Effects Of Short Carbon Fibers Research Articles

The Effect of Short Carbon Fiber and Hydrothermal Carbon Content on Impact and Wear Properties of Epoxy Composites

This study aims to investigate the effect of different weight fractions (3%, and 5%) of short carbon fibers (SCFs) and hydrothermal carbons (HTCs) on the impact and wear properties of epoxy matrix composites. The samples were fabricated using the hand lay-up method. Izod impact tests were applied to the unnotched samples. To investigate the wear properties of pure epoxy and composites, reciprocating wear tests were conducted. Also, a Scanning Electron Microscope has been used for observation of the morphology of the broken and worn surfaces of pure Epoxy and (SCFs and HTCs) reinforced epoxy-based composites. Results showed that HTCs have remarkable effects on improving the wear resistance rate as compared to SCFs reinforced composites. However, SCFs reinforced epoxy composites have better energy-absorbing effects compared to HTCs epoxy-reinforced composites.

Effect of Short Carbon Fiber Reinforcement on Mechanical Properties of 3D-Printed Acrylonitrile Butadiene Styrene.

The effect of short carbon fiber (SCF) filler on the mechanical properties of 3D-printed acrylonitrile butadiene styrene (ABS) was investigated. The fused filament fabrication (FFF) method was used for the manufacturing of samples. Elastic properties and strength characteristics of samples made of conventional ABS and SCF-reinforced ABS were compared in tensile and bending tests. Fracture toughness and critical strain energy release rate were also determined. In addition, 3D-printed monofilament SCF-reinforced samples were fabricated, the internal structure of which was analyzed using microcomputed tomography (micro-CT). Based on the tomography data, finite-element (FE) models of representative volume elements (RVEs) of the reinforced material were created and used for the numerical calculation of effective characteristics. Numerical and experimental results for the effective elastic properties were compared with the Mori-Tanaka homogenization technique. The ABS samples filled with SCF showed considerably higher mechanical characteristics than those of the conventional ABS. Finally, the dependence between the strength characteristics and elastic properties of the samples on the diameter of the nozzle used for 3D printing was established. 3D-printed ABS reinforced with SCF demonstrated a gain in tensile strength and fracture toughness by 30% and 20%, respectively. Interlayer adhesion strength in flexure tests showed an increase of 28% compared to pure ABS samples.

Effect of short carbon fibers on the thermal conductivities of Csf/AZ91D composites

Developing metal matrix composites with lightweight and high thermal conductivities (TCs) to realize high-efficiency thermal management is of great significance. Herein, a strategy for preparing short carbon fiber preform without any chemical binder through the application of vacuum filtration is proposed. High in-plane and nearly unaltered out-plane thermal conductive magnesium matrix composites with short carbon fibers have been prepared by the independently developed liquid-solid extrusion following the vacuum infiltration (LSEVI) technique. The in-plane TCs of the composites reaches 72.16 W·(m·K)−1, a 50.3% enhancement compared to the matrix. The microstructures of the carbon fibers and magnesium matrix before and after the fabrication processing are characterized using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy (RS). The composites display attractive thermal properties and this work provides an efficient approach to prepare short fiber-related thermal conductive metal matrix composites with a refined thermal management capacity.

The Role of Al4C3 Morphology in Tensile Properties of Carbon Fiber Reinforced 2024 Aluminum Alloy during Thermal Exposure.

The aluminum alloy drill pipe suffers long-term high-temperature conditions during ultra-deep well drilling. In this paper, the samples were prepared by vacuum hot pressing, followed by hot extrusion and T6 heat treatment. The mechanical properties of short carbon fiber reinforced 2024 aluminum alloy composites (SCFs/2024 Al) and the microstructure evolution at the interface region thermal exposure at 160 °C for 500 h are discussed. The experimental results showed that the effect of short carbon fiber on 2024 aluminum alloy remained steady throughout the whole process of the heat exposure experiment. The distribution and volume of interface products (Al4C3) changed with the prolonging of heat exposure time, and connected after coarsening. The evolution of the morphology of Al4C3 relieved the stress of the interface between carbon fiber and aluminum alloy matrix and enhanced the mechanical properties of the composite.

Effect of short-carbon fiber and nano-carbon fiber as reinforcement on microstructure and properties of hot-rolled aluminum matrix composites

Effect of short-carbon fiber and nano-carbon fiber as reinforcement on microstructure and properties of hot-rolled aluminum matrix composites

Studying the Effect of Short Carbon Fiber on Fused Filament Fabrication Parts Roughness via Machine Learning.

Along with the characteristic staircase effect, short carbon fibers, added to reinforce Fused Filament Fabrication parts, can significantly worsen the resulting surface finishing. Concerning this topic, the present work intends to improve the existing knowledge by analyzing 2400 measurements of arithmetic mean roughness Ra corresponding to different combinations of six process parameters: the content by weight of short carbon fibers in polyethylene terephthalate glycol (PETG) filaments f, layer height h, surface build angle θ, number of walls w, printing speed s, and extruder diameter d. The collected measurements were represented by dispersion and main effect plots. These representations indicate that the most critical parameters are θ, f, and h. Besides, up to a carbon fiber content of 12%, roughness is mainly affected by the staircase effect. Hence, it would be likely to obtain reinforced parts with similar roughness to unreinforced ones. Different machine learning methods were also tested to extract more information. The prediction model of Ra using the Random Forest algorithm showed a correlation coefficient equal to 0.94 and a mean absolute error equal to 2.026 μm. In contrast, the J48 algorithm identified a combination of parameters (h = 0.1 mm, d = 0.6 mm, and s = 30 mm/s) that, independent of the build angle, provides a Ra < 25 μm when using a 20% carbon fiber PETG filament. An example part was printed and measured to check the models. As a result, the J48 algorithm correctly classified surfaces with low roughness (Ra < 25 μm), and the Random Forest algorithm predicted the Ra value with an average relative error of less than 8%.

An assessment of mechanical behavior of glass fiber/epoxy composites with secondary short carbon fiber reinforcements

AbstractUtilizing recycled or short fibers for making useful engineering composite component is a present research trend and requirement. Current research work explicates the effect of short carbon fibers (SCF) used as secondary reinforcement in woven glass/epoxy hybrid composites and evaluates their mechanical properties. Different concentrations (0.1, 0.3, and 0.5 wt%) of SCF were incorporated to assess the tensile, flexural, and interlaminar fracture toughness (Mode I and II) of the resulted composites. Composites with 0.1 wt% SCF showed 29.02% and 16.08% increment in the tensile and flexural strength, respectively. For Mode I and Mode II interlaminar fracture toughness tests, 0.1 wt% SCF‐GE samples showed the highest strain energy release rate. Double cantilever beam specimens were used for Mode I testing and an improvement of 13.49% invalue was observed. End‐notched flexure method was used for the Mode II tests, and 0.1 wt% SCF‐GE samples showed 20.45% increase invalues. This paper explains the various reasons and mechanisms for obtaining such results. Scanning electron microscopy of the fractured surfaces was carried out to perceive the diverse failure micro‐mechanisms that could have been involved.

Room‐/High‐Temperature Mechanical Properties of Titanium Matrix Composites Reinforced with Discontinuous Carbon Fibers

The reinforcing effect of short carbon fibers (CFs) in Ti−6Al−4V (TC4) matrix composites fabricated by powder metallurgy is investigated by mechanical testing at room/high temperatures. Different mass fractions of CFs (0−3%) are dispersed into TC4 matrix by high‐energy ball milling. CFs/TC4 powder mixtures are then consolidated by hot isostatic pressing to obtain CFs/TC4 composites. Microscopic morphology, phase composition, and interfacial microstructure of CFs/TC4 composites are thoroughly characterized by various electron microscopies and Raman spectra. It is found that all composites fail before yielding at room‐temperature tensile tests, which is due to the unpleasant bonding condition between CFs and TC4. However, the 1% CFs/TC4 composite fractures in a ductile mode at elevated temperatures. The reinforcing effect of CFs becomes more prominent with the increase in testing temperature. At 700 °C, the 1% CFs/TC4 composite registers 74% improvement in the yield strength compared with the TC4 matrix, which suggests the excellent reinforcing effect of CFs among available reinforcements in the literature. The results suggest that short CFs might be a suitable reinforcement candidate for high‐temperature applications of titanium matrix composites.

The preparation and performance of non-woven carbon tissue reinforced adhesive film for bonding CFRP-aluminum

This study developed a kind of non-woven carbon tissue reinforced adhesive film (NWCTRAF) with high bonding strength and reliability by interleaving the NWCT into the adhesive film. The manufacturing process, bonding strength, Weibull distribution, metallography of cross-section, and fracture surface morphology of NWCTRAF specimens were investigated. The results showed that the average bonding strength and Weibull characteristic strength (WCS) of single lap joint (SLJ) were 27.4a and 28.2 MPa, which increased by 17.6% and 15.1%, respectively compared with the blank specimen, and the Weibull modulus risen from 9.51 to 18.72, which indicated that NWCTRAF specimens had higher bonding reliability. The mechanism of micro-crack formation was obtained by analyzing the cross-section of loading 95% WCS without visible damage. The metallographic section showed that the microcracks of the blank specimen originated from the interface between carbon fiber-reinforced polymer (CFRP) and adhesive layer, while the microcracks of the NWCTRAF specimen originated from the resin-rich regions between the carbon fiber fabric layers in CFRP. Typical failure modes were gained from optical microscope and SEM. Failure modes of blank specimen included more interface failure of CFRP-adhesive and Al-adhesive, while NWCTRAF specimen had more carbon fiber tearing and delamination of CFRP. The fracture morphology of adhesively cohesive failure included the pull-out of short carbon fibers and the appearance of rough and multi-stage resin in the NWCTRAF specimen, which improved the toughness of the adhesive layer. The bridging effect of short carbon fibers in the NWCTRAF disperse and transfer stress to CFRP and fail at resin-rich regions of CFRP, decrease the bonding interface's direct failure, and improve the bonding strength and reliability.

High-Performance Polyamide/Carbon Fiber Composites for Fused Filament Fabrication: Mechanical and Functional Performances

This study is focused on the 3D printing by fused filament fabrication (FFF) process of short carbon-fiber-reinforced polyamide (PA) composites. In particular, the effect of short carbon fiber (CF) on the mechanical, electrical and piezoresistivity properties of 3D-printed polyamide (PA) composite parts has been analyzed. In comparison with neat PA, the results revealed that the carbon fibers effectively improved all assessed mechanical properties of PA/CF composites. In particular, in XY build orientation, PA/CF 3D-printed composites exhibited a tensile strength of 96 MPa and a tensile modulus of 7.9 GPa, with an increment of + 34 and + 147%, respectively, when compared to the neat PA. Interlayer strength of 3D-printed PA and PA/CF composites reaches similar values, in the range 26-28 MPa. The impact strength of 3D-printed XY parts was reduced by the presence of CF. However, the fracture toughness of PA/CF composite 3D-printed parts was slightly higher in comparison with that of neat PA. Electrical resistivity of PA/CF 3D-printed parts is gradually decreasing from 1.7 × 104 to 0.7 × 104 Ω cm in the temperature range from − 16 to 100 °C. The piezoresistivity tests revealed that an exponential resistance change occurs for both compression-molded and 3D-printed PA/CF samples once strained in tension. A gauge factor of 3D-printed parts of about 65 ± 5 was determined from cyclic strains in the elastic region.

Enhanced oxidation properties of ZrB2–SiC composite with short carbon fibers at 1600 °C

This study investigated the effect of short carbon fiber (Cf) on the oxidation behavior of ZrB2–SiC composites with fiber volume fractions in the range of 0–20%. Precisely, highly dense composite compacts were manufactured by hot-press process at 2000 °C and 30 MPa for 60min. The addition of Cf increased the relative density of sintered composite The oxidation treatment at 1600 °C in air tube furnace for 0.5 h revealed that oxidation rate of ZrB2–SiC-Cf composites decreased from 292.4 μm/h to 77.6 μm/h (almost 73.5% decline), when the content of Cf changed from 0 to 20%. Moreover, Cf played important roles in blocking and deflecting oxygen diffusion during the oxidation process, which provided a local reduction environment of oxidation products.

Mechanical, tribological, and biological properties of carbon fiber/hydroxyapatite reinforced hybrid composites

AbstractThe present study aims to investigate the effect of short carbon fiber (SCFs) and hydroxyapatite (HAp) content on mechanical, tribological, and biological properties of high‐density polyethylene (HDPE) matrix composites. The proposed HDPE/SCFs‐HAp hybrid composites with good mechanical‐tribological behavior and biocompatibility might be used as novel implants in orthopedics. The composites were developed using twin‐screw extrusion and compression molding methods. Hardness, tensile, and 3‐point bending tests were performed to investigate the mechanical properties of hybrid composites. To evaluate wear performance of the samples, three different loads (10, 20, and 30 N) were applied in simulated body fluid. Biological activities of the hybrid composite samples were investigated. Results show that HDPE‐10%SCFs‐10%HAp sample provides optimum mechanical, tribological, and biological properties.

Influence of carbon fiber content on bio-tribological performances of high-density polyethylene

The present study aims to investigate the effect of short carbon fiber (SCFs) content on wear performance of high-density polyethylene (HDPE). SCFs reinforced composites with different weight fractions (5 wt%, 10 wt%, 15 wt% and 20 wt%) were fabricated by melt compounding and compression molding. To evaluate bio- tribological performance of the samples, three different loads (20 N, 40 N and 60 N) were applied to simulate body fluid (SBF) environment against stainless steel counterface. The scanning electron microscope was used to investigate the morphology of composite granules and worn surfaces of samples. Also, the hardness test was conducted for all samples. The results show that the hardness of high-density polyethylene increases significantly depending on the short carbon fiber content. 20 wt% SCFs reinforced composite exhibited the highest hardness, which is 34% improvement compared to the pure HDPE. However, the same trend was not observed for wear resistance of composites. Composites containing 10 wt% SCFs showed best wear performance in SBF fluid conditions.

Static and Dynamic Mechanical Performance of Carbon Fiber Reinforced Polyethersulfone Composites

This study has been carried out to demonstrate the effect of short carbon fiber (SCF) loading on static and dynamic mechanical performance of polyethersulfone (PES) composites. Different combinations of SCF/PES composites were prepared by extrusion followed by injection molding. The static mechanical properties such as hardness, tensile and flexural properties of PES based composites were analyzed following ISO standards. As engineering materials, the polymer composites with high modulus as well as excellent damping properties are of great interest in aerospace and automotive industries for severe dynamic environment. Furthermore, in addition to static properties of composites, dynamic mechanical behaviour of PES based composites was evaluated. Mechanical test results showed that increasing the SCF wt. % in the composites increases the hardness, tensile and flexural properties. Furthermore, the optimal SCF loading was found to be 30 wt. % for significantly improving the overall composite mechanical performance. Upon the reinforcing of SCFs, an improvement in the storage modulus was found. Based on the fractographic analysis, orientation and aligned structure of carbon fibers, good bonding of fibers within the matrix and better fiber-matrix interaction were the primary reasons leading to the improvement of mechanical properties. The optimized composite (PES with 30 wt. % of SCF) could be used in automotive components like frames, flap covers and gears of printing machinery.

The effect of short carbon fibers on rheological behaviour and mechanical properties of metakaolin-slag geopolymer binder

This study investigates the effects of short carbon fibers addition on rheological behaviour of geopolymer binder and final mechanical strength of prepared composite. The pure geopolymer binder and variously carbon fiber reinforced composites were tested. The pure geopolymer binder was synthesized by alkalination of calcined claystone powder and milled blast furnace slag by potassium silicate solution. The binders reinforced by carbon fibers were prepared under the same conditions. Mixtures were accordingly reinforced by 20 wt% of short and milled fibers, respectively. The effect of fibers length (3 mm and ≤ 0.5 mm) was studied with regard to rheological behaviour of prepared mixtures and mechanical properties of final composites. The rheological properties were determined in accordance to flow properties by rotational rheometry. The final properties were determined by measurements of flexural strength after 3, 28 and 280 days and by means of optical and scanning electron microscopy. The results indicate that milled carbon fibers had a slight effect on flow properties compared to pure binder. In contrast, 3 mm long carbon fibers significantly increased viscosity and noticeably decreased workability by interlocking mechanism of individual fibers. Moreover, it was proved that addition of milled fibers had a low reinforcement effect on composite samples and led only to slight improvement of stress-strain behaviour. On the contrary, the reinforcement by 3 mm carbon fibers improved the stress-strain properties and significantly increase ultimate flexural strength (approximately 5 times) compared to pure geopolymer binder in all studied time intervals.

Characteristics of spark plasma sintered ZrB2-SiC-SCFs composites

The effects of short carbon fibers on sinterability, flexural strength, fracture toughness and thermal shock resistance of spark plasma sintered ZrB2-SiC composites were investigated. Four samples containing 10, 20, 30 and 40 vol% of short carbon fibers (SCFs) were consolidated by spark plasma sintering at 1800 °C for 6 min under an external pressure of 40 MPa. Mechanical properties of the samples including flexural strength and fracture toughness were measured via three-point bending strength test and indentation method, respectively. Fractographical investigations were carried out via scanning electron microscopy. Thermal shock resistance of the samples was also studied via quenching method. Obtained results showed that a higher fraction of SCFs (10 vol% SCFs to 40 vol% SCFs) leads to lower relative density (90.8–89.1%) and higher amount of open porosity (7.8 vol% to 8.9%). It is also indicated that SCFs ascent from 10 to 40 vol% improve the fracture toughness from 4.1 to 5.1 MPa m1/2 by promoting toughening mechanisms such as crack deflection, branching, and pull-out. Finally, it was cleared that by SCFs ascent from 10 to 40 vol%, ΔTC increases from 530 °C up to 600 °C.

Effect of short carbon fiber on thermal, mechanical and tribological behavior of phenolic-based brake friction materials

The phenolic-based brake friction composites containing 0, 1, 2 and 4 vol% carbon fiber were fabricated in this study. Thermogravimetric analysis (TGA) revealed the adverse impact of carbon fiber on the thermal stability of the composites under air atmosphere. Differential scanning calorimetry (DSC) of the uncured samples indicated the positive impact of carbon fiber on the crosslink density of the phenolic resin. Viscoelastic results drawn from the dynamic-mechanical analysis (DMA) suggested that inclusion of carbon fiber increased the storage modulus and decreased the damping factor of the frictional composites. The tribological behavior of the specimens was assessed with a chase type friction tester. Both the friction coefficient and specific wear rate decreased with enhancing carbon fiber content. Furthermore, carbon fiber deteriorated the fade behavior of the developed composites. The TGA, DSC and DMA results were used to justify and interpret the observed tribological behavior.

Modification effects of short carbon fibers on mechanical properties and fretting wear behavior of UHMWPE composites

The present work comparatively studied the modification effects of short carbon fiber (CF) on the mechanical properties and fretting wear behavior of ultra‐high molecular weight polyethylene (UHMWPE)/CF composites. The interactions between CFs and UHMWPE interface were also investigated in detail. The results showed that, with the increase in fiber content, the compressive modulus and hardness of the composites increased, while its impact strength decreased. It was found that filling of CF can reduce the friction and wear of UHMWPE. In addition, the UHMWPE‐based composites reinforced with nitric acid‐treated CF exhibited better mechanical properties, lower friction coefficient, and higher wear resistance than those of untreated UHMWPE/CF composites. This was attributed to the improvement of interfacial adhesion and compatibility between CF and UHMWPE matrix caused by surface chemical modification of CF. Copyright © 2015 John Wiley &amp; Sons, Ltd.

Toughening effect of short carbon fibers in the ZrB2–ZrSi2 ceramic composites

Abstract The toughening effect of the short carbon fibers in the ZrB2–ZrSi2 ceramic composites were investigated, where the ZrB2–ZrSi2 ceramics without carbon fibers were used as the reference. The mechanical properties were evaluated by means of flexural and SENB tests, respectively. The microstructure was characterized by SEM equipped with EDS. The results found that the short carbon fibers were uniformly incorporated in the ZrB2–ZrSi2 matrix and the relative density was about 97.92%. The flexural strength of short carbon fiber-reinforced ZrB2–ZrSi2 composites is 437 MPa; the fracture toughness and the work of fracture are 6.89 MPa m1/2 and 259 J/m2, respectively, which increased significantly in comparing with composites without fibers. The microstructure analysis revealed that the improved fracture toughness could be attributed to the fiber bridging, the fiber–matrix interface debonding and the fiber pullout, which consumed more fracture energy during the fracture process.

The effect of short carbon fibers on the thermoelectric and mechanical properties of p-type CeFe4Sb12 skutterudite composites

Abstract Short carbon fiber-reinforced p-type skutterudite CeFe 4 Sb 12 composites were fabricated by a melting-annealing process combined with spark plasma sintering, the effect of carbon fibers on the thermoelectric and mechanical properties were investigated, and the relationship between the microstructure and the mechanical properties of the composites were elucidated. The results indicate that the carbon fibers were well distributed throughout the matrix and were in intimate contact with the CeFe 4 Sb 12 grains without interlayers. Both the flexural strength and the fracture toughness of CeFe 4 Sb 12 were enhanced with the addition of the carbon fibers. Considering the tradeoff between the thermoelectric and mechanical properties, the optimal carbon fiber content was found to be 1 vol.%. The flexural strength of the composite containing 1 vol.% fiber was improved by 53%, whereas the fracture toughness and ZT value remained nearly unchanged.