scholarly journals PRODUCTION OF VOIDS IN PURE METALS BY HIGH ENERGY HEAVY ION BOMBARDMENT.

1971 ◽  
Author(s):  
G.L. Kulcinski ◽  
J.L. Brimhall ◽  
H.E. Kissinger
2012 ◽  
Vol 388 (13) ◽  
pp. 132014
Author(s):  
Jianrong Sun ◽  
Zhiguang Wang ◽  
Yuyu Wang ◽  
Cunfeng Yao ◽  
Kongfang Wei ◽  
...  

1984 ◽  
Vol 37 ◽  
Author(s):  
R. P. Livi ◽  
S. Paine ◽  
C. R. Wie ◽  
M. H. Mendenhall ◽  
J. Y. Tang ◽  
...  

AbstractThin gold films over GaAs wafers with different dopants (Cr, Si, Te, and Zn) were used to study the role of he substrate electronic properties in the electrical contact and adhesion modification induced by MeV/nucleon heavy ion bombardment. The enhanced adhesion was studied using a scratch test; the results show very different modifications of adhesion depending on the bulk electronic properties of the substrate. The sample with a Cr compensation doped substrate showed enhancement in adhesion for beam doses as low as 1012 ions/cm2, but Si and Te doped (n–type) substrates showed a sudden enhancement in adhesion for doses around 1014 ions/cm2. Samples with Si and Te doped substrates were used to sudy the bombarding ion dE/dx dependence of the induced adhesion for 19F and 35C1 ions with electronic stopping power ranging from 161 eV/Å to 506 eV/Å. In this range the dose threshold fgfjhe ops! of induced adhesion has a power law dependence, D = D0(dE/dx)− (1.90 ± 1.0)


Author(s):  
L.E. Murr

The production of void lattices in metals as a result of displacement damage associated with high energy and heavy ion bombardment is now well documented. More recently, Murr has shown that a void lattice can be developed in natural (colored) fluorites observed in the transmission electron microscope. These were the first observations of a void lattice in an irradiated nonmetal, and the first, direct observations of color-center aggregates. Clinard, et al. have also recently observed a void lattice (described as a high density of aligned "pores") in neutron irradiated Al2O3 and Y2O3. In this latter work, itwas pointed out that in order that a cavity be formed,a near-stoichiometric ratio of cation and anion vacancies must aggregate. It was reasoned that two other alternatives to explain the pores were cation metal colloids and highpressure anion gas bubbles.Evans has proposed that void lattices result from the presence of a pre-existing impurity lattice, and predicted that the formation of a void lattice should restrict swelling in irradiated materials because it represents a state of saturation.


Author(s):  
A. K. Rai ◽  
R. S. Bhattacharya ◽  
M. H. Rashid

Ion beam mixing has recently been found to be an effective method of producing amorphous alloys in the binary metal systems where the two original constituent metals are of different crystal structure. The mechanism of ion beam mixing are not well understood yet. Several mechanisms have been proposed to account for the observed mixing phenomena. The first mechanism is enhanced diffusion due to defects created by the incoming ions. Second is the cascade mixing mechanism for which the kinematicel collisional models exist in the literature. Third mechanism is thermal spikes. In the present work we have studied the mixing efficiency and ion beam induced amorphisation of Ni-Ti system under high energy ion bombardment and the results are compared with collisional models. We have employed plan and x-sectional veiw TEM and RBS techniques in the present work.


Author(s):  
Charles W. Allen ◽  
Robert C. Birtcher

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.


2000 ◽  
Vol 15 (15) ◽  
pp. 2269-2288
Author(s):  
SANATAN DIGAL ◽  
RAJARSHI RAY ◽  
SUPRATIM SENGUPTA ◽  
AJIT M. SRIVASTAVA

We demonstrate the possibility of forming a single, large domain of disoriented chiral condensate (DCC) in a heavy-ion collision. In our scenario, rapid initial heating of the parton system provides a driving force for the chiral field, moving it away from the true vacuum and forcing it to go to the opposite point on the vacuum manifold. This converts the entire hot region into a single DCC domain. Subsequent rolling down of the chiral field to its true vacuum will then lead to emission of a large number of (approximately) coherent pions. The requirement of suppression of thermal fluctuations to maintain the (approximate) coherence of such a large DCC domain, favors three-dimensional expansion of the plasma over the longitudinal expansion even at very early stages of evolution. This also constrains the maximum temperature of the system to lie within a window. We roughly estimate this window to be about 200–400 MeV. These results lead us to predict that extremely high energy collisions of very small nuclei (possibly hadrons) are better suited for observing signatures of a large DCC. Another possibility is to focus on peripheral collisions of heavy nuclei.


2003 ◽  
Vol 554 (1-2) ◽  
pp. 21-27 ◽  
Author(s):  
Alex Krasnitz ◽  
Yasushi Nara ◽  
Raju Venugopalan

1984 ◽  
Vol 71 (6) ◽  
pp. 1429-1431 ◽  
Author(s):  
Y. Kitazoe ◽  
O. Hashimoto ◽  
H. Toki ◽  
Y. Yamamura ◽  
M. Sano

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