Journal articles on the topic 'Carbon composites Effect of high temperatures on'
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1
Huang, E. Wen, Chung Kai Chang, Wen Jay Lee, Soo Yeol Lee, Jun Wei Qiao, and Chung Hao Chen. "Thermal-Effect Study on a Carbon-Carbon Composite Using Synchrotron X-Ray Measurements & Molecular Dynamics Simulation." Materials Science Forum 777 (February 2014): 35–39. http://dx.doi.org/10.4028/www.scientific.net/msf.777.35.
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Carbon-carbon composites are deemed as candidate materials for application in very high temperature reactors. In a very high temperature reactor, carbon-carbon composite materials would experience severe environmental impacts from high temperatures. As a result, we applied non-destructive ex-situ diffraction experiments to investigate the microstructure changes of the carbon-carbon composite materials experiencing different temperatures. In this study, the samples were prepared in a format of a three-dimensional pitch-based carbon-carbon composite. The samples were heated to 500 (°C), 700 (°C), and 900 (°C) for 2 minutes, respectively. In order to understand the temperature effect on carbon-carbon composite, we facilitated the high penetration of the synchrotron X-ray diffraction at National Synchrotron Radiation Research Center to examine the evolution of microstructures subjected to heat treatment. The results show that the lattice parameters of a-axis and c-axis evolve upon heating. The molecular dynamics simulation results suggest that the early-stage rearrangement is originated from the release of the defects.
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Cao, Sheng Hu, Zhi Shen Wu, and Feng Li. "Effects of Temperature on Tensile Strength of Carbon Fiber and Carbon/Epoxy Composite Sheets." Advanced Materials Research 476-478 (February 2012): 778–84. http://dx.doi.org/10.4028/www.scientific.net/amr.476-478.778.
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With the increased use of carbon fiber reinforced polymer (CFRP) composites in civil infrastructure, understanding the fire structural performance of these materials is an important safety issue. In this paper, the effect of temperature on the tensile strength of carbon fibers and carbon/epoxy composite sheets was experimentally determined from 20°C to 500°C. Meanwhile, in order to better understand the strength degradation of carbon fiber-polymer composites at elevated and high temperatures, the tension tests were also performed for pure epoxy resin and CFRP sheets by means of 10°C off-axis at the range of 20-80°C, respectively. The experimental results reveal that the strength decrease of carbon composites under tensile loading at elevated and high temperatures is dependent on both thermal softening of the epoxy polymer matrix and thermally-activated weakening of the fibers. The reduction in strength of carbon fiber is attributed to oxidation of the high strength grapheme layer at the near-surface fiber region.
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Abbas, Imran, Yanxiang Wang, Hassan Elahi, Muhammad Ali Siddiqui, Mudaser Ullah, and Faisal Qayyum. "Effect of MoSi2-Si3N4/SiC Multi-Layer Coating on the Oxidation Resistance of Carbon/Carbon Composites above 1770 K." Journal of Composites Science 4, no. 3 (July 3, 2020): 86. http://dx.doi.org/10.3390/jcs4030086.
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To improve the oxidation resistance of carbon/carbon composites at high temperatures (>1770 K), they were coated with MoSi2-Si3N4/SiC. The slurry and pack cementation methods were adopted to deposit the inner SiC layer and outer MoSi2-Si3N4 layer. The phase composition, microstructure, and elemental distributions in the coating were analyzed using SEM, XRD, EDS, and Raman spectroscopy. Oxidation tests show that the deposited multi-layer coating can protect the carbon/carbon matrix from oxidation at high temperatures (>1770 K) for 150h and that the coating can withstand 40 thermal cycles between 1773 and 300 K. It is observed that Si3N4 assists in the formation of a dense SiO2 layer at a high temperature, which plays a vital role in increasing the thermal cyclic and oxidation resistance of the coating itself. The weight loss of coated carbon/carbon composite is attributed to the formation of micro-cracks and diffusion of SiO2, MoO3, and N2 out of the material at high temperatures.
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Iorfida, Antonio, Sebastiano Candamano, Fortunato Crea, Luciano Ombres, Salvatore Verre, and Piero de Fazio. "Bond Behaviour of FRCM Composites: Effects of High Temperature." Key Engineering Materials 817 (August 2019): 161–66. http://dx.doi.org/10.4028/www.scientific.net/kem.817.161.
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The fire remains one of the serious potential risks to most buildings and structures, as recently it’s been witnessed in Paris’ historic Notre Dame Cathedral and London’s Grenfell Tower. Concrete and masonry construction materials suffer physiochemical changes and mechanical damage caused by heating that is usually confined to the outer surface but can eventually compromise their load-bearing capacity. FRCM systems could provide when applied, supplemental fire insulation on pre-existing structural members, but there is a lack of knowledge about their properties in those conditions. This experimental work, thus, aims to evaluate the mechanical behaviour of carbon-FRCM and basalt-FRCM composites bonded to masonry substrate after high temperature exposure. Temperatures of 100 °C, 300 °C and 500 °C over a period of three hours were used to investigate the degradation of their mechanical properties. Single lap shear bond tests were carried out to evaluate the bond-slip response and failure modes. For all the tested temperatures higher peak stresses were measured for carbon-FRCM composite than basalt ones. Furthermore, low-density basalt-FRCM composite showed higher peak stresses and lower global slips up to 300 °C than high-density one. Carbon-FRCM composite failure mode was not effected by temperature. High-density basalt-FRCM composite showed a change in failure mode between 300 °C and 500 °C.
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Leng, Ling, Xin You, Jianhong Yi, Caiju Li, Yichun Liu, Taofang Zeng, and Dong Fang. "In-Situ Preparation of High-Performance CNS/Cu Composites with Molten Salt Route." Nano 16, no. 05 (April 29, 2021): 2150056. http://dx.doi.org/10.1142/s1793292021500569.
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Carbon nanosheets (CNSs) reinforced copper composites are obtained with a molten salt route for uniform distribution of carbon in the copper matrix. The structures and properties of the composite are thoroughly characterized and tested. The mechanical properties of the composite are greatly improved compared to pure copper. The effects of annealing temperatures and carbon contents on the mechanical properties of composites are investigated and discussed. When the annealing temperature is 800∘C, the composite has excellent comprehensive properties. Its yield strength is 283 MPa, which is 3.14 times that of pure copper, and its hardness is 78[Formula: see text]HV, which is 1.77 times of pure copper. The simple and low-cost preparation process opens up a novel route for the preparation of high-performance copper-based composites.
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Yang, Baifeng, Zhufeng Yue, Xiaoliang Geng, Peiyan Wang, Jian Gan, and Baohua Liao. "Effects of space environment temperature on the mechanical properties of carbon fiber/bismaleimide composites laminates." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 232, no. 1 (November 5, 2017): 3–16. http://dx.doi.org/10.1177/0954410017740382.
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The effects of space environment temperatures on specific carbon fiber/bismaleimide composite laminates were evaluated using the simulated environment test method. The tests were performed at −120 ℃, room temperature, 150 ℃, 170 ℃, and 200 ℃. The material responses were characterized through an assessment of mechanical properties including tensile, compressive, and in-plane shear properties. The experimental results showed that transverse tensile/compressive and in-plane shear responses, which are strongly related to matrix properties, were sensitive to temperature especially high temperature above the glass transition temperature. Failure morphologies on both the microscopic and macroscopic scales were discussed. It was found that matrix fracture and delamination was more likely at high temperatures, while the interface strength was higher at low temperatures. The effects of extreme temperatures on mechanical responses of composites, as well as dynamic thermomechanical analysis results, are shown. Failure envelopes for these carbon fiber / bismaleimide composites at different temperatures based on Hashin criteria are depicted to help designers to avoid drawbacks introduced by temperature.
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Haincová, Eliška, and Pavlína Hájková. "Effect of Boric Acid Content in Aluminosilicate Matrix on Mechanical Properties of Carbon Prepreg Composites." Materials 13, no. 23 (November 27, 2020): 5409. http://dx.doi.org/10.3390/ma13235409.
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This work presents carbon fabric reinforced aluminosilicate matrix composites with content of boric acid, where boron replaces aluminum ions in the matrix and can increase the mechanical properties of composites. Five different amounts of boric acid were added to the alkaline activator for preparing six types (including alkaline activator without boric acid) of composites by the prepreg method. The influence of boric acid content in the matrix on the tensile strength, Young’s modulus and interlaminar strength of composites was studied. Attention was also paid to the influence of boron content on the behavior of the matrix and on the internal structure of composites, which was monitored using a scanning electron microscope. The advantage of the aluminosilicate matrix is its resistance to high temperatures; therefore, tests were also performed on samples affected by temperatures of 400–800 °C. The interlaminar strength obtained by short-beam test were measured on samples exposed to 500 °C either hot (i.e. measured at 500 °C) or cooled down to room temperature. The results showed that the addition of boron to the aluminosilicate matrix of the prepared composites did not have any significant effect on their mechanical properties. The presence of boron affected the brittleness and swelling of the matrix and the differences in mechanical properties were evident in samples exposed to temperatures above 500 °C. All six prepared composites showed tensile strength higher than 320 MPa at laboratory temperature. The boron-free composite had the highest strength 385 MPa. All samples showed a tensile strength higher than 230 MPa at elevated temperatures up to 500 °C.
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Johnston, Joel P., J. Michael Pereira, Charles R. Ruggeri, and Gary D. Roberts. "High-speed infrared thermal imaging during ballistic impact of triaxially braided composites." Journal of Composite Materials 52, no. 25 (March 19, 2018): 3549–62. http://dx.doi.org/10.1177/0021998318765290.
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Ballistic impact experiments were performed on triaxially braided polymer matrix composites to study the heat generated in the material due to projectile velocity and penetration damage. Triaxially braided (0/+60/−60) composite panels were manufactured with T700S standard modulus carbon fiber and two epoxy resins. The PR520 (toughened) and 3502 (untoughened) resin systems were used to make different panels to study the effects of resin properties on temperature rise. The ballistic impact tests were conducted using a single stage gas gun, and different projectile velocities were applied to study the effect on the temperature results. Temperature contours were obtained from the back surface of the panel during the test through a high speed, infrared thermal imaging system. The contours show that high temperatures were locally generated and more pronounced along the axial tows for the T700S/PR520 composite panels; whereas, tests performed on T700S/3502 composite panels, using similar impact velocities, demonstrated a widespread area of lower temperature rises. Nondestructive, ultrasonic C-scan analyses were performed to observe the failure patterns in the impacted composite panels and correlate the C-scan results with the temperature contours. Overall, the impact experimentation showed temperatures exceeding 252℃ (485°F) in both composites which is well above the respective glass transition temperatures for the polymer constituents. This expresses the need for further high strain rate testing with measurement of the temperature and deformation fields in order to fully understand the complex behavior and failure of the material and to improve the confidence in designing aerospace components with these materials.
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Rahaman, M., Tapan Kumar Chaki, and D. Khastgir. "Temperature Dependent Electrical Properties of Conductive Composites (Behavior at Cryogenic Temperature and High Temperatures)." Advanced Materials Research 123-125 (August 2010): 447–50. http://dx.doi.org/10.4028/www.scientific.net/amr.123-125.447.
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Extrinsically conductive polymer composites can be developed by incorporation of conductive filler in suitable polymer matrix. The formation of conductive network in insulating matrix due to filler aggregation at and above percolation is responsible for electrical conductivity of such composites. The present investigation deals with effect of temperature on conductive composites made from different blends of Ethylene-Vinyl copolymer (EVA) and Acrylonitrile-Butadiene copolymer (NBR) filled with particulate carbon filler. The electrical properties of these composites depend on blend composition and filler loading. High temperature (303-393K) DC-resistivity against temperature for EVA and EVA blends composites show positive coefficient of temperature (PCT effect) followed by negative coefficient of temperature (NCT effect) thus passing through a maxima which corresponds to crystalline melting temperature(~348K) of EVA phase. Further the variation of conductivity during heating cooling cycle does not coincides and leads to some kind of thermal hysteresis due to change in conductive network structure. However in low temperature region (10-300K), the resistivity is found to increase with decrease in temperature (NCT effect) and hysteresis effect is also marginal compared to that observed in high temperature region. This difference resistivity/conductivity vs temperature behavior in two different temperature zones suggests that different two mechanisms are operative in the system.
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Zhong, Wen, Siqiang Chen, and Zhe Tong. "High-Temperature Tribological Behavior of HDPE Composites Reinforced by Short Carbon Fiber under Water-Lubricated Conditions." Materials 15, no. 13 (June 27, 2022): 4508. http://dx.doi.org/10.3390/ma15134508.
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The polymer water-lubricated bearing is widely used in marine transmission systems, and the tribological properties can be improved by addition of inorganic nano-fillers. The aim of this study is to investigate the effect of SCFs and temperature on the water-lubricating properties of high-density polyethylene (HDPE) composites. HDPE composites reinforced by varying content of short carbon fibers (SCFs) were fabricated via twin-screw extrusion and injection molding techniques to study the hardness and surface wettability of those composites. The tribological properties under water-lubricated conditions were investigated through a pin-on-disk reciprocating tribometer under different temperatures. The results showed that the increase in hardness of HDPE composites reached maximum to 42.9% after adding 25 wt % SCFs. The contact angle also increased with the increase in SCFs content and reached a maximum of 95.2° as the amount of SCFs increased to 20 wt %. The incorporation of SCFs increased the wear resistance and lubricating property of HDPE composites at different temperatures. The HDPE composite containing 20 wt % SCFs showed the lowest friction coefficient of 0.076 at 40 °C, and the wear track depth reached a maximum of 36.3 mm at 60 °C. Based on the surface wetting property and wear analysis, potential effect mechanisms of fillers and temperature were discussed. The knowledge from this study is useful for designing the anti-wear water-lubricated polymer bearing.
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Zhang, Chi, Jinhao Wu, Qingnan Meng, Youhong Sun, and Mao Wen. "The Evolution of Interfacial Microstructure and Fracture Behavior of Short Carbon Fiber Reinforced 2024 Al Composites at High Temperature." Applied Sciences 9, no. 17 (August 23, 2019): 3477. http://dx.doi.org/10.3390/app9173477.
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The short carbon fiber reinforced 2024 Al composites were fabricated through powder metallurgy. The effect of short carbon fiber content on the interfacial microstructure and fracture behavior of the composites at different temperatures were investigated. The results showed that the dislocation accumulation was formed in the aluminum matrix due to the thermal expansion mismatch between carbon fiber and aluminum matrix. With the testing temperature increasing, the size of interfacial product Al4C3 and precipitates Al2Cu became larger, and the segregation of Al2Cu was found coarsening around Al4C3. The addition of short carbon fiber improved the hardness and modulus of the aluminum matrix in the vicinity of the interface between carbon fiber and aluminum matrix. Compared to the matrix 2024 Al, the yield strength and ultimate tensile strength of the composites first increased and then decreased with increasing short carbon fiber content at room temperature 423 Kand 523 K. The fracture surface of the composites at room temperature was characterized by shear failure of fiber, while the interface debonding and fiber pulled-out became predominant fracture morphologies for the fracture surface at increased temperatures.
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Nagel, Julian, Thomas Hanemann, Bastian E. Rapp, and Guido Finnah. "Enhanced PTC Effect in Polyamide/Carbon Black Composites." Materials 15, no. 15 (August 5, 2022): 5400. http://dx.doi.org/10.3390/ma15155400.
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Self-heating nanocomposites with a positive temperature coefficient (PTC) provide outstanding potential for a broad range of engineering applications in automobile, spacecraft, or smart building. Therefore, extensive studies have been carried out to understand thermo-electrical behavior. However, some controversies remain, especially on the material composition, to clarify influencing factors on the PTC performance. In this study, the thermo-electrical behaviors of injection molded carbon black (CB)/polyamide (PA) nanocomposites have been investigated. Three types of CB with well-defined specific surface area and polyamides with high and low crystallinity were selected to provide a guideline for self-heating devices including PTC-Effects. Significantly reduced specific resistances up to 2.7 Ω·cm were achieved by incorporating CB with a high specific surface area into a highly crystalline PA. Noticeable PTC-Effects of ~53% and average surface temperatures up to 147 °C have been observed due to self-heating, which confirms a promising material performance as a heating device.
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Sekulić, D. R., I. M. Djordjević, M. V. Gordić, Zijah Burzić, and M. M. Stevanović. "Gamma Radiation Effects on Mechanical Properties of Carbon/Epoxy Composites." Materials Science Forum 518 (July 2006): 549–54. http://dx.doi.org/10.4028/www.scientific.net/msf.518.549.
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Unidirectional and angle-ply carbon/epoxy laminates were gamma irradiated up to doses of 12 and 20 MGy. Composites with two different, low and high temperature epoxy matrices have been submitted to irradiation and subsequent mechanical testing. The radiation effects were studied by measuring in-plane, interalminar shear and transverse tensile strength, as well as interlaminar strain energy release rate of tested composites. The immersion of composite plate in water at 80 oC and mechanical measurements at elevated temperatures emphasized irradiation effects on mechanical properties.
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Hu, Zhaopeng, Junwei Zhou, Yihu Song, Qiang Zheng, and Wanjie Wang. "Strain softening of natural rubber composites filled with carbon black and aramid fiber." Journal of Rheology 67, no. 1 (January 2023): 157–68. http://dx.doi.org/10.1122/8.0000474.
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Engineered rubber vulcanizates may contain a low content of short fibers and a high content of nanoparticles while the effects of the different fillers on the softening behavior are not yet explored. Herein, influences of carbon black (CB) and short aramid fiber (AF) on the Payne and Mullins effects of natural rubber composites are investigated for the first time by creating master curves of dynamic modulus or dissipation energy with respect to the straining responses of the matrix. It is revealed that the composite vulcanizates demonstrate the Payne effect characterized by decay of storage modulus, weak overshoot of loss modulus, and very weak high-order harmonics; this effect is mainly dominated by the rubber matrix experiencing microscopic strain amplitude enlarged by the filler. The composite vulcanizates exhibit the Mullins effect that becomes increasingly marked with increasing filler loading and is partially recovered by thermal annealing at relatively high temperatures. The energy dissipation during cyclic tensions is rooted in the viscoelastic deformation of the matrix and the filler-rubber interfacial debonding. The former is marked at room temperature where the rubber phase undergoes a crystallization-melting process during loading-unloading. The latter being marked in the presence of a small content of AF causes yieldinglike deformation for the virgin composites at low tensile strains, and its contribution to the softening is not recoverable during thermal annealing. The results show that the viscoelastic matrix is of importance in controlling the softening of the composite vulcanizates, which will be of guiding significance to conduct research studies on high-performance rubber composites products.
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Haincová, Eliška, Pavlína Hájková, and Jan Kohout. "Prepregs for Temperature Resistant Composites." Materials 12, no. 23 (December 3, 2019): 4012. http://dx.doi.org/10.3390/ma12234012.
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In this paper, carbon fabric reinforced inorganic matrix composites were prepared. The inorganic matrix based on alkali activated aluminosilicate was used because of its resistance to fire and the temperatures up to 1000 °C. Influence of heat treatment of fabric, high temperature treatment of composite and preparation method on the mechanical properties and morphology of the composites were studied. The preparation of composites with the subsequent steps of impregnation, layering and curing of the composites was compared with the prepreg preparation method, which separates the impregnation of the reinforcement from the production of the composite. The SEM photographs show no differences in morphology between composites prepared from heat treated fabric and composites prepared from original fabrics. All four series of samples were comparatively saturated with matrix. Despite this, tensile properties of heat-treated fabric composites were negatively affected. While composites with heat-treated fabric reached the tensile strength up to 274 MPa, composites prepared without heat-treated fabric exhibited strengths higher than 336 MPa. Samples exposed to temperatures reaching 600 °C retained up to 40% of their original strength. The effect of composite preparation method on the tensile properties of the composites has not been proved.
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Jacobson, Kohl, Sam Strassler, Courtney Spalt, Sara Henry, Arthur Powers, and Donald W. Radford. "Effect of Fiber/Matrix Interface Modification on Basalt Fiber Reinforced Geopolymer Composites." Recent Progress in Materials 3, no. 1 (December 22, 2020): 1. http://dx.doi.org/10.21926/rpm.2101008.
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Continuous fiber reinforced geopolymer matrix composites offer the potential for use in structural applications at temperatures up to 700°C, while enabling the manufacture at temperatures below 100°C. Studies have investigated a variety of high temperature structural fiber reinforcements, including carbon, SiC and Al2O3. While there has been active research into various grades of Al2O3 fibers, SiC is most commonly used for high temperature reinforcement of geopolymers in oxidizing environments. Both families of reinforcement are relatively expensive and are capable of use temperatures which exceed those of the geopolymer. Basalt fibers have the potential to be a good match for the geopolymer matrix, both in terms of upper use temperature and cost. In this study, Basalt fabric reinforced geopolymer composites were prepared with fibers having three different surface conditions, as-received (silane sized), cleaned, and carbon-coated, to investigate the effect of fiber-matrix interface on the mechanical properties. All specimens were fabricated, cured at 80°C and conditioned at 250°C for 5 hours to create the baseline specimens. More than half of the 70 specimens manufactured were exposed to an additional 5 hours at 650°C. Flexural strength, strain-to-failure and modulus were determined at ambient temperature via 4-point bend testing. The as-received and cleaned specimens showed moduli approaching theoretical predictions, indicating a strong interfacial bond, resulting in brittle failures at low loads. The carbon coating resulted in a three-fold increase in strength after the 250°C conditioning and retained a strength higher than the other specimens, even after the 650°C treatment. This strength increase did come with a reduced modulus, suggesting that the stress transfer between fiber and matrix in the carbon-coated basalt fiber reinforced geopolymer composites had also been reduced. While the carbonaceous interphase was not expected to be stable at the higher temperatures in an oxidizing environment, the results do indicate that significant Basalt fiber reinforced geopolymer strength gains are possible through the implementation of a tailored fiber/matrix interface as a crack blunting mechanism.
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Tanaka, Kazuto, Jun Nishio, Tsutao Katayama, and Shinichi Enoki. "Effect of High Temperature on Fiber/Matrix Interfacial Properties for Carbon Fiber/Polyphenylenesulfide Model Composites." Key Engineering Materials 627 (September 2014): 173–76. http://dx.doi.org/10.4028/www.scientific.net/kem.627.173.
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To use Carbon Fiber Reinforced Thermoplastics (CFRTP) for automobile applications, mechanical properties of CFRTP under actual operating temperatures are needed to be clarified. When focusing on heat resistance of CFRTP, to use Polyphenylenesulfide (PPS) for the matrix is desirable. However, the effect of high temperature on mechanical properties of CFRTP using PPS has not been clarified yet. In this study, single fiber pull-out tests of CF/PPS model composites under high temperature were conducted to reveal the fiber/matrix interfacial properties.
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Zhang, Zhi Li, Hong Xiang Zhai, Yang Zhou, Zhen Ying Huang, and Ming Xing Ai. "Preparation of Composites from Al and Ti3AlC2 and its Tribo-Chemistry Reactions against Low Carbon Steel." Key Engineering Materials 368-372 (February 2008): 989–91. http://dx.doi.org/10.4028/www.scientific.net/kem.368-372.989.
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Al/Ti3AlC2 composites containing 50vol% Al were prepared with high purity of polycrystalline Ti3AlC2 and aluminum powders by pressureless-sintering route at temperatures of 700°C~ 800°C The tribological properties of the composites were investigated by sliding the composites block dryly against low carbon steel disk under high sliding speed. Before and after friction test, the morphology and phase analysis were observed by scanning electron microscope (SEM) and X-ray diffraction (XRD), separately. A definite tribo-glazing layer was found over the worn surface of the composite block, which was the results of tribo-chemical oxidation reaction and the cause forming it could be the high frictional temperature and the mechanical catabolism between the surface of Al/Ti3AlC2 and low carbon steel during sliding friction. The effect of Ti3AlC2 on tribological properties of Al/Ti3AlC2 composite and the possible tribo-chemical reaction mechanism on surface layer of Al/Ti3AlC2 were suggested.
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Xu, Liang, Yi He, Yaoxiong Jia, Shaohua Ma, and Li Hui. "Effects of thermal–oxidative aging on the mechanical properties of open-hole T800 carbon fiber/high-temperature epoxy composites." High Performance Polymers 32, no. 5 (October 31, 2019): 494–505. http://dx.doi.org/10.1177/0954008319883691.
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T800 carbon fiber/high-temperature epoxy resin composites with holes were subjected to thermal–oxidative aging, and the effects of different aging temperatures and times on the composite properties were investigated. The mass loss, surface topography, open-hole tensile performance, fracture morphologies, dynamic mechanical properties, and infrared spectra were analyzed. The results showed that chemical aging did not occur with thermal–oxidative aging at 70°C and 130°C. However, chemical aging occurred at 190°C. At 70°C, 130°C, and 190°C, all samples showed a slight increase followed by a slight decrease and stabilization in the open-hole tensile strength. The open-hole tensile strength was maximized after 240 h aging at different temperatures; the open-hole tensile strength after 1920 h aging exceeded that of the unaged samples. All composites experienced through-hole failure. With aging, the glass transition temperature ( T g) was gradually increased and then decreased. After 960 h aging at different temperatures, T g was maximized.
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Kúdela, Stanislav, Juraj Koráb, and Pavol Štefánik. "Effect of Temperature on the Complex Modulus of Mg-Based Unidirectionally Aligned Carbon Fiber Composites." Materials 15, no. 21 (November 5, 2022): 7812. http://dx.doi.org/10.3390/ma15217812.
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Composite materials based on magnesium–lithium (MgLi) and magnesium–yttrium (MgY) matrices reinforced with unidirectional carbon fibers were prepared using the gas pressure infiltration method. Two types of carbon fibers were used, high-strength PAN-based T300 fibers and high-modulus pitch-based Granoc fibers. The PAN-based carbon fibers have an internal turbostratic structure composed of crystallites. The pitch-based carbon fibers have a longitudinally aligned graphite crystal structure. The internal carbon fiber structure is crucial in the context of the interfacial reaction with the alloying element. There are various mechanisms of bonding to carbon fibers in the case of magnesium–lithium and magnesium–yttrium alloys. This paper presents the use of the DMA method for the characterization of the role of alloying elements in the quality of interfacial bonding and the influence on the complex modulus at increasingly elevated temperatures (50–250 °C). The complex modulus values of the composites with T300 fibers were in the range of 118–136 GPa. The complex modulus values of the composites with Granoc fibers were in the range of 198–236 GPa. The damping capacity of magnesium-based unidirectionally aligned carbon fiber composites is related to the quality of the interfacial bonding.
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Kopan, A. R. "Effect of Y2O3 on the Si3N4-carbon interaction at high temperatures." Refractories and Industrial Ceramics 40, no. 5-6 (May 1999): 185–86. http://dx.doi.org/10.1007/bf02762280.
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Wang, Shiyu, Lihua Wen, Jinyou Xiao, Ming Lei, Xiao Hou, and Jun Liang. "The Out-of-Plane Compression Response of Woven Thermoplastic Composites: Effects of Strain Rates and Temperature." Polymers 13, no. 2 (January 14, 2021): 264. http://dx.doi.org/10.3390/polym13020264.
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The dynamic mechanical response of high-performance thermoplastic composites over a wide range of strain rates is a challenging research topic for extreme environmental survivability in the field of aerospace engineering. This paper investigates the evolution of the dynamic properties of woven thermoplastic composites with strain rate and damage process at elevated temperatures. Out-of-plane dynamic-compression tests of glass-fiber (GF)- and carbon-fiber (CF)-reinforced polyphenylene sulfide (PPS) composites were performed using a split Hopkinson pressure bar (SHPB). Results showed that thermoplastic composites possess strain-rate strengthening effects and high-temperature weakening dependence. GF/PPS and CF/PPS composites had the same strain-rate sensitivity (SRS) below the threshold strain rate. The softening of the matrix at elevated temperatures decreased the modulus but had little effect on strength. Some empirical formulations, including strain-rate and temperature effects, are proposed for more accurately predicting the out-of-plane dynamic-compression behavior of thermoplastic composites. Lastly, the final failure of the specimens was examined by scanning electron microscopy (SEM) to explore potential failure mechanisms, such as fiber-bundle shear fracture at high strain rates and stretch break at elevated temperatures.
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García-Moreno, Irene, Miguel Caminero, Gloria Rodríguez, and Juan López-Cela. "Effect of Thermal Ageing on the Impact Damage Resistance and Tolerance of Carbon-Fibre-Reinforced Epoxy Laminates." Polymers 11, no. 1 (January 17, 2019): 160. http://dx.doi.org/10.3390/polym11010160.
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Composite structures are particularly vulnerable to impact, which drastically reduces their residual strength, in particular, at high temperatures. The glass-transition temperature (Tg) of a polymer is a critical factor that can modify the mechanical properties of the material, affecting its density, hardness and rigidity. In this work, the influence of thermal ageing on the low-velocity impact resistance and tolerance of composites is investigated by means of compression after impact (CAI) tests. Carbon-fibre-reinforced polymer (CFRP) laminates with a Tg of 195 °C were manufactured and subjected to thermal ageing treatments at 190 and 210 °C for 10 and 20 days. Drop-weight impact tests were carried out to determine the impact response of the different composite laminates. Compression after impact tests were performed in a non-standard CAI device in order to obtain the compression residual strength. Ultrasonic C-scanning of impacted samples were examined to assess the failure mechanisms of the different configurations as a function of temperature. It was observed that damage tolerance decreases as temperature increases. Nevertheless, a post-curing process was found at temperatures below the Tg that enhances the adhesion between matrix and fibres and improves the impact resistance. Finally, the results obtained demonstrate that temperature can cause significant changes to the impact behaviour of composites and must be taken to account when designing for structural applications.
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Yang, Tingli, Chuang Dong, Yiyang Rong, Zongyi Deng, Pengfei Li, Pengkun Han, Minxian Shi, and Zhixiong Huang. "Oxidation Behavior of Carbon Fibers in Ceramizable Phenolic Resin Matrix Composites at Elevated Temperatures." Polymers 14, no. 14 (July 7, 2022): 2785. http://dx.doi.org/10.3390/polym14142785.
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Carbon fiber fabric-reinforced phenolic resin composites are widely used as thermal protection materials for thermal protection systems in hypersonic vehicles and capsules. In this work, carbon fiber fabric-reinforced boron phenolic resin composites modified with MoSi2 and B4C were prepared via a compression molding technique. The high-temperature performance of the composites as well as the oxidation behavior of the carbon fibers was studied. The results indicate that the incorporation of B4C improves the performance of composites at high temperatures. The residual weight rate of composites with 15 phr B4C (BP-15) sufficiently increased from 23.03% to 32.91% compared with the composites without B4C (BP-0). After being treated at 1400 °C for 15 min, the flexural strength of BP-15 increased by 17.79% compared with BP-0. Compared with BP-0, the line ablation rate and mass ablation rate of BP-15 were reduced by 53.96% and 1.56%, respectively. In addition, MoSi2 and B4C particles had a positive effect on the oxidation of carbon fibers in the composites. After treatment at 1400 °C, the diameter of the as-received carbon fiber was reduced by 31.68%, while the diameter of the carbon fiber in BP-0 and BP-15 decreased by 15.12% and 6.14%, respectively. At high temperatures, the liquid B2O3 from B4C and MoSi2-derived complex-phase ceramics (MoB, MoB2, Mo2C, Mo4.8Si3C0.6) acted as an oxygen barrier, effectively mitigating the oxidation degree of the carbon fibers.
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Li, Juanzi, Wei Fan, Tao Liu, Linjia Yuan, Lili Xue, Wensheng Dang, and Jiaguang Meng. "The temperature effect on the inter-laminar shear properties and failure mechanism of 3D orthogonal woven composites." Textile Research Journal 90, no. 23-24 (June 3, 2020): 2806–17. http://dx.doi.org/10.1177/0040517520927009.
Full textAbstract:
Recent increases in the use of carbon fiber reinforced plastics, especially for high-temperature applications, has induced new challenges in evaluating their mechanical properties. The effects of temperature on the shear performance of 3-dimensional orthogonal and 2-dimensional plain woven composites were compared in this study through double-notch shear tests. A scanning electron microscope was employed to investigate the fiber/matrix interface properties to reveal the failure characteristics. The results showed that temperature had a visible impact on the inter-laminar shear strength (ILSS), deformation modes, and failure mechanism. The ILSS decreased as temperature increased, which was caused by the degradation of the matrix properties and fiber/matrix interface properties at high temperature. A finite element model was established to analyze the transient deformation process and the damage mechanism of the 3D orthogonal woven composite. This indicated that Z-binder yarns could improve the delamination resistance of 3D orthogonal woven composites, especially under high temperatures. The changes in failure modes of the 3D orthogonal woven composites was put down to thermal softening of the epoxy resin caused by high temperature and the undulation of the yarns.
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Ross, Michael, R. Jenkins, Charles Nelson, and Peter Joyce. "High Temperature Effects during High Energy Laser Strikes on Embedded Fiber Bragg Grating Sensors." Sensors 19, no. 6 (March 23, 2019): 1432. http://dx.doi.org/10.3390/s19061432.
Full textAbstract:
As the applications of fiber Bragg gratings (FBGs) continue to grow and become more advanced, it becomes necessary to understand their behavior when exposed to high temperatures in unique situations. In these experiments, uniform 1530-nm fiber Bragg gratings and Type K Cr-Al thermocouples were embedded in three-ply carbon fiber composites. A 100 W high energy laser (HEL) heated the composites to high temperatures over timespans less than one second, and FBG spectral data and thermocouple temperature data were collected during each HEL heating test. The data from three high energy laser tests that represent different levels of damage to the FBG are analyzed to explore the spectral response and thermal decay of embedded FBG sensors when exposed to high temperatures over short timespans. Results are compared to a previously proposed power-law model describing the decay of FBGs in bare fiber when held at constant temperatures over much longer timespans.
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Brown, Avery, Charles E. Bakis, and Edward Smith. "Experimental evaluation of carbon/epoxy laminates with concentrated carbon nanotube interlayers for high damping." Journal of the Acoustical Society of America 150, no. 4 (October 2021): A343. http://dx.doi.org/10.1121/10.0008526.
Full textAbstract:
Carbon nanotubes (CNTs) embedded in carbon/epoxy (c/ep) composites offer a lightweight, stiff solution with high damping for structural components. To manufacture CNT/c/ep hybrid composites with high concentrations of CNTs, a CNT yarn interlayer concept is used. Through a mechanism known as stick-slip, the interface between CNTs and c/ep laminates dissipate energy during dynamic cycling. It is predicted that altering the interfacial bond strength can enhance dynamic properties: loss factor, loss modulus, and storage modulus. In this research, the effect of surface treatments on CNT yarns prior to inserting the CNTs into the laminate was explored to determine if the dynamic properties of the composite were enhanced. It was determined that 2,3-dibromo-1,4-butanediol (23D14B), Triton X-100 (TX) and a solution of sulfuric and nitric (S/N Acid) were the best treatments of 12 tested based on the increased dynamic properties. For a composite with 5 vol% CNT yarn interlayers, 23D14B, TX, and S/N Acid increased Loss Factor by 230%, 130%, and 160%, respectively. Elevated temperature, moisture-saturated/elevated temperature, and cyclic loading frequency were investigated on 5vol. % CNT interlayers to determine their effects on dynamic properties of the CNT hybrid composites.
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Cui, Yu Qing, and Zhong Wei Yin. "Carbon-fibre-reinforced modified cyanate ester winding composites and their thermomechanical properties." High Performance Polymers 31, no. 2 (January 21, 2018): 154–67. http://dx.doi.org/10.1177/0954008317753526.
Full textAbstract:
Although the extensive research has expanded on the modification of cyanate ester (CE) resins and the mechanical properties of CE composites, very few studies have been conducted on carbon fibre (CF)/modified CE winding composites and the thermomechanical properties of the composites. In this research, epoxy (EP)-modified novolac cyanate ester (NCE) and bismaleimide (BMI)-modified NCE resins were prepared. The CF/modified CE winding composites were manufactured, and their thermomechanical properties were tested. The optimal winding process was determined, and a preheating technique was implemented. Then, the EP/CE resin (10:90) and the BMI–DBA/CE resin (10:90) were selected as the resin matrix of the winding composite based on the viscosity properties, mechanical properties and thermal analysis (using thermogravimetric analysis and differential scanning calorimetry) of the modified CE resin. The selected resin exhibited good manufacturability at 70°C, good thermal stability and high Tg (above 370°C). The thermomechanical property tests indicate that the modified CE resin composite exhibits an outstanding mechanical strength at room temperature and at high temperatures (130°C, 150°C and 180°C) compared with that of the pure CE resin composite. The reasons for this enhancement can be attributed to a toughening mechanism and the effect of sizing agents on the CFs.
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Mandell, J. F., D. H. Grande, and J. Jacobs. "Tensile Behavior of Glass/Ceramic Composite Materials at Elevated Temperatures." Journal of Engineering for Gas Turbines and Power 109, no. 3 (July 1, 1987): 267–73. http://dx.doi.org/10.1115/1.3240035.
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This paper describes the tensile behavior of high-temperature composite materials containing continuous Nicalon ceramic fiber reinforcement and glass and glass/ceramic matrices. The longitudinal properties of these materials can approach theoretical expectations for brittle matrix composites, failing at a strength and ultimate strain level consistent with those of the fibers. The brittle, high-modulus matrices result in a nonlinear stress-strain curve due to the onset of stable matrix cracking at 10 to 30 percent of the fiber strain to failure, and at strains below this range in off-axis plies. Current fibers and matrices can provide attractive properties well above 1000°C, but composites experience embrittlement in oxidizing atmospheres at 800 to 1000°C due to oxidation of a carbon interface reaction layer. The oxidation effect greatly increases the interface bond strength, causing composite embrittlement.
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Sharma, Sumit, Pramod Kumar, and Rakesh Chandra. "Carbon nanotube reinforced titanium composites: An experimental and molecular dynamics study." Journal of Composite Materials 52, no. 29 (May 4, 2018): 4117–23. http://dx.doi.org/10.1177/0021998318774931.
Full textAbstract:
In this study, the mechanical properties of carbon nanotube reinforced titanium (CNT–Ti) composites have been predicted using molecular dynamics approach. An experimental study was also conducted in which spark plasma sintering was used for preparing the composites. The effect of variation in carbon nanotube volume fraction ( V f), temperature, and strain on the elastic moduli ( E11, E22, and E33) and the shear modulus ( G Reuss) of CNT–Ti composites was studied. The elastic and shear moduli were all found to increase significantly because of the increasing carbon nanotube V f. Even at temperatures approaching 1 K, the CNT–Ti composites show high values of elastic and shear moduli. The elastic moduli tend to attain a constant value at high levels of strain. The results obtained from experiments corroborated the molecular dynamics results.
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Markov, A. V., V. A. Markov, and A. S. Chizhov. "The influence of the characteristics of polyethylene on thermoelectric properties of their composites with black carbon." Plasticheskie massy, no. 5-6 (July 17, 2021): 18–23. http://dx.doi.org/10.35164/0554-2901-2021-5-6-18-23.
Full textAbstract:
The work is devoted to the study of the effect of characteristics (melt flow and density) of various grades of polyethylene on the electrical resistance of polyethylene composites with carbon black at normal and elevated temperatures. Such polyethylene composites are characterized by abnormally high values of the positive temperature coefficient of electrical resistance in the melting temperature range of the polyethylene matrix. This causes the effect of power self-regulation of such heaters (selfregulating polymer heaters). It has been established that the content of carbon black, which provides a stable and clear effect of self-regulation of such heaters, is located in a concentration region approaching the region of the second concentration-structural percolation transition, which for all investigated polyethylene composites was about 12 vol% of carbon black. The growth rate of electrical resistance at these carbon-black contents is influenced by crystallinity of the polyethylene matrix.
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Nam, Tran H., Ken Goto, Toshiki Kamei, Yoshinobu Shimamura, Yoku Inoue, Satoshi Kobayashi, and Shinji Ogihara. "Improved mechanical properties of aligned multi-walled carbon nanotube/thermoplastic polyimide composites by hot stretching." Journal of Composite Materials 53, no. 9 (September 3, 2018): 1241–53. http://dx.doi.org/10.1177/0021998318796916.
Full textAbstract:
High heat resistance composites based on thermoplastic polyimide resin and aligned multi-walled carbon nanotube sheets have been developed using hot-melt processing method with a vacuum-assisted system. The horizontally aligned carbon nanotube sheets were produced from vertically aligned carbon nanotube arrays using drawing and press-winding techniques. Effects of processing conditions, carbon nanotube contents, and hot stretching on the mechanical properties of the composites were examined. The aligned carbon nanotube/thermoplastic polyimide composites were fabricated successfully at a temperature of 410℃ under 2 MPa pressure. The surface morphologies of the composites showed high alignment and dense packing of carbon nanotubes, and a good impregnation of the thermoplastic polyimide matrix into the aligned carbon nanotube sheets. The best mechanical properties of the aligned carbon nanotube/thermoplastic polyimide composites were achieved at the carbon nanotube volume fraction of about 50% in this study. Hot stretching of the aligned carbon nanotube/thermoplastic polyimide composites at the temperatures above the glass transition temperature and below the melting temperature improved the mechanical properties of the composites considerably.
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Saleem, Alteer, Veljko Petrovic, Aleksandar Grbovic, Jasmina Lozanovic-Sajic, and Igor Balac. "Numerical evaluation of the elastic properties of carbon fiber reinforced composite material at elevated and lowered temperatures." Science of Sintering 53, no. 1 (2021): 127–36. http://dx.doi.org/10.2298/sos2101127s.
Full textAbstract:
The effect of elevated and lowered temperatures on the elastic properties of carbon fiber-epoxy composite material was studied using multi-phase unit cell (MPUC) numerical model. Evaluation of the elastic properties of carbon fiber-epoxy composite material is based on the finite element method. Obtained results confirmed that elevated and lowered temperature has noticeable influence on elastic properties of carbon fiber-epoxy composite material. As demonstrated, this fact has considerable influence on accurate evaluation of generated thermal stresses in real laminated composite structures, exposed to extremely high or low operating temperatures.
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Zhang, Shao Wei, Yan Wen, and H. Aygul Yeprem. "Low Temperature Synthesis of High Quality Zirconium Carbide Powder." Applied Mechanics and Materials 319 (May 2013): 219–23. http://dx.doi.org/10.4028/www.scientific.net/amm.319.219.
Full textAbstract:
Pure submicron-sized ZrC powder was successfully synthesized in KCl by using ZrO2, Mg and carbon black as the starting raw materials. KCl showed strong accelerating effect on the molten salt synthesis. As a result, the reaction temperature was reduced to as low as 800oC, which is much lower than the temperatures used by most of the other synthesis techniques reported so far. It is believed that both ZrO2 and carbon black had acted as the “templates” in the synthesis process. High quality ZrC powders prepared with the present technique could be used for making important ZrC based composites for various applications.
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De La Vega, A., L. A. S. de A. Prado, J. Z. Kovacs, W. Bauhofer, and K. Schulte. "SWCNT as Cure-Induced Stress Sensors in Epoxy Nanocomposites." Solid State Phenomena 151 (April 2009): 48–53. http://dx.doi.org/10.4028/www.scientific.net/ssp.151.48.
Full textAbstract:
Given their unique set of properties, carbon nanotubes are rapidly gaining importance as stress/damage sensors in addition to as mere reinforcing elements in polymer composites. In this work, single-walled carbon nanotubes (SWCNT) are used to monitor internal stresses developing during the curing process of thermoset materials. SWCNT-epoxy composites with high dispersion quality were obtained via calandering. In situ Raman spectroscopy was used to identify chemical and thermal induced stresses by following the changes in the G’-band versus time and temperature. Thermal shrinkage prompts a pronounced effect on the spectral shifts of the composite, pointing at its dominant role (over chemical shrinkage) on the development of the internal stress field. Above Tg, Raman shifts due to temperature increase are found to be negligible, confirming the existence of a stress releasing mechanism. Shift rate of the composites cooling from their processing temperatures depended on the combination of matrix/SWCNT type, pointing at the role of interfacial strength on the load transfer efficiency.
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Zhou, Fei, Jiwen Zhang, Shoutan Song, Dong Yang, and Chao Wang. "Effect of Temperature on Material Properties of Carbon Fiber Reinforced Polymer (CFRP) Tendons: Experiments and Model Assessment." Materials 12, no. 7 (March 28, 2019): 1025. http://dx.doi.org/10.3390/ma12071025.
Full textAbstract:
Material properties at elevated temperatures are important factors in the fire safety design and numerical analysis of concrete members strengthened with fiber reinforced polymer (FRP) composites. Most of the previous research mainly focused on tensile strength and elastic modulus in conventional steady state temperature tests. However, the transient state test method is more realistic for strengthening concrete structures. At the same time, the coefficient of thermal expansion of FRP composites is also one of the important factors affecting concrete members at elevated temperatures. This paper presents a detailed experimental investigation on the longitudinal thermal expansion deformation, and the mechanical properties of carbon FRP (CFRP) tendons with 8 mm diameter in the steady state and transient state. The results indicate that longitudinal deformation of CFRP tendons is negative at high temperature; in addition, the transient state test results of CFRP tendons are slightly higher than the steady state test results. The final part of this paper assesses the accuracy of different empirical models. Furthermore, a new equation calculating the properties of CFRP composites at elevated temperatures is presented with the numerical fitting technique, which is in good agreement with the experimental results.
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Ayyagari, Suma, Marwan Al-Haik, Yixin Ren, and Dhriti Nepal. "Effect of Nano-Reinforcement Topologies on the Viscoelastic Performance of Carbon Nanotube/Carbon Fiber Hybrid Composites." Nanomaterials 10, no. 6 (June 22, 2020): 1213. http://dx.doi.org/10.3390/nano10061213.
Full textAbstract:
In this investigation, multi-walled carbon nanotubes (MWCNTs) were grown over carbon fiber fabrics via a relatively nondestructive synthesis technique. The MWCNTs patches were grown into three different topologies: uniform, fine patterned and coarse patterned. Hybrid carbon fiber-reinforced polymer composites (CFRPs) were fabricated based on the patterned reinforcements. Tensile tests, dynamic mechanical thermal analyses (DMTA) and flexure load relaxation tests were carried out to investigate the effect of the patterned nano-reinforcement on the static, dynamic, glass transition, and viscoelastic performance of the hybrid composites. Results revealed that the hybrid composite based on fine-patterned topology achieved better performance over all other configurations as it exhibited about 19% improvement in both the strength and modulus over the reference composite with no MWCNTs. Additionally, the increase in glass transition for this composite was as high as 13%. The damping parameter (tan δ) was improved by 46%. The stress relaxation results underlined the importance of patterned MWCNTs in minimizing the stress decay at elevated temperatures and loading conditions. Utilizing patterned MWCNTs topology significantly reduced the stress decay percentage at the thermomechanical conditions 60 MPa and 75 °C from 16.7% to 7.8%. These improvements are attributed to both the enhanced adhesion and large interface area by placing MWCNTs and by inducing an interlocking mechanism that allows the interaction of the three constituents in load transfer, crack deflection and hindering undesired viscoelastic deformations under different thermomechanical loadings.
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Sun, Qian, Huifeng Zhang, Chuanbing Huang, and Weigang Zhang. "Fabrication of C/C–SiC–ZrB2 Ultra-High Temperature Composites through Liquid–Solid Chemical Reaction." Crystals 11, no. 11 (November 7, 2021): 1352. http://dx.doi.org/10.3390/cryst11111352.
Full textAbstract:
In this paper, we aimed to improve the oxidation and ablation resistance of carbon fiber-reinforced carbon (CFC) composites at temperatures above 2000 °C. C/C–SiC–ZrB2 ultra-high temperature ceramic composites were fabricated through a complicated liquid–solid reactive process combining slurry infiltration (SI) and reactive melt infiltration (RMI). A liquid Si–Zr10 eutectic alloy was introduced, at 1600 °C, into porous CFC composites containing two kinds of boride particles (B4C and ZrB2, respectively) to form a SiC–ZrB2 matrix. The effects and mechanism of the introduced B4C and ZrB2 particles on the formation reaction and microstructure of the final C/C–SiC–ZrB2 composites were investigated in detail. It was found that the composite obtained from a C/C–B4C preform displayed a porous and loose structure, and the formed SiC–ZrB2 matrix distributed heterogeneously in the composite due to the asynchronous generation of the SiC and ZrB2 ceramics. However, the C/C–SiC–ZrB2 composite, prepared from a C/C–ZrB2 preform, showed a very dense matrix between the fiber bundles, and elongated plate-like ZrB2 ceramics appeared in the matrix, which were derived from the dissolution–diffusion–precipitation mechanism of the ZrB2 clusters. The latter composite exhibited a relatively higher ZrB2 content (9.51%) and bulk density (2.82 g/cm3), along with lower open porosity (3.43%), which endowed this novel composite with good mechanical properties, including pseudo-plastic fracture behavior.
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Liang, Ming, Linping Su, Peizhao Li, Jingtao Shi, Zhanyong Yao, Jizhe Zhang, Hongguang Jiang, and Weixin Luo. "Investigating the Rheological Properties of Carbon Nanotubes/Polymer Composites Modified Asphalt." Materials 13, no. 18 (September 14, 2020): 4077. http://dx.doi.org/10.3390/ma13184077.
Full textAbstract:
The utilization of nanomaterials in the field of binder materials for road paving has attracted researchers’ attention in recent years. This study presented the performance properties of a binder modified with carbon nanotubes (CNT) and polyethylene (PE). The rheological properties, adhesion behavior, morphology, and storage stability of the modified asphalt were investigated. Experimental analysis indicated a positive effect of CNT/PE composites on the performance of the binder. The results indicate that the combined use of CNT and PE shows a significant enhancement on complex modulus, viscosity, and creep recovery of the binder at high temperatures and a great decrease in compliance, indicating great resistance to permanent deformation. Meanwhile, only using CNT to improve the high temperature performance of the binder is limited due to high shear mixing. CNT/PE modifiers enhance the cracking resistance at low temperatures and moisture damage resistance. The CNT/PE melt mixing composites endow asphalt with stronger cracking resistance, better resistance to moisture damage and workability. Asphalt with CNT/PE composites formed an even dispersion system. Notably, CNT bridges on the interface between PE phase and asphalt for the two modified asphalts, which reinforces the cohesion of interface. Asphalt with CNT/PE composites showed improved storage stability in comparison with PE modified asphalt.
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Rozhdestvenska, Liudmyla, Kateryna Kudelko, Yevhen Kolomiiets, Yuliya Dzyazko, and Volodymyr Ogenko. "MEMBRANES FUNCTIONALIZED WITH 1d, 2d and 3d CARBON MATERIALS." Ukrainian Chemistry Journal 87, no. 4 (May 17, 2021): 79–110. http://dx.doi.org/10.33609/2708-129x.87.04.2021.79-110.
Full textAbstract:
Modification of polymer and ceramic membranes by modern one-, two- and three- dimensional carbon nanomaterials (carbon nanotubes, fullerenes and their derivatives, oxidized and reduced graphene) is considered. It is shown that carbon materials can be incorporated into membrane matrices both as independent components and as a part of multicomponent modifier. The main methods of modification are the addition of modifiers to the polymer solution with subsequent making of polymer membranes, incorporation of nanoparticles of carbon nanomaterials into the pristine membranes, deposition on the outer membrane surface, formation of nanoparticles directly in the pores of the ceramic matrix. Composite membranes containing carbon nanoparticles are used for pervaporation, gas separation, baromembrane processes and low-temperature fuel cells. The addition of carbon nanomaterials to polymers provides better mechanical strength of the membranes. Hydrophilic carbon modifiers increase the resistance of membranes to fouling by organic substances and biofouling, improves their separation ability. Ion-exchange membranes modified with fullerenol and oxidized graphene maintain high proton conductivity at elevated temperatures and low humidity. Сarbon additives increase membrane productivity in baromembrane processes. This effect is especially evident for materials modified with nanotubes: their smooth surface ensures fast liquid transport. These carbon nanomaterials are characterized by antibacterial activity. Composites consisting of nanotubes and an ion-exchange biopolymer, and composites with oxidized graphene and inorganic ion exchanger, give to membranes selectivity to inorganic ions. Ceramic membranes modified with carbon nanoparticles that were formed in the pores of matrices by carbonization of synthetic polymers and polysaccharides have the same properties.
Besides, these composites reject organic dyes too. The separating ability of composite membranes ocuures due to both dimensional and charge effects. Carbon or composite nanoparticles block the pores of the membranes. The pores formed by the modifier prevent penetration of large particles of organic substances, for example, protein macromolecules. The charge effect is realized due to the functional groups of the modifier. For membranes modified with fullerenols, the retaining of low molecular weight organic substances occurs due to adsorption. Fullerene-modified gas separation and pervaporation membranes show increased permeability and selectivity.
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Liu, Bing, Zewen Zhuge, Song Zhao, Yitong Zou, Ke Tong, Lei Sun, Xiaoyu Wang, et al. "Effects of Diamond on Microstructure, Fracture Toughness, and Tribological Properties of TiO2-Diamond Composites." Nanomaterials 12, no. 21 (October 24, 2022): 3733. http://dx.doi.org/10.3390/nano12213733.
Full textAbstract:
The reinforcements represented by graphene nanoplatelets, graphite, and carbon nanotubes have demonstrated the great potential of carbon materials as reinforcements to enhance the mechanical properties of TiO2. However, it is difficult to successfully prepare TiO2-diamond composites because diamond is highly susceptible to oxidation or graphitization at relatively high sintering temperatures. In this work, the TiO2-diamond composites were successfully prepared using high-pressure sintering. The effect of diamond on the phase composition, microstructure, mechanical properties, and tribological properties was systemically investigated. Diamond can improve fracture toughness by the crack deflection mechanism. Furthermore, the addition of diamond can also significantly reduce the friction coefficient. The composite composed of 10 wt.% diamond exhibits optimum mechanical and tribological properties, with a hardness of 14.5 GPa, bending strength of 205.2 MPa, fracture toughness of 3.5 MPa∙m1/2, and a friction coefficient of 0.3. These results enlarge the family of titania-based composites and provide a feasible approach for the preparation of TiO2-diamond composites.
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Prakash, R., Vijayan Krishnaraj, and Jamal Sheikh-Ahmad. "High-speed edge trimming of carbon fiber-reinforced polymer composites using coated router tools." Journal of Composite Materials 53, no. 28-30 (June 12, 2019): 4189–202. http://dx.doi.org/10.1177/0021998319856071.
Full textAbstract:
During trimming of edges of carbon fiber-reinforced polymer composite parts, issues such as resin degradation, delamination, and poor surface finish at the trimmed edges, and increased tool wear in cutting tools used is common. Therefore, it is essential to carry out investigations on edge trimming of carbon fiber-reinforced polymer to find the effect of cutting forces generated and the cutting tool temperature induced at different high speeds and feeds conditions. In this work, two different-coated router tools of titanium aluminum nitride-coated and diamond-like carbon-coated routers were used for investigating the effect of these coatings on cutting force and cutting tool temperature which affect the surface quality of trimmed carbon fiber-reinforced polymer. From the investigation, it was found that the diamond-like carbon-coated router tool has generated lower cutting forces, cutting tool temperatures, and, in turn, better surface finish even at high-speed conditions when compared to other tools. Due to the complex geometry of the router tool, online tool wear monitoring by acoustic emission technique was employed. Acoustic emission signals were taken as the measuring index of tool wear which shows good correlation with direct tool wear measurements. From the experiments, it was found that the tool performance of the diamond-like carbon-coated router is superior when compared to other tools. In addition, for edge trimming of carbon fiber-reinforced polymer composite parts, the diamond-like carbon router tool performed without much disturbance for a length of machining of around 5.9 m which is about 46% of increase in length of machining when compared to uncoated router tool.
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Aborkin, Artemiy V., Dmitriy V. Bokaryov, Sergey A. Pankratov, and Alexey I. Elkin. "Increasing the Flow Stress during High-Temperature Deformation of Aluminum Matrix Composites Reinforced with TiC-Coated CNTs." Ceramics 6, no. 1 (January 10, 2023): 231–40. http://dx.doi.org/10.3390/ceramics6010013.
Full textAbstract:
In this work, composites based on AA5049 aluminium alloy reinforced with multiwalled carbon nanotubes (CNTs) and multiwalled TiC-coated CNTs were prepared by powder metallurgy. For the first time, the effect of TiC coating on the CNT surface on the flow stress of aluminum matrix composites under compressive conditions at 300–500 °C has been investigated. It was found that composites reinforced with TiC-coated CNTs have a higher flow stress during high-temperature deformation compared to composites reinforced with uncoated CNTs. Moreover, with an increasing temperature in the 300–500 °C range, the strengthening effect increases from 14% to 37%. Compared to the reference sample of the matrix material without reinforcing particles, obtained by the same technological route, the composites reinforced with CNTs and CNT-hybrid structures had a 1.8–2.9 times higher flow stress during high-temperature deformation. The presented results show that the modification of the CNTs surface with ceramic nanoparticles is a promising structure design strategy that improves the heat resistance of aluminum matrix composites. This extends the potential range of application of aluminum matrix composites as a structural material for operation at elevated temperatures.
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Khattab, Ahmed. "Cure Cycle Effect on High-Temperature Polymer Composite Structures Molded by VARTM." Journal of Composites 2013 (April 28, 2013): 1–6. http://dx.doi.org/10.1155/2013/162657.
Full textAbstract:
This paper presents an analytical and experimental investigation of cure cycle effect on carbon-fiber reinforced high-temperature polymer composite structures molded by vacuum assisted resin transfer molding (VARTM). The molded composite structure consists of AS4-8 harness carbon-fiber fabrics and a high-temperature polymer (Cycom 5250-4-RTM). Thermal and resin cure analysis is performed to model the cure cycle of the VARTM process. The temperature and cure variations with time are determined by solving the three-dimensional transient energy and species equations within the composite part. Several case studies were investigated by the developed analytical model. The same cases were also experimentally investigated to determine the ultimate tensile strength for each case. This study helps in developing a science based technology for the VARTM process for the understanding of the process behavior and the effect of the cure cycle on the properties of the molded high-temperature polymer composites.
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Li, Long, Xie Rong Zeng, He Jun Li, Xin Bo Xiong, Xiao Hua Li, and Sheng Hui Xie. "Influence of Low-Level Oxidation on Mechanical Property of Two-Dimension Carbon/Carbon Composites." Advanced Materials Research 47-50 (June 2008): 455–58. http://dx.doi.org/10.4028/www.scientific.net/amr.47-50.455.
Full textAbstract:
The effect of low-level oxidation (weight loss less than 6wt.%) on mechanical property of two-dimension (2D) carbon/carbon (C/C) composites was investigated in present work. C/C samples were oxidized in a mixture gas, composed of 10vol%O2 and 90vol%N2, at temperatures of 850°C and 1300°C, respectively. The strength of C/C composites before and after oxidation was measured by three point flexural tests. At different temperature, similar influences of low-level oxidation on mechanical property of C/C samples were observed. As a result, failure of the as-received composites was accompanied by brittle, catastrophic reduction in force. As oxidation progressed, the fracture model of oxidized samples changed from brittle model to pseudoplastic failure model. Especially, the changes of flexural strength with the weight loss increasing could be divided into two stages: (i) at low weight loss, the strength increased with weight loss and is slightly higher than that of the unoxidized composites; (ii) at high weight loss, the strength decreased gradually with the weight loss.
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Ma, Yuqin, Fei Li, Wei Xu, Yuyang Zhang, Yi Xu, Haiyin Guo, and Yatao Li. "Influence of Extrusion Temperature on Properties of Graphene Oxide-Carbon Fiber/Epoxy Composite Prepared by Vacuum Infiltration Hot-Press-Forming Experimental System." Nanomaterials 12, no. 21 (October 30, 2022): 3839. http://dx.doi.org/10.3390/nano12213839.
Full textAbstract:
Graphene oxide-carbon fiber/epoxy (GO-CF/EP) composites with extrusion temperatures of 30, 40, 50, 60 and 70 °C were prepared by a vacuum infiltration hot-press-forming experimental system (VIHPS). The effects of extrusion temperature on the microstructure, fracture mechanism and mechanical properties of GO-CF/EP composites were investigated. It was found that the best mechanical property of composites and infiltration effect of the matrix in the fiber gap were obtained at the temperature of 50 °C, and the bending strength of the composite reached 728 MPa. The fiber was pulled out and broken under the wrapping of the matrix. The matrix viscosity was high, and the fluidity was poor when the extrusion temperature was low. The poor infiltration of the matrix resulted in many fibers failing to bond together, resulting in the disorderly breakage of fiber bundles. Under the condition of higher temperature, the flow speed of the matrix could be improved. However, part of the matrix was extruded during the extrusion process, and cracks and other defects occurred during the loading, which caused the brittle fracture of the specimen.
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Zhou, Ping, Pu Rong Jia, and Wen Ge Pan. "Mechanical Response of T300/BMP350 Composites under Tensile Loading at Room and Elevated Temperatures." Advanced Materials Research 1035 (October 2014): 138–43. http://dx.doi.org/10.4028/www.scientific.net/amr.1035.138.
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In this paper, the effect of elevated temperature on the behavior of carbon fiber-reinforced T300/BMP350 unidirectional laminates was studied by loading static tensile on 0°, 90°and ±45° lay-up. The stress-strain relationships of the laminates under different temperatures were obtained. The effect of temperature on the mechanical properties of materials was systematically studied. The damage and failure mechanisms of the material were studied by analyzing the material stress-strain curves and the failure modes. Results show that the T300/BMP350 polyimide matrix composites have a strong resistance to high temperature. For 0° and 90° lay-up, the retentions of tensile strength and modulus are more than 80% and 50%, respectively. High temperature has little effect on the material failure modes. Finally, based on the test results, an empirical formula which relates strength and temperature of the material was fitted.
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Gnanaseelan, Minoj, Kristin Trommer, Maik Gude, Rafal Stanik, Bartlomiej Przybyszewski, Rafal Kozera, and Anna Boczkowska. "Effect of Strain on Heating Characteristics of Silicone/CNT Composites." Materials 14, no. 16 (August 12, 2021): 4528. http://dx.doi.org/10.3390/ma14164528.
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In this work, silicone/carbon nanotube (CNT) composites were produced using a spread coating process, followed by morphological investigations and determination of their electrical properties and heating behaviour through the application of electric potential. Composites containing varying amounts of CNT (1–7%) were investigated for their thermal behaviour with the use of an IR camera. Subsequently, thermal behaviour and electrical properties were measured when the samples were stretched (up to 20%). With the 7% CNT composites, which had a conductivity of 106 S/m, it was possible to achieve a temperature of 155 °C at a relatively low voltage of 23 V. For high CNT contents, when the potential was controlled in such a way as to maintain the temperature well below 100 °C, the temperature remained almost constant at all levels of strain investigated. At higher potentials yielding temperatures around 100 °C and above, stretching had a drastic effect on temperature. These results are critical for designing composites for dynamic applications requiring a material whose properties remain stable under strain.
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Yang, Yisha, Duxin Li, Gaojie Si, Qilong Liu, and Yue Chen. "Improved thermal and mechanical properties of carbon fiber filled polyamide 46 composites." Journal of Polymer Engineering 37, no. 4 (May 1, 2017): 345–53. http://dx.doi.org/10.1515/polyeng-2016-0092.
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Abstract The thermal and mechanical properties of polyamide 46 (PA46) filled with carbon fiber (CF/PA46) composites were studied. CF/PA46 was fabricated by the method of melt blending and injection molding. The results showed that thermal conductivity, tensile strength and impact strength of the composite increased with the increase of weight fraction of CF, however, the elongation at the break decreased as its weight fraction increased. The addition of CF had little effect on the melting temperature of composites, while the crystallization onset (To) and crystallization peak (Tp) temperatures of composites shifted to higher points. The scanning electron microscope images showed that when the weight fraction of CF was increased, the CF was more likely to form thermal chains and a network. When the CF weight fraction was 40%, thermal conductivity was 1.49 W/(m·K), approximately 5.54 times as high as that of the pure PA46, and the thermal diffusivity was 0.9755 mm2/s, 6.5 times higher than that of the pure matrix. Comparing the experimental data with the three expected thermal conduction models data, the Maxwell-Eucken thermal conduction model was considered more suitable for the PA46/CF composite, in which the weight fraction of the filler was <10% in the thermal conductive system.
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Alobaidi, Hadeel A., and Nabeel Almuramady. "Influence of heat aging on tensile test in rubber-epoxy composites." Al-Qadisiyah Journal for Engineering Sciences 15, no. 2 (August 29, 2022): 132–35. http://dx.doi.org/10.30772/qjes.v15i2.839.
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Composite materials using natural rubber as the main matrix are popular these days because of the wide applications of rubber materials in modern industries. Rubber materials also have damping properties, energy absorption, and exposure to continuous loads and different environmental conditions. In this research, the effect of temperatures on the rubber-epoxy composite with different ratios (0%, 10%, 20%, 30%, 40%, and 50%) of carbon has been studied. Where comparison was made between heat-aged and un-aged samples using the tensile test. To know the effect of high temperatures on the rubber-epoxy composite, it was done in a heated oven at a temperature of 70. The results obtained from the tensile test observed a decrease in tensile strength and elongation when exposed to thermal aging.