scholarly journals Thermal conductivity and bending strength of SiC composites reinforced by pitch-based carbon fibers

2022 ◽  
Vol 11 (2) ◽  
pp. 247-262
Author(s):  
Liyang Cao ◽  
Yongsheng Liu ◽  
Yunhai Zhang ◽  
Yejie Cao ◽  
Jingxin Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Content ◽  
Carbon Fibers ◽  
Reaction Temperature ◽  
Bending Strength ◽  
Ceramic Composites ◽  
Future Application ◽  
Pull Out ◽  
Sic Composites ◽  
Thermal Conductivities

AbstractIn this work, pitch-based carbon fibers were utilized to reinforce silicon carbide (SiC) composites via reaction melting infiltration (RMI) method by controlling the reaction temperature and resin carbon content. Thermal conductivities and bending strengths of composites obtained under different preparation conditions were characterized by various analytical methods. Results showed the formation of SiC whiskers (SiCw) during RMI process according to vapor—solid (VS) mechanism. SiCw played an important role in toughening the Cpf/SiC composites due to crack bridging, crack deflection, and SiCw pull-out. Increase in reaction temperature during RMI process led to an initial increase in thermal conductivity along in-plane and thickness directions of composites, followed by a decline. At reaction temperature of 1600 °C, thermal conductivities along the in-plane and thickness directions were estimated to be 203.00 and 39.59 W/(m·K), respectively. Under these conditions, bending strength was recorded as 186.15±3.95 MPa. Increase in resin carbon content before RMI process led to the generation of more SiC matrix. Thermal conductivities along in-plane and thickness directions remained stable with desirable values of 175.79 and 38.86 W/(m·K), respectively. By comparison, optimal bending strength improved to 244.62±3.07 MPa. In sum, these findings look promising for future application of pitch-based carbon fibers for reinforcement of SiC ceramic composites.

Preparation and Properties of Rigid Carbon Felt Thermal Insulation

2015 ◽  
Vol 833 ◽  
pp. 48-51 ◽  
Author(s):  
Wei Shi ◽  
Jia Yan Li ◽  
Qi Fan You ◽  
Tong Lu ◽  
Yi Tan
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Insulation ◽  
Bending Strength ◽  
High Thermal Conductivity ◽  
Carbon Felt ◽  
Matrix Concentration ◽  
Thermal Conductivities

Matrix derived from resin after carbonization in rigid carbon felt thermal insulation has many advantages. The microstructures and properties of these materials were investigated in this paper. Results showed that matrix tend to accumulate at the intersections of fibers. This can improve mechanical properties and have a little influence on thermal conductivities of the composites. The excellent bending strength of 2.66MPa, compressive strength of 0.91MPa and a high thermal conductivity of 0.81W/(m·K) (at 1500°C) with a matrix concentration of 32.7% is achieved. However, high thermal conductivity is harmful for those materials which are used as thermal insulators.

Fabrication and Properties of Cf/Ti3SiC2-SiC Composites Using Ti3SiC2 as Inert Filler

2012 ◽  
Vol 512-515 ◽  
pp. 681-684 ◽  
Author(s):  
Jin Shan Yang ◽  
Shao Ming Dong ◽  
Ping He ◽  
Qing Gang Li ◽  
Bin Wu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Bending Strength ◽  
Chemical Resistance ◽  
Ceramic Matrix ◽  
Xrd Analysis ◽  
Low Density ◽  
Pyrolysis Process ◽  
Sic Composites ◽  
Polymer Infiltration

Because of its combined characteristics of metals and ceramics, such as low density, high Young’s modulus, thermal and chemical resistance with low hardness, high electrical and thermal conductivity, it was expected that the introduction of Ti3SiC2 to fiber reinforced ceramic matrix can make the composite own some unique properties. In the present research, Ti3SiC2 powders used as inert fillers were fabricated by the in-situ reaction between Ti and polycarbosilane mixtures. The purity of Ti3SiC2 powders analyzed by XRD was determined by RIR method, which is a semi-quantitative XRD analysis. The results showed that the purity of Ti3SiC2 powders is about 96%. Cf/Ti3SiC 2-SiC composites are obtained by polymer infiltration and pyrolysis process using Ti3SiC2 powders as the inert fillers. The bending strength of Cf/Ti3SiC2-SiC composites was about 160 MPa.

scholarly journals Development and Characterization of Lightweight Geopolymer Composite Reinforced with Hybrid Carbon and Steel Fibers

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5741
Author(s):  
Agnieszka Baziak ◽  
Kinga Pławecka ◽  
Izabela Hager ◽  
Arnaud Castel ◽  
Kinga Korniejenko
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Carbon Fibers ◽  
Bending Strength ◽  
Steel Fiber ◽  
Steel Fibers ◽  
Reinforced Composite ◽  
Geopolymer Matrix ◽  
Geopolymer Composites

The aim of this paper is to analyze the influence of hybrid fiber reinforcement on the properties of a lightweight fly ash-based geopolymer. The matrix includes the ratio of fly ash and microspheres at 1:1. Carbon and steel fibers have been chosen due to their high mechanical properties as reinforcement. Short steel fibers (SFs) and/or carbon fibers (CFs) were used as reinforcement in the following proportions: 2.0% wt. CFs, 1.5% wt. CFs and 0.5% wt. SFs, 1.0% wt. CFs and 1.0% wt. SFs, 0.5% wt. CFs and 1.5% wt. SFs and 2.0% wt. SFs. Hybrid reinforcement of geopolymer composites was used to obtain optimal strength properties, i.e., compressive strength due to steel fiber and bending strength due to carbon fibers. Additionally, reference samples consisting of the geopolymer matrix material itself. After the production of geopolymer composites, their density was examined, and the structure (using scanning electron microscopy) and mechanical properties (i.e., bending and compressive strength) in relation to the type and amount of reinforcement. In addition, to determine the thermal insulation properties of the geopolymer matrix, its thermal conductivity coefficient was determined. The results show that the addition of fiber improved compressive and bending strength. The best compressive strength is obtained for a steel fiber-reinforced composite (2.0% wt.). The best bending strength is obtained for the hybrid reinforced composite: 1.5% wt. CFs and 0.5% wt. SFs. The geopolymer composite is characterized by low thermal conductivity (0.18–0.22 W/m ∙ K) at low density (0.89–0.93 g/cm3).

scholarly journals Ultra High Performance Concrete Reinforced with Short Steel and Carbon Fibers

2015 ◽  
Vol 1 ◽  
pp. 193 ◽  
Author(s):  
Genadijs Šahmenko ◽  
Andrejs Krasnikovs ◽  
Artūrs Lukašenoks ◽  
Māris Eiduks
Keyword(s):  
Carbon Fibers ◽  
High Performance ◽  
Bending Strength ◽  
High Performance Concrete ◽  
Steel Fibers ◽  
Cement Matrix ◽  
Cracking Behavior ◽  
Combined Application ◽  
Pull Out ◽  
Bearing Stress

<p class="R-AbstractKeywords"><span lang="EN-US">Fibers are usually used in High Performance Concrete with a purpose to increase bending strength and ductility. Important properties are the peak value of bearing stress (strength) and post-cracking behavior of bended element. In the framework of an experimental part, Ultra High Performance mix compositions were prepared using intensive mixer. Short steel fibers and carbon micro fibers in amount of 1% by volume, as well as its combination were used for cement matrix reinforcing. Results of compressive and bending tests proved an increase of strength value in the case of use both steel and carbon fibers. Carbon fibers were decreased the effect of explosive collapse of the UHPC cement matrix, at the same time still brittle bending behavior was take place. Steel fibers considerably improved bending ductility thanks to a pull-out mechanism of steel fibers. The best results were achieved in the case of combined application of both carbon and steel fibers.</span></p>

Bending properties and failure mechanisms of three-dimensional hybrid woven spacer composites with glass and carbon fibers

2019 ◽  
Vol 89 (21-22) ◽  
pp. 4502-4511 ◽  
Author(s):  
Liyong Wang ◽  
Xiaohua Liu ◽  
Sidra Saleemi ◽  
Yinjiang Zhang ◽  
Yiping Qiu ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
Carbon Fibers ◽  
Composite Structures ◽  
Bending Strength ◽  
Hybrid Composites ◽  
Three Dimensional ◽  
Core Layer ◽  
Bending Test ◽  
Pull Out ◽  
The Face

Three-dimensional (3D) woven spacer composites are competitive materials in aerospace fields due to their excellent integrated, light-weight structure. The face sheets of the 3D woven spacer composites are crucial for the mechanical properties. In this study, 3D hybrid composites, which are composed of glass and carbon fibers in the face sheets and glass fiber in the core layer as reinforcement and epoxy resin as the matrix, were designed and fabricated. The bending test results show that with the increase of the carbon fibers in the face sheets, the normalized bending strength of hybrid spacer composites showed limited improvement, while their normalized bending moduli and bending stiffnesses were significantly improved. The optical and scanning electron microscope images of the fractured surfaces reveal that the fibers in the top face sheet, which is under compression by the indenter, are damaged first and cause the failure of the entire structure, whereas the fibers in the bottom face sheets are stretched during the bending test and slightly damaged. In addition, in the failure cross-sections, pull-out of the carbon fibers is observed due to its limited interfacial bonding with the epoxy resin. This work could help optimize 3D hybrid woven spacer composite structures for better performance and lower cost.

The Properties of Oxidated Carbon Fibers Reinforced Cement

2010 ◽  
Vol 163-167 ◽  
pp. 1203-1206
Author(s):  
Xian Feng Xu ◽  
Yan Yan Hu
Keyword(s):  
Mechanical Properties ◽  
Carbon Fibers ◽  
Bending Strength ◽  
Physical And Mechanical Properties ◽  
Oxidation Treatment ◽  
Pull Out ◽  
The Matrix ◽  
Reinforced Cement ◽  
Short Time ◽  
Fiber Reinforce

Carbon fiber (CF)is the most important reinforcement in advanced composites.Carbon fiber-reinforce cement（CFRC）possess all right mechanical properties.Carbon fiber-reinforce cement（CFRC）was produced after Carbon fibers (T700) were slightly oxidized by the method of oxidation treatment at 773K in air for a short time. The result indicates that the density of CFRC reduces, porosity enhances, the bending strength and the compressive strength enhance when carbon fibers increases,by detecting the pre-and post-treatment physical and mechanical properties of CFRC, observing the microstructure of the fracture of the Side Bend Test samples. SEM morphology shows that the fracture of carbon fibers without oxidation is pull-out failure mainly while these with oxidation is pull- cut failure mainly. In a word,Carbon fibers with slight oxidation can improve the combine state of the interface between the fibers and the matrix, and accordingly improve the mechanical properties of the CFRC.

scholarly journals Enhanced Mechanical Property of RMI C/SiC Composites with Optimized Porous Carbon Structure by Heat Treatment

2020 ◽  
Author(s):  
Ruru Guo ◽  
Zhijian Li ◽  
Lu Li ◽  
Peng Wang ◽  
Chaoli Ma
Keyword(s):  
Heat Treatment ◽  
Mechanical Property ◽  
Porous Carbon ◽  
Bending Strength ◽  
Molten Silicon ◽  
Carbon Structure ◽  
Pull Out ◽  
Matrix Cracks ◽  
Sic Composites

Abstract C/SiC composites were fabricated by reactive melt infiltration (RMI) using porous C/C preforms as the skeleton, followed by the infiltration of molten silicon. A convenient technique of heat treatment in the range of 1500 to 2400 oC was applied to modify the porous carbon structure. The effects of heat treatment on the porous C/C preforms and the as-synthesized C/SiC composites were investigated in detail. The results show that the optimal porous carbon structure could be obtained after heat treatment at 1500 oC. After 1500 oC heat treatment, the median pore size and porosity of the porous C/C preform were 9.3 µm and 13.65% respectively, which were in favor of the subsequent infiltration of molten Si. The C/SiC composites with the optimized porous carbon structure showed a dense and uniform morphology without obvious cracks. Their bending strength could be up to 276 MPa, which was 28% higher than that of the C/SiC composites with untreated C/C preforms. However, with the increasing heat treatment temperature (2400 oC), the bending strength of the as obtained composites began to decrease because of the degradation of in-situ fiber strength. The optimized C/SiC composites exhibited a typical pseudo-plastic fracture behavior with obvious fiber pull-out. The improved mechanical property could be ascribed to the lower porosity of composites, the higher in-situ strength of fibers and the reduced matrix cracks.

scholarly journals Microstructure and Mechanical Properties of TiN–TiB2–hBN Composites Fabricated by Reactive Hot Pressing Using TiN–B Mixture

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7198
Author(s):  
Qianglong He ◽  
Tian Tian ◽  
Shi Tian ◽  
Wenchao Guo ◽  
Yunwei Shi ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Hot Pressing ◽  
Bending Strength ◽  
Raw Materials ◽  
Ceramic Composites ◽  
Structural Defects ◽  
Highly Active ◽  
Pull Out ◽  
Uniform Dispersion ◽  
Reactive Hot Pressing

In this study, TiN–TiB2–hBN composite ceramics were prepared via reactive hot pressing using TiN and amorphous B powders as raw materials. Different sintering temperatures and composition ratios were studied. The results show that the 70 vol% TiN–17.6 vol% TiB2–12.4 vol% hBN ceramic composites obtained ideal comprehensive properties at 1600 °C. The relative density, Vickers hardness, bending strength, and fracture toughness were 99%, 11 GPa, 521 MPa, and 4.22 MPa·m1/2, respectively. Densification was promoted by the highly active reaction product TiB2, and the structural defects formed in the grains. Meanwhile, the good interfacial bonding between TiN and TiB2 grains and the uniform dispersion of ultrafine hBN in the matrix contributed to the excellent bending strength. Moreover, the toughening mechanism of crack deflection and grain pull-out improved the fracture toughness.

Bending Strength of Steel Fibre Reinforced Concrete Ribbed Slab Panel

2018 ◽  
Vol 15 (1) ◽  
pp. 15
Author(s):  
AMIR SYAFIQ SAMSUDIN ◽  
MOHD HISBANY MOHD HASHIM ◽  
SITI HAWA HAMZAH ◽  
AFIDAH ABU BAKAR
Keyword(s):  
Reinforced Concrete ◽  
Bending Strength ◽  
Steel Fibre ◽  
Concrete Slab ◽  
Future Application ◽  
Fibre Reinforcement ◽  
Fibre Reinforced Concrete ◽  
Conventional Concrete ◽  
Steel Fibre Reinforced Concrete ◽  
Bending Load

Nowadays, demands in the application of fibre in concrete increase gradually as an engineering material. Rapid cost increment of material causes the increase in demand of new technology that provides safe, efficient and economical design for the present and future application. The introduction of ribbed slab reduces concrete materials and thus the cost, but the strength of the structure also reduces due to the reducing of material. Steel fibre reinforced concrete (SFRC) has the ability to maintain a part of its tensile strength prior to crack in order to resist more loading compared to conventional concrete. Meanwhile, the ribbed slab can help in material reduction. This research investigated on the bending strength of 2-ribbed and 3-ribbed concrete slab with steel fibre reinforcement under static loading with a span of 1500 mm and 1000 mm x 75 mm in cross section. An amount of 40 kg/m steel fibre of all total concrete volume was used as reinforcement instead of conventional bars with concrete grade 30 N/mm2. The slab was tested under three-point bending. Load versus deflection curve was plotted to illustrate the result and to compare the deflection between control and ribbed slab. This research shows that SFRC Ribbed Slab capable to withstand the same amount of load as normal slab structure, although the concrete volume reduces up to 20%.

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