Addition Of Short Carbon Fibers Research Articles

Short carbon fiber-reinforced PLA composites: influence of 3D-printing parameters on the mechanical and structural properties

3D printing, particularly “fused filament fabrication” (FFF), plays a crucial role in Industry 4. FFF is widely used for creating complex structures and multi-material parts across various industries such as food industry, fashion industry, and manufacturing sectors. The properties of FFF-produced objects are remarkably affected by printing parameters. This study explores the impact of printing parameters and the addition of short carbon fibers on the strength of polylactic acid (PLA) printed samples. The lowering layer height, increasing feed rate and extrusion temperature boost impact strength, while a smaller raster angle enhances it. Meanwhile, an improved flexural strength is achieved by adjusting layer height, extrusion temperature, and raster angle. Higher extrusion temperatures enhance tensile strength, microstructure, and reduce porosity. Lower layer height improves flexural and impact strength (28.05% increase in 0.1 mm layer height), higher feed rate boosts strengths (12.56% improvement in 7 mm3/s feed rate), and elevated extrusion temperatures enhance impact strength (14.49% increase in 230 °C extrusion temperature) but reduce flexural strength (14.44% decrease). Incorporating carbon fibers in PLA negatively affects the microstructure but increases crystallinity, raising the melting temperature and lowering cold-crystallization temperature. The introduction of carbon fibers into PLA results in a complex interplay of mechanical and thermal properties.Graphical abstract

Mechanical property and thermal stability of short carbon fiber reinforced polysulfonamide composites

AbstractIn this paper, polysulfonamide‐based composite materials (SCF/PSAf composite) reinforced by the short carbon fiber were prepared. The mechanical properties and thermal stability of SCF/PSAf composite were characterized experimentally and compared with those of polysulfonamide‐based single‐polymer composites (PSA SPCs). Results showed that SCF/PSAf composites exhibit higher thermal stability due to the excellent thermal stability of SCFs. Furthermore, the additional short carbon fibers also considerably enhance the flexure strength of PSA SPCs due to the strong interfacial bonding between SCF and PSAf. The properties and understanding of SCF/PSAf composite obtained in this work can benefit further applications of this novel composite material.Highlights SCF/PSAf composites are prepared by hot compression, and the adhesion between the PSA matrix and SCF is good. The flexural strength of the SCF/PSAf composite is about 2.5 times higher than that of PSA SPCs. The storage modulus of SCF/PSAf composites is about 3.5 times higher than that of PSA SPCs. The addition of short carbon fibers helps to improve the thermal properties of SCF/PSAf composites. SCF/PSAf composite has a stronger ability to resist deformation and a higher operating temperature than the PSA SPCs do.

Enhanced electrodynamic properties acrylonitrile butadiene styrene composites containing short-chopped recycled carbon fibers and magnetite

The development of new polymer composites with conductive and magnetic fillers that are compatible with additive manufacturing (AM) is a highly topical issue. In this work, we discussed the effect of short virgin/reclaimed carbon fibers and magnetite on the electrodynamic properties of acrylonitrile butadiene styrene (ABS) in the X-band frequencies. The choice of selected frequency range is connected with a large number of various radio engineering systems operating with these frequencies, including radar and satellite communication systems. Composites with the addition of short carbon fiber and magnetite exhibit excellent shielding factors ranging from 37.9 to 33.7 dB at frequencies 8–12 GHz. A detailed study of the electrodynamic parameters revealed the attractive properties of reclaimed carbon fiber as a component of shielding materials, especially with the simultaneous addition of magnetite. It should be noted that for this particular composite, the permittivity imaginary part increase was up to −23.96 (88 %) at 8 GHz compared to the virgin carbon fiber and magnetite composite.

Developing ternary composite phase change materials with two different phase change temperatures for battery thermal management

Paraffin wax (PW), as a phase change material (PCM), with high latent heat, is likely to be used in battery thermal management. However, the application of PW is remarkably limited due to its low thermal conductivity, poor mechanical properties, and easy leakage after melting. Here, we prepared a novel ternary composite phase change material (CPCM) to eliminate melt leakage with high thermal conductivity, stable morphology, and two different phase change temperatures. The step cooling data confirmed that when the proportions of myristic acid (MA), palmitic acid (PA), and PW are 3:1:4, there are two phase transition points at 35.88 ℃ and 46.26 ℃, respectively. The addition of short carbon fiber (SCF) and carbon black (CB) with different particle sizes significantly improved the thermal conductivity of the PCM up to 8.7 W/mK. The addition of silicone rubber (SR) film not only avoids the liquid PCM leakage but also improves its mechanical properties. At the highest discharge rate, the maximum temperature of a large capacity square terpolymer lithium battery is 47.03 ℃ due to excellent thermos conductivity. Furthermore, the ternary CPCM does not melt completely at the end of discharge. Compared with the CPCM with single phase transition temperature, the two different phase transition temperatures have excellent balanced performance. After two phase change temperature controlling processes, the rise of battery surface temperature is effectively delayed, and the working time of the CPCM is prolonged. Hence, the developed CPCM is more suitable for the battery thermal management system (BTMS).

Functionally graded polyetheretherketone-based composites additively manufactured by material extrusion using a transition interface design method

The addition of short carbon fibers (CFs) and glass fibers (GFs) can significantly enhance the mechanical properties of polyetheretherketone (PEEK); however, ductility is significantly reduced. Owing to the significant differences in mechanical, thermal and tribological properties of CF/GF-PEEK, PEEK-based functionally graded materials (FGMs) are promising materials for 3D printing. This paper proposes a novel method for preparing FGMs using continuous welding filaments to improve the comprehensive performance of 3D printed CF/GF-PEEK. In addition, two innovative graded interface design methods are proposed for extrusion-based 3D printing of FGMs. Furthermore, a series of 3D printing experiments were conducted to verify our design methods. The 3D-printed FGMs composed of CF/GF-PEEK composites possess excellent toughness while maintaining good mechanical properties and interlayer bonding performance. The elongation at the fracture of the FGMs prepared in this study increased by 150% compared to those of fiber reinforced PEEK composites. The overall mechanical properties of FGMs with graded interfacial layers are improved by about 12% compared with those of the FGMs without transitional structures.

Multi-functional glass/carbon fibers hybrid inter/intra laminated composites

A detailed experimental study was performed on the piezo-resistive damage sensing of novel electrically conductive inter/intra glass/carbon fiber hybrid epoxy laminated composites reinforced with micro carbon fibers along the thickness direction between the laminates using electro-flocking technique. The electrical resistance is determined by four-circumferential probe measurements under tensile and flexure loads. Intralaminar hybrid composites’ mechanical and electrical properties showed a dependency on layup angle, with glass fibers along the loading direction showed the highest initial resistance value (1180 Ω) and ultimate tensile strength (400 MPa). Intra-ply composites with [±45/∓45] layup orientation demonstrated the lowest ultimate tensile strength (57 MPa) and the highest elongation at break (9.7%). Mechanical and electrical properties of interlaminar hybrid composites showed a dependency on the number of carbon fiber laminates. More carbon fiber laminates within the composite layup produces a lower initial resistance value (0.37 Ω) and higher ultimate tensile strength (247 MPa). In both intra and inter composites cases, with the addition of short carbon fibers, the initial resistance decreased. In some cases, with the addition of short carbon fibers the failure mechanisms changed. Composites of all types experienced much higher percentage change in resistance under flexural loading due to severe interlaminar failure compared to corresponding cases under tensile loading conditions. These results are useful for designing composite structures with emphasis on structural health monitoring.

Effect of Elevated Temperature on Bending Fatigue Behavior for Neat and Reinforced Polyamide 6,6

Recently, considering polymer composite in manufacturing of mechanical parts can be caused a fatigue failure due to the very long time of exposure to cyclic loading and may at environmental temperatures higher than their glass transition temperature; therefore, in this paper, a comprehensive investigation for bending fatigue behavior at room and elevated temperatures equal to 60 °C, 70°C, and 80 °C will be done. Rotating bending test machine was manufactured for this purpose supplied with a connected furnace to perform fatigue tests at elevated temperatures. The obtained results appeared that the increase in applied stress and temperature caused a clear reduction in fatigue life; also the addition of carbon nanotubes enhanced the fatigue life at different temperatures by 183%, 205%, 218%, and 240%, respectively while the addition of short carbon fibers improved fatigue life by 324%, 351%, 387%, and 415%, respectively. As well as, Polyamide 6,6/carbon fiber composite appeared fatigue limit at temperatures equal to 20°C and 60°C and stresses approximately equal to 55 MPa and 38 MPa respectively.

Effect of the Addition of Short Carbon Fiber on Thermal Insulation Properties of ZrB<sub>2</sub>- SiC Hot-Pressed Ceramics

Short carbon fibers reinforced ZrB2-SiC ceramics were prepared by hot pressing sintering process. The short carbon fibers with different volume fractions (0.2.4.6.8.10.20) were added for improving the thermal insulation properties of ZrB2-SiC ceramics. The experimental results showed that as the content of short carbon fiber increased, the thermal diffusivity decreased from 43.9m2/s to 32.9m2/s, the thermal conductivity decreased from 104.3 W/(m·K) to 72.9 W/(m·K) and thermal insulation performance reduced by 43.1%, respectively. The enhancement of the thermal insulation properties is mainly due to high interfacial thermal resistance of short carbon fiber and matrix.

The Evolution of Interfacial Microstructure and Fracture Behavior of Short Carbon Fiber Reinforced 2024 Al Composites at High Temperature

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.

Effects of short carbon fiber content on microstructure and mechanical property of short carbon fiber reinforced Nb/Nb5Si3 composites

The short carbon fiber reinforced Nb/Nb5Si3 composites were innovatively fabricated by ball milling and spark plasma sintering. The effects of short carbon fiber contents (0.50 wt. %, 1.0 wt. %, 1.5 wt. % and 2.0 wt. %) on the microstructure and mechanical property of short carbon fiber reinforced Nb/Nb5Si3 the composites were investigated. The results show that the content of interfacial phase Nb4C3 increases with the increase of short carbon fiber content. Compared to the matrix Nb/Nb5Si3, the mechanical properties of the composites are improved significantly owing to the addition of short carbon fiber. It is found that the increase of short carbon fiber content contributes to the enhancement of Vickers hardness, ultimate tensile strength and fracture toughness of the composites. The fracture surfaces are characterized by interface debonding and fiber pull-out, which indicate that a medium bonding strength of the interface between fiber and matrix was obtained in this composite. The interface debonding and fiber pull-out behavior play the important role in the fracture process, which are the dominant toughening mechanisms of the short carbon fiber reinforced Nb/Nb5Si3 composites.

Planar deposition flow modeling of fiber filled composites in large area additive manufacturing

The rapid transition of the Fused Filament Fabrication (FFF) Additive Manufacturing (AM) process from small scale prototype models to large scale polymer deposition has been driven, in part, by the addition of short carbon fibers to the polymer feedstock. The addition of short carbon fibers improves both the mechanical and thermal properties of the printed beads. The improvements to the anisotropic mechanical and thermal properties of the polymer feedstock are dependent on the spatially varying orientation of short carbon fibers which is itself a function of the velocity gradients in the flow field throughout the nozzle and in the extrudate during deposition flow. This paper presents a computational approach for simulating the deposition flow that occurs in the Large Area Additive Manufacturing (LAAM) process and the effects on the final short fiber orientation state in the deposited polymer bead and the resulting bead mechanical and thermal properties. The finite element method is used to evaluate Stokes flow for a two-dimensional planar flow field within a Strangpresse Model 19 LAAM polymer deposition nozzle. A shape optimization method is employed to compute the shape of the polymer melt flow free surface below the nozzle exit as the bead is deposited on a moving print platform. Three nozzle configurations are considered in this study. Fiber orientation tensors are calculated throughout the fluid domain using the Folgar-Tucker fiber interaction model. The effective bulk mechanical properties, specifically the longitudinal and transverse moduli, and the coefficient of thermal expansion, are also calculated for the deposited bead based on the spatially varying fiber orientation tensors. Fiber orientation is found to be highly aligned along the deposition direction of the resulting bead and the computed properties through the thickness of the bead are found to be affected by nozzle height during deposition.

Mechanical, electrical and self-sensing properties of cementitious mortars containing short carbon fibers

This paper is aimed at exploring mechanical, electrical and self-sensing properties of cement-based mortars through the addition of short carbon fibers, at different dosages (2%, 3%, 4% by weight of cement). Compression and bending tests on carbon fiber reinforced mortars (CFRM) were performed. The addition of carbon fibers showed to enhance the mortars’ flexural strength by increasing the fibers content, while no improvement was found in the compressive strength. Electrical resistivity of the CFRM, at different days of curing, was evaluated by AC impedance measurements, using two stainless steel wire meshes as electrodes. The electrical resistivity decreased with time, until reaching a constant value after about 60 days of curing. Carbon fibers were able to drastically reduce the mortar resistivity, up to values below 150 Ω cm. The effect of fibers dosage on the ability of the mortar to change its electrical resistivity when subjected to different stress states was also studied. The specimens were gradually loaded up to 50–60% of the maximum compressive strength, carrying out two loading/unloading cycles, while resistivity was measured using a conductivity meter. Depending on the fibers dosage and stress state within the material, CFRM resistivity changed with significant variations.

Physical and Mechanical Properties of Polypropylene-Wood-Carbon Fiber Hybrid Composites

Effects of the addition of short carbon fibers (CFs) on the mechanical, physical, and morphological properties of polypropylene (PP) and wood-polypropylene composites (WPCs) were investigated. Hybrid composites (mix of wood and CFs) were manufactured in a two-stage process, pellet extrusion and samples mold injection with varying amounts of poplar wood fiber (0%, 20%, 30%, and 40%) and CFs (0%, 3%, 6%, and 9%), with and without maleic anhydride grafted PP (MAPP) as a coupling agent. The composites were prepared with extrusion blending followed by injection molding. The samples where then tested for mechanical and physical properties, and fractured surfaces where observed with scanning electron microscopy. The results indicated that the addition of CFs to WPCs improved the tensile and flexural strength and the modulus of elasticity but had only a small influence on elongation at break and impact strength. The density of hybrid composites slightly increased with CFs proportion but their water absorption was not affected. Scanning electron micrographs of the tensile fractured specimens showed improved adhesion of CFs and poplar with the PP matrix in the presence of a coupling agent.

Effect of Carbon Fibers on Thermal and Mechanical Properties of Metakaolin-Fly Ash-Based Geopolymers

This paper presents results from a set of experiments carried out to evaluate the effect of carbon fibers on thermal and mechanical properties of metakaolin fly-ash-based geopolymers. Bending and compression tests were conducted at ambient temperature and after exposure to elevated temperatures on fiber-reinforced geopolymers with varying proportions of carbon fibers, metakaolin, and fly ash. Also, crack propagation, dimensional changes, and temperature gradients in geopolymers with different carbon fiber content were recorded during and after heating. Data from these tests show that the addition of short carbon fibers in geopolymers provides an effective mechanism for controlling temperature-induced cracking and thermal deformation, and this in turn enhances bending strength under high temperatures. The enhancement in bending strength under high temperatures, due to the presence of carbon fibers, is higher in geopolymers with higher fly ash content than that with lower fly ash content. Further, the addition of carbon fibers has no significant effect on compressive strength of geopolymers both at ambient temperature and after exposure to high temperatures.

Dielectric and Mechanical Properties of Hot‐Pressed Sintered Csf/Al2O3 Ceramic Composites

High densified Csf/Al2O3 ceramic composites were prepared by hot‐pressed sintering using α‐Al2O3 powders and short carbon fibers as starting materials. Dielectric and mechanical properties of these composites were evaluated. The results show that the addition of short carbon fiber (Csf) conducting fillers renders the composites radar absorbing ability, while the hardness around 90 HRF and strength around 300 MPa are also obtained in these composites. Both the fiber content and the length can be used to optimize the dielectric property at the frequency range 8.2–12.4 GHz. The results indicate that Csf/Al2O3 composite is a promising radar absorbing material with load‐bearing ability.

Damping Properties of Polyurethane/Epoxy Graft Interpenetrating Polymer Network Composites Filled with Short Carbon Fiber and Nano-SiO2

A series of short carbon fiber (CF) and nano-SiO2 filled polyurethane (PU)/epoxy resin (EP) graft interpenetrating polymer network (IPN) composites were prepared. The damping properties as well as tensile and impact strength of the IPN composites were studied systematically in terms of composition. Results revealed that the addition of short CF and nano-SiO2 can significantly improve the damping properties of pure PU/EP IPN, particularly at higher frequencies. Mechanical tests showed that the tensile strength of the IPN composites was improved after the incorporation of short CF and nano-SiO2, while the impact resistance of the composites was impaired after the addition of CF and higher content (beyond 1 wt%) of nano-SiO2. It is proposed that the CF and nano-SiO2 filled IPN composites would be useful as structural damping materials.

Synthesis and Properties of Carbon Short Fiber Reinforced ZrCuNiAl Metallic Glass Matrix Composite

Carbon short fiber reinforced Zr50.5Cu36.45Ni4.05Al9 metallic glass matrix composite was synthesized. The microstructure, thermal behavior, and compressive property of composite are investigated. The improvement of thermal stability and Young’s modulus are due to the addition of short carbon fiber. The limited reaction occurs between the matrix and short fiber by reducing the reactive time, and only a ZrC reaction zone with about 150 nm in width forms. Such interfacial reaction can improve the wettability and tighten the bonding at the interface, and consequently enhance the strength of composite. The effect of interfacial reactive production on the compressive property is also discussed.

Damping analysis of polyurethane/epoxy graft interpenetrating polymer network composites filled with short carbon fiber and micro hollow glass bead

A series of short carbon fiber (CF) and micro hollow glass bead (HGB) filled polyurethane (PU)/epoxy resin (EP) graft interpenetrating polymer network (IPN) composites were prepared. The damping properties, thermal stability properties as well as tensile and impact strength of IPN composites were studied systematically. Results revealed that the addition of short carbon fiber and micro HGB can significantly improve the damping properties of pure PU/EP IPN and can improve the thermal decomposition temperature. Mechanical tests showed that the tensile strength of the IPN composites could be improved after the incorporation of short carbon fiber and micro HGB, while the impact resistance of the composites was impaired after the addition of micro HGB. It is expected that the carbon fiber and micro HGB filled IPN composites may be used as structural damping materials.

Analysis of the Mechanical Properties in Short Carbon Fiber-toughened ZrB2—SiC Ultra-high Temperature Ceramic

ZrB2—20 vol.% SiC ceramics with additional 20 vol.% short carbon fibers were developed to promote graceful failure using hot-pressing technique. The influence of short carbon fiber on the strength, and modulus of composite was analyzed and estimated using a modified rule of mixtures. The calculation results showed that a little decrease in flexural strength from 502 to 445 MPa and elastic modulus from 414 to 322 GPa was due to the lower elastic modulus of short carbon fiber. An apparent increase in fracture toughness from 2.0 to 6.56 MPa m1/2 was obtained with the addition of short carbon fiber. And the fracture toughness was analyzed and calculated based on the toughening mechanisms of crack deflection, fiber pullout, and crack bridging. Calculated results were in good agreement with experimental results.

Effect of silica fume particle size on mechanical properties of short carbon fiber reinforced concrete

The addition of short carbon fibers (CF) in concrete leads to changes of both the mechanical and electrical properties of the hardened product. The addition of silica fume (SF) to concrete mixtures with CF facilitates an even distribution of fibers within the mixture volume and improves the strength and multifunctional properties of the product. In this work the influence of the particle size distribution of commercial SF on the strength properties of CF reinforced concrete has been studied. Also the influence of the addition of methyl-cellulose as a fiber dispersing agent that improves the homogeneity of the mixture has been studied. The results show a different behavior of concrete depending of the average SF particle size (between 1 μm and 60 μm). The evolution of the elastic compressive modulus of carbon fiber reinforced concrete (CFRC) is linked to the one of the compressive strength, with a good coincidence with the CEB (Comité Euro-International du Béton) formula values. This parameter is only slightly decreased by the addition of methyl-cellulose.