Crystallization of nano-size thallous oxide during ion irradiation of Tl-Ba-Ca-Cu-O high-temperature superconductors

1995 ◽  
Vol 53 ◽  
pp. 214-215
Author(s):  
P. P. Newcomer ◽  
L. M. Wang ◽  
M. L. Miller ◽  
R. C. Ewing
Keyword(s):  
High Temperature ◽  
Ion Irradiation ◽  
Ion Beam ◽  
High Temperature Superconductors ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Planetary Science ◽  
University Of New Mexico ◽  
The University ◽  
Nano Size

The Tl-Ba-Ca-Cu-O class of type-II high temperature superconductors (HTS) have Tc's as high as 125K. Although they have good critical current values, when a field is applied the weak pinning and consequent flow of magnetic vortices are a major impediment to the usefulness of these materials. Ion irradiation has been shown to enhance the pinning. High quality single crystals, as determined with x-ray precession and HRTEM, with sharp HTS Meissner signals, were irradiated with 1.5 MeV Kr+ and Xe+ ions using the HVEM-Tandem facility at Argonne National Laboratory. Ion beam microstructural modification was studied in-situ using electron diffraction and after irradiation using HRTEM and nano-beam EDS on Tl-1212 and Tl-2212 (numbers designate the stoichiometry Tl-Ba- Ca-Cu-O) single-crystal HTS. After irradiation, microstructure was studied using the JEOL 2010 in the Earth and Planetary Science Department at the University of New Mexico in order to characterize the resulting irradiation-induced nano-size precipitates.

Electron and ion irradiation-induced dissolution of mechanical twins in the intermetalic U3Si: An in situ HVEM study

1989 ◽  
Vol 47 ◽  
pp. 652-653
Author(s):  
Charles W. Allen ◽  
Robert C. Birtcher
Keyword(s):  
Elevated Temperatures ◽  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Heavy Ion ◽  
High Energy ◽  
Mechanical Twinning ◽  
In Situ Experiments

The uranium silicides, including U3Si, are under study as candidate low enrichment nuclear fuels. Ion beam simulations of the in-reactor behavior of such materials are performed because a similar damage structure can be produced in hours by energetic heavy ions which requires years in actual reactor tests. This contribution treats one aspect of the microstructural behavior of U3Si under high energy electron irradiation and low dose energetic heavy ion irradiation and is based on in situ experiments, performed at the HVEM-Tandem User Facility at Argonne National Laboratory. This Facility interfaces a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter to a 1.2 MeV AEI high voltage electron microscope, which allows a wide variety of in situ ion beam experiments to be performed with simultaneous irradiation and electron microscopy or diffraction.At elevated temperatures, U3Si exhibits the ordered AuCu3 structure. On cooling below 1058 K, the intermetallic transforms, evidently martensitically, to a body-centered tetragonal structure (alternatively, the structure may be described as face-centered tetragonal, which would be fcc except for a 1 pet tetragonal distortion). Mechanical twinning accompanies the transformation; however, diferences between electron diffraction patterns from twinned and non-twinned martensite plates could not be distinguished.

Amorphization Kinetics of Zr (Cr,Fe)2 Under Ion Irradiation

1992 ◽  
Vol 279 ◽  
Author(s):  
A. T. Motta ◽  
L. M. Howe ◽  
P. R. Okamoto
Keyword(s):  
Neutron Irradiation ◽  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Matrix Interface ◽  
Thin Foils ◽  
Intermetallic Precipitates ◽  
Kinetics Of

ABSTRACTThin foils of Zircaloy-4 were irradiated with 350 KeV 40Ar ions in the dual ion beam/HVEM facility at Argonne National Laboratory at 300 – 650 K. The irradiation-induced araorphization of the intermetallic precipitates Zr (Cr, Fe)2 and Zr2 (Ni, Fe) was studied in situ. For Zr (Cr,Fe)2 precipitates the dose-to-amorphization was found to increase exponentially with temperature, with a critical temperature of about 650 K. The amorphization morphology was shown to be homogeneous, with no preferential site for nucleation, in contrast to neutron-irradiation amorphization which started at the precipitate-matrix interface. For Zr2 (Ni,Fe) precipitates it was found that amorphization occurred at 550 K and 600 K, whereas in neutron irradiation no amorphization has been observed at those temperatures. The results are discussed in the context of the previous experimental results of neutron and electron irradiation and likely amorphization mechanisms are proposed.

HREM study of phase transformation induced by ion irradiation in Al-Cu-Co-Ge single decagonal quasicrystal

1996 ◽  
Vol 54 ◽  
pp. 722-723
Author(s):  
L.F. Chen ◽  
L.M. Wang ◽  
R.C. Ewing
Keyword(s):  
Phase Transformation ◽  
Ion Irradiation ◽  
National Laboratory ◽  
Research Field ◽  
In Situ Tem ◽  
Decagonal Quasicrystal ◽  
University Of New Mexico ◽  
Fundamental Understanding ◽  
The University

Irradiation-induced phase transformation in crystals has been an interesting research field for the past twenty years. Since the discovery of quasicrystals in Al-based alloys, there have been some reports on irradiation-induced phase transformation in quasicrystals by in situ TEM observations. However, detailed study on phase transformation in quasicrystals under ion irradiation at atomic level using HREM is necessary for the fundamental understanding of the process. In this paper, we report the results from a systematic HREM study on phase transformation induced by ion irradiation in Al-Cu-Co-Ge single decagonal quasicrystal (31.4 wt.% Cu, 21.8 wt.% Co and 5.4 wt.% Ge).The TEM specimens of single decagonal quasicrystal were prepared perpendicular to the tenfold axis. The transformation in single quasicrystal was studied by in situ TEM during 1.5 MeV Xe+ ion irradiation at room temperature using the HVEM-Tandem Facility at Argon National Laboratory and examined in detail by HREM using a JEM2010 microscope at the University of New Mexico after the irradiation.

Radiation-induced disordering and amorphization—An in situ HVEM study of uranium silicide with comparison to natural processes in zirconolite

1990 ◽  
Vol 48 (4) ◽  
pp. 534-535
Author(s):  
R. C. Birtcher ◽  
L. M. Wang ◽  
C. W. Allen ◽  
R. C. Ewing
Keyword(s):  
Electron Irradiation ◽  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Heavy Ion ◽  
High Energy ◽  
In Situ Tem ◽  
In Situ Experiments

We present here results of in situ TEM diffraction observations of the response of U3Si and U3Si2 when subjected to 1 MeV electron irradiation or to 1.5 MeV Kr ion irradiation, and observations of damage occuring in natural zirconolite. High energy electron irradiation or energetic heavy ion irradiation were performed in situ at the HVEM-Tandem User Facility at Argonne National Laboratory. In this Facility, a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter have been interfaced to a 1.2 MeV AEI high voltage electron microscope. This allows a wide variety of in situ experiments to be performed with simultaneous ion irradiation and conventional transmission electron microscopy. During the electron irradiation, the electron beam was focused to a diameter of about 2 μ.m at the specimen thin area. The ion beam was approximately 2 mm in diameter and was uniform over the entire specimen. With the specimen mounted in a heating holder, the temperature increase indicated by the furnace thermocouple during the ion irradiation was typically 8 °K.

Ion Beam Modification of TI-Ba-Ca-Cu-O Type High Temperature Superconductors During Irradiation

1994 ◽  
Vol 373 ◽  
Author(s):  
P.P. Newcomer ◽  
L. M. Wang ◽  
B. Morosin
Keyword(s):  
High Temperature ◽  
Ion Irradiation ◽  
Ion Beam ◽  
High Temperature Superconductors ◽  
Ion Beam Modification ◽  
Moiré Fringes ◽  
High Resolution Tem ◽  
20 Nm ◽  
Induced Crystallization

AbstractMicrostructural modification of high temperature superconductor (HTS) single-crystal plates of T1-1212 and T1-2212 (numbers designate the Tl/Ba/Ca/Cu cation ratio) was studied during 1.5 MeV Kr+ and Xe+ ion irradiation with in-situ electron diffraction and after ion irradiation with high resolution TEM (HRTEM). Similar in-situ temperature dependence effects are seen for both phases. During irradiations from 22K to 673K, an amorphous halo develops after very low ion dose or fluence (l.7X1012 ions/cm2). During irradiation at 100K and 300K, complete amorphization is obtained, while at 22K and ≥533K, the halo fades slightly and a polycrystalline ring pattern develops, indicating ion irradiation induced crystallization occurred. After a low ion dose (8.5XlO12ions/cm2) at 100K and 300K, HRTEM reveals amorphous regions 5 -20 nm in size which are not columnar and do not all penetrate the entire sample thickness. At 22K and ≥533K, Moire fringes and misoriented crystallites of cascade size are observed. The 4 - 6nm crystallites are thallium-rich.

Irradiation-induced grain growth in gold and copper: In situ HVEM studies at 75-300 K

1989 ◽  
Vol 47 ◽  
pp. 644-645
Author(s):  
Charles W. Allen
Keyword(s):  
Grain Growth ◽  
Ion Irradiation ◽  
Boundary Migration ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Average Grain Size ◽  
Growth Phenomenon ◽  
In Situ Experiments

When thin polycrystalline films of Au, Cu and various other materials are subjected to energetic ion irradiation, the average grain size increases even at cryogenic temperatures. As is the case with many ion beam processes, this phenomenon of ion irradiation induced grain growth exhibits only a very mild temperature dependence. This contribution is based on in situ experiments, performed at the HVEM-Tandem User Facility at Argonne National Laboratory. This Facility interfaces a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter to a 1.2 MV AEI high voltage electron microscope, which allows a wide variety of in situ ion beam experiments to be performed with simultaneous irradiation and electron microscopy or diffraction. A series of in situ ion and/or electron irradiation experiments is being performed at the HVEM-Tandem Facility at Argonne which have shown clearly for fine grained Au films that two mechanisms for growth are operative for the ion beam case: grain boundary migration as in normal thermal grain growth and grain coalescence which is similar in appearance to recrystallization by subgrain coalescence. Especially in the case of Au for which ion-induced growth is relatively rapid, such in situ experiments also demonstrate the importance of dislocation activity which is a consequence of the collision cascade damage associated with ion irradiation. Existing theories for irradiation-induced grain growth assume that growth occurs by boundary migration and that only point defects generated at grain boundaries are responsible for the growth phenomenon.

Ion-Induced Amorphization of Murataite

2002 ◽  
Vol 713 ◽  
Author(s):  
Jie Lian ◽  
Sergey V. Yudintsev ◽  
Sergey V. Stefanovsky ◽  
Olga I. Kirjanova ◽  
Rodney C. Ewing
Keyword(s):  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Pyrochlore Structure ◽  
Fluorite Structure ◽  
In Situ Tem ◽  
Cell Parameters ◽  
Unit Cells ◽  
Radiation Resistant

ABSTRACTMurataite A4B2C7O22-x, where A = Na+, Ca2+, REE3+, An3+/4+; B = Mn2+/3+, Zn2+; C = Ti4+, Fe3+, Al3+; 0≤x≤1, is an isometric, derivative of the fluorite-structure. Murataite is potentially suitable as a phase for the immobilization of rare earth (REE) and actinide elements (An). Murataite structures with three-(3C), five-(5C), and eight-fold (8C) multiples of the fluorite unit cell parameters have been identified. Radiation-induced amorphization of murataite has been investigated by 1 MeV Kr+ ion irradiation of three ceramic samples produced by melting in a resistive furnace and a cold crucible at 1400-1600 °C. The 1 MeV Kr+ ion irradiations were performed at room temperature using IVEM-Tandem Facility at Argonne National Laboratory. Radiation damage was observed by in-situ TEM. Initially, the irradiation caused disordering of the murataite structure. Murataite was rendered fully amorphous at a dose of (1.7∼1.9)Á1018 ion/m2. The pyrochlore structure phase (2C) is more radiation resistant to ion irradiation-induced amorphization than the murataite structure. Combining results on murataite with those pyrochlore and fluorite, a generally increasing trend in the susceptibility to ion beam damage is found in the fluorite-related structures as a function of the increasing multiples of the fluorite unit cells.

Temperature and Ion-Mass Dependence of Amorphization Dose for Ion Beam Irradiated Zircon (ZrSiO4)

1992 ◽  
Vol 279 ◽  
Author(s):  
L. M. Wangl ◽  
R. C. Ewing ◽  
W. J. Weber ◽  
R. K. Eby
Keyword(s):  
Temperature Dependence ◽  
Low Temperatures ◽  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Temperature Limit ◽  
Temperature Curve ◽  
Mass Dependence ◽  
The Third

ABSTRACTThe temperature dependence of amorphization dose for zircon under 1.5 MeV Kr ion irradiation has been investigated using the HVEM-Tandem Facility at Argonne National Laboratory. Three regimes were observed in the amorphization dose-temperature curve. In the first regime (15 to 300 K), the critical amorphization dose increased from 3.06 to 4.5 ions/nm2. In the second regime (300 to 473 K), there is little change in the amorphization dose. In the third regime (> 473 K), the amorphization dose increased exponentially to 8.3 ions/nm2 at 913 K. This temperature dependence of amorphization dose can be described by two processes with different activation energies (0.018 and 0.31 eV respectively) which are attributed to close pair recombination in the cascades at low temperatures and radiation-enhanced epitaxial recrystallization at higher temperatures. The upper temperature limit for amorphization of zircon is estimated to be 1100 K. The ion-mass dependence of the amorphization dose (in dpa) has also been discussed in terms of the energy to recoils based on data obtained from He, Ne, Ar, Kr, Xe irradiations and a 238Pu-doped sample.

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