scholarly journals Effects of the Surface on Displacement Cascades Produced by Heavy-Ion Irradiation of Ni3Al and Cu3Au

1996 ◽  
Vol 439 ◽  
Author(s):  
S. Müller ◽  
M. L. Jenkins ◽  
C. Abromeit ◽  
H. Wollenberger
Keyword(s):  
Ion Irradiation ◽  
Incident Angle ◽  
Ion Beam ◽  
Heavy Ion ◽  
Small Population ◽  
Dislocation Loops ◽  
Near Surface ◽  
Ion Energy ◽  
Heavy Ion Irradiation ◽  
Transmission Electron

AbstractStereo transmission electron microscopy has been used to characterise the distribution in depth of disordered zones and associated dislocation loops in the ordered alloys Ni3Al and Cu3Au after heavy ion irradiation, most extensively for Ni3Al irradiated with 50 keV Ta+ ions at a temperature of 573 K. The Cu3Au specimen was irradiated with 50 keV Ni+ ions at an incident angle of 45° at a temperature of 373 K. In Ni3Al the defect yield, i.e. the probability for a disordered zone to contain a loop was found to be strongly dependent on the depth of the zone in the foil, varying from about 0.7 for near-surface zones to about 0.2 in the bulk. The sizes and shapes of disordered zones were only weakly dependent on depth, except for a small population of zones very near the surface which were strongly elongated parallel to the incident ion beam. In Cu3Au the surface had a smaller but still significant effect on the defect yield. The dependence of the tranverse disordered zone diameter d on ion energy E for Ta+ irradiation of NiA was found to follow a relationship d = k1, E1/α with k, = 2.4 ± 0.4 and α = 3.3 ± 0.4. A similar relationship with the same value of α is valid for a wide variety of incident ion/target combinations found in the literature.

Phase Transitions During Ion-Beam Irradiation of the Perovskite-structure Oxides

1997 ◽  
Vol 481 ◽  
Author(s):  
A. Meldrum ◽  
L. A. Boatner ◽  
R. C. Ewingt
Keyword(s):  
Perovskite Structure ◽  
Low Dose ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Heavy Ion ◽  
Dislocation Loops ◽  
Ion Beam Irradiation ◽  
Melting Temperatures ◽  
Heavy Ion Irradiation ◽  
Domain Boundaries

ABSTRACTSeveral perovskite-structure oxide compounds, including CaTiO3, SrTiO3, BaTiO3, KNbO3, and KTaO3 were irradiated by 800 keV Kr+ ions in order to investigate and compare their response to heavy-ion irradiation. The critical amorphization temperature Tc, above which amorphization could not be induced, was found to increase in the order SrTiO3 → CaTiO3 → BaTiO3 → KNbO3 → KTaO3. No single physical parameter explains the observed sequence, although Tc correlates well with the melting temperatures. The well-known solid state phase transformations in these materials did not have a significant effect on the dose required for amorphization. Domain boundaries were observed in the pristine samples; however, after only a low dose, the boundaries became poorly defined and, with increasing dose, eventually disappeared. Dislocation loops were observed to aggregate at the domain boundaries.

Ion beam-mixing effects in nearly lattice-matched AlInN/GaN heterostructures by swift heavy ion irradiation

2012 ◽  
Vol 167 (7) ◽  
pp. 506-511 ◽  
Author(s):  
G. Devaraju ◽  
S. V.S. Nageswara Rao ◽  
N. Srinivasa Rao ◽  
V. Saikiran ◽  
T. K. Chan ◽  
...  
Keyword(s):  
Ion Irradiation ◽  
Ion Beam ◽  
Heavy Ion ◽  
Ion Beam Mixing ◽  
Swift Heavy Ion Irradiation ◽  
Heavy Ion Irradiation ◽  
Mixing Effects ◽  
Swift Heavy Ion ◽  
Lattice Matched

Amortization and Recrystallization of 6H-SiC by ion Beam Irradiation

1994 ◽  
Vol 339 ◽  
Author(s):  
V. Heera ◽  
R. Kögler ◽  
W. Skorupa ◽  
J. Stoemenos
Keyword(s):  
Ion Irradiation ◽  
Ion Beam ◽  
Surface Region ◽  
Ion Beam Irradiation ◽  
Surface Layers ◽  
Near Surface ◽  
Transmission Electron ◽  
Amorphous Surface ◽  
Amorphous Sic

ABSTRACTThe evolution of the damage in the near surface region of single crystalline 6H-SiC generated by 200 keV Ge+ ion implantation at room temperature (RT) was investigated by Rutherford backscattering spectroscopy/chanelling (RBS/C). The threshold dose for amorphization was found to be about 3 · 1014 cm-2, Amorphous surface layers produced with Ge+ ion doses above the threshold were partly annealed by 300 keV Si+ ion beam induced epitaxial crystallization (IBIEC) at a relatively low temperature of 480°C For comparison, temperatures of at least 1450°C are necessary to recrystallize amorphous SiC layers without assisting ion irradiation. The structure and quality of both the amorphous and recrystallized layers were characterized by cross-section transmission electron microscopy (XTEM). Density changes of SiC due to amorphization were measured by step height measurements.

scholarly journals Microstructure Evolution in ZrCx with Different Stoichiometries Irradiated by Four MeV Au Ions

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3768
Author(s):  
Boxin Wei ◽  
Dong Wang ◽  
Yujin Wang ◽  
Haibin Zhang
Keyword(s):  
Radiation Damage ◽  
Microstructure Evolution ◽  
Vacancy Concentration ◽  
Ion Beam ◽  
Grazing Incidence ◽  
Dislocation Loops ◽  
Black Dot ◽  
X Ray Diffraction ◽  
Near Surface ◽  
Transmission Electron

ZrCx ceramics with different stoichiometries were irradiated under a four MeV Au ion beam in doses of 2 × 1016 ions/cm2 at room temperature, corresponding to ~130 dpa. Grazing incidence, X-ray diffraction and transmission electron microscopy were performed to study the radiation damage and microstructure evolution in ZrCx ceramics. With the decrease in C/Zr ratio, the expansion of ZrCx lattice became smaller after irradiation. Some long dislocation lines formed at the near-surface, while, in the area with the greatest damage (depth of ~400 nm), large amounts of dislocation loops formed in ZrC, ZrC0.9 and ZrC0.8. With the increase in carbon vacancy concentration, the size of the dislocation loops gradually decreased. Few dislocation loops were found in ZrC0.7 after irradiation, and only black-dot defects were found in the area with the greatest damage. For the non-stoichiometric ZrCx, with the increase of the intrinsic vacancies, the number of C interstitials caused by irradiation decreased, and the recombination barrier of C Frenkel pairs reduced. The above factors will reduce the total number of C interstitials after cascade cooling, suppressing the formation and growth of dislocation loops, which is significant for the enhancement of the tolerance of radiation damage.

scholarly journals Significance of Heavy-Ion Beam Irradiation-Induced Avermectin B1a Production by EngineeredStreptomyces avermitilis

2017 ◽  
Vol 2017 ◽  
pp. 1-13
Author(s):  
Shu-Yang Wang ◽  
Yong-Heng Bo ◽  
Xiang Zhou ◽  
Ji-Hong Chen ◽  
Wen-Jian Li ◽  
...  
Keyword(s):  
Ion Irradiation ◽  
Ion Beam ◽  
Heavy Ion ◽  
Streptomyces Avermitilis ◽  
Specific Productivity ◽  
Original Strain ◽  
Beam Irradiation ◽  
Ion Beam Irradiation ◽  
Heavy Ion Irradiation ◽  
Heavy Ion Beam

Heavy-ion irradiation technology has advantages over traditional methods of mutagenesis. Heavy-ion irradiation improves the mutation rate, broadens the mutation spectrum, and shortens the breeding cycle. However, few data are currently available regarding its effect onStreptomyces avermitilismorphology and productivity. In this study, the influence of heavy-ion irradiation onS. avermitiliswhen cultivated in approximately 10 L stirred-tank bioreactors was investigated. The specific productivity of the avermectin (AVM) B1a-producing mutantS. avermitilis147-G58 increased notably, from 3885 to 5446 μg/mL, approximately 1.6-fold, compared to the original strain. The mycelial morphology of the mutant fermentation processes was microscopically examined. Additionally, protein and metabolite identification was performed by using SDS-PAGE, 2- and 3-dimensional electrophoresis (2DE and 3DE). The results showed that negative regulation gene deletion of mutants led to metabolic process upregulating expression of protein and improving the productivity of an avermectin B1a. The results showed that the heavy-ion beam irradiation dose that corresponded to optimal production was well over the standard dose, at approximately 80 Gy at 220 AMeV (depending on the strain). This study provides reliable data and a feasible method for increasing AVM productivity in industrial processes.

Radiation Effects in Nonmetals: Amorphization, Phase Decomposition, and Nanoparticles

1998 ◽  
Vol 540 ◽  
Author(s):  
A. Meldrum ◽  
L.A. Boatner ◽  
C.W. White ◽  
D.O. Henderson
Keyword(s):  
Ion Implantation ◽  
Electron Irradiation ◽  
Radiation Effects ◽  
Elevated Temperatures ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Semiconductor Nanocrystals ◽  
Heavy Ion ◽  
Fused Silica ◽  
Near Surface

AbstractRadiation effects in nonmetals have been studied for well over a century by geologists, mineralogists, physicists, and materials scientists. The present work focuses on recent results of investigations of the ion-beam-induced amorphization of the ABO4 compounds – including the orthophosphates (LnPO4; Ln = lanthanides) and the orthosilicates: zircon (ZrSiO4), hafnon (HfSiO4), and thorite (ThSiO4). In the case of the orthosilicates, heavy-ion irradiation at elevated temperatures causes the precipitation of a nanocrystalline metal oxide. Electron irradiation effects in these amorphized insulating ceramics can produce localized recrystallization on a nanometer scale. Similar electron irradiation techniques were used to nucleate monodispersed compound semiconductor nanocrystals formed by ion implantation of the elemental components into fused silica. Methods for the formation of novel structural relationships between embedded nanocrystals and their hosts have been developed and the results presented here demonstrate the general flexibility of ion implantation and irradiation techniques for producing unique near-surface microstructures in ion-implanted host materials.

Effect of Cascade Remnants on Freely Migrating Defects in Cu -1 % Au Alloys

1995 ◽  
Vol 396 ◽  
Author(s):  
A. Iwase ◽  
L. E. Rehn ◽  
P. M. Baldo ◽  
L. Funk
Keyword(s):  
Heavy Ions ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Heavy Ion ◽  
The Other ◽  
Inert Gas ◽  
Heavy Ion Irradiation ◽  
Simultaneous Irradiation ◽  
Radiation Induced ◽  
Cu Ions

AbstractThe effects of cascade remnants on Freely Migrating Defects (FMD) were studied by measuring Radiation-Induced Segregation (RIS) in Cu-l%Au at 400°C during simultaneous irradiation with 1.5-MeV He and (400-800)-keV heavy ions (Ne, Ar or Cu). The large RIS observed during 1.5-MeV He-only irradiation was dramatically suppressed under simultaneous heavy ion irradiation. For Cu simultaneous irradiation, the suppression disappeared immediately after the Cu irradiation ceased, while for simultaneous inert gas (Ne or Ar) irradiation, the suppression persisted after the ion beam was turned off. These results demonstrate that the displacement cascades created by heavy ions introduce additional annihilation sites, which reduce the steady-state FMD concentrations. As the cascade remnants produced by Cu ions are thermally unstable at 400°C, the RIS suppression occurs only during simultaneous irradiation. On the other hand, the inert gas atoms which accumulate in the specimen apparently stabilize the cascade remnants, allowing the suppression to persist.

Ion beam mixing of ZnO/SiO2 and Sb/Ni/Si interfaces under swift heavy ion irradiation

2002 ◽  
Vol 91 (3) ◽  
pp. 1129-1134 ◽  
Author(s):  
Saskia Kraft ◽  
Beate Schattat ◽  
Wolfgang Bolse ◽  
Siegfried Klaumünzer ◽  
Felix Harbsmeier ◽  
...  
Keyword(s):  
Ion Irradiation ◽  
Ion Beam ◽  
Heavy Ion ◽  
Ion Beam Mixing ◽  
Swift Heavy Ion Irradiation ◽  
Heavy Ion Irradiation ◽  
Swift Heavy Ion

scholarly journals Heavy ion irradiation induced dislocation loops in AREVA’s M5® alloy

2012 ◽  
Vol 423 (1-3) ◽  
pp. 170-182 ◽  
Author(s):  
R.M. Hengstler-Eger ◽  
P. Baldo ◽  
L. Beck ◽  
J. Dorner ◽  
K. Ertl ◽  
...  
Keyword(s):  
Ion Irradiation ◽  
Heavy Ion ◽  
Dislocation Loops ◽  
Heavy Ion Irradiation ◽  
Induced Dislocation
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