scholarly journals Effects of Ion Implantation and Temperature on Radiation-Induced Segregation In Ni-9Al Alloys

1996 ◽  
Vol 439 ◽  
Author(s):  
M. J. Giacobbe ◽  
N. Q. Lam ◽  
P. R. Okamoto ◽  
N. J. Zaluzec ◽  
J. F. Stubbins
Keyword(s):  
National Laboratory ◽  
Argonne National Laboratory ◽  
Kirkendall Effect ◽  
Implantation Dose ◽  
Accelerator Facility ◽  
Strong Suppression ◽  
Suppression Effect ◽  
Voltage Electron ◽  
Radial Segregation ◽  
Radiation Induced

AbstractThe effects of Ne and Sc implantation on radiation-induced segregation (RIS) in Ni- 9at.%Al were studied in-situ utilizing the high-voltage electron microscopeffandem accelerator facility at Argonne National Laboratory. A highly-focused 900-keV electron beam generated radial defect fluxes which, in turn, induced the transport of Al atoms toward the center of the electronirradiated area via the inverse-Kirkendall effect. The radial segregation rate of Al atoms was monitored by measuring the diameter of the γ′-Ni3Al zone which formed in the Al-enriched area during irradiation. Ne and Sc implantation effects on RIS were investigated at 550°C, while Ne effects were also examined at 625°C to determine the influence of temperature on the ability of Ne to act as defect trapping sites, causing RIS suppression. It was found that the RIS suppression effect of Ne increased with increasing irradiation temperature, and that Sc had a small RIS suppression effect which increased with increasing Sc implantation dose. Ne bubbles which formed during implantation are believed to be responsible for its strong suppression effect.

scholarly journals In-Situ Hvem Studies of Radiation-Induced Segregation In Ni-Al Alloys During Simultaneous Irradiation with Electrons and Ions

1995 ◽  
Vol 396 ◽  
Author(s):  
M. J. Giacobbe ◽  
N. Q. Lam ◽  
P. R. Okamoto ◽  
J. F. Stubbins
Keyword(s):  
National Laboratory ◽  
Argonne National Laboratory ◽  
Kirkendall Effect ◽  
Radial Component ◽  
Al Alloy ◽  
Tandem Accelerator ◽  
Accelerator Facility ◽  
Radial Segregation ◽  
Radiation Induced

AbstractThe effects of 75-keV Ne+ and 300-keV Ni+ bombardment on electron radiation-induced segregation (RIS) in a Ni-9at%Al alloy were investigated in-situ using the HVEM (high voltage electron microscope)/Tandem accelerator facility at Argonne National Laboratory. The radial component of defect fluxes generated by a highly-focused 900-keV electron beam was used to induce segregation of Al atoms towards the center of the electron irradiated area via the inverse-Kirkendall effect. The radial segregation rate was monitored by measuring the increase in the diameter of the Al enriched zone within which γ'-νi3αl precipitates form during irradiation. Both dual electron-ion and pre-implanted ion-electron irradiations were performed in an attempt to separate the contributions of energetic displacement cascades and implanted ions acting as defect trapping sites to RIS suppression. It was found that 75-keV Ne implantation has a retarding effect on RIS.

The formation and recrystallization of amorphous zones produced in GaAS by ion irradiation

1988 ◽  
Vol 46 ◽  
pp. 460-461
Author(s):  
M. W. Bench ◽  
I. M. Robertson ◽  
M. A. Kirk
Keyword(s):  
Ion Irradiation ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Heavy Ion ◽  
Accelerator Facility ◽  
Voltage Electron ◽  
Transmission Electron ◽  
Ion Accelerator ◽  
Lattice Damage ◽  
Insight Into

Transmission electron microscopy experiments have been performed to investigate the lattice damage created by heavy-ion bombardments in GaAs. These experiments were undertaken to provide additional insight into the mechanisms by which individual amorphous zones and eventually amorphous layers are created. To understand these mechanisms, the structure of the defects created as a function of material, irradiating ion, dose, dose rate, and implantation tenperature have been studied using TEM. Also, the recovery of the crystalline structure by annealing has been investigated.These experiments were performed at the High-Voltage Electron Microscope - Ion Accelerator Facility at Argonne National Laboratory. This facility consists of an HVEM which has been interfaced with two ion accelerators. This coupling, plus the availability of several specimen stages permits ion irradiations to be performed in the specimen chamber of the microscope at controlled temperatures from 10 to 1000 K.

scholarly journals In-situ investigation of ion-implantation effects on radiation-induced segregation in Ni-Al alloys

1996 ◽  
Vol 54 ◽  
pp. 988-989
Author(s):  
M.J. Giacobbe ◽  
N.Q. Lam ◽  
P.R. Okamoto ◽  
N.J. Zaluzec ◽  
J.F. Stubbins
Keyword(s):  
Electron Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Beam Diameter ◽  
Total Electron ◽  
Radial Segregation ◽  
In Situ Investigation ◽  
In Situ Experiments ◽  
Radiation Induced

In-situ experiments using the HVEM (high voltage electron microscope)/Tandem accelerator facility at Argonne National Laboratory were performed to determine the effects of 400-keV Zr+ and 75-keV Ne+ implantation on electron radiation-induced segregation (RIS) in Ni-9at.%Al at 550°C and 450°C, respectively. The alteration of RIS kinetics by Ne implantation was studied at two different doses. A highly-focused 900-keV electron beam, which produces a radial defect flux away from the beam center, was used to induce segregation of Al atoms in the opposite direction via the inverse-Kirkendall effect. Within the irradiated zone, Al enrichment drives the formation of γ′-Ni3Al precipitates, and the radial segregation rate of Al was monitored by measuring the growth of the precipitate zone.When a thin film is subject to a focused, electron beam, a non uniform defect distribution is produced. The effective beam diameter, D∘, is defined by IT= I∘ (πD∘/2)2 where IT is the total electron current and I∘ is the peak electron flux.

Effects of krypton ion irradiation on the structure and morphology of germanium — An in situ TEM study

1990 ◽  
Vol 48 (4) ◽  
pp. 536-537
Author(s):  
L.M. Wang ◽  
R.C. Birtcher
Keyword(s):  
Ion Irradiation ◽  
Morphological Changes ◽  
Amorphous Material ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
In Situ Tem ◽  
Tandem Accelerator ◽  
Accelerator Facility ◽  
Voltage Electron

Although it was initially thought that irradiation could not further damage an amorphous material, an anomalous ion-induced morphological instability on the surface of amorphous Ge has been reported previously by several authors. In this study, the structural and morphological changes of Ge were monitored during 1.5 MeV Kr ion irradiation by in situ TEM to obtain insight into the damage evolution in ion-irradiated Ge.The in situ study was performed on the HVEM-Tandem Accelerator Facility at Argonne National Laboratory. The facility consists of a modified Kratos/AEI EM7 high voltage electron microscope (HVEM) and a 2 MV tandem ion accelerator. The samples were jet-polished polycrystalline Ge (99.99999 at. % pure) TEM discs with grain size > 5 μm in dimension. The Kr ion irradiation was carried out at room temperature, and the electron energy of the HVEM was 300 kV. According to a TRIM computer simulation, over 99% of the Kr ions penetrate through the electron transparent areas of the Ge sample, and a dose of 1×1015 Kr/cm2 created an average of ∽4 displacements per atom and an average Kr concentration of ∽12 appm in the observation region of the sample.

scholarly journals Radiation-induced decomposition of U(VI) alteration phases of UO2

2006 ◽  
Vol 932 ◽  
Author(s):  
Satoshi Utsunomiya ◽  
Rodney C. Ewing
Keyword(s):  
Spent Nuclear Fuel ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Voltage Electron ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Radiation Induced ◽  
The Stability ◽  
Induced Decomposition

ABSTRACTU6+−phases are common alteration products of spent nuclear fuel under oxidizing conditions, and they may potentially incorporate actinides, such as long-lived 239Pu and 237Np, delaying their transport to the biosphere. In order to evaluate the ballistic effects of α-decay events on the stability of the U6+−phases, we report, for the first time, the results of ion beam irradiations (1.0 MeV Kr2+) for six different structures of U6+-phases: uranophane, kasolite, boltwoodite, saleeite, carnotite, and liebigite. The target uranyl-minerals were characterized by powder X-ray diffraction and identification confirmed by SAED (selected area electron diffraction) in TEM (transmission electron microscopy). The TEM observation revealed no initial contamination of uraninite in these U6+ phases. All of the samples were irradiated with in situ TEM observation using 1.0 MeV Kr2+ in the IVEM (intermediate-voltage electron microscope) at the IVEM-Tandem Facility of Argonne National Laboratory. The ion flux was 6.3 × 1011 ions/cm2/sec. The specimen temperatures during irradiation were 298 and 673 K, respectively. The Kr2+-irradiation decomposed the U6+-phases to nanocrystals of UO2 at doses as low as 0.006 dpa. The cumulative doses for the pure U6+-phases, e.g., uranophane, at 0.1 and 1 million years (m.y.) are calculated to be 0.009 and 0.09 dpa using SRIM2003. However, with the incorporation of 1 wt.% 239Pu, the calculated doses reach 0.27 and ∼1.00 dpa in ten thousand and one hundred thousand years, respectively.Under oxidizing conditions, multiple cycles of radiation-induced decomposition to UO2 followed by alteration to U6+-phases should be further investigated to determine the fate of trace elements that may have been incorporated in the U6+-phases.

scholarly journals In Situ TEM Observations of Heavy Ion Damage in Gallium Arsenide

1988 ◽  
Vol 100 ◽  
Author(s):  
M. W. Bench ◽  
I. M. Robertson ◽  
M. A. Kirk
Keyword(s):  
Low Temperature ◽  
Room Temperature ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Heavy Ion ◽  
In Situ Tem ◽  
Accelerator Facility ◽  
Transmission Electron ◽  
Ion Accelerator

ABSTRACTTransmission electron microscopy experiments have been performed to investigate the lattice damage created by heavy-ion bombardments in GaAs. These experiments have been performed in situ by using the HVEN - Ion Accelerator Facility at Argonne National Laboratory. The ion bcorbardments (50 keV Ar+ and Kr+) and the microscopy have been carried out at temperatures rangrin from 30 to 300 K. Ion fluences ranged from 2 × 1011 to 5 × 1013 ions cm−2.Direct-inpact amorphization is observed to occur in both n-type and semi-insulating GaAs irradiated to low ion doses at 30 K and room temperature. The probability of forming a visible defect is higher for low temperature irradiations than for room temperature irradiations. The amorphous zones formed at low temperature are stable to temperatures above 250 K. Post implantation annealing is seen to occur at room temperature for all samples irradiated to low doses until eventually all visible damage disappears.

In Situ Radiation Damage Studies of Ca3Zr2FeAlSiO12 and Ca3Hf2FeAlSiO12

2008 ◽  
Vol 1124 ◽  
Author(s):  
Karl R Whittle ◽  
Mark Blackford ◽  
Gregory R Lumpkin ◽  
Katherine L Smith ◽  
Nestor J Zaluzec
Keyword(s):  
Nuclear Waste ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Voltage Electron ◽  
Significant Difference ◽  
User Facility ◽  
High Level Nuclear Waste ◽  
Nuclear Waste Immobilization ◽  
High Level

AbstractGarnets, A3B2C3O12, are considered to be potential host phases for the immobilization of high-level nuclear waste as they can accommodate a number of elements of interest, including Zr, Ti and Fe. The naturally occurring garnet, kimzeyite, Ca3(Zr,Ti)2(Si,Al,Fe)3O12, can contain ˜30wt% Zr. An understanding of the radiation tolerance of these materials is crucial to their potential use in nuclear waste immobilization. In this study two synthetic analogues of kimzeyite of composition Ca3Zr2FeAlSiO12 and Ca3Hf2FeAlSiO12 were monitored in situ during irradiation with 1.0 MeV Kr ions using the intermediate voltage electron microscope-Tandem User Facility (IVEM) at Argonne National Laboratory. The structure of these materials was previously determined by neutron diffraction and 57Fe Mössbauer spectroscopy. Ca3Zr2FeAlSiO12 and Ca3Hf2FeAlSiO12 have very similar structural properties with cubic Ia3d symmetry, the only significant difference being the presence of Zr and Hf, respectively, on the 6 coordinated B sites.

scholarly journals Ion-Beam Mixing and Solid-State Reaction in Zr-Fe Multilayers

1996 ◽  
Vol 439 ◽  
Author(s):  
A. Paesano ◽  
A. T. Motta ◽  
R. C. Birtcher ◽  
E. A. Ryan ◽  
S. R. Teixeira ◽  
...  
Keyword(s):  
Solid State ◽  
Amorphous Phase ◽  
Solid State Reaction ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Reaction Products ◽  
Phase Selection ◽  
Voltage Electron ◽  
Multilayered Thin Films

AbstractVapor-deposited Zr-Fe multilayered thin films with various wavelengths and of overall composition either 50% Fe or Fe-rich up to 57 % Fe were either irradiated with 300 keV Kr ions at temperatures from 25K to 623 K to fluences up to 2 × 1016 cm−2, or simply annealed at 773K in-situ in the Intermediate Voltage Electron Microscope at Argonne National Laboratory. Under irradiation, the final reaction product is the amorphous phase in all cases studied, but the dose to amorphization depends on the temperature and on the wavelength. In the purely thermal case (annealing at 773 K), the 50–50 composition produces the amorphous phase but for the Fe-rich multilayers the reaction products depend on the multilayer wavelength. For small wavelength, the amorphous phase is still formed, but at large wavelength the Zr-Fe crystalline intermetallic compounds appear. These results are discussed in terms of existing models of irradiation kinetics and phase selection during solid state reaction.

Ion Beam Irradiation of Lanthanum Compounds in the Series La2O3-TiO2

2010 ◽  
Vol 1265 ◽  
Author(s):  
Karl Whittle ◽  
Mark Blackford ◽  
Robert Aughterson ◽  
Katherine L Smith ◽  
Gregory R Lumpkin ◽  
...  
Keyword(s):  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Inverse Correlation ◽  
Critical Temperatures ◽  
Voltage Electron ◽  
Local Environments ◽  
Two Systems ◽  
User Facility

AbstractThin crystals of La2O3, La2/3TiO3, La2TiO5, and La2Ti2O7 have been irradiated in situ using 1 MeV Kr2+ ions in the Intermediate Voltage Electron Microscope-Tandem User Facility (IVEM-Tandem), at the Argonne National Laboratory (ANL). We observed that La2O3 remained crystalline to a fluence greater than 3.1 × 1016 ions cm-2 at a temperature of 50 K. The four binary oxide compounds in the two systems were observed through the crystalline-amorphous transition as a function of ion fluence and temperature. Results from the ion irradiations give critical temperatures for amorphisation (Tc) of 840 K for La2Ti2O7, 865 K for La2/3TiO3, and 1027 K for La2TiO5. The Tc values observed in this study, together with previous data for TiO2, are discussed with reference to the phase diagrams for La2O3-TiO2 systems and the different local environments within the crystal structures. Results suggest an observable inverse correlation between Tc and melting temperature (Tm) in the two systems.

Sign in / Sign up

Export Citation Format

Share Document