The Experts below are selected from a list of 6183 Experts worldwide ranked by ideXlab platform
Peter Hodgson - One of the best experts on this subject based on the ideXlab platform.
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hydroxyapatite titania sol gel coatings on titanium Zirconium Alloy for biomedical applications
Acta Biomaterialia, 2007Co-Authors: Cuie Wen, Peter HodgsonAbstract:A simple sol–gel method was developed for hydroxyapatite/titania (HA/TiO2) coatings on non-toxic titanium–Zirconium (TiZr) Alloy for biomedical applications. The HA/TiO2-coated TiZr Alloy displayed excellent bioactivity when soaked in a simulated body fluid (SBF) for an appropriate period. Differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction and scanning electron microscopy-energy dispersive spectrometry were used to characterize the phase transformations and the surface structures and to assess the in vitro tests. The HA/TiO2 layers were spin-coated on the surface of TiZr Alloy at a speed of 3000 rpm for 15 s, followed by a heat treatment at 600 °C for 20 min in an argon atmosphere sequentially. The TiO2 layer exhibited a cracked surface and an anatase structure and the HA layer displayed a uniform dense structure. Both the TiO2 and HA layers were 25 μm thick, and the total thickness of the HA/TiO2 coatings was 50 μm. The TiZr Alloy after the above HA/TiO2 coatings displayed excellent bone-like apatite-forming ability when soaked in SBF and can be anticipated to be a promising load-bearing implant material.
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hydroxyapatite titania sol gel coatings on titanium Zirconium Alloy for biomedical applications
Acta Biomaterialia, 2007Co-Authors: Cuie Wen, Peter HodgsonAbstract:A simple sol-gel method was developed for hydroxyapatite/titania (HA/TiO(2)) coatings on non-toxic titanium-Zirconium (TiZr) Alloy for biomedical applications. The HA/TiO(2)-coated TiZr Alloy displayed excellent bioactivity when soaked in a simulated body fluid (SBF) for an appropriate period. Differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction and scanning electron microscopy-energy dispersive spectrometry were used to characterize the phase transformations and the surface structures and to assess the in vitro tests. The HA/TiO(2) layers were spin-coated on the surface of TiZr Alloy at a speed of 3000rpm for 15s, followed by a heat treatment at 600 degrees C for 20min in an argon atmosphere sequentially. The TiO(2) layer exhibited a cracked surface and an anatase structure and the HA layer displayed a uniform dense structure. Both the TiO(2) and HA layers were 25microm thick, and the total thickness of the HA/TiO(2) coatings was 50microm. The TiZr Alloy after the above HA/TiO(2) coatings displayed excellent bone-like apatite-forming ability when soaked in SBF and can be anticipated to be a promising load-bearing implant material.
Benjamin Maier - One of the best experts on this subject based on the ideXlab platform.
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unveiling damage mechanisms of chromium coated Zirconium based fuel claddings by coupling digital image correlation and acoustic emission
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2020Co-Authors: David C Roache, Jorie Walters, Javier Romero, Alex Jarama, Clifton H Bumgardner, Frederick M Heim, Benjamin MaierAbstract:Abstract Coated nuclear fuel claddings offer a promising, near-term solution to address the demand for next-generation, accident-tolerant fuel systems. It is expected that they will possess superior mechanical properties and greater oxidation resistance compared to current cladding technology, allowing for improved performance during beyond design-basis accident conditions. Here, we present a methodology to determine the failure mechanisms of chromium-coated Zirconium-Alloy claddings under expected, critical loading conditions. Three-dimensional digital image correlation and acoustic emission techniques were used in situ to monitor spatial strain and crack development of the claddings under two key, de-coupled loading conditions: expanding plug and four-point bending. Critical strain levels, at which cracking initiated, were determined to be 0.4% ehoop and 0.4% exx for expanding plug and four-point bending, respectively. A two-dimensional fracture model was also developed for the expanding plug loading condition based on inputs determined from mechanical testing. It was concluded that coating fracture of expanding plug specimens was axisymmetric across the specimen circumference and occurred rapidly through the thickness of the chromium coating. Subsequent high temperature steam oxidation experiments on tested (cracked) expanding plug specimens showed no signs of oxidation degradation to the underlying Zirconium Alloy, thereby showcasing the effectiveness of the chromium coating. This comprehensive, multi-scale study is intended to inform future testing of next-generation, coated claddings and identify the resulting failure mechanisms that arise in beyond design basis accident conditions.
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development of cold spray chromium coatings for improved accident tolerant Zirconium Alloy cladding
Journal of Nuclear Materials, 2019Co-Authors: Benjamin Maier, Hwasung Yeom, Greg Johnson, Tyler Dabney, Jorie Walters, Javier Romero, Hemant Shah, Kumar SridharanAbstract:Abstract The development of a cold spray process for the deposition of chromium (Cr) coatings on Zirconium-Alloys is presented with the goal of improving the accident tolerance of light water reactor (LWR) fuel cladding tubes. The cold spray parameters and feedstock powders were varied to attain the desired coating properties such as thickness, microstructure, and oxidation resistance, on both Zircaloy-4 flat specimens and Optimized ZIRLO™ cladding tubes. The coated samples were tested at temperatures up to 1300 °C in air to investigate the oxidation performance and inter-diffusion between the Cr coatings and the underlying Zirconium-Alloy substrate. To simulate the performance of the coatings under normal LWR operating conditions, the coated samples were also tested in a steam autoclave at 400 °C and 10.3 MPa. Microstructures, phases, and hardnesses of the feedstock powders and as-deposited coatings were examined, and oxidation and inter-diffusion profiles were quantified in post-oxidation test samples. Overall, cold sprayed Cr coatings show significant promise for enhancing the accident tolerance of Zirconium-Alloy fuel cladding in LWRs both in terms of performance and cost-effective manufacturability.
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development of cold spray coatings for accident tolerant fuel cladding in light water reactors
JOM, 2018Co-Authors: Benjamin Maier, Hwasung Yeom, Greg Johnson, Tyler Dabney, Jorie Walters, Javier Romero, Hemant Shah, Kumar SridharanAbstract:The cold spray coating process has been developed at the University of Wisconsin-Madison for the deposition of oxidation-resistant coatings on Zirconium Alloy light water reactor fuel cladding with the goal of improving accident tolerance during loss of coolant scenarios. Coatings of metallic (Cr), Alloy (FeCrAl), and ceramic (Ti2AlC) materials were successfully deposited on Zirconium Alloy flats and cladding tube sections by optimizing the powder size, gas preheat temperature, pressure and composition, and other process parameters. The coatings were dense and exhibited excellent adhesion to the substrate. Evaluation of the samples after high-temperature oxidation tests at temperatures up to 1300°C showed that the cold spray coatings significantly mitigate oxidation kinetics because of the formation of thin passive oxide layers on the surface. The results of the study indicate that the cold spray coating process is a viable near-term option for developing accident-tolerant Zirconium Alloy fuel cladding.
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magnetron sputter deposition of Zirconium silicide coating for mitigating high temperature oxidation of Zirconium Alloy
Surface & Coatings Technology, 2017Co-Authors: Hwasung Yeom, Peng Xu, Benjamin Maier, Robert D Mariani, Steven Fronek, Kumar SridharanAbstract:Abstract The air oxidation behavior of Zirconium-silicide coatings for three stoichiometries, namely, Zr2Si, ZrSi, and ZrSi2, at 700 °C has been investigated. These three coatings were deposited on a Zirconium-Alloy substrate using a magnetron sputter process at a low temperature. Argon gas pressure was observed to have a profound effect on the coating microstructure, with lower pressures favoring a denser and more protective microstructure. Coatings of ZrSi2 stoichiometry clearly showed superior oxidation resistance presumably due to the formation of a thin protective oxide layer, consisting of nanocrystalline SiO2 and ZrSiO4 in amorphous Zr-Si-O matrix. The thermal stability of the coatings was evaluated by annealing in an argon environment, and this also assisted in eliciting the effects of oxidation-induced inward Si migration. Thicker coatings of ZrSi2 were prepared and evaluated for oxidation resistance at 700 °C for longer exposure times, as well as at 1000 °C and 1200 °C. Once again the thin oxide layer provided for significant oxidation resistance. Pre-oxidizing the samples at 700 °C prior to 1000 °C and 1200 °C oxidation tests substantially reduced the extent of oxidation. Insights into the fundamental mechanisms of the oxidation behavior of Zirconium-silicide coatings were obtained using a combination of scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy techniques. One potential application of these coatings is to enhance the oxidation resistance of Zirconium-Alloy fuel cladding in light water reactors under normal and accident conditions.
Cuie Wen - One of the best experts on this subject based on the ideXlab platform.
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hydroxyapatite titania sol gel coatings on titanium Zirconium Alloy for biomedical applications
Acta Biomaterialia, 2007Co-Authors: Cuie Wen, Peter HodgsonAbstract:A simple sol–gel method was developed for hydroxyapatite/titania (HA/TiO2) coatings on non-toxic titanium–Zirconium (TiZr) Alloy for biomedical applications. The HA/TiO2-coated TiZr Alloy displayed excellent bioactivity when soaked in a simulated body fluid (SBF) for an appropriate period. Differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction and scanning electron microscopy-energy dispersive spectrometry were used to characterize the phase transformations and the surface structures and to assess the in vitro tests. The HA/TiO2 layers were spin-coated on the surface of TiZr Alloy at a speed of 3000 rpm for 15 s, followed by a heat treatment at 600 °C for 20 min in an argon atmosphere sequentially. The TiO2 layer exhibited a cracked surface and an anatase structure and the HA layer displayed a uniform dense structure. Both the TiO2 and HA layers were 25 μm thick, and the total thickness of the HA/TiO2 coatings was 50 μm. The TiZr Alloy after the above HA/TiO2 coatings displayed excellent bone-like apatite-forming ability when soaked in SBF and can be anticipated to be a promising load-bearing implant material.
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hydroxyapatite titania sol gel coatings on titanium Zirconium Alloy for biomedical applications
Acta Biomaterialia, 2007Co-Authors: Cuie Wen, Peter HodgsonAbstract:A simple sol-gel method was developed for hydroxyapatite/titania (HA/TiO(2)) coatings on non-toxic titanium-Zirconium (TiZr) Alloy for biomedical applications. The HA/TiO(2)-coated TiZr Alloy displayed excellent bioactivity when soaked in a simulated body fluid (SBF) for an appropriate period. Differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction and scanning electron microscopy-energy dispersive spectrometry were used to characterize the phase transformations and the surface structures and to assess the in vitro tests. The HA/TiO(2) layers were spin-coated on the surface of TiZr Alloy at a speed of 3000rpm for 15s, followed by a heat treatment at 600 degrees C for 20min in an argon atmosphere sequentially. The TiO(2) layer exhibited a cracked surface and an anatase structure and the HA layer displayed a uniform dense structure. Both the TiO(2) and HA layers were 25microm thick, and the total thickness of the HA/TiO(2) coatings was 50microm. The TiZr Alloy after the above HA/TiO(2) coatings displayed excellent bone-like apatite-forming ability when soaked in SBF and can be anticipated to be a promising load-bearing implant material.
M R Daymond - One of the best experts on this subject based on the ideXlab platform.
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effect of temperature and loading sense on deformation induced phase transformation in a high sn content Zirconium Alloy
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2019Co-Authors: Chris Cochrane, M R DaymondAbstract:Abstract The activation of a phase transformation during plastic deformation of the Zirconium Alloy, Excel (Zr-3.5Sn-0.8Mo-0.8Nb), has been investigated using a combination of in situ neutron diffraction and electron microscopy. The effect of temperature and tension/compression asymmetry on the activation of the phase transformation is identified. While the phase transformation is readily activated in tension at room temperature and 100 °C, a significant drop in the transformation rate was observed at 200 °C. This temperature dependence appears to be independent of loading direction relative to material texture and depends on the specific crystallography and thermodynamics of the β → α transformation in Zirconium. Loading in compression did not result in the activation of the phase transformation.
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retention of metastable β phase in a two phase quaternary Zirconium Alloy
Materials & Design, 2018Co-Authors: C Cochrane, M R DaymondAbstract:Abstract This study investigates the retention of greater than equilibrium β phase in a two-phase Zirconium Alloy. We provide experimental data exploring two factors that impact the retention of β phase following heat treatment of a two-phase quaternary Zirconium Alloy, Zr-3.5Sn-0.8Mo-0.8Nb. Heat treatment temperature and quenching rate are varied to establish a criterion for metastable β phase retention and determine the excess free energy of the metastable phase as a function of solutionizing temperature. It is possible to retain a microstructure with up to 46 vol% β phase at room temperature in this Alloy, which has a stable room temperature β phase content of 8 vol%.
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phase transformation temperatures and solute redistribution in a quaternary Zirconium Alloy
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 2018Co-Authors: C Cochrane, M R DaymondAbstract:This study investigates the phase stability and redistribution of solute during heating and cooling of a quaternary Zirconium Alloy, Excel (Zr-3.2Sn-0.8Mo-0.8Nb). Time-of-flight neutron diffraction data are analyzed using a novel Vegard’s law-based approach to determine the phase fractions and location of substitutional solute atoms in situ during heating from room temperature up to 1050 °C. It is seen that this Alloy exhibits direct nucleation of the βZr phase from martensite during tempering, and stable retention of the βZr phase to high temperatures, unlike other two-phase Zirconium Alloys. The transformation strains resulting from the \(\alpha \leftrightarrow \beta \) transformation are shown to have a direct impact on the development of microstructure and crystallographic texture.
Rodolfo Bruniera Anchieta - One of the best experts on this subject based on the ideXlab platform.
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mechanical property assessment of bone healing around a titanium Zirconium Alloy dental implant
Clinical Implant Dentistry and Related Research, 2014Co-Authors: Rodolfo Bruniera Anchieta, Marta Aldassarri, Fernando P S Guastaldi, Nick Tova, Malvi N Janal, Ja Gottlow, Michel Dard, Ryo JimboAbstract:Background It has been reported that titanium–Zirconium Alloy with 13–17% Zirconium (TiZr1317) implants show higher biomechanical stability and bone area percentage relative to commercially pure titanium (cpTi) grade 4 fixtures. Purpose This study aimed to determine whether the higher stability for TiZr1317 implants is associated with higher mechanical properties of remodeling bone in the areas around the implants. Materials and Methods This study utilized 36 implants (n = 18: TiZr1317, n = 18: cpTi), which were placed in the healed ridges of the mandibular premolar and first molar of 12 mini pigs (n = 3 implants/animal). After 4 weeks in vivo, the samples were retrieved, and resin-embedded histologic sections of approximately 100 μm in thickness were prepared. In order to determine the nanomechanical properties, nanoindentation (n = 30 tests/specimen) was performed on the bone tissue of the sections under wet conditions with maximum load of 300 μN (loading rate: 60 μN/s). Results The mean (± standard deviation) elastic modulus (E) and hardness (H) for the TiZr1317 group were 2.73 ± 0.50 GPa and 0.116 ± 0.017 GPa, respectively. For the cpTi group, values were 2.68 ± 0.51 GPa and 0.110 ± 0.017 GPa for E and H, respectively. Although slightly higher mechanical properties values were observed for the TiZr1317 implants relative to the cpTi for both elastic modulus and hardness, these differences were not significant (E = p > 0.75; H = p > 0.59). Conclusions The titanium–Zirconium Alloy used in this study presented similar degrees of nanomechanical properties to that of the cpTi implants.
