author(s):  
Luke Hsiung ◽  
Scott Tumey ◽  
Michael Fluss ◽  
Yves Serruys ◽  
Francois Willaime
Keyword(s):  
Mechanical Alloying ◽  
Ferritic Steel ◽  
Ion Irradiation ◽  
Complex Oxide ◽  
Helium Bubbles ◽  
Ods Steel ◽  
Transmission Electron ◽  
Radiation Induced ◽  
State Amorphization

ABSTRACTStructures of nanoparticles and their role in dual-ion irradiated Fe-16Cr-4.5Al-0.3Ti-2W-0.37Y2O3 (K3) ODS ferritic steel produced by mechanical alloying (MA) were studied using high-resolution transmission electron microscopy (HRTEM) techniques. The observation of Y4Al2O9 complex-oxide nanoparticles in the ODS steel imply that decomposition of Y2O3 in association with internal oxidation of Al occurred during mechanical alloying. HRTEM observations of crystalline and partially crystalline nanoparticles larger than ~2 nm and amorphous cluster-domains smaller than ~2 nm provide an insight into the formation mechanism of nanoparticles/clusters in MA/ODS steels, which we believe involves solid-state amorphization and re-crystallization. The role of nanoparticles/clusters in suppressing radiation-induced swelling is revealed through TEM examinations of cavity distributions in (Fe + He) dual-ion irradiated K3-ODS steel. HRTEM observations of helium-filled cavities (helium bubbles) preferably trapped at nanoparticle/clusters in dual-ion irradiated K3-ODS are presented.

Helium Implantation of Ultrafine Grained Tungsten within a TEM

2014 ◽  
Vol 1645 ◽  
Author(s):  
K. Hattar ◽  
O. El-Atwani ◽  
M. Efe ◽  
T.J. Novakowski ◽  
A. Suslova ◽  
...  
Keyword(s):  
Nuclear Reactors ◽  
Ion Irradiation ◽  
Tungsten Alloys ◽  
Helium Bubbles ◽  
Transmission Electron ◽  
Radiation Properties ◽  
Ultrafine Grained ◽  
Theoretical Predictions ◽  
Helium Implantation ◽  
Future Work

ABSTRACTMany theoretical predictions have suggested that the confined length scales and increased interface density of various nanostructured materials may result in desired thermal, mechanical, and radiation properties. An important aspect of this for next generation nuclear reactors is understanding the change in swelling resulting from helium evolution in tungsten alloys, as a function of grain size and grain boundary type. This study investigated this using a new ion irradiation transmission electron microscope (TEM) facility that has been developed at Sandia National Laboratories and is capable of ion implanting helium at energies up to 20 keV. It was demonstrated in this feasibility study that helium could be implanted into an ultrafine grained tungsten TEM sample produced by severe plastic deformation. The size and density of the helium bubbles formed during the experiment appear nearly constant; while the larger voids formed appear to be dependent on the local microstructure. Future work is underway to both optimize the facility, as well as better understand the evolution of ultrafine grained tungsten resulting from both helium implantation and displacement damage.

scholarly journals Electron Beam Effects during In-Situ Annealing of Self-Ion Irradiated Nanocrystalline Nickel

2015 ◽  
Vol 1809 ◽  
pp. 13-18 ◽  
Author(s):  
Brittany Muntifering ◽  
Rémi Dingreville ◽  
Khalid Hattar ◽  
Jianmin Qu
Keyword(s):  
Electron Beam ◽  
Nuclear Reactor ◽  
Ion Irradiation ◽  
Nanocrystalline Nickel ◽  
Transmission Electron ◽  
Radiation Induced ◽  
Reactor Materials ◽  
Diffraction Patterns ◽  
Underlying Mechanisms

ABSTRACTTransmission electron microscopy (TEM) is a valuable methodology for investigating radiation-induced microstructural changes and elucidating the underlying mechanisms involved in the aging and degradation of nuclear reactor materials. However, the use of electrons for imaging may result in several inadvertent effects that can potentially change the microstructure and mechanisms active in the material being investigated. In this study, in situ TEM characterization is performed on nanocrystalline nickel samples under self-ion irradiation and post irradiation annealing. During annealing, voids are formed around 200 °C only in the area illuminated by the electron beam. Based on diffraction patterns analyses, it is hypothesized that the electron beam enhanced the growth of a NiO layer resulting in a decrease of vacancy mobility during annealing. The electron beam used to investigate self-ion irradiation ultimately significantly affected the type of defects formed and the final defect microstructure.

Superior Radiation Resistance of ODS Ferritic Steels

2010 ◽  
Vol 654-656 ◽  
pp. 2791-2794 ◽  
Author(s):  
Ryuta Kasada ◽  
Hiromasa Takahashi ◽  
Hirotatsu Kishimoto ◽  
Kentaro Yutani ◽  
Akihiko Kimura
Keyword(s):  
Ferritic Steel ◽  
Ion Irradiation ◽  
Oxide Dispersion Strengthened ◽  
Preferential Formation ◽  
Nano Oxide ◽  
Dual Beam ◽  
Transmission Electron ◽  
The Matrix ◽  
Oxide Particles ◽  
Helium Implantation

The oxide dispersion strengthened (ODS) ferritic steel and non-ODS reduced-activation ferritic (RAF) steel were irradiated at 773 K by means of a dual-beam ion irradiation technique to a dose of 0.4 dpa with simultaneous helium implantation up to 1000 appm. Microstructural changes were investigated by transmission electron microscopy. The RAF steel showed a preferential formation of cavities at grain boundaries, precipitate interfaces and dislocations. In contrast, the ODS ferritic steel showed a homogeneous and fine distribution of cavities in the matrix. This paper discusses the superior resistance of the ODS ferritic steel against development of cavities in terms of the effects of nano-oxide particles dispersed in the matrix.

scholarly journals Comparison between Subsequent Irradiation and Co-Irradiation into SIMP Steel

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1393
Author(s):  
Yong Wang ◽  
Tongmin Zhang ◽  
Qing Liao ◽  
Junyuan Yang ◽  
Weigang Gu ◽  
...  
Keyword(s):  
Martensitic Steel ◽  
Ion Irradiation ◽  
Material Microstructure ◽  
Critical System ◽  
Spallation Target ◽  
Lattice Disorder ◽  
Nano Indentation ◽  
Transmission Electron ◽  
Radiation Induced ◽  
New Perspective

A modern Chinese ferritic/martensitic steel SIMP, is a new perspective nuclear structural material for the spallation target in accelerator driven sub-critical system. In this work, aimed at exploring the radiation resistance properties of this material, we investigate the differences between simultaneous Fe and He ions irradiation and He implantation of SIMP steel pre-irradiated by Fe self-ions. The irradiations were performed at 300 °C. The radiation-induced hardening was evaluated by nano-indentation, while the lattice disorder was investigated by transmission electron microscopy. Clear differences were found in the material microstructure after the two kinds of the ion irradiation performed. Helium cavities were observed in the co-irradiated SIMP steel, but not the case of He implantation with Fe pre-irradiation. In the same time, the size and density of Frank loops were different in the two different irradiation conditions. The reason for the different observed lattice disorders is discussed.

scholarly journals Enhancing the phase stability of ceramics under radiation via multilayer engineering

2021 ◽  
Vol 7 (26) ◽  
pp. eabg7678
Author(s):  
Hongliang Zhang ◽  
Jianqi Xi ◽  
Ranran Su ◽  
Xuanxin Hu ◽  
Jun Young Kim ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Phase Stability ◽  
First Principles Calculations ◽  
Tem Analysis ◽  
Promising Strategy ◽  
Transmission Electron ◽  
Radiation Induced ◽  
Composition Changes ◽  
Annealing Defects

In metallic systems, increasing the density of interfaces has been shown to be a promising strategy for annealing defects introduced during irradiation. The role of interfaces during irradiation of ceramics is more unclear because of the complex defect energy landscape that exists in these materials. Here, we report the effects of interfaces on radiation-induced phase transformation and chemical composition changes in SiC-Ti3SiC2-TiCx multilayer materials based on combined transmission electron microscopy (TEM) analysis and first-principles calculations. We found that the undesirable phase transformation of Ti3SiC2 is substantially enhanced near the SiC/Ti3SiC2 interface, and it is suppressed near the Ti3SiC2/TiC interface. The results have been explained by ab initio calculations of trends in defect segregation to the above interfaces. Our finding suggests that the phase stability of Ti3SiC2 under irradiation can be improved by adding TiCx, and it demonstrates that, in ceramics, interfaces are not necessarily beneficial to radiation resistance.

Radiation Induced Structural Changes in Normal Spinels

2007 ◽  
Vol 1043 ◽  
Author(s):  
David Simeone ◽  
Gianguido Baldinozzi ◽  
Dominique Gosset ◽  
Leo Mazerolles ◽  
Lionel Thome
Keyword(s):  
Radiation Effects ◽  
Structural Changes ◽  
Ion Irradiation ◽  
Atomic Scale ◽  
X Ray Diffraction ◽  
Unified Framework ◽  
X Ray ◽  
Transmission Electron ◽  
Radiation Induced ◽  
Diffraction Patterns

AbstractIon irradiation induced phase transformations in three normal spinel compounds MgAl2O4, MgCr2O4 and ZnAl2O4 have been investigated by X-ray diffraction, Raman spectroscopy and Transmission Electron Microscopy. This work presents a unified framework to describe the radiation effects in normal spinels. Irradiation modifies the atomic and mesoscopic structures of theses spinels in different ways. At the atomic scale, it produces the inversion of the cations in the spinel structure which can always be described within its usual Fd-3m space group. At the mesoscopic scale, it produces microdomains, responsible for the important changes in the X-ray diffraction patterns.

scholarly journals Ion irradiation induced phase transformation in gold nanocrystalline films

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Pranav K. Suri ◽  
James E. Nathaniel ◽  
Nan Li ◽  
Jon K. Baldwin ◽  
Yongqiang Wang ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Ion Irradiation ◽  
Face Centered Cubic ◽  
Ambient Conditions ◽  
Free Standing ◽  
Hexagonal Close Packed ◽  
Transmission Electron ◽  
Precession Electron Diffraction ◽  
Radiation Induced ◽  
Face Centered

Abstract Gold is a noble metal typically stable as a solid in a face-centered cubic (FCC) structure under ambient conditions; however, under particular circumstances aberrant allotropes have been synthesized. In this work, we document the phase transformation of 25 nm thick nanocrystalline (NC) free-standing gold thin-film via in situ ion irradiation studied using atomic-resolution transmission electron microscopy (TEM). Utilizing precession electron diffraction (PED) techniques, crystallographic orientation and the radiation-induced relative strains were measured and furthermore used to determine that a combination of surface and radiation-induced strains lead to an FCC to hexagonal close packed (HCP) crystallographic phase transformation upon a 10 dpa radiation dose of Au4+ ions. Contrary to previous studies, HCP phase in nanostructures of gold was stabilized and did not transform back to FCC due to a combination of size effects and defects imparted by damage cascades.

scholarly journals HRTEM Study of Oxide Nanoparticles in 16Cr-4Al-2W-0.3Ti-0.3Y2O3 ODS Steel

2009 ◽  
Vol 1215 ◽  
Author(s):  
Luke Hsiung ◽  
Mike Fluss ◽  
Mark Wall ◽  
Akihiko Kimura
Keyword(s):  
Spherical Shape ◽  
Complex Oxide ◽  
Oxide Nanoparticles ◽  
Orientation Relationships ◽  
Oxide Compound ◽  
Ods Steel ◽  
Transmission Electron ◽  
Interfacial Structures ◽  
20 Nm ◽  
Amorphous Nanoparticles

AbstractCrystal and interfacial structures of oxide nanoparticles in 16Cr-4Al-2W-0.3Ti-0.3Y2O3 ODS ferritic steel have been examined using high-resolution transmission electron microscopy (HRTEM) techniques. Oxide nanoparticles with a complex-oxide core and an amorphous shell were frequently observed. The crystal structure of complex-oxide core is identified to be mainly monoclinic Y4Al2O9 (YAM) oxide compound. Orientation relationships between the oxide and matrix are found to be dependent on the particle size. Large particles (> 20 nm) tend to be incoherent and have a spherical shape, whereas small particles (< 10 nm) tend to be coherent or semi-coherent and have a faceted interface. The observations of partially amorphous nanoparticles lead us to propose three-stage mechanisms in order to rationalize the formation of oxide nanoparticles containing core/shell structures in as-fabricated ODS steels.

Annealing Of Radiation Damage in Tungsten

1970 ◽  
Vol 28 ◽  
pp. 412-413
Author(s):  
Robert C. Rau ◽  
John Moteff
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Radiation Damage ◽  
Thermal Annealing ◽  
Neutron Fluence ◽  
Dislocation Loops ◽  
Defect Clusters ◽  
Polycrystalline Tungsten ◽  
Transmission Electron ◽  
Radiation Induced

Transmission electron microscopy has been used to study the thermal annealing of radiation induced defect clusters in polycrystalline tungsten. Specimens were taken from cylindrical tensile bars which had been irradiated to a fast (E > 1 MeV) neutron fluence of 4.2 × 1019 n/cm2 at 70°C, annealed for one hour at various temperatures in argon, and tensile tested at 240°C in helium. Foils from both the unstressed button heads and the reduced areas near the fracture were examined.Figure 1 shows typical microstructures in button head foils. In the unannealed condition, Fig. 1(a), a dispersion of fine dot clusters was present. Annealing at 435°C, Fig. 1(b), produced an apparent slight decrease in cluster concentration, but annealing at 740°C, Fig. 1(C), resulted in a noticeable densification of the clusters. Finally, annealing at 900°C and 1040°C, Figs. 1(d) and (e), caused a definite decrease in cluster concentration and led to the formation of resolvable dislocation loops.

On Future Directions in Pathology

1982 ◽  
Vol 40 ◽  
pp. 274-277
Author(s):  
Benjamin F. Trump ◽  
Irene K. Berezesky ◽  
Raymond T. Jones
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Clinical Pathology ◽  
Future Directions ◽  
Diagnostic Pathology ◽  
The Past ◽  
Transmission Electron ◽  
Organ Systems ◽  
The Many

The role of electron microscopy and associated techniques is assured in diagnostic pathology. At the present time, most of the progress has been made on tissues examined by transmission electron microscopy (TEM) and correlated with light microscopy (LM) and by cytochemistry using both plastic and paraffin-embedded materials. As mentioned elsewhere in this symposium, this has revolutionized many fields of pathology including diagnostic, anatomic and clinical pathology. It began with the kidney; however, it has now been extended to most other organ systems and to tumor diagnosis in general. The results of the past few years tend to indicate the future directions and needs of this expanding field. Now, in addition to routine EM, pathologists have access to the many newly developed methods and instruments mentioned below which should aid considerably not only in diagnostic pathology but in investigative pathology as well.

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