Hybrid Composite Samples Research Articles

Mechanical Characterization of Areca Fiber and Coconut Shell Powder Reinforced Hybrid Composites

The use of natural fibers in polymer matrix composites are increases because of their advantages like good stiffness, strength, environmental friendly, low cost and biodegradable. In the present investigation, hybrid fiber reinforced composites are fabricated using areca fiber and coconut shell powder (CSP) as reinforcement in epoxy resin. Unidirectional areca fiber and CSP reinforced epoxy composites were fabricated by varying the overall fiber loading (10, 20, 30, and 40 wt.%) and different weight ratios of areca fiber and CSP (1:1, 1:3, and 3:1). Effect of fiber loading and weight ratio on mechanical properties like tensile strength, tensile modulus, flexural strength, flexural modulus, interlaminar shear strength (ILSS), impact energy and surface hardness of hybrid composites were evaluate experimentally. All the hybrid composite samples fabrication and mechanical testing was done as per ASTM standards. The experimental investigation reveals that the tensile, flexural and ILSS properties show their maximum values at 30 wt.% of fiber loading with areca fiber and CSP weight ratio as 1:1. From the impact and hardness results it has been found that composites with areca fiber and CSP weight ratio as 3:1 and 1:1 respectively shows their maximum values at 40 wt.% of fiber loading. Interfacial analysis of the hybrid composites were also observed by using scanning electron microscope (SEM).

Effect of graphene nano-platelets on mechanical and impact characteristics of carbon/Kevlar reinforced epoxy hybrid nanocomposites

The influence of various graphene nano-platelets (GNPs) content on the tensile, flexural and Charpy impact characteristics of carbon, Kevlar and hybrid carbon/Kevlar fibers reinforced epoxy matrix composites was investigated. Both of composite configurations as carbon and Kevlar at outer and core skins were experimentally tested. The SEM images for flexural specimens were taken to observe the adhesion mechanism of GnPs particles with fiber/epoxy system. It is found that hybridization with Kevlar layers is contributed a positive effect on the hybrid carbon/Kevlar laminate structures in terms of tensile, flexural and impact behaviour. The incorporation of GnPs particles in hybrid and non-hybrid composite samples results in significant improvements in tensile, flexural and impact properties, and the greatest improvement occurs within the GnPs particle content of 0.1 and 0.25 wt%, indicating that the interfacial bonding between the matrix and the fibers is better due to the large surface area of the GnPs and the good entanglement between the GnPs layers and the matrix chains. The samples of impact test are experimented for edgewise and flatwise directions.

Effect of Reinforcement, Load and sliding distance on Al-4.5%wt Copper Matrix Hybrid Composites

Aluminum is prospectively a significant material for tribological appliances for the reason that of its less density and superior thermal conductivity. However, aluminium by itself displays deprived tribological properties. Hence, the investigation of the tribological performance of aluminium based composite materials is flattering increasingly significant. Hence in the present research tribological behavior of Al-4.5%wt copper reinforced with varying percentage of zircon sand (2% -8% in increments of 2 %) with and without 2%wt graphite of hybrid composite samples prepared by friction stir casting technique.. To know the allocation of particles and bonding flanked by reinforcement with matrix, microstructure of the composites and base alloy were premeditated by means of “Optical and Scanning Electron Microscopy”. The wear loss was computed employing pin on disc apparatus at room temp underneath dry sliding state. The investigation reveals that the wear rate of Al-4.5%wtCu alloy effected by composition, load and speed.

Effect of Surface Modification on the Properties of Polypropylene Matrix Reinforced with Coir Fibre and Yam Peel Particulate.

Polypropylene composites reinforced with coir fibre and yam peel particulate were produced using compression moulding machine. Treated and untreated coir fibres were used; 1.5 M NaOH was used for the treated coir fibres. Yam peel was grouped into two, treated and untreated; the treated was modified using 1 M solution of NaOH and HCl in the proportion of 30% and 70%, respectively. The yam peel which was sun-dried for 14 days was pulverized and sieved to −45 µm. Samples were developed using treated and untreated reinforcements (TCF/YPP and UCF/YPP) at constant coir fibre proportion (15%) and varied amount of yam peel particulate (2, 4, 6, and 8 wt.%). The hybrid composite samples developed were probed for mechanical properties and thermal and wear behaviour. The level of particles agglomeration at the fibre-matrix interface was examined using scanning electron microscope. The results show that sample reinforced with treated 4 wt.% coir fibre and yam peel particulate had optimum mechanical properties. However, the thermal conductivity of composite samples increased with fibre addition. All composite samples developed had better resistance to abrasion when compared to the control sample.

Experimental investigation on mechanical properties of FeCoCrNiMo High Entropy Alloy & B4C reinforced Al6061 hybrid MMCs

Metal matrix composites are the new innovating materials used in daily life for quite some time. In the current research work Al6061 is used as matrix material and FeCoCrNiMo High Entropy Alloy (HEA) and Boron Carbide (B4C) used as reinforcements. An attempt has been taken to fabricate hybrid MMCs considering aforementioned matrix and reinforcements through manual stir casting method by varying the volumetric concentrations (1%, 2% & 3%) of reinforcements. After fabrication, combined effects of HEA and B4C reinforcements on mechanical properties (tensile strength, hardness and impact strength) of MMCs have been studied. The results indicate that hybrid composite samples show superior mechanical properties compared to pure Al6061. Mechanical properties are improved with increased vol% of FeCoCrNiMo High Entropy Alloy. The maximum 29%, 11.8% & 25.3% improvement in ultimate tensile strength, toughness & hardness were observed with Al6061 + 3%HEA + 1%B4C hybrid composite sample compared to pure Al6061.

Effect of finishing and polishing systems on the surface roughness and color change of composite resins.

BackgroundThis study is to examine the surface roughness and color changes occurring on composite resins following the application of different finishing and polishing systems. Material and MethodsIn our study, a total of 200 samples were prepared from composites resin (6×2 mm) containing supra-nano, submicron hybrid, nanohybrid, nano-ceramic and microhybrid filler. They were polished with diamond, aluminum oxide, silicon carbide finishing and polishing systems. The initial color values of composite samples were measured with a spectrophotometer and surface roughness values with a profilometer. After that, samples were immersed of coffee solution and color measurements were repeated on the 1st and 7th day. The differences between surface roughness (Ra) and color change values (∆Eab) were evaluated using two-way analysis of variance (ANOVA) test (p<0.05). ResultsFinishing and polishing systems produced a statistically significant difference between the surface roughness values of nano-ceramic, submicron hybrid and microhybrid composite resin samples (p<0.05). Supra nano composite, which showed the lowest surface roughness after all finishing and polishing systems, showed the least color change after 7 days compared to other composite groups (p<0.05). The microhybrid composite with the highest surface roughness was the most color changing composite group (p<0.5). ConclusionsThe spiral finishing and polishing system containing diamond particles was the system to provide the least color difference on all composite groups. However, color differences of all composite resin groups were found to exceed the perceptibility threshold (PT) and acceptability threshold (AT). Key words:Composite resin, color stability, surface roughness.

Effect of moisture absorption on the mechanical properties of jute/glass hybrid sandwich composites

Abstract The use of composites has been increasing day by day due to their specific properties such as high strength to weight ratios, high modulus to weight ratio, corrosion resistance, and wear resistance. The objective of this work is to evaluate the moisture absorption effect on the mechanical properties of hybrid sandwich composite structures formed by epoxy resin, reinforced by woven fabrics of glass and jute fibres, with a central layer of polyethylene foam. The structures used for the current study is fabricated by hand layup technique. The water absorption characteristics of the fibres are obtained by immersing the composite samples in normal water at room temperature at different intervals of time. The different sandwich composite structures are prepared and are compared with pure jute fibre composite. The testing of specimens is carried out as per ASTM standards. The tensile, flexural and impact tests on dry and wet hybrid and non-hybrid sandwich composite samples are examined. The study shows that the mechanical properties of the jute/glass fibres are improved by using foam. However, as a result of water penetrating the fibre/matrix interface, longer water- immersion times reduced the tensile, flexural and impact strength of the composites.

Python implementation of fuzzy logic for artificial intelligence modelling and analysis of important parameters in drilling of hybrid fiber composite (HFC)

Composite materials present the advantage of being able to be specially designed for a particular application by combining appropriate reinforcement materials with a matrix material suited to withstand the operant conditions. The use of Hybrid-Fiber Composites (HFCs) addresses the need for greener manufacturing processes while also meeting product specifications in a wide range of applications, all for nominal prices. In order to improve our understanding of the machining processes compatible with HFCs, this paper presents findings from a study in which the effects of drilling on glass-flax-hemp fibre hybrid composite samples are observed and modeled. Pivotal parameters in drilling, namely drill bit diameter, spindle speed and feed rate are studied, and a fuzzy-logic inference system (FIS) coded in Python is used to model the thrust force and torque acting on the composite sample. A comparison between experimentally obtained and model-generated values of the same indicate very good correlation, thus verifying the effectiveness of the FIS.

Quantifying dielectric and microwave absorption properties of barium titanate and strontium ferrite filled polymer composites

In the present study, dielectric and microwave absorbing properties of barium titanate (BaTiO3) and strontium ferrite (SrFe12O19) filled thermoplastic polyurethane composites were investigated. The variations of the dielectric parameters of the BaTiO3 filled composite samples with filler concentration were also modeled and simulated by the power-law model to predict dielectric coefficients of the samples for higher filler concentrations. Comparing the prediction of the Power-law model and experimental measured dielectric values indicate that the Power-law model predicts dielectric parameters of the composite with acceptable accuracy. Microwave absorption analyses of the composite samples showed that SrFe12O19 is more effective than BaTiO3 on the enhancement of microwave absorption capability of TPU. The hybrid composite samples that contained both SrFe12O19 and BaTiO3 were also prepared, and their microwave absorption performance was evaluated. It was observed that much lower RL values than that of the composite samples, which were filled SrFe12O19 or BaTiO3 could be obtained by the hybrid composites. However, absorption bandwidth of them was narrower than counterparts that contained the same amount of SrFe12O19.

Investigations on mechanical behavior of hot rolled Al7075/TiO2/Gr hybrid composites

In the present work, influence of titanium dioxide (TiO2) and graphite (Gr) hybrid reinforcement on microstructure and mechanical behavior of Al7075 alloy is studied. Al7075 and its hybrid composite samples were fabricated by using stir-casting and hot rolling technique. Hot rolling was carried out at a temperature of 450 °C with a reduction-ratio of 90%. Microstructure examination showed a good dispersion of titanium dioxide and graphite reinforcement particles with excellent bond with Al7075 matrix alloy. In case of hot rolling, both the reinforcements were found to be aligned in the direction of rolling. The microhardness and tensile strength of hybrid composites were remarkably improved in case of hot rolling compared to that of cast composites.

Intrinsic cellulosic fiber architecture and their effect on the mechanical properties of hybrid composites

This study is mainly focused on the intrinsic fiber parameters and their influence on the mechanical properties of the hybrid composites. Cellulosic fibers are extracted from mesocarp of Cocos nucifera fruit and outer mat of Luffa cylindrica fruit. The inherent fiber parameters such as fiber diameter, lumen diameter, cell wall thickness are observed under light microscope. Micro-fibrillar angle is found using X-ray diffraction technique. Three varieties of hybrid polymer composite samples are fabricated using Cocos nucifera and Luffa cylindrica fibers as reinforcements in the ratio 2:1, 1:1 and 1:2 respectively employing hand layup technique with their combined weight maintained as 30%. Significant response in the Load Vs Deflection curve and mechanical properties of the hybrid composites are found attributing to the difference in the respective weight proportion of the constituent fibers in the hybrid composite system. Results exemplify that the hybrid composite sample comprising Cocos nucifera and Luffa cylindrica fibers in the ratio 1:2 capitulates the maximum flexural strength and impact strength of 31.05 MPa and 14.24 kJ/m2 respectively when compared with other hybrid composites. The reason for the difference in mechanical strength of hybrid composite samples containing two different fibers is found to be related to the built-in architecture and physical characteristics of the constituent fibers. The morphology of the fractured samples are examined and reported. It is concluded that properties of hybrid composites can be tailor made depending upon the requirements either by using the Cocos nucifera fibers to impart ductility or Luffa cylindrica fibers to impart brittleness.

Cerium vanadate/carbon nanotube hybrid composite nanostructures as a high-performance anode material for lithium-ion batteries

Li + insertion/de-insertion process into/out for the pristine CeVO 4 and CeVO 4 /CNT HCNS electrodes. • Pristine CeVO 4 and CeVO 4 /CNT HCNS were successfully prepared via a silicone oil-bath method. • The Li insertion/de-insertion electrochemical reaction with the CeVO 4 was analyzed. • The discharge performance of CeVO 4 /CNT HCNS electrode was improved compared to the pristine CeVO 4 . • The electrode delivered a reversible capacity of 586.82 mA h g −1 after 1200 cycles at 500 mA g −1 . The pristine CeVO 4 and CeVO 4 /CNT hybrid composite nanostructured samples were facilely synthesized using a simple silicone oil-bath method. From the X-ray diffraction results, the formation of tetragonal CeVO 4 with an additional minor phase of V 2 O 5 was identified. When investigated as an anode material for lithium (Li)-ion batteries, the CeVO 4 /CNT hybrid composite nanostructure (HCNS) electrode demonstrated improved Li storage performance over the pristine CeVO 4 . The Li insertion/de-insertion electrochemical reaction with the CeVO 4 was analyzed on the basis of cyclic voltammetry study. The cyclic voltammetry analysis revealed that the three-step reduction of V 5+ to V 3+ , V 3+ to V 2+ , and V 2+ to V + processes is involved and among them, only V 5+ to V 3+ is reversible during the Li-ion insertion into CeVO 4 . The CeVO 4 /CNT HCNS electrode exhibited a discharge capacity as high as 443 mA h g −1 (capacity retention of 96.3%) over 200 cycles at 100 mA g −1 , whereas the pristine CeVO 4 is limited to 138 mA h g −1 (capacity retention of 48%). Even at a high current density of 500 mA g −1 , the CeVO 4 /CNT HCNS electrode delivered an excellent reversible capacity of 586.82 mA h g −1 after 1200 cycles.

Investigation of Microstructures, Mechanical Properties of AZ91E Hybrid Composite Reinforced with Silicon Carbide and Fly Ash

In this study, the stir casting processing technique was used to produce the AZ91E hybrid composite reinforced with Silicon Carbide (SiC) and Fly ash (FA) particles in different weight percentages varying from 0 to 10%.30 μm in size. This paper investigates the micro structural phenomena and partial mechanical behavior (i.e., tensile strength, hardness, and fracture toughness) of AZ91E alloy reinforced with SiC and FA. Scanning Electron Microscope (SEM) furnished with Energy Dispersive X-ray spectroscopy (EDX) was used to investigate the microstructures. The results show that the SiC and Fly-ash particles are uniformly distributed in the matrix, and there is no sign of SiC and Fly ash agglomerations. The densities of the composites varied from1.805–1.829 g/cm3.The results of hybrid composite samples are then compared with as AZ91E alloy samples. This study found that the addition of both a hard reinforcement (e.g., SiC) and soft reinforcement (e.g., fly ash) remarkably improves the mechanical property such as tensile strength, the hardness of magnesium composites. However, the fracture toughness and elongation of magnesium composites were decreased due to grain refinement due to the addition of reinforcement particles. The tensile test results obtained from the experimental process were compared with finite element method results. The finite element results were in good agreement with the experimental results.

Impact and Flexural Strength of Kaolinite / Glass Fibers Reinforced Heat-Cured Acrylic Denture

Nowadays, most materials used to manufacture denture base are heat-cured PMMA, to overcome the low strength of this material, different methods were used to strengthen the denture base and enhanced their properties. This study investigated the effect of glass fiber woven powder kaolinite (Al2Si2O5 (OH) 4) to influence and strength of flexure. Acrylic and kaolinite powders were mixed together and mixed again with acrylic liquid to prepare hybrid composite samples. Woven glass fiber composite was prepared by inserting woven glass fiber between the two halves of the dough. PMMA reinforced by (0, 20) wt% of woven glass fibers or/and (0, 2, 5, 7) wt% of kaolinite powder to prepare eight experimental groups (n= 7). The fractured surface was an evaluation by scanning electron microscope (SEM). X-ray diffraction and Fourier transforminfrared spectra FTIR tests were used to examine kaolinite powder. Samples were tested with the use of a Charpy testing machine for impact test and Instron tensile testing machine for flexural test after storage in water for 10 days at 37 °C. The results showed woven glass fibers with clay powder together significantly increased the mechanical properties of PMMA.

Influence of designated properties on the characteristics of dombeya buettneri fiber/graphite hybrid reinforced polypropylene composites

This research presents the behavior of dombeya buettneri fiber/graphite hybrid composites which was studied to harness a favorable balance between the inherent advantages and disadvantages of natural and synthetic reinforcements. The fibers after extraction were chemically treated for surface modification. The composite was developed using compression molding process by randomly dispersing the reinforcements in the polypropylene matrix in predetermined proportions. The developed samples were tested to ascertain the response of the materials to the selected properties. Experimental results showed that hybrid composite sample C which is a blend of 12 wt% dombeya buettneri fiber (DBF) and 8 wt% graphite particle (GP) gave enhanced results in many of the properties which includes; hardness, impact, thermal insulation and abrasion resistance properties. Also, the hybrid composites sample denoted as sample E which is the blend of 6 wt% DBF and 14 wt% GP produce higher enhancement in the flexural properties and Young’s Modulus of Elasticity than other samples. Composite sample reinforced with dombeya buettneri fiber as single reinforced composites performed more in ultimate tensile strength compared to other samples while graphite particle reinforced sample emerges as the best in thermal conductivity. Diffusion of water into the composites also obeys Fick’s law where sample C was seen to be the best among the composites. It was therefore, discovered that the synergy between the two reinforcements has encouraged the improvement of polypropylene (PP) properties in a unique mode.

Low-cost and novel preparation of porous NiS2/graphene heterojunctions photoanodes for high-efficiency dye-sensitized solar cells

It's critical and challenging to investigate cost-effective and strong electrocatalyst within the advancement of large scaled dye-sensitized solar cells (DSSCs). In this work, we develop a novel strategy to prepare NiS2 microspheres interface with 2D graphene nanosheets constructed through a facile hydrothermal technique. Na2S2O3·5H2O plays an important role as the reducing agent for GO as well as the sulfur source for NiS2. The microstructures, morphologies and optical properties of the NiS2/graphene hybrid composite samples were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and N2 adsorption–desorption isotherm, UV–Vis diffuse reflectance spectra and photoluminescence spectra analysis. A significant narrowing the band gap (2.69 eV–2.44 eV) and control the prevention of electron-hole pair recombination process was examined through UV and PL studies. The J-V characteristics of the fabricated sandwich type DSSC device was monitored and the results demonstrate that NiS2/graphene hybrid photoanode displayed an excellent electrocatalytic activity in the reduction of I3− showing a power conversion efficiency of 12.56%, which is 2.5 times better than bare NiS2 photoanode (5.02%). This is ascribed to the low resistance to diffusion and transfer of electrolyte ions. These results suggest that the NiS2/graphene prepared through a facile process is a promising substitute to Pt electrode.

Experimental study on tribological (dry sliding wear) behaviour of polyester matrix hybrid composite reinforced with particulate wood charcoal and periwinkle shell

Polyester based hybrid composites is developed using 75 µm sized wood charcoal and periwinkle shell as particulate reinforcements in various proportions of mixture. Hardness, dry sliding wear and morphological examinations were performed on the hybrid composite samples using Brinell hardness tester, pin-on-disc tribometer and SEM-EDX techniques respectively. The results from the study revealed that all the hybrid composites have improved properties over the unreinforced polyester resin and polyester sample reinforced with only wood charcoal at 5 wt% reinforcement concentration. Optimal combination of hardness and wear properties was obtained by the hybrid composite sample reinforced with equal proportions of wood charcoal and periwinkle shell particles. Further additions of periwinkle shell particles over the content of wood charcoal powder in the 25:75 ratio, induced a sharp decrease in hardness and wear properties of the hybrid composites below that of the unreinforced polyester resin. SEM-EDX analysis revealed the presence of varying proportions of carbon, calcium, silicon, potassium, iron and aluminium as the major elements, which resulted in the observed hardness, and wear properties of the hybrid composites. Optimal reinforcement weight fraction and combination of wear parameters required for minimum wear rate and improved hardness was established using one factor RSM design.

Effect of Ageing on the Tracking Characteristics of High-Temperature Vulcanized Silicone Rubber Hybrid Composites for High Voltage Insulation.

Micro-sized aluminum trihydrate (ATH) filled silicone rubber is useful as insulation in the electric power system. The addition of nanofillers can improve further, its overall performance. However, the degradation of such silicone insulator due to ageing has not yet been thoroughly analysed. Motivated by this, an investigation was done to observe the effect of ageing on the tracking, and the material characteristics of SiO2 nanofillers added micro-sized ATH-filled Silicone rubber. For this, the samples were prepared using different weight percentage of SiO2 nanofillers and were thermally-aged and water-aged in the laboratory environment. A well-regulated tracking-test setup was assembled, and the leakage current characteristics of the fresh, thermal-aged and water-aged samples were observed, as per international electro technical commission standard (IEC) 60,587. After tracking, the surface morphology of these samples was studied using scanning electron microscopy (SEM). Further, energy dispersive X-ray analysis (EDAX) was carried out to observe the elements present at the surface and, Fourier transform infra-red (FTIR) spectroscopy was conducted to study the changes in the chemical structure. Investigations through the leakage current, SEM, EDAX and FTIR revealed that the addition of nanofillers improved the tracking characteristics of the aged hybrid composite insulation samples, thereby minimising any early failures.

Microstructural and mechanical properties of a novel Al-based hybrid composite reinforced with metallic glass and ceramic particles

A new type of Fe-based metallic glass (FMG) and SiC reinforced hybrid composite was successfully developed. The current work was set to evaluate the microstructure and mechanical properties of the hybrid composite consolidated through the spark plasma sintering (SPS) process. The densities of the samples were determined in order to examine the performance of the sintering process. The experimental results indicated that, in the composites having larger amounts of FMG particles, the reinforcements/matrix interfaces were free from any discontinuities. The quantitative analysis of microstructural features revealed that the more homogenous distribution of reinforcing particles was occurred for FMG rich composites. The microstructural analysis of the samples pointed that the amorphous structure of the FMG reinforcement remained unchanged and no interfacial chemical products were created in the consolidated samples. It was also found that using FMG along with SiC particles in the samples led to the more strengthening of the Al matrix compared to using just one type of reinforcement particles. In the current study, the hybrid composite reinforced with 7 vol% of FMG and 3 vol% of SiC particles demonstrated the optimum combination of compressive yield strength (98 MPa) and strain to fracture (62.8%). The strengthening mechanisms in all the consolidated samples were calculated quantitatively considering the load bearing of reinforcing particles, grain boundary and strain hardening mechanisms. The strain hardening with the contribution of about 30% in the yield strength was the predominant strengthening mechanism in the composite samples. Also, there was a reasonable agreement between the calculated and experimentally obtained yield strength for hybrid composite samples.

Measuring electrical, thermal and mechanical properties of DC-stressed HTV silicone rubber loaded with nano/micro-fillers exposed to long-term aging

High-voltage polymeric insulators used on transmission lines are likely to degrade due to the multiple environmental stresses as well as electrical surface discharges. In this paper, multi-stress aging performance of high-temperature vulcanized silicone rubber (HTV-SR) filled with different concentrations of silica and alumina trihydrate (ATH) is explored under DC voltage for a period of 5000 h. The degradation of the test specimens has been studied using partial discharge measurement, thermogravimetric analysis, differential scanning calorimetry and mechanical strength analysis. Moreover, partial discharge performance was assessed to see its linkage to aging. When comparing the partial discharge data of the composite with the neat HTV-SR, it is observed that the partial discharge inception voltage of composite samples increases up to 50%. Furthermore, the number of discharge pulses and their magnitude is lower in the composite specimens as compared to the unfilled neat samples. This improvement appears to be caused by nano-particles which reduce oxidation reactions on the surface and the tightness of the bond between polymer matrix and nano-filler particles. The measured mechanical strength and thermal stability data also show the improved performance of hybrid composite samples. This investigation confirms that hybrid composites are quite resistant to aging as compared to neat HTV-SR.