Carbon Fiber Matrix Research Articles

Graphene-controlled FeSe nanoparticles embedded in carbon nanofibers for high-performance potassium-ion batteries

Iron selenide (FeSe) has drawn attention due to its resource-rich, environment-friendly, and low toxicity advantages. However, FeSe, like many transition metal selenides, has some limitations, including low conductivity and massive volume expansion during charge and discharge. Thus, graphene oxide-controlled FeSe nanoparticles embedded in carbon nanofibers were created using graphene oxide as an additive in the electrospinning precursor. The composites as the anodes for potassium-ion batteries (KIBs) can maintain an excellent capacity of 409 mA h g−1 at a current density of 0.2 A g−1 after 400 cycles with the capacity retention of nearly 100%. Even at 2 A g−1, the capacity can maintain 200 mA h g−1 after 1700 cycles with the capacity retention of about 80.9%. It was discovered that the addition of graphene oxide can reduce the diameter of FeSe nanoparticles and cause most nanoparticles to be wrapped in carbon fibers, which can relieve volume expansion and improve composite stability. Furthermore, the graphene and carbon fiber matrix can result in high K-ion diffusion kinetics, improved material conductivity, and enhanced pseudo-capacitance performance, endowing composites with excellent cycling and rate performance. The strategy of using graphene oxide to control the microstructure and improve the conductivity of carbon fiber composites may provide a new idea for future application and development of carbon fibers in other energy devices.

Tetrafunctional template-assisted strategy to preciously construct co-doped Sb@C nanofiber with longitudinal tunnels for ultralong-life and high-rate sodium storage

Antimony (Sb) is an attractive alloy-type anode material for sodium-ion batteries (SIBs) owing to its high theoretical capacity and the very appropriate reaction potential. However, it suffers from rapid capacity fading and poor rate performance caused by the huge volume changes (∼390%) and sluggish kinetics during sodiation and desodiation, severely hindering its practical application. Structural or component-based modulation strategies alone are usually not effective in solving all issues. Herein, we rationalized the facile construction of N, S co-doped Sb and carbon nanofibers (Sb@N,S-CNFs) with longitudinal tunnels through a tetrafunctional template-assisted strategy, taking into account the overall structural and compositional considerations. The pyrolysis of Sb2S3 nanorod template and the volatilization of Sb results in the formation of void space and Sb nanorods in longitudinal tunnels as well as the doping of Sb nanodots and sulfur in carbon fiber matrix. This well-designed multilevel structure optimized for favorable annealing time not only effectively mitigates large volume changes, but also greatly improves the diffusion kinetics of ions and electrons, thus resulting in much improved rate performance (219 mAh g−1 at 4 A g−1) and cycling stability (85.1% capacity retention after 1000 cycles at 2 A g−1) in half cells as well as a favorable rate capability and cycling performance in full cells matched with Na3V2(PO4)2O2F cathode. Additionally, the multifunctional template-assisted strategy provides precious guidance for the rational design and construction of high-performance electrode materials.

Damage to inverse hybrid laminate structures: an analysis of shear strength test

Abstract Hybrid laminates with continuous fiber reinforcement, such as glass reinforced aluminium laminate (GLARE), aramid reinforced aluminum laminate (ARALL), or carbon reinforced aluminum laminate (CARALL), have been developed to increase the lightweight potential and fatigue resistance applied for aircraft structures. However, the use of thermosetting matrices imposes material limitations regarding recycling, malleability, and manufacturing-cycle times. The inverse hybrid laminate approach is based on a continuous fiber-reinforced thermoplastic matrix, in which a metal insert is integrated. For efficient manufacturing of the novel composites in high-volume production processes, conventional sheet metal–forming methods have been applied. It helped to reduce the cycle times and the costs of the forming equipment compared to currently used hybrid laminate-processing technologies. The present study analyzes the damage to the inverse hybrid laminate structures resulting from the interlaminar shear strength test. The tests were performed for eight laminate material configurations, which differed by the type and directions of the reinforced glass and carbon fibers in the polyamide matrix and the number of the fiber-reinforced polymer (FRP) layers in the laminates. Industrial computed tomography and scanning electron microscopy were used for analysis. Observed damages, including fiber–matrix debonding, fiber breakages, matrix fractures, interfacial debonding, and delamination in selected areas of the material, are strictly dependent on the laminate configurations. FRP layers reinforced by fibers perpendicular to the bending axis presented better resistance against fractures of the matrix, but their adhesion to the aluminum inserts was lower than in layers reinforced by fibers parallel to the bending axis.

Debonding-on-demand adhesive film using internal Joule heating effect of the steel-aramid braided reinforcement

Carbon fiber-reinforced polymer (CFRP) composite materials are widely employed as lightweight and high-strength materials. Recently, interest in reuse has increased in terms of price and environmentally friendly. In this study, a novel adhesive film that can selectively control adhesive strength was studied. This debonding-on-demand (DOD) adhesive film is stitched by stainless steel fibers to be heated up to 239.3 °C in 5 min through Joule heating. The polymeric adhesive layer in the midst of the carbon plies is thermally damaged, and then it is successfully delaminated with no further damage to the carbon fiber or CFRP matrix materials. Thermal, optical, and mechanical testing were performed on the prepared DOD film. It is noted that the optimal structure of DOD film includes electrical insulation layers, and the number of stitch lines is carefully designed for reliable bonding and debonding performance.

Inelastic neutron spectra of polyacrylonitrile-based carbon fibers

We present the vibrational spectra of polyacrylonitrile-based carbon fibers collected using inelastic neutron scattering. We ascertain the behavior of a broad range of vibrational spectra that are optically silent, and demonstrate a direct connection between these modes and thermomechanical properties of the fibers. We show directionally dependent coupling of hydrogen in the carbon fiber matrix, which is directly linked to mechanical properties. Further, we show hydrogen preferentially couples to the midband of the vibrational spectrum, and that there are higher overall mode populations in the traditional Raman D--G intervalley region, suggesting involvement of these modes in tensile strength reduction and transport properties.

High-Performance Thermal Interface Materials with Magnetic Aligned Carbon Fibers.

Thermal interface materials with high thermal conductivity and low hardness are crucial to the heat dissipation of high-power electronics. In this study, a high magnetic field was used to align the milled carbon fibers (CFs, 150 μm) in silicone rubber matrix to fabricate thermal interface materials with an ordered and discontinuous structure. The relationship among the magnetic field density, the alignment degree of CFs, and the properties of the resulting composites was explored by experimental study and theoretical analysis. The results showed higher alignment degree and enhanced thermal conductivity of composites under increased magnetic flux density within a certain curing time. When the magnetic flux density increased to 9 T, the CFs showed perfect alignment and the composite showed a high thermal conductivity of 11.76 W/(m·K) with only 20 vol% CF loading, owing to the ordered structure. Meanwhile, due to the low filler loading and discontinuous structure, a low hardness of 60~70 (shore 00) was also realized. Their thermal management performance was further confirmed in a test system, revealing promising applications for magnetic aligned CF–rubber composites in thermal interface materials.

Oxidation behaviors of carbon fiber reinforced multilayer SiC-Si3N4 matrix composites

Oxidation behaviors of carbon fiber reinforced SiC matrix composites (C/SiC) are one of the most noteworthy properties. For C/SiC, the oxidation behavior was controlled by matrix microcracks caused by the mismatch of coefficients of thermal expansion (CTEs) and elastic modulus between carbon fiber and SiC matrix. In order to improve the oxidation resistance, multilayer SiC-Si3N4 matrices were fabricated by chemical vapor infiltration (CVI) to alleviate the above two kinds of mismatch and change the local stress distribution. For the oxidation of C/SiC with multilayer matrices, matrix microcracks would be deflected at the transition layer between different layers of multilayer SiC-Si3N4 matrix to lengthen the oxygen diffusion channels, thereby improving the oxidation resistance of C/SiC, especially at 800 and 1000 °C. The strength retention ratio was increased from 61.9% (C/SiC-SiC/SiC) to 75.7% (C/SiC-Si3N4/SiC/SiC) and 67.8% (C/SiC-SiC/Si3N4/SiC) after oxidation at 800 °C for 10 h.

Impedance spectroscopy applied to the study of conductive cements

The addition of carbon fibers is the main alternative used for the manufacturing of conductive cements since, at a relative low price, provides a good combination of structural and functional properties. There are many different applications for this type of system, such as the manufacturing of heating elements or anodes for the cathode protection methodology. Most of the studies in this area are focused to the improvement of the dispersion of carbon fibers in the cement matrix. This objective is validated by measures of resistivity. According to this objective, there is no a universal method to verify these measures, but many alternatives can be found on the literature: measures with two or four electrodes, direct or alternating current testing…, impeding comparative analyses. This research offers the impedance methodology, already used for the characterization of common cement pastes without any reinforcements, as an option for the analysis of conductive cements. In this study, different variables are included, such as the type and quantity of dispersants to create a homogeneous mixture. The adjustment of the obtained results, following an equivalent electric model for this kind of systems, allowed us to determine the values of conductivity of different mixtures. With the use of this technique, it is possible to identify the polarization phenomena associated to the carbon fibers, being of interest in order to validate the dispersion of the fibers.

High mechanical properties of covalently functionalized carbon fiber and polypropylene composites by enhanced interfacial adhesion derived from rationally designed polymer compatibilizers

The carbon fiber reinforced plastics (CFRP) are still limited the used in the automotive industry mainly by the weak interfacial adhesion between the fiber and polymer matrix . Herein, to improve interfacial interactions between the carbon fiber (CF) and polypropylene (PP) matrix, poly(dimethylaminoethyl methacrylate)- b -poly(methyl methacrylate) (PDMAEMA- b -PMMA, PDM) compatibilizers are applied to functionalize the CF surface through a covalent bonding with epoxide groups on the chemically modified CF surface with tertiary amines in the PDMAEMA block, which induced intermolecular entanglement with PP chains with the PMD compatibilizers. The acquired compatibilizer-functionalized CF (CECF) was applied to fabricate PP composites by a melt-mixing method. The highly improved interfacial adhesion between the CECF and PP was confirmed by evaluating thermal, morphological, rheological, and mechanical properties. Based on the significantly enhanced interfacial adhesion, notably, the tensile strength and modulus of the CECF/PP composite exhibited a massive increase by ca. 312% and 664%, respectively, relative to those of the PP resin. The Ashby plot facilitated understanding that the acquired mechanical properties of the CECF/PP composite showed a relatively ideal position compared to reported PP composites and centered on the commercially available region in automotive components. • Applied carbon fibers were modified by covalent fuctionalization. • Rationally designed compatibilizers offer enhanced interfacial adhesion. • CECF/PP composites achieved significantly high mechanical properties.

Research progress on the quality and efficiency of carbon fiber reinforced thermoplastic polymer composites processed by laser

Carbon fiber reinforced plastics (CFRP) has been widely used in aerospace, military weapons, new energy and high-end vehicles due to its specific and superior strength, low density and long-lasting wear resistance. The processing of CFRP is very different from the traditional metal processing because of its heterogeneous structure, anisotropy and superior wear resistance of CFRP. Usually, CFRP has often various defects in mechanical processing and water jet processing, such as interlayer tearing, fiber pull-out, delamination, tool wear, and abrasive penetration. Through laser processing, the problems of CFRP materials existing in mechanical processing can be overcome. However, due to the huge differences in thermal physical properties such as thermal conductivity and vaporization temperature of carbon fiber and resin in CFRP, its laser processing also turns out to have some issues, such as heat-affected zone and fiber end expansion. This paper summarizes the research results of CFRP laser processing in China and internationally. Research progress was introduced in detail from various aspects including laser and material mechanism as well as laser processing parameters. It reports the experimental and theoretical studies covering the process accuracy in edge quality and the thermal characteristics in terms of heat-affected zone. Eliminating the heat-affected zone in the polymer matrix are considered the major obstacles of CFRP industrial applications. The methods of improving processing efficiency by increasing material removal rate and reducing processing time were reviewed. The influence of different thermal conductivity of carbon fiber and resin matrix in CFRP on the processing quality was discussed. Finally, the development trend and challenges of thermal conductivity of carbon fiber and resin in CFRP in theoretical modeling were proposed.

Comparison of lightning strike behavior between carbon fiber reinforced materials with thermoset resin matrix and thermoplastic resin matrix

One of the weak points of the structures made of carbon fibre reinforced materials and thermosetting matrix is its mechanical impact behavior. In order to improve it, materials reinforced with carbon fiber and thermoplastic resin matrix are under study. In addition to the mechanical properties there are other factors to consider before introducing any structural material in the manufacturing of an aircraft, such as its lightning strike behavior. Materials properties that influence this behavior are mainly electrical, thermal and also mechanical; and these properties are modified from thermoset resins to thermoplastics. Within the Clean Sky program Airbus Defense and Space has carried out preliminary tests on flat panels manufactured by Fidamc with a carbon fibre reinforced material and thermoplastic resin matrix with two different configurations, both layout and additional (with and without metallization) The tests objective was the evaluation and comparison of the damages obtained after a lightning strike in flat panels made of traditional materials (thermoset matrix) with those made with new thermoplastic matrix materials. Both the mechanical damage and the temperatures generated in the material (using a thermal camera during the test) were analyzed in order to compare the thermal behavior of the thermoplastic matrix against the thermostable. This article shows the work done as well as results and conclusions.

The feasibility of fast slotting thick CFRP laminate using fiber laser-CNC milling cooperative machining technique

Thermal damage is inevitable during laser cutting CFRP laminates due to significantly different thermal properties between carbon fiber and resin matrix, which severely affects the assembly accuracy and service performance of composite structures. This work proposed a newly designed fiber laser-CNC milling cooperative machining technique to slot 10.0 mm thick CFRP plates, it integrated the advantages of high efficiency and high material removal rate during high-power laser cutting process, together with good surface quality in milling with limited cutting allowance and high cutting speed. The influence of different machining strategy/method, cutting parameters and thermal damage on surface quality and morphology were comprehensively investigated. Thermal defects including cracks, striations, protruding fibers and matrix recession were the main damage during laser processing thick CFRP laminates, while laser-CNC milling cooperative machining technique successfully slotted 10.0 mm thick CFRP plate without thermal damage and kerf angle with the surface roughness (Sa) down to 5.4 μm. Experimental results from this work indicated that the proposed cooperative machining technique was an alternative method for slotting thick CFRP laminates with superior quality and efficiency.

Uncertainty Analysis of an Optoelectronic Strain Measurement System for Flywheel Rotors.

The strain in a fast spinning carbon fiber flywheel rotor is of great interest for condition monitoring, as well as for studying long-term aging effects in the carbon fiber matrix. Optoelectronic strain measurement is a contactless measurement principle where a special reflective pattern is applied to the rotor which is scanned by a stationary optical setup. It does not require any active electronic components on the rotor and is suited for operation in a vacuum. In this paper, the influences of the key parts comprising the optoelectronic strain measurement are analyzed. The influence of each part on the measurement result including the uncertainty is modeled. The total uncertainty, as well as each part’s contribution is calculated. This provides a valuable assessment of requirements for component selection, as well as tolerances of mechanical parts and processes to reach a final target measurement uncertainty or to estimate the uncertainty of a given setup. We have shown that the edge quality of the special reflective pattern has the strongest influence, and how to improve it. Considering all influences, it is possible to measure strain with an uncertainty of less than at a rotation speed of .

DESIGN OF FIBER METAL LAMINATE AS A BODY MATERIAL WITH CARBON FIBER METHOD

The combat vehicles that Indonesia Army belong to most of the materials are steel, for example the armored vehicle anoa 6x6. Steel material is used as a fire protection on the vehicle, it will greatly affect the performance of the vehicle. It is caused the steel material has a high density, which is around 7750 kg/m3to 8050 kg/m3. So, with a large enough volume of the vehicle body, it will increase the burden of the vehicle. As well as the engine load will increase, and more power is needed to be able to move the vehicle. Seeing these problems, it is necessary to have a research or study on alternative materials to replace the body of a combat vehicle that can withstand fire from opposing weapons that cause personnel to be injured. In this study, experimental and simulation methods were used using the ansys application to analyze the strength of the composite material in the form of an aluminum layer that had been treated to increase the hardness value. Furthermore, it is coated with a composite material using a carbon fiber matrix of epoxy, HGM and polyurethane. The coating material is called Fiber Metal Laminate (FML), so the material used has a lighter density, the load received by the vehicle engine is lighter, and the performance of the vehicle will be more effective and efficient.

Chemo‐mechanical properties of carbon fiber reinforced geopolymer interphase

AbstractGeopolymers, as a potentially environmentally friendly alternative to Portland cement, are increasingly attracting attention in the construction industry. Various methods have been applied for customizing the properties of geopolymers and improving their commercial viability. One of the promising methods for refining the properties of geopolymers such as their toughness is the use of short fibers. The effectiveness of a high‐strength short fiber in the geopolymer matrix is largely dependent on the interfacial bonding between the fiber and its surrounding matrix. While the importance of this interfacial chemistry is highlighted in the literature, the characteristics of this bonding structure have not been fully understood. In this paper, we aim to investigate the bonding mechanism between the carbon fiber and metakaolin‐based geopolymer matrix. For the first time, the existence and nature of the chemical bonding at the interfacial region (interphase) between carbon fiber and geopolymer matrix has been revealed. X‐ray pair distribution function computed tomography (PDF‐CT), field emission‐scanning electron microscopy imaging, and nanoindentation techniques are employed to discern the chemo‐mechanical properties of the interphase. PDF‐CT results show the emergence of a new atom–atom correlation at the interfacial region (around 1.82 Å). This correlation is a characteristic of interfacial bonding between the fiber and its surrounding matrix, where the existence of chemical linkages (potentially VAl‐O‐C) between fibers and the matrix contributes to the adhesion between the two constituents making up the composite. Due to such chemical bonding, the nanomechanical properties of the interfacial region fall between that of the carbon fiber and geopolymer. The combination of advanced techniques is proved useful for enhancing our understanding of the interfacial chemistry between fibers and the binding matrix. This level of knowledge facilitates the engineering of composite systems through the manipulation of their nanostructure.

Mechanical and vibrational characteristics of MacPherson strut composite bearing units based on short carbon fiber/polyamide 66

MacPherson strut bearing units (MSBUs) were fabricated with short carbon fiber/polyamide 66 by injection molding. The mechanical and vibrational characteristics of MSBUs were analyzed. The results showed that tensile specimens using carbon fibers showed increased strength and stiffness compared to those using glass fibers. In injection-molded MSBUs, there is a good degree of dispersion of the carbon fibers in the polymer matrix, and the fibers are observed to have good interfacial bonding with the matrix This is guaranteed by microstructures and enhanced tensile strength in comparison with that of glass fibers. In addition, the use of carbon fibers led to a decrease in the weight of the MSBUs. A modal test showed that natural frequencies of the product were beyond the excitation frequency range generally applied to an automotive vehicle, and durability was not a problem even during an excitation experiment of 1000 000 cycles. Through the above analysis, the combination of carbon fibers and polyamide 66 can be a solution for MSBUs to provide better mechanical performance and light weight.

Numerical simulation of paint stripping on CFRP by pulsed laser

Carbon-fiber-reinforced polymer (CFRP) composite is widely used in aerospace industry. The protective paint on the CFRP of aircraft needs to be removed after reaching a certain useful life. Laser cleaning has the advantages of high efficiency and environmental protection. However, the main obstacle to the application of laser cleaning on CFRP is the thermal damage caused by the laser radiation absorbed on the surface or inside of the substrate. In order to understand the interaction between laser and each layer of material, and the influence of laser parameters on the substrate temperature rise. Based on the ‘element death’ technique of the finite element (FE) method, a numerical model of material removal on a heterogeneous fiber–matrix mesh was established, which can accurately simulate the heat transfer process between carbon fiber and resin matrix. The effects of laser energy density, spot overlap rate and adjacent scanning line interval on material removal and the peak temperature of the substrate were investigated. The results show that the pulsed laser paint removal process will produce two high temperature zones on the resin layer and the heterogeneous material, and the superposition of adjacent pulse energy can significantly increase the temperature rise of the substrate.

Estimation of axial compressive strength of unidirectional carbon fiber reinforced plastic considering local fiber kinking

In this study, the global fiber kinking theory proposed by Budiansky and Fleck for the estimation of axial compressive strength of unidirectional carbon fiber reinforced plastic was modified for the localized fiber kinking problem. The deterministic mechanism of the compressive strength and kink-band width was interpreted using a graphical method. Carbon fiber reinforced plastic was manufactured from carbon fiber and epoxy matrix using prepreg and autoclave technology, and the axial compressive strength was measured. The nonlinear shear stress–strain curves of the composite and matrix were also measured using V-notched beam, in-plane shear, and torsion tests. The composite axial compressive strength and kink-band width were estimated based on the composite and matrix shear properties, respectively, and the estimated values were in good agreement with the experimental results.

Dual-Sizing Effects of Carbon Fiber on the Thermal, Mechanical, and Impact Properties of Carbon Fiber/ABS Composites

Dual-sizing effects with either epoxy or polyurethane (PU) on the thermal, mechanical, and impact properties of carbon fiber/acrylonitrile-butadiene-styrene (ABS) composites produced by extrusion and injection molding processes were investigated. The heat deflection temperature, dynamic mechanical, tensile, flexural, and impact properties of the composites reinforced with either (epoxy + epoxy) or (epoxy + PU) dual-sized carbon fiber were higher than those commercially single-sized with epoxy. The result indicated that the dual-sized carbon fiber significantly contributed not only to improving the heat deflection temperature and the storage modulus, but also to improving the tensile, flexural, and impact properties of carbon fiber/ABS composites. The highest improvement of the composite properties was obtained from the composite with (epoxy + PU) dual-sized carbon fiber. The improvement of the mechanical and impact properties was explained by the enhanced interfacial bonding between carbon fiber and ABS matrix and by the length distribution analysis of carbon fibers present in the resulting composites. The fiber–matrix interfacial behavior was qualitatively well-supported in terms of fiber pull-out, fiber breaking pattern, and debonding gaps between the fiber and the matrix, as observed from the fracture surface topography. This study revealed that the properties of carbon fiber/ABS composites prepared by extrusion and injection molding processes were improved by dual-sizing carbon fiber, which was performed after a commercial epoxy sizing process, and further improved by using PU as an additional sizing material.

Improved interfacial shear strength of CF/PA6 and CF/epoxy composites by grafting graphene oxide onto carbon fiber surface with hyperbranched polyglycerol

The interfacial properties between carbon fiber (CF) and polymer matrix are critical to the performance of CF reinforced composites. Herein, we reported a new method of tailoring the interfacial properties by grafting graphene oxide (GO) onto the CF surface with hyperbranched polyglycerol (HPG), which could improve the interfacial shear strength (IFSS) and heat resistance of CF/PA6 and CF/epoxy (EP) composites. A large number of hydroxyl groups were introduced onto CF surface by using HPG as a new coupling agent, which improved the grafting amount of GO, the polarity, wettability and surface energy of CF. The IFSS of composites at different temperature was investigated by microbond test. The results showed that after introducing GO into the interface, the IFSS of CF reinforced PA6 and epoxy composites increased by 44% and more than 30%, respectively. Moreover, the IFSS of GO modified CF/EP1 composites at 85°C was only 9.1% lower than that at 25°C. In addition, the IFSS of the CF/PA6 and CF/EP2 composites could be kept stable when the ambient temperature was lower than the melting point or glass transition temperature of the resin matrix. Finally, the interfacial enhancement mechanism was further analyzed in details.