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.

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.

In situ TEM studies of irradiation effects for materials improvement

1991 ◽  
Vol 49 ◽  
pp. 452-453
Author(s):  
Charles W. Allen
Keyword(s):  
Nuclear Reactor ◽  
Austenitic Stainless Steels ◽  
High Energy ◽  
Point Of View ◽  
In Situ Tem ◽  
Irradiation Effects ◽  
Tem Analysis ◽  
Radiation Induced ◽  
Analytical Tools

Irradiation effects studies employing TEMs as analytical tools have been conducted for almost as many years as materials people have done TEM, motivated largely by materials needs for nuclear reactor development. Such studies have focussed on the behavior both of nuclear fuels and of materials for other reactor components which are subjected to radiation-induced degradation. Especially in the 1950s and 60s, post-irradiation TEM analysis may have been coupled to in situ (in reactor or in pile) experiments (e.g., irradiation-induced creep experiments of austenitic stainless steels). Although necessary from a technological point of view, such experiments are difficult to instrument (measure strain dynamically, e.g.) and control (temperature, e.g.) and require months or even years to perform in a nuclear reactor or in a spallation neutron source. Consequently, methods were sought for simulation of neutroninduced radiation damage of materials, the simulations employing other forms of radiation; in the case of metals and alloys, high energy electrons and high energy ions.

Effects of High-Energy Ions on Synthetic Quartz

1972 ◽  
Vol 30 ◽  
pp. 544-545
Author(s):  
Joseph J. Comer ◽  
Charles Bergeron ◽  
Lester F. Lowe
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
High Energy ◽  
Transmission Electron ◽  
Kikuchi Lines ◽  
High Energy Ions ◽  
Diffraction Patterns ◽  
Dauphiné Twinning ◽  
Beam Damage

Using a Van De Graaff Accelerator thinned specimens were subjected to bombardment by 3 MeV N+ ions to fluences ranging from 4x1013 to 2x1016 ions/cm2. They were then examined by transmission electron microscopy and reflection electron diffraction using a 100 KV electron beam.At the lowest fluence of 4x1013 ions/cm2 diffraction patterns of the specimens contained Kikuchi lines which appeared somewhat broader and more diffuse than those obtained on unirradiated material. No damage could be detected by transmission electron microscopy in unannealed specimens. However, Dauphiné twinning was particularly pronounced after heating to 665°C for one hour and cooling to room temperature. The twins, seen in Fig. 1, were often less than .25 μm in size, smaller than those formed in unirradiated material and present in greater number. The results are in agreement with earlier observations on the effect of electron beam damage on Dauphiné twinning.

In situ TEM Studies of agglomeration of sub-nanometer Ru layers in Ru/C multilayers

1992 ◽  
Vol 50 (1) ◽  
pp. 256-257
Author(s):  
Tai D. Nguyen ◽  
Ronald Gronsky ◽  
Jeffrey B. Kortright
Keyword(s):  
Layered Structure ◽  
Driving Force ◽  
High Energy ◽  
Superior Performance ◽  
In Situ Tem ◽  
Rayleigh Instability ◽  
Practical Applications ◽  
Transmission Electron ◽  
Diffraction Patterns

Nanometer period Ru/C multilayers are one of the prime candidates for normal incident reflecting mirrors at wavelengths < 10 nm. Superior performance, which requires uniform layers and smooth interfaces, and high stability of the layered structure under thermal loadings are some of the demands in practical applications. Previous studies however show that the Ru layers in the 2 nm period Ru/C multilayer agglomerate upon moderate annealing, and the layered structure is no longer retained. This agglomeration and crystallization of the Ru layers upon annealing to form almost spherical crystallites is a result of the reduction of surface or interfacial energy from die amorphous high energy non-equilibrium state of the as-prepared sample dirough diffusive arrangements of the atoms. Proposed models for mechanism of thin film agglomeration include one analogous to Rayleigh instability, and grain boundary grooving in polycrystalline films. These models however are not necessarily appropriate to explain for the agglomeration in the sub-nanometer amorphous Ru layers in Ru/C multilayers. The Ru-C phase diagram shows a wide miscible gap, which indicates the preference of phase separation between these two materials and provides an additional driving force for agglomeration. In this paper, we study the evolution of the microstructures and layered structure via in-situ Transmission Electron Microscopy (TEM), and attempt to determine the order of occurence of agglomeration and crystallization in the Ru layers by observing the diffraction patterns.

Automatic analysis of Kikuchi diffraction patterns

1994 ◽  
Vol 52 ◽  
pp. 900-901
Author(s):  
H. Weiland ◽  
D. P. Field
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Spatial Resolution ◽  
Relevant Information ◽  
Crystalline Materials ◽  
Large Size ◽  
Transmission Electron ◽  
New Type ◽  
Diffraction Patterns ◽  
Orientation Determination

Recent advances in the automatic indexing of backscatter Kikuchi diffraction patterns on the scanning electron microscope (SEM) has resulted in the development of a new type of microscopy. The ability to obtain statistically relevant information on the spatial distribution of crystallite orientations is giving rise to new insight into polycrystalline microstructures and their relation to materials properties. A limitation of the technique in the SEM is that the spatial resolution of the measurement is restricted by the relatively large size of the electron beam in relation to various microstructural features. Typically the spatial resolution in the SEM is limited to about half a micron or greater. Heavily worked structures exhibit microstructural features much finer than this and require resolution on the order of nanometers for accurate characterization. Transmission electron microscope (TEM) techniques offer sufficient resolution to investigate heavily worked crystalline materials.Crystal lattice orientation determination from Kikuchi diffraction patterns in the TEM (Figure 1) requires knowledge of the relative positions of at least three non-parallel Kikuchi line pairs in relation to the crystallite and the electron beam.

scholarly journals In Situ Observation of Electron-Beam-Induced Formation of Nano-Structures in PbTe

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 163
Author(s):  
Iryna Zelenina ◽  
Igor Veremchuk ◽  
Yuri Grin ◽  
Paul Simon
Keyword(s):  
Electron Beam ◽  
Gas Phase ◽  
Threshold Current ◽  
Threshold Current Density ◽  
Atomic Scale ◽  
In Situ Observation ◽  
Nano Structures ◽  
Transmission Electron ◽  
Initial Crystal

Nano-scaled thermoelectric materials attract significant interest due to their improved physical properties as compared to bulk materials. Well-shaped nanoparticles such as nano-bars and nano-cubes were observed in the known thermoelectric material PbTe. Their extended two-dimensional nano-layer arrangements form directly in situ through electron-beam treatment in the transmission electron microscope. The experiments show the atomistic depletion mechanism of the initial crystal and the recrystallization of PbTe nanoparticles out of the microparticles due to the local atomic-scale transport via the gas phase beyond a threshold current density of the beam.

scholarly journals Microstructure and properties of nano-laminated Y3Si2C2 ceramics fabricated via in situ reaction by spark plasma sintering

2021 ◽  
Vol 10 (3) ◽  
pp. 578-586
Author(s):  
Lin-Kun Shi ◽  
Xiaobing Zhou ◽  
Jian-Qing Dai ◽  
Ke Chen ◽  
Zhengren Huang ◽  
...  
Keyword(s):  
Spark Plasma Sintering ◽  
Atomic Scale ◽  
Max Phase ◽  
X Ray Diffraction ◽  
Selected Area Electron Diffraction ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Spark Plasma ◽  
Diffraction Patterns

AbstractA nano-laminated Y3Si2C2 ceramic material was successfully synthesized via an in situ reaction between YH2 and SiC using spark plasma sintering technology. A MAX phase-like ternary layered structure of Y3Si2C2 was observed at the atomic-scale by high resolution transmission electron microscopy. The lattice parameters calculated from both X-ray diffraction and selected area electron diffraction patterns are in good agreement with the reported theoretical results. The nano-laminated fracture of kink boundaries, delamination, and slipping were observed at the tip of the Vickers indents. The elastic modulus and Vickers hardness of Y3Si2C2 ceramics (with 5.5 wt% Y2O3) sintered at 1500 °C were 156 and 6.4 GPa, respectively. The corresponding values of thermal and electrical conductivity were 13.7 W·m-1·K-1 and 6.3×105 S·m-1, respectively.

In-Situ Electrochemical Transmission Electron Microscopy for Battery Research

2014 ◽  
Vol 20 (2) ◽  
pp. 484-492 ◽  
Author(s):  
B. Layla Mehdi ◽  
Meng Gu ◽  
Lucas R. Parent ◽  
Wu Xu ◽  
Eduard N. Nasybulin ◽  
...  
Keyword(s):  
Electron Beam ◽  
Silicon Nanowires ◽  
Electrochemical Processes ◽  
Transmission Electron ◽  
Experimental Parameters ◽  
Scanning Transmission ◽  
Electrode Interface ◽  
Electron Microscopes

AbstractThe recent development of in-situ liquid stages for (scanning) transmission electron microscopes now makes it possible for us to study the details of electrochemical processes under operando conditions. As electrochemical processes are complex, care must be taken to calibrate the system before any in-situ/operando observations. In addition, as the electron beam can cause effects that look similar to electrochemical processes at the electrolyte/electrode interface, an understanding of the role of the electron beam in modifying the operando observations must also be understood. In this paper we describe the design, assembly, and operation of an in-situ electrochemical cell, paying particular attention to the method for controlling and quantifying the experimental parameters. The use of this system is then demonstrated for the lithiation/delithiation of silicon nanowires.

In situ observation of the motion of ferroelectric domain walls in Bi4Ti3O12 single crystals

2016 ◽  
Vol 49 (5) ◽  
pp. 1645-1652 ◽  
Author(s):  
Wanneng Ye ◽  
Lingli Tang ◽  
Chaojing Lu ◽  
Huabing Li ◽  
Yichun Zhou
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Single Crystals ◽  
Transmission Electron Microscope ◽  
Domain Walls ◽  
Domain Switching ◽  
Ferroelectric Domain ◽  
In Situ Observation ◽  
Transmission Electron

Five types of ferroelectric domain walls (DWs) are present in Bi4Ti3O12 single crystals (Ye et al., 2015). Here their motion was investigated in situ using transmission electron microscopy and optical microscopy. The motion of P (a)-90° DWs, P (a)-180° DWs and P (c)-180° DWs was observed through electron beam poling in a transmission electron microscope. The growth of new P s(a)-180° nanodomains was frequently seen and they tended to nucleate at preexisting P s(a)-90° DWs. Irregularly curved P (c)-180° DWs exhibit the highest mobility, while migration over a short range occurs occasionally for faceted P s(a)-90° DWs. In addition, the motion of P s(a)-90° DWs and the growth/annihilation of new needle-like P s(a)-90° domains in a 20 µm-thick crystal were observed under an external electric field on an optical microscope. Most of the new needle-like P s(a)-90° domains nucleate at preexisting P s(a)-90° DWs and the former are much smaller than the latter. This is very similar to the situation for P s(a)-180° domain switching induced by electron beam poling in a transmission electron microscope. Our observations suggest the energy hierarchy for different domains of P s(c)-180° ≤ P s(a)-180° ≤ P s(a)-90° ≤ new needle-like P s(a)-90° in ferroelectric Bi4Ti3O12.

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