| People | Locations | Statistics |
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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Swadener, John G.
Aston University
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (20/20 displayed)
- 2022Experimental testing of fracture fixation plates – A reviewcitations
- 2013Direct measurement of coherency limits for strain relaxation in heteroepitaxial core/shell nanowirescitations
- 2010Crystal orientation effects in scratch testing with a spherical indentercitations
- 2009Oxygen effects on irradiated tantalum alloyscitations
- 2009A micro-compression study of shape-memory deformation in U-13 at.% Nbcitations
- 2009Effect of microstructure upon elastic behaviour of human tooth enamelcitations
- 2008Characterization of oxide layers grown on D9 austenitic stainless steel in lead bismuth eutecticcitations
- 2008An exploratory study to determine applicability of nano-hardness and micro-compression measurements for yield stress estimationcitations
- 2008Influence of impact angles on penetration rates of CRAs exposed to a high velocity multiphase flow
- 2007Anomalies in stiffness and damping of a 2D discrete viscoelastic system due to negative stiffness componentscitations
- 2006Nanoindentation measurement of surface residual stresses in particle-reinforced metal matrix compositescitations
- 2006Mechanical properties and the evolution of matrix molecules in PTFE upon irradiation with MeV alpha particlescitations
- 2006Study on fatigue and energy-dissipation properties of nanolayered Cu/Nb thin filmscitations
- 2005Thermal stability of sputter-deposited 330 austenitic stainless-steel thin films with nanoscale growth twinscitations
- 2004Heavy ion irradiation effects in zirconium nitride
- 2003Increasing the fracture toughness of silicon by ion implantationcitations
- 2002Deformation microstructure under nanoindentations in Cu using 3D x-ray structural microscopycitations
- 2002Shear induced toughening in bonded jointscitations
- 2001Measurement of residual stress by load and depth sensing indentation with spherical indenterscitations
- 2000Experimental and simulated grain boundary groove profiles in tungstencitations
Places of action
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article
Mechanical properties and the evolution of matrix molecules in PTFE upon irradiation with MeV alpha particles
Abstract
<p>The morphology, chemical composition, and mechanical properties in the surface region of α-irradiated polytetrafluoroethylene (PTFE) have been examined and compared to unirradiated specimens. Samples were irradiated with 5.5 MeV<sup>4</sup>He<sup>2+</sup>ions from a tandem accelerator to doses between 1 × 10<sup>6</sup>and 5 × 10<sup>10</sup>Rad. Static time-of-flight secondary ion mass spectrometry (ToF-SIMS), using a 20 keV C<sub>60+</sub>source, was employed to probe chemical changes as a function of a dose. Chemical images and high resolution spectra were collected and analyzed to reveal the effects of a particle radiation on the chemical structure. Residual gas analysis (RGA) was utilized to monitor the evolution of volatile species during vacuum irradiation of the samples. Scanning electron microscopy (SEM) was used to observe the morphological variation of samples with increasing a particle dose, and nanoindentation was engaged to determine the hardness and elastic modulus as a function of a dose. <br/> The data show that PTFE nominally retains its innate chemical structure and morphology at a doses <10<sup>9</sup>Rad. At α doses ≥10<sup>9</sup> Rad the polymer matrix experiences increased chemical degradation and morphological roughening which are accompanied <br/> by increased hardness and declining elasticity. At α doses >10<sup>10</sup> Rad the polymer matrix suffers severe chemical degradation and material loss. Chemical degradation is observed in ToF-SIMS by detection of ions that are indicative of fragmentation, unsaturation, and functionalization of molecules in the PTFE matrix. The mass spectra also expose the subtle trends of crosslinking within the α-irradiated polymer matrix. ToF-SIMS images support the assertion that chemical degradation is the result of a particle irradiation and show morphological roughening of the sample with increased a dose. High resolution SEM images more clearly illustrate the morphological roughening and the mass loss that accompanies high doses of a particles. RGA confirms the supposition that the outcome of chemical degradation in the PTFE matrix with continuing irradiation is evolution of volatile species resulting in morphological roughening and mass loss. Finally, we reveal and discuss relationships between chemical structure and mechanical properties such as hardness and elastic modulus.</p>