Статті в журналах: "SiC components"

1

Rivera, Kevin, Tommy Muth, John Rhoat, Matt Ricci, and Otto J. Gregory. "Novel temperature sensors for SiC–SiC CMC engine components." Journal of Materials Research 32, no. 17 (June 9, 2017): 3319–25. http://dx.doi.org/10.1557/jmr.2017.216.

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Hijikata, Yasuto, Hiroyuki Yaguchi, Sadafumi Yoshida, Y. Takata, K. Kobayashi, S. Shin, H. Nohira, and Takeshi Hattori. "Characterization of Oxide Films on SiC Epitaxial (000-1) Faces by Angle-Resolved Photoemission Spectroscopy Measurements Using Synchrotron Radiation." Materials Science Forum 483-485 (May 2005): 585–88. http://dx.doi.org/10.4028/www.scientific.net/msf.483-485.585.

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Thermal oxide films on SiC epitaxial (000-1) C-faces have been characterized by angle-resolved photoemission spectroscopy (AR-PES). The structure of wet oxide/SiC C-face interface was compared with that of dry oxide/SiC C-face, as well as that of dry oxide/SiC Si-face, in order to clarify why a MOS device of SiC C-face achieved good electrical properties. The improvement in electrical properties was confirmed by AR-PES measurements, evidencing differences in binding energy between SiC and the Si4+ components in Si2p and valence band region, and in binding energy between SiC and the CHx components in C1s. The reason for the improvement in electrical property of MOS devices by use of SiC C-face are discussed in terms of depth profiles of oxide films calculated from the AR-PES results.

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3

Rivera, Kevin, and Otto J. Gregory. "Strain Gages for SiC–SiC Ceramic Matrix Composite Engine Components." IEEE Sensors Letters 2, no. 3 (September 2018): 1–4. http://dx.doi.org/10.1109/lsens.2018.2854828.

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4

Kreifeldt, Erik. "STRONG MARKET FORECAST FOR SIC COMPONENTS." Optics and Photonics News 7, no. 1 (January 1, 1996): 11. http://dx.doi.org/10.1364/opn.7.1.000011.

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5

David, Patrick, Joelle Blein, Yannick Pierre, Denis Rochais, and Maxime Zabiego. "New Textile Structures and Film-Boiling Densification for SiC/SiC Components." EPJ Web of Conferences 51 (2013): 01004. http://dx.doi.org/10.1051/epjconf/20135101004.

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6

Jin, Jie, and Shen Hao Wang. "Preparation of C/SiC Composites by SLA-Intergrated Liquid Silicon Infiltration Method." Advanced Materials Research 152-153 (October 2010): 1146–50. http://dx.doi.org/10.4028/www.scientific.net/amr.152-153.1146.

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Phenolic resin was used as the raw material, formed a mold for complex-shaped component by rapid-prototyping. It was composed of SiC, C and Si. The sample hardness was analyzed through statistical comparison. The phase composition of C/SiC composite was investigated by XRD and microstructures of C/SiC ceramic components were observed with scaning electron microscope. The ceramic components obtained at 1500 by reactive infiltration of Si into porous C-template. The porous structure formed by photecurable resin and starch powders pyrolysis could effectively prevent the C-template from cracking and reduce the stress. It also facilitate penetrating Si to the C-template to form SiC.

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7

Tian, Xiaoyong, and Dichen Li. "Rapid manufacture of net-shape SiC components." International Journal of Advanced Manufacturing Technology 46, no. 5-8 (May 30, 2009): 579–87. http://dx.doi.org/10.1007/s00170-009-2109-5.

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8

Yi, J., Xiao Dong He, and Chun Long Guan. "Influence of Liquid Evaporation on the Components of SiC High Emissivity Coating." Key Engineering Materials 434-435 (March 2010): 568–71. http://dx.doi.org/10.4028/www.scientific.net/kem.434-435.568.

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The process of Electron Beam-Physical Vapor Deposition (EB-PVD) preparing SiC coating with liquid evaporation was firstly discussed from a thermodynamic viewpoint. The results showed that the ratio of SiC in the as-deposited coating gradually increases and tends to reach a stable maximum of 0.73 with the evaporation temperature increase from 2500 K to 3400 K. To verify the thermodynamic analysis, amorphous SiC coating was deposited on Si substrate by EB-PVD at 3100 K. SiC concentration across the cross section of coating was calculated from the area of elements spectrum in X-ray photoelectron spectroscopy (XPS) depth profile analysis. The results showed that the average SiC concentration was about 0.7.

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9

He, Chun Lin, Jian Ming Wang, and Qing Kui Cai. "Effects of Particle Size and Volume Fraction on Extrusion Texture of SiC_p/Al Metal Matrix Composites." Advanced Materials Research 194-196 (February 2011): 1437–41. http://dx.doi.org/10.4028/www.scientific.net/amr.194-196.1437.

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The texture development was investigated in the extruded Al and Al metal matrix composites (MMCs) reinforced with SiC particles of different sizes and volume fractions. During extrusion, both the unreinforced Al and the MMCs develop a strong fiber texture with two components: <111> and <100>. When SiC is introduced into aluminum, the main component of texture is not modified, but the intensity of the component evolves with the volume fraction and average size of SiC particles. For the MMCs reinforced with 3.5μm SiC particles, the texture intensity of the Al matrix tends to decrease as the SiC volume fraction increases, and it is lower than that in the unreinforced Al. However, for the MMCs reinforced with 25 nm and 150 nm SiC particles, the texture intensity of the Al matrix is higher than that in the unreinforced matrix, and it increases with increasing the SiC volume fraction. It is found that superfine particles may introduce some new component into the deformation texture, and the texture intensity increases as the SiC particle size decreases.

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10

ALKAN, YELDA, BHARAT B. BISWAL, PAUL A. TAYLOR, and TARA L. ALVAREZ. "Segregation of frontoparietal and cerebellar components within saccade and vergence networks using hierarchical independent component analysis of fMRI." Visual Neuroscience 28, no. 3 (May 2011): 247–61. http://dx.doi.org/10.1017/s0952523811000125.

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AbstractPurpose: Cortical and subcortical functional activity stimulated via saccade and vergence eye movements were investigated to examine the similarities and differences between networks and regions of interest (ROIs). Methods: Blood oxygenation level-dependent (BOLD) signals from stimulus-induced functional Magnetic Resonance Imaging (MRI) experiments were analyzed studying 16 healthy subjects. Six types of oculomotor experiments were conducted using a block design to study both saccade and vergence circuits. The experiments included a simple eye movement task and a more cognitively demanding prediction task. A hierarchical independent component analysis (ICA) process began by analyzing individual subject data sets with spatial ICA to extract spatial independent components (sIC), which resulted in three ROIs. Using the time series from each of the three ROIs per subject, per oculomotor experiment, a temporal ICA was used to compute individual temporal independent components (tICs). For each of the three ROIs, the individual tICs from multiple subjects were entered into a second temporal ICA to compute group-level tICs for comparison. Results: Two independent spatial maps were observed for each subject (one sIC showing activity in the frontoparietal regions and another sIC in the cerebellum) during the six oculomotor tasks. Analysis of group-level tICs revealed an increased latency in the cerebellar region when compared to the frontoparietal region. Conclusion: Shared neuronal behavior has been reported in the frontal and parietal lobes, which may in part explain the segregation of frontoparietal functional activity into one sIC. The cerebellum uses multiple time scales for motor learning. This may result in an increased latency observed in the BOLD signal of the cerebellar group-level tIC when compared to the frontal and parietal group-level tICs. The increased latency offers a possible explanation to why ICA dissects the cerebellar activity into an sIC. The hierarchical ICA process used to calculate group-level tICs can yield insight into functional connectivity within complex neural networks.

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11

Seetala, Naidu V., and Marquavious T. Webb. "Spark Plasma Heat Treated ZrB₂-SiC and HfB₂-SiC Composites." Materials Science Forum 783-786 (May 2014): 1176–81. http://dx.doi.org/10.4028/www.scientific.net/msf.783-786.1176.

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Ultra-high-temperature ceramics (UHTC) such as ZrB2 and HfB2 with SiC nanofiller are useful for propulsion and thermal protection systems. ZrB2 and HfB2 with 10-20 wt% SiC were prepared using ultra-sonication, rotary evaporation, and spark plasma heat treatment to high temperatures (~2,000°C) and pressures (50-60 MPa). We used positron annihilation lifetime spectroscopy (PALS) to study the nanoporosity, SEM for particle size distribution, and microhardness tester for Vickers hardness. The PALS studies were performed using a 22Na positron source and the positron lifetime spectra were analyzed to three components using POSFIT program. The first and second components are related to positrons annihilating in bulk and in vacancy clusters, respectively; and the third component to positronium annihilation in nanopores within the granules. The PALS results indicate that HfB2 has larger vacancy clusters and nanopores with lesser concentrations compared to ZrB2 and SiC. The SEM observations showed that HfB2 has larger particles compared to ZrB2 and SiC showed wide range of size distribution. The Vickers-Hardness Number (VHN) is measured for spark plasma heat treated composites using a microhardness tester and the results indicate that 10wt%SiC composite has higher hardness compared to 20wt%SiC in both ZrB2-SiC and HfB2-SiC composites. HfB2-SiC composites seem to be more brittle compared to ZrB2-SiC composites. This may be due to larger size and smoother surface of HfB2 particles (600 nm) compared to ZrB2 particles (240 nm).

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12

Hancock, Jon M. "Proposed Architecture for SiC Switches and Diodes in a Switch Mode Power Supply." Materials Science Forum 556-557 (September 2007): 1011–14. http://dx.doi.org/10.4028/www.scientific.net/msf.556-557.1011.

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This SiC diodes and switches provide greatly enhanced performance at higher operating voltage, but the base material provides a high barrier to adoption in commercial systems. Commercial adoption has not occurred by adopting SiC components in place of Si devices, but only when the characteristics of SiC components can successfully leverage system performance and cost. Doing so requires a close look at current roadblocks and examining topologies and techniques that can bring more optimal system performance (density, efficiency, cost) with SiC components. High density converters using conventional components are becoming limited by the volume and cost of passive components, particularly the EMI filters and bulk filter capacitors. To address this and demonstrate the performance capabilities of SiC in SMPS, a PWM isolation converter is proposed using the resonant reset forward converter in an interleaved configuration. This topology can extend energy recovery from the primary bulk bus capacitor used for hold up time, as well as minimizing filtering requirements for input and output capacitors. The interleaved converter is developed from cascode switches using experimental SiC JFETs, in a configuration derived from previous work with a single switch converter. Overall performance as well as design issues will be discussed.

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13

Orlova, T. S., D. V. Il’in, B. I. Smirnov, I. A. Smirnov, R. Sepulveda, J. Martinez-Fernandez, and A. R. de Arellano-Lopez. "Electrical properties of bio-SiC and Si components of the SiC/Si biomorphic composite." Physics of the Solid State 49, no. 2 (February 2007): 205–10. http://dx.doi.org/10.1134/s1063783407020035.

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14

Kohyama, Akira. "Advanced SiC/SiC Composite Materials for Fourth Generation Gas Cooled Fast Reactors." Key Engineering Materials 287 (June 2005): 16–21. http://dx.doi.org/10.4028/www.scientific.net/kem.287.16.

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As one of the most important breakthrough in the field of SiC/SiC composite materials, the new process called Nano-powder Infiltration and Transient Eutectoid (NITE) Process has been developed. The outstanding total properties of the NITE SiC/SiC composites are presented. Then, the current efforts to make attractive GFR based on the NITE SiC/SiC composites and the technology R & D to make reactor components with the NITE SiC/SiC composites are provided together with our efforts on innovative reactor designs.

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15

Berberich, Stefan, A. Goñi, Wolfgang Schäper, and Manfred Kolm. "Monocrystalline and Polycrystalline SiC in EADS Astrium Space Applications." Materials Science Forum 615-617 (March 2009): 919–24. http://dx.doi.org/10.4028/www.scientific.net/msf.615-617.919.

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Of all the wide bandgap semiconductors, SiC is currently the most attractive material for aerospace applications. It offers significant advantages at high temperatures and high voltage levels while benefiting from an excellent thermal conductivity, the resistance to a harsh radiation environment (in particular in medium low orbits (MEO) where the Van Allan belts show a high concentration of electron and proton radiation) and an advanced materials technology. Due to the significant progress in the last years in monocrystalline SiC material fabrication and process technology, the space industry is increasingly interested in exploiting the SiC characteristics for electronic application. Although the requirement for space components are highly demanding with space qualified technological processes required, it is expected that high quality commercial SiC components submitted to a stringent screening process will allow the realisation of highly reliable space components. Electronic applications of monocrystalline SiC for space mainly exploit the high breakdown electric field which allows for lower specific on-resistances due to high doping and thinner drift region layers in vertical SiC power device structures. Among all SiC power devices, high voltage rectifiers have reached the highest degree of maturity. EADS Astrium has started evaluation activities of commercially available 1200 V SiC diodes and also 4.5 kV diodes developed in the frame of the ESA CHPCA (components for high power conditioning application) project. One application is power supply of ion thrusters on satellites which require electric power in the range of 2 to 8 kW at voltages of 1 to 2 kV. Mechanical aerospace applications of polycrystalline SiC

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16

Grujicic, Mica, Rohan Galgalikar, S. Ramaswami, Jennifer Snipes, Ramin Yavari, and Rajendra K. Bordia. "Multi-physics modeling and simulations of reactive melt infiltration process used in fabrication of ceramic-matrix composites (CMCs)." Multidiscipline Modeling in Materials and Structures 11, no. 1 (June 8, 2015): 43–74. http://dx.doi.org/10.1108/mmms-06-2014-0035.

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Purpose – A multi-physics process model is developed to analyze reactive melt infiltration (RMI) fabrication of ceramic-matrix composite (CMC) materials and components. The paper aims to discuss this issue. Design/methodology/approach – Within this model, the following key physical phenomena governing this process are accounted for: capillary and gravity-driven unsaturated flow of the molten silicon into the SiC/SiC CMC preform; chemical reactions between the silicon melt and carbon (either the one produced by the polymer-binder pyrolysis or the one residing within the dried matrix slurry); thermal-energy transfer and source/sink phenomena accompanying reactive-flow infiltration; volumetric changes accompanying chemical reactions of the molten silicon with the SiC preform and cooling of the as-fabricated CMC component to room temperature; development of residual stresses within, and thermal distortions of, the as-fabricated CMC component; and grain-microstructure development within the SiC matrix during RMI. Findings – The model is validated, at the material level, by comparing its predictions with the experimental and modeling results available in the open literature. The model is subsequently applied to simulate RMI fabrication of a prototypical gas-turbine engine hot-section component, i.e. a shroud. The latter portion of the work revealed the utility of the present computational approach to model fabrication of complex-geometry CMC components via the RMI process. Originality/value – To the authors’ knowledge, the present work constitutes the first reported attempt to apply a multi-physics RMI process model to a gas-turbine CMC component.

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17

Kreutz, E. W., R. Weichenhain, A. Horn, and R. Poprawe. "Manufacturing of Precise SiC Components by Nd:YAG Laser Radiation." Solid State Phenomena 80-81 (November 2001): 441–46. http://dx.doi.org/10.4028/www.scientific.net/ssp.80-81.441.

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18

Aiello, G., H. Golfier, J. F. Maire, Y. Poitevin, and J. F. Salavy. "Modeling of SiCf/SiC composite structures for nuclear components." Fusion Engineering and Design 51-52 (November 2000): 73–79. http://dx.doi.org/10.1016/s0920-3796(00)00376-8.

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19

Liu, Shan Hua, Hai Peng Qiu, Ling Wang, Bing Yu Zhang, Ming Wei Chen, Wei Jie Xie, and Yan Yuan Liang. "The Microstructure and Shear Properties of SiC/SiC Composite Pins with Designed SiC Fiber Preform." Solid State Phenomena 281 (August 2018): 367–74. http://dx.doi.org/10.4028/www.scientific.net/ssp.281.367.

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In order to obtain the near net shaped SiC/SiC composite pins without the processing cost, four kinds of SiC fiber pin preforms including the knitting yarn and core yarn with two dimension braided structure were designed. The SiC/SiC composite pins were fabricated by precursor infiltration pyrolysis (PIP) process used a liquid SiC ceramic precursor. The results showed that, the near net shaped SiC/SiC composite pins could be obtained by using the designed SiC fiber preform and the graphite mould with curved groove. The macrostructure and microstructure of the SiC/SiC composite pins were observed by scanning electron microscope. Both the single shear stress-displacement curves and the double shear stress-displacement curves of the different kinds of SiC/SiC composite pins showed the saddle-shaped, which indicated the fracture model of the SiC/SiC composites pins was non-catastrophic, and the SiC/SiC composite pins in this paper possessed the secondary bearing capacity. This paper may provide some new ideas for fiber reinforced SiC ceramic matrix composites components designers.

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20

Teshome, Million, Zenebe Wolde, Abel Gedefaw, and Anteneh Asefa. "Improving surgical informed consent in obstetric and gynaecologic surgeries in a teaching hospital in Ethiopia: A before and after study." BMJ Open 9, no. 1 (January 2019): e023408. http://dx.doi.org/10.1136/bmjopen-2018-023408.

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ObjectivesEven though surgical informed consent (SIC) has marked benefits, in many settings the information is not provided appropriately. In Ethiopia, minimal attention is given to SIC. This study assesses whether an intervention designed to improve SIC in obstetric and gynaecologic surgeries is associated with receipt of SIC components.DesignPre-intervention and post-intervention surveys were conducted at Hawassa University Comprehensive Specialized Hospital among women who underwent obstetric or gynaecologic surgeries. The intervention consisted of a 3-day training on standard counselling for surgical procedures offered to health professionals. A total of 457 women were surveyed (230 pre-intervention, 227 post-intervention). An adjusted Poisson regression analysis was used to identify the association between the intervention and the number of SIC components received.ResultsThe majority of participants were 25–34 years of age in both the pre-intervention and post-intervention groups (p=0.66). 45.7% of the pre-intervention and 51.5% of the post-intervention survey participants underwent elective surgery (p=0.21). Additionally, 70.4% of pre-intervention survey participants received counselling immediately before surgery, compared with 62.4% of post-intervention participants (p<0.001). 5.7% of pre-intervention and 6.6% of post-intervention participants reported the belief that SIC consists entirely of signing on a piece of paper (p=0.66). After controlling for effects of potential confounders, the number of SIC components reported by post-intervention survey participants was 16% higher than what is received by pre-intervention ones (adjusted coefficient=1.16 (1.06–1.28)). Having elective versus emergency surgery was not associated with the number of components received by participants in either group (adjusted coefficient=0.98 (0.88–1.09)).ConclusionTraining on the delivery of standard SIC is associated with receipt of a higher number of standard counselling components. However, there is a need to evaluate whether a one-time intervention leads to sustained improvement. A system-wide study of factors that promote SIC is required.

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Akturk, Akin, Neil Goldsman, Ahayi Ahyi, Sarit Dhar, Brendan Cusack, and Minseo Park. "SPICE Modeling of Advanced Silicon Carbide High Temperature Integrated Circuits." Materials Science Forum 858 (May 2016): 1070–73. http://dx.doi.org/10.4028/www.scientific.net/msf.858.1070.

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Due to the wide band-gap and high thermal conductivity of the 4H polytype of silicon carbide (SiC) as well as the maturity of this polytype’s fabrication processes, 4H-SiC offers an extremely attractive wide bandgap semiconductor technology for harsh environment applications spanning a variety of markets. To this end, 4H-SiC power electronics is gradually emerging as the technology of choice for next-generation power electronics; however, relatively limited progress has been made with regards to silicon carbide integrated circuits (ICs). We address this problem by developing fabrication and design methods for the SiC IC components themselves, as well as complementary SPICE type compact models for these components, and thereby facilitate the development of future SiC ICs and Process Design Kits (PDKs).

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22

Fernie-King, Barbara A., David J. Seilly, Alexandra Davies, and Peter J. Lachmann. "Streptococcal Inhibitor of Complement Inhibits Two Additional Components of the Mucosal Innate Immune System: Secretory Leukocyte Proteinase Inhibitor and Lysozyme." Infection and Immunity 70, no. 9 (September 2002): 4908–16. http://dx.doi.org/10.1128/iai.70.9.4908-4916.2002.

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ABSTRACT Streptococcal inhibitor of complement (SIC) is a 31-kDa extracellular protein of a few, very virulent, strains of Streptococcus pyogenes (particularly M1 strains). It is secreted in large quantities (about 5 mg/liter) and inhibits complement lysis by blocking the membrane insertion site on C5b67. We describe investigations into the interaction of SIC with three further major components of the innate immune system found in airway surface liquid, namely, secretory leukocyte proteinase inhibitor (SLPI), lysozyme, and lactoferrin. Enzyme-linked immunosorbent assays showed that SIC binds to SLPI and to both human and hen egg lysozyme (HEL) but not to lactoferrin. Studies using 125I-labeled proteins showed that SIC binds approximately two molecules of SLPI and four molecules of lysozyme. SLPI binding shows little temperature dependence and a small positive enthalpy, suggesting that the binding is largely hydrophobic. By contrast, lysozyme binding shows strong temperature dependence and a substantial negative enthalpy, suggesting that the binding is largely ionic. Lysozyme is precipitated from solution by SIC. Further studies examined the ability of SIC to block the biological activities of SLPI and lysozyme. An M1 strain of group A streptococci was killed by SLPI, and the antibacterial activity of this protein was inhibited by SIC. SIC did not inhibit the antiproteinase activity of SLPI, implying that there is specific inhibition of the antibacterial domain. The antibacterial and enzymatic activities of lysozyme were also inhibited by SIC. SIC is the first biological inhibitor of the antibacterial action of SLPI to be described and may prove to be an important tool for investigating this activity in vivo. Inhibition of the antibacterial actions of SLPI and lysozyme would be advantageous to S. pyogenes in establishing colonization on mucosal surfaces, and we propose that this is the principal function of SIC.

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Bhushan, Rajesh Kumar, and Deepak Sharma. "Fabrication and analysis of AA6082/Si3N4 and AA6082/SiC composites." International Journal of Structural Integrity 11, no. 2 (October 23, 2019): 277–85. http://dx.doi.org/10.1108/ijsi-06-2019-0058.

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Purpose Sound microstructure components are necessary for reliability and safety; hence, these components are used in aircraft, satellite, automobiles and ships, where many commercial alloys are not suitable. The paper aims to discuss this issue. Design/methodology/approach AA6082/Si3N4 and AA6082/SiC composites were fabricated using the stir-casting process considering 5, 10 and 15 vol.% of reinforcement particles. Density and porosity of AA6082/Si3N4 and AA6082/SiC composites were calculated. Characterization was done using an X-ray (EDX) detector, attached to SEM. The effect of addition of Si3N4 and SiC particulates in the AA6082 was investigated. Findings Results showed that Si3N4 and SiC particulates had good wettability with AA6082 and were uniformly distributed in AA6082 matrix. No adverse effects of reactions were noticed in the microstructure of AA6082/Si3N4 and AA6082/SiC composites. Research limitations/implications AA6082 with more than 15 vol.% of Si3N4 and AA6082/SiC reinforcement particles do not find industrial application where high hardness and tensile strength are required. Practical implications Components made from AA6082/Si3N4 and AA6082/SiC composites find their application where high hardness with better tensile strength is required. Social implications Naturally and locally available materials are utilized for fabrication. Originality/value Little work is available in the literature on fabrication and characterization of AA6082/Si3N4 and AA6082/SiC composites. The authors have identified the process parameters at which proper fabrication is done and sound microstructure is obtained.

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Shepherd, Paul, Ashfaqur Rahman, Shamim Ahmed, A. Matt Francis, Jim Holmes, and H. Alan Mantooth. "500 kHz – 5 MHz Phase-Locked Loops in High-Temperature Silicon Carbide CMOS." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2014, HITEC (January 1, 2014): 000076–83. http://dx.doi.org/10.4071/hitec-tp15.

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Silicon Carbide (SiC) integrated circuits processes show promise for improved performance in high temperature, high radiation, and other extreme environments. The circuits described are the first implementations of phase-locked or delay-locked loops in SiC. The PLL utilizes a common charge-pump topology including a fully integrated passive loop filter, and were designed with a target maximum operating frequency of 5 MHz. Component blocks use novel topologies to optimize performance in a SiC CMOS process. Experimental results of both the complete PLL as well as the Phase Frequency Detector and Voltage Controlled Oscillator components are presented. Operation of the PLL at frequencies up to 1.5 MHz is demonstrated through test results of unpackaged die.

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Casalegno, Valentina, Qiu Ling Chen, Qiu Ling Chen, Milena Salvo, Federico Smeacetto, Andrea Ventrella, and Monica Ferraris. "Joining of Advanced Ceramics, Glasses and Composites at Politecnico di Torino, Italy." Key Engineering Materials 434-435 (March 2010): 197–201. http://dx.doi.org/10.4028/www.scientific.net/kem.434-435.197.

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An overview of the last 16 years of activity on joining of advanced ceramics, glasses and ceramic matrix composites at Politecnico di Torino (Italy) will be presented. Results on thermal assisted direct bonding (TADB) of glasses for lab-on-chip devices, C/C composites to Cu-alloys for nuclear fusion components (ITER), SiC and SiC/SiC joints for nuclear components (fusion and fission), glass joining of foam glass, C/C joints for aerospace applications, ceramics to stainless steels for Solid Oxide Fuel Cells (SOFC), will be shown. Mechanical tests on joined components will be discussed, in particular, the results of an experimental campaign on carbon/carbon and ceramic joints tested in pure and apparent shear by nine different configurations.

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Kong, Chunyuan, Zhigang Sun, Xuming Niu, and Yingdong Song. "Moment methods for C/SiC woven composite components reliability and sensitivity analysis." Science and Engineering of Composite Materials 21, no. 1 (January 1, 2014): 121–28. http://dx.doi.org/10.1515/secm-2012-0058.

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AbstractA kind of reliability analysis method for C/SiC woven composite components was proposed, which is based on moment methods. Moment methods combining with perturbation method, the central difference method, as well as the Edgeworth series are applied to calculate the reliability of complex component for its effectivity and accuracy. The results computed by moment methods are sensitive to the distribution of parameters; thus, reliability sensitivity analysis has been performed. The reliability and sensitivity information of the complex components can be accurately and quickly obtained using a practical computer program. Finally, the proposed reliability-sensitivity analysis method is applied to CMCs components design. By comparing with Monte Carlo simulation, the numerical results demonstrate that the proposed approach provides accurate, convergent, and computationally efficient for finite element method-based reliability analysis in engineering practice.

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Rajan, T. P. D., and B. C. Pai. "Processing of Functionally Graded Aluminium Matrix Composites by Centrifugal Casting Technique." Materials Science Forum 690 (June 2011): 157–61. http://dx.doi.org/10.4028/www.scientific.net/msf.690.157.

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Functionally graded materials (FGM) possess a gradual transition in the composition or microstructure within a component inducing gradual changes in the functions and properties of the material with varying location. The present investigation is to form functionally graded aluminum composites with varying microstructural features and properties gradation using centrifugal casting by varying the material and process parameters. The ex-situ Al-SiC FGM has shown graded distribution of SiC towards the outer periphery and Al-SiC-Graphite has shown both particle gradations of SiC and Graphite towards inner periphery due to hindered settling phenomena. In in-situ Al-Si and Al-Si-Mg2Si system the particles are distributed towards the inner periphery of the casting. The paper also emphasizes on selected engineering components and tailoring their graded structures and properties by utilization of suitable reinforcement combinations and process parameters are discussed.

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28

Wereszczak, A. A., and T. P. Kirkland. "Creep Performance of Candidate SiC and Si3N4 Materials for Land-Based, Gas Turbine Engine Components." Journal of Engineering for Gas Turbines and Power 119, no. 4 (October 1, 1997): 799–806. http://dx.doi.org/10.1115/1.2817057.

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The tensile creep-rupture performance of a commercially available gas pressure sintered silicon nitride (Si3N4) and a sintered silicon carbide (SiC) is examined at 1038, 1150, and 1350°C. These two ceramic materials are candidates for nozzles and combustor tiles that are to be retrofitted in land-based gas turbine engines, and interest exists to investigate their high-temperature mechanical performance over service times up to, and in excess of, 10,000 hours (≈14 months). To achieve lifetimes approaching 10,000 hours for the candidate Si3N4 ceramic, it was found (or it was estimated based on ongoing test data) that a static tensile stress of 300 MPa at 1038 and 1150°C, and a stress of 125 MPa at 1350°C cannot be exceeded. For the SiC ceramic, it was estimated from ongoing test data that a static tensile stress of 300 MPa at 1038°C, 250 MPa at 1150°C, and 180 MPa at 1350°C cannot be exceeded. The creep-stress exponents for this Si3N4 were determined to be 33, 17, and 8 for 1038, 1150, and 1350°C, respectively. The fatigue-stress exponents for the Si3N4 were found to be equivalent to the creep exponents, suggesting that the fatigue mechanism that ultimately causes fracture is controlled and related to the creep mechanisms. Little success was experienced at generating failures in the SiC after several decades of time through exposure to appropriate tensile stress; it was typically observed that if failure did not occur on loading, then the SiC specimens most often did not creep-rupture. However, creep-stress exponents for the SiC were determined to be 57, 27, and 11 for 1038, 1150, and 1350°C, respectively. For SiC, the fatigue-stress exponents did not correlate as well with creep-stress exponents. Failures that occurred in the SiC were a result of slow crack growth that was initiated from the specimen’s surface.

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29

Grujicic, M., JS Snipes, R. Galgalikar, R. Yavari, V. Avuthu, and S. Ramaswami. "Multi-length-scale derivation of the room-temperature material constitutive model for SiC/SiC ceramic-matrix composites." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 231, no. 5 (August 16, 2015): 443–62. http://dx.doi.org/10.1177/1464420715600002.

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In the present work, multi-length-scale physical and numerical analyses are used to derive a SiC/SiC ceramic matrix composite (CMC) material model suitable for use in a general room-temperature, finite element-based, structural/damage analysis of gas turbine engine components. Due to its multi-length-scale character, the material model incorporates the effects of fiber/tow (e.g. the volume fraction of the filaments, thickness of the filament coatings, decohesion properties of the coating/matrix interfaces, quality, as quantified by the Weibull distribution parameters, of the filament, coating, and matrix materials, etc.) and ply/lamina (e.g. the 0°/90° cross-ply vs. plain-weave architectures, the extent of tow crimping in the case of the plain-weave plies, cohesive properties of the inter-ply boundaries, etc.) length-scale microstructural/architectural parameters on the mechanical response of the CMCs. To identify and quantify the contribution of the aforementioned parameters on the material response, detailed numerical procedures involving the representative volume elements and the virtual mechanical tests are developed and utilized. The resulting homogenized turbine-engine component-level material model is next integrated into a user-material subroutine and used, in conjunction with a commercial finite element program, to analyze the foreign object damage experienced by a toboggan-shaped turbine shroud segment. The results obtained clearly revealed the role different fiber/tow and ply/lamina microstructural parameters play in the structural/damage response of the gas-turbine CMC components.

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30

Guo, Xiaorui, Qian Xun, Zuxin Li, and Shuxin Du. "Silicon Carbide Converters and MEMS Devices for High-temperature Power Electronics: A Critical Review." Micromachines 10, no. 6 (June 19, 2019): 406. http://dx.doi.org/10.3390/mi10060406.

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The significant advance of power electronics in today’s market is calling for high-performance power conversion systems and MEMS devices that can operate reliably in harsh environments, such as high working temperature. Silicon-carbide (SiC) power electronic devices are featured by the high junction temperature, low power losses, and excellent thermal stability, and thus are attractive to converters and MEMS devices applied in a high-temperature environment. This paper conducts an overview of high-temperature power electronics, with a focus on high-temperature converters and MEMS devices. The critical components, namely SiC power devices and modules, gate drives, and passive components, are introduced and comparatively analyzed regarding composition material, physical structure, and packaging technology. Then, the research and development directions of SiC-based high-temperature converters in the fields of motor drives, rectifier units, DC–DC converters are discussed, as well as MEMS devices. Finally, the existing technical challenges facing high-temperature power electronics are identified, including gate drives, current measurement, parameters matching between each component, and packaging technology.

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31

Hino, T., E. Hayashishita, Y. Yamauchi, M. Hashiba, Y. Hirohata, and A. Kohyama. "Helium gas permeability of SiC/SiC composite used for in-vessel components of nuclear fusion reactor." Fusion Engineering and Design 73, no. 1 (April 2005): 51–56. http://dx.doi.org/10.1016/j.fusengdes.2005.01.002.

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32

Wiśniewski, Paweł. "Evaluating Silicon Carbide-Based Slurries and Molds for the Manufacture of Aircraft Turbine Components by the Investment Casting." Crystals 10, no. 6 (May 29, 2020): 433. http://dx.doi.org/10.3390/cryst10060433.

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Silicon carbide (SiC) is a promising material for the fabrication of ceramic shell molds due to its high mechanical strength, hardness, thermal shock resistance, and thermal conductivity compared with commonly used slurries. This article describes the test results of casting materials, i.e., SiC-based powders and aqueous binders with aluminum oxide nanoparticles, as well as the parameters of slurries used for prime coats and structural layers. Tests were also performed to evaluate the physical and mechanical properties of SiC-based shell molds for the manufacture of aircraft turbine components. Two SiC-based slurries with solid concentrations of 65 and 70 wt.% were prepared, and their viscosity, density, pH, quantity, thickness, and copper plate adhesion (plate weight test) were investigated. Fourteen days were required to prepare and evaluate the slurry parameters. The results showed that SiC-based slurries had a Zahn cup #4 outflow time of 33.1 s to fabricate the first two coats and 14.8 s to fabricate the shell mold structural layers. Three series of SiC-based shell mold samples were prepared: after dewaxing (PW1), after burnout preheating at 700 °C (PW2), and after annealing at 1200 °C (PW3). The bending mechanical strength, Young’s modulus, and Weibull’s modulus of the samples were calculated, and the roughness (Ra and Rq) and microstructures of samples were also analyzed (SEM). Inner defects were evaluated by CMT (µCT). The Ra and Rq values of the prime coat of the SiC-based shell mold did not exceed 5 µm. The fabricated SiC shell molds had bending mechanical strengths from 1.21–2.28 MPa, Young’s modulus of 102.97–207.66 MPa, and a Weibull’s modulus from 5.36–9.94. The shell molds fabricated on the technical scale met the requirements specified for industrial shell molds.

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33

Grivickas, Paulius, Stephen Sampayan, Kipras Redeckas, Mikas Vengris, and Vytautas Grivickas. "Probing of Carrier Recombination in n- and p-Type 6H-SiC Using Ultrafast Supercontinuum Pulses." Materials Science Forum 821-823 (June 2015): 245–48. http://dx.doi.org/10.4028/www.scientific.net/msf.821-823.245.

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Excess carrier dynamics in 6H-SiC substrates with n- and p-type moderate doping were detected using femtosecond pump-probe measurements with supercontinuum probing. Band-to-band recombination and carrier trapping were determined as the main recombination processes in both materials. Spectral fingerprints corresponding to each of these recombination components were obtained using the global and target analysis. It was shown that, in spite of background doping, the band-to-band recombination in 6H-SiC is dominated by the excess electron absorption component and the carrier trapping is dominated by the excess hole absorption.

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34

Park, K., and C. Sung. "Characterization of SiC fiber-reinforced SiC composites by TEM." Proceedings, annual meeting, Electron Microscopy Society of America 52 (1994): 632–33. http://dx.doi.org/10.1017/s042482010017089x.

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SiC fiber-reinforced SiC composites have been accepted to have considerable potential as an engineering structural ceramic for numerous high-temperature applications, such as various heat engine components. In this study, the microstructure of matrix, fiber, and matrix/fiber interface of SiC fiber (SCS-6, Textron)-reinforced nitrogen-treated SiC composites was characterized using transmission electron microscopy (TEM). Cross-sectional TEM samples were prepared by mechanical grinding, dimpling, and ion-milling. The samples were analyzed using a Philips EM400T TEM and a Noran ultrathin window Micro-Z detector.The α-Si3N4 was formed in the porous SiC matrix by nitriding (Fig. 1(a)). The porous SiC matrix can permit easy and continuous penetration of the nitriding gas and rapid escape of the reaction and volatilization products, thus favoring vapor-phase reactions. In the case of huge SiC grains, the α-Si3N4 was formed at the surface of the huge SiC grains. Rod-shaped Si2N2O phase was often observed in the porous matrix. Figs. 1(b), (c), and (d) show electron diffraction patterns obtained from the α-SiC, α-Si3N4, Si2N2O phases, respectively.

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35

Chailloux, Thibaut, Cyril Calvez, Nicolas Thierry-Jebali, Dominique Planson, and Dominique Tournier. "SiC Power Devices Operation from Cryogenic to High Temperature: Investigation of Various 1.2kV SiC Power Devices." Materials Science Forum 778-780 (February 2014): 1122–25. http://dx.doi.org/10.4028/www.scientific.net/msf.778-780.1122.

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The aim of this study consists in comparing the effects of temperature on various SiC power devices. Electrical characteristics have been measured for temperatures from 100K to 525K. All devices are suitable for high temperature. However, SiC MOSFETs are not a good choice for cryogenic temperature, while SiC BJTs are less affected by temperature than other components, especially for cryogenic temperature.

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36

Ohtsuka, Kenichi, T. Nakatani, A. Nagae, H. Watanabe, Y. Nakaki, Y. Fujii, K. Fujihira, S. Nakata, and N. Yutani. "Defect Related Leakage Current Components in SiC Schottky Barrier Diode." Materials Science Forum 725 (July 2012): 53–56. http://dx.doi.org/10.4028/www.scientific.net/msf.725.53.

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SiC Schottky barrier diodes were fabricated and measured properties were characterized by device simulation. Most of devices show low leakage current, however, a few devices show leakage current larger than the values estimated from deviation of drift layer parameters. The leakage current component remarkable in lower voltage and saturating at higher voltage is related to Schottky barrier tunneling at macroscopic defects. The component remarkable in higher voltage is considered to be due to microscopic defect related generation current, concerning with non-stoichiometry.

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37

Qu, Ling, Cong Zhang, Qing Huang, and Wenjie Yuan. "Influence of components on rheological behavior of SiC-based slurries." IOP Conference Series: Materials Science and Engineering 231 (September 2017): 012136. http://dx.doi.org/10.1088/1757-899x/231/1/012136.

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38

Sutherland, Ken. "Solvent-Extractable Components of Linseed Oil Paint Films." Studies in Conservation 48, no. 2 (January 2003): 111–35. http://dx.doi.org/10.1179/sic.2003.48.2.111.

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39

Zhang, Yu Di, Hai Feng Hu, Chang Rui Zhang, and Guang De Li. "Online-Joining of C/SiC-C/SiC via Slurry Reaction and Precursor Infiltration and Pyrolysis Process with C/SiC Pins." Key Engineering Materials 531-532 (December 2012): 135–40. http://dx.doi.org/10.4028/www.scientific.net/kem.531-532.135.

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C/SiC composites have widely application prospects in the field of aeronautic and aerospace for their excellent properties. The joining of C/SiC composites is a key to fabricate large and complex components. In this paper, 1D C/SiC pins were prepared by precursor infiltration and pyrolysis (PIP) process and used to join C/SiC composites by Slurry react (SR) and PIP process. The shear strength of the C/SiC pins with different carbon fiber volumes was investigated with the maximum shear strength as high as 339.46MPa. Influences of C/SiC pins on the joining properties of C/SiC composites were studied. The shear strength and flexural strength of C/SiC-C/SiC joining are improved from 9.17MPa and 30.41MPa without pins to 20.06MPa and 75.03MPa with one C/SiC pin (diameter 2mm), respectively. The reliability of C/SiC-C/SiC joining is also improved with C/SiC pins in that the fracture mode changes from catastrophic without pins to non-catastrophic. The SEM photos show a strong bond between joining layer and C/SiC composites without obvious interface.

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40

Li, Zhuan, Peng Xiao, and Xiang Xiong. "Tribological Characteristics of Different Components on C/C-SiC Composites Fabricated by Warm Compacted In Situ Reaction." Applied Mechanics and Materials 268-270 (December 2012): 59–62. http://dx.doi.org/10.4028/www.scientific.net/amm.268-270.59.

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C/C-SiC brake composites, based on reinforcement of carbon fiber and dual matrix of carbon and silicon carbide, were fabricated by warm compacted-in situ reacted process. Rules about the influence of different components on the friction and wear characteristics of the C/C-SiC composites are ascertained. As hard particle, the SiC has the function to the formation of friction film, which is in favor of increasing the coefficient of friction (COF) and decreasing the wear rate. The resin carbon plays the role of enhancing the COF, but they are easy to be cut and increase the wear rate. The graphite plays the lubrication function, and right volume content of graphite is helpful to forming friction film to reduce the wear rate. The C/C-SiC composite fabricated by the warm compacted-in situ reaction can with best tribological performance when the components volume fraction of carbon fibre, SiC, graphite and resin carbon are 15.5%, 37.0%, 22.1% and 20.8%, respectively, which the COF and the wear rate can reach the maximum and the minimun value of 0.44 and 1.1μm/cycle respectively.

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41

Lu, Yang Wei, Yu Di Zhang, Hai Feng Hu, and Chang Rui Zhang. "Online-Joining of C/SiC-C/SiC via Precursor Infiltration and Pyrolysis Process." Key Engineering Materials 368-372 (February 2008): 1044–46. http://dx.doi.org/10.4028/www.scientific.net/kem.368-372.1044.

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A novel, online-joining of C/SiC-C/SiC method, precursor infiltration and pyrolysis, was used to obtain high temperature stable joining SiC composition, while joining process was highly consistent with C/SiC preparation process. The compositions of joining ingredients and process parameters were investigated to determine the maximum joining strength of C/SiC-C/SiC at room and high temperatures. The optimum weight ratio of (polycarbosilane/divinyl benzene)/SiC powder is 3/1, and ramping rate of pyrolysis is 2°C/min, and cycles of infiltration and pyrolysis is 6. The flexural strengths of joining components remained stable up to 1200°C (50.8MPa), but decreased to 30.5MPa at 1500°C, while the tensile strengths remained rather stable (20.5MPa) up to 1500°C, and decreased to 8.4MPa at 1800°C.

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42

Shakhov, Lev V., Alexander A. Lebedev, Natalia V. Seredova, Sergey P. Lebedev, Vitalii V. Kozlovski, Alexander V. Zubov, and Irina P. Nikitina. "Investigation of the Influence of Structural Defects on the PL Spectra in n-3C-SiC." Materials Science Forum 1004 (July 2020): 278–83. http://dx.doi.org/10.4028/www.scientific.net/msf.1004.278.

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The photoluminescence spectra were studied in 3C-SiC / 4H-SiC heterostructures and single crystals of 3C-SiC. It was shown that 3C-SiC epitaxial layers grown on 4H-SiC substrates have significantly less structural perfection than 3C-SiC single crystals. It was found that doping with aluminum leads to the appearance of characteristic photoluminescence (PL) both in the epitaxial layers and in 3C-SiC single crystals. At the same time, the irradiation of the epitaxial layers does not lead to the appearance of “defective PL (DFL), as is observed for single crystals. It was suggested that the twin boundaries existing in 3C-SiC epitaxial layers could serve as getters of radiation defects that are components of donor – acceptor pairs (DAP) responsible for DFL.

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43

Splieth, Christian H., Ruth M. Santamaria, Roger Basner, Elisabeth Schüler, and Julian Schmoeckel. "40-Year Longitudinal Caries Development in German Adolescents in the Light of New Caries Measures." Caries Research 53, no. 6 (2019): 609–16. http://dx.doi.org/10.1159/000501263.

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This study assessed the 40-year longitudinal caries development in German adolescents in the light of the sixth National Oral Health Survey in Children (NOHSC, 2016) employing initial DMFT (IDMFT), Significant Caries Index (SiC) and Specific Affected Caries Index (SaC). On the basis of the current NOHSC (randomized cluster selection using school list or regional community school surveys, 55,956 12-year-old sixth-graders examined by 482 calibrated community/study dentists) DMFT, SiC, a novel IDMFT including initial lesions (IT) and the recently introduced SaC were calculated and also recalculated for national and international surveys from the last 4 decades. In 2016, 78.8% of children were caries-free (DMFT = 0), 65.5% including IT lesions. The mean DMFT was 0.44 (single components: DT = 0.14, MT = 0.02, FT = 0.29, IT = 0.52) showing a clear association with the school type as marker for the socio-economic status. The mean number of affected teeth in children with DMFT >0 was 2.07 (SaC) in comparison to almost 9 teeth in the 1970s. The current care index on the tooth level was 66.3%, leaving only 7.7% of children with restorative treatment needs. Longitudinally, a continuous caries decline of more than 80%, including the risk groups (SiC/SaC), to an internationally extremely low level was observed. In conclusion, the National Oral Health Surveys reveal a continuous caries decline to a very low caries level in 12-year-old 6th-graders in Germany even if IT lesions are included (IDMFT). In spite of proportional reductions in the risk groups (SiC/SaC), the polarized caries distribution according to socio-economic parameters reveals the need for targeted preventive programmes.

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44

Matli, Penchal Reddy, Ubaid Fareeha, Rana Abdul Shakoor, Moinuddin Yusuf, Adel Mohamed Amer Mohamed, and Manoj Gupta. "Fabrication and Mechanical Properties of Extruded Al-SiC Nanocomposites." Nano Hybrids and Composites 16 (June 2017): 9–12. http://dx.doi.org/10.4028/www.scientific.net/nhc.16.9.

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This work aims to investigate the effect of SiC addition on structural, microstructural and mechanical properties of developed Al-Sic nanocomposites. Al metal matrix composites reinforced by nanosized SiC particles were fabricated using high energy ball milling and microwave sintering process followed by hot extrusion. The XRD analysis indicated that the dominant components were Al and SiC. SEM/EDX micrographs showed homogenous distribution of SiC nanoparticles in Al matrix. Mechanical characterizations revealed that the addition of nanosize SiC particulates to a simultaneous increase in microhardnes, yield strength, ultimate compressive/tensile strength and reduction in ductility of the matrix. This improvement in mechanical properties can be attributed to the homogeneous distribution of reinforcement (SiC particles) and dispersion strengthening mechanism.

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45

McEntire, B. J., R. R. Hengst, W. T. Collins, A. P. Taglialavore, and R. L. Yeckley. "Ceramic Component Processing Development for Advanced Gas Turbine Engines." Journal of Engineering for Gas Turbines and Power 115, no. 1 (January 1, 1993): 1–8. http://dx.doi.org/10.1115/1.2906678.

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Norton/TRW Ceramics (NTC) is developing ceramic components as part of the DOE-sponsored Advanced Turbine Technology Applications Project (ATTAP). NTC’s work is directed at developing manufacturing technologies for rotors, stators, vane-seat platforms, and scrolls. The first three components are being produced from a HIPed Si3N4, designated NT154. Scrolls were prepared from a series of siliconized silicon-carbide (Si-SiC) materials designated NT235 and NT230. Efforts during the first three years of this five-year program are reported. Developmental work has been conducted on all aspects of the fabrication process using Taguchi experimental design techniques. Appropriate materials and processing conditions were selected for power beneficiation, densification, and heat-treatment operations. Component forming has been conducted using thermal-plastic-based injection molding (IM), pressure slip-casting (PSC), and Quick-Set™ injection molding.1 An assessment of material properties for various components from each material and process were made. For NT154, characteristic room-temperature strengths and Weibull Moduli were found to range between ≈920 MPa to ≈1 GPa and ≈10 to ≈19, respectively. Process-induced inclusions proved to be the dominant strength-limiting defect regardless of the chosen forming method. Correction of the lower observed values is being addressed through equipment changes and upgrades. For the NT230 and NT235 Si-SiC, characteristic room-temperature strengths and Weibull Moduli ranged from ≈240 to ≈420 MPa, and 8 to 10, respectively. At 1370°C, strength values for both the HIPed Si3N4 and the Si-SiC materials ranged from ≈480 MPa to ≈690 MPa. The durability of these materials as engine components is currently being evaluated.

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46

Rumyantsev, V., Andrey Osmakov, S. Boykov, and V. Fishev. "Stereological Microstructure Description of Structural SiC Ceramics as Composite Material." Advances in Science and Technology 65 (October 2010): 130–34. http://dx.doi.org/10.4028/www.scientific.net/ast.65.130.

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Within unified stereological approach the silicon carbide-based ceramics SiSiC , SSiC, and LPSiC are treated as binary compositions, that despite certain structure ordering differences might be similarly described as comprising topologically continuous component (that provides the high level of physical and mechanical properties), and a discrete component. The paper demonstrates the necessity of using dimensionless criterial parameters for adequate description of the integral microstructure ordering level; said parameters including the characteristics of both continuous and discrete components of the composite ceramic material. Generalized equations are derived for compound stereological parameters of the discussed materials, along with statistically reliable approximations of the strength characteristics as functions of these parameters.

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47

Verrilli, M. J., and D. Brewer. "Characterization of Ceramic Matrix Composite Fasteners Exposed in a Combustor Linear Rig Test." Journal of Engineering for Gas Turbines and Power 126, no. 1 (January 1, 2004): 45–49. http://dx.doi.org/10.1115/1.1639005.

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Combustion tests on SiC/SiC CMC components were performed in an aircraft combustion environment using the rich-burn, quick-quench, lean-burn (RQL) sector rig. SiC/SiC fasteners were used to attach several of these components to the metallic rig structure. The effect of combustion exposure on the fastener material was characterized via microstructural examination. Fasteners were also destructively tested, after combustion exposure, and the failure loads of fasteners exposed in the sector rig were compared to those of as-manufactured fasteners. Combustion exposure reduced the average fastener failure load by 50% relative to the as-manufactured fasteners for exposure times ranging from 50 to 260 hours. The fasteners exposed in the combustion environment demonstrated failure loads that varied with failure mode. Fasteners that had the highest average failure load, failed in the same manner as the unexposed fasteners.

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48

COCKS, A. C. F., and F. A. LECKIE. "PERFORMANCE DIAGRAMS FOR CERAMIC MATRIX COMPOSITE COMPONENTS SUBJECTED TO CYCLIC THERMO-MECHANICAL LOADING." Journal of Multiscale Modelling 01, no. 03n04 (July 2009): 433–50. http://dx.doi.org/10.1142/s1756973709000165.

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Ceramic matrix composites (CMCs) are candidates for pressurized tubes which operate under conditions of severe cyclic thermal loading. Simple models describing the properties of CMCs are used to estimate the behaviour of a pressurized tube subjected to cyclic thermal loading and to establish shakedown and failure conditions. Analytical procedures are described which evaluate the component response in the cyclic state. The approach is illustrated by analysing the classical Bree problem assuming material properties which are representative of a SiC/SiC composite. Performance diagrams are presented which identify safe operating conditions and the extent of damage in the component.

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49

Nakabayashi, Masashi, Tatsuo Fujimoto, Masakazu Katsuno, Noboru Ohtani, Hiroshi Tsuge, Hirokatsu Yashiro, Takashi Aigo, Taizo Hoshino, Hosei Hirano, and Kohei Tatsumi. "Growth of Crack-Free 100mm-Diameter 4H-SiC Crystals with Low Micropipe Densities." Materials Science Forum 600-603 (September 2008): 3–6. http://dx.doi.org/10.4028/www.scientific.net/msf.600-603.3.

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The theromoelastic stress in post-growth SiC crystals has been investigated in order to suppress the cracks which were frequently observed in SiC crystals with larger diameters. Optimizing the temperature distribution in growing crystals lead to reduction of tensile stress components, and thus resulting in crack-free 100mm diameter SiC crystals with micropipe (MP) densities of 0.025/cm2. The concept of process optimization we established is confirmed to be effective to the growth of large diameter SiC crystals with mechanical stability.

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50

Лебедев, А. А., И. П. Никитина, Н. В. Середова, Н. К. Полетаев, С. П. Лебедев, В. В. Козловский та А. В. Зубов. "Исследование влияния структурных дефектов на спектры фотолюминесценции в n-3C-SiC". Письма в журнал технической физики 45, № 11 (2019): 28. http://dx.doi.org/10.21883/pjtf.2019.11.47820.17755.

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AbstractPhotoluminescence (PL) spectra have been studied in 3 C -SiC/4 H -SiC heterostructures and 3 C ‑SiC single crystals. It was shown that epitaxial 3 C -SiC layers grown on 4 H -SiC substrates have a markedly poorer crystal perfection than do 3 C -SiC single crystals. It was found that doping with aluminum gives rise to a characteristic PL both in epitaxial layers and in 3 C -SiC single crystals. At the same time, the electron irradiation of epitaxial layers does not give rise to defect-related PL, in contrast to what is observed for single crystals. An assumption is made that the twin boundaries existing in epitaxial 3 C -SiC layers can serve as getters of radiation defects that are components of donor–acceptor pairs responsible for the “defect-related” PL.

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