Bending Strength Of Composites Research Articles

Improvement in the thermal conductivities and bending strengths of graphite film/Cu composites by matrix alloying with Zr

Graphite film/Cu composites were fabricated by the hot-pressing sintering method. The thermal conductivities and bending strengths of the composites were improved by matrix alloying with Zr. By sanding the surface of the graphite film, carbides were easily generated at the interface. The presence of carbides at the interface transformed the interfacial bonding characteristics from mechanical to physical-chemical bonding. Enhanced interfacial bonding could improve the thermal conductivity of the composites. The optimum Zr addition amount was 1.5 wt%, and the thermal conductivity of the composites was 725 W/mK. The enhanced interfacial bonding improved the composite bending strength. When the Zr concentration was 2 wt%, the composite bending strength was 34 MPa, which was an increase of 100 % compared with that of the absence of Zr.

Investigation of manufacture variables on the mechanical properties of CFRP prepared by electrodeposition resin molding method

This study used the electrodeposition resin molding method (EDRM), an easy and effective technique, to create composite materials. Because it’s a new technique, consideration of the impact of various production parameters on composite qualities was necessary. The effects of altering these EDRM voltage and electrical current conditions on the static and dynamic properties of composites were examined and tuned to fit the objective. Three distinct voltage values (100, 150, and 200 V) and five different current conditions (0.5, 0.75, 1.00, 1.25, and 1.50 A) were used for the manufacturing variables. In accordance with that, the effectiveness of heat treatment was also evaluated using two distinct temperature profiles. The bending strength of composites was somewhat influenced by the voltage and current conditions of the EDRM, but not in a particularly significant way. However, the bending strength of composites was significantly impacted by the heat curing temperature as well as the heat curing time.

TITANIUM BASED FIBRELESS COMPOSITES

Novel composites made of titanium and Ti-Ti5Si3 eutectic were obtained and their mechanical properties were studied. It was shown that the eutectic inclusions play a reinforcing role like brittle fibres do it with respect to metal matrix. It was also shown that the composite microstructure produced at some technological regimes loses its pronounced original layered microstructure and forms a new composite type. The mechanical properties of such type of the composite look attractive. The bending strength of composites based on pure titanium reaches 1300 MPa, this characteristic can be about 1500 MPa in case of using low strength OT4-0 alloy (Ti-(0.4-1.4)Al - (05- 1.3)Mn) as the matrix. The composites reveal sufficiently high plasticity.

An investigation of the mechanical characteristics of natural particle‐reinforced glass and epoxy composites after immersion in acidic and basic aging solutions

AbstractThis study aimed to ascertain the alterations in aging responses of fiber‐reinforced composites, as well as the effects of their natural particle reinforcement, through exposure to acidic and alkaline solutions. Specimens were produced with 0 wt. % (neat), 1 wt. %, 2 wt. % and 3 wt. % particle ratios from acorn and pinecone particles. A particle content of 2 wt. % was determined to yield the best mechanical properties in all mechanical tests conducted for pinecone reinforcement. The highest improvement in strength, observed in 3 wt. % pinecone‐reinforced composites, reached 22.5% at flexural strength. HCl and NaOH diluted in water were chosen as aging solutions. Mechanical tests were repeated at different stages of aging. According to the findings, 1 wt. % particle‐reinforced composites showed better resilience to the mechanical property reduction effect of aging compared to the 2 wt. % and 3 wt. % particle‐reinforced composites. At a particle ratio of 2 wt. %, the acorn‐reinforced specimens exhibit their highest maximum penetration force, which is 5% higher than that of the 0 wt. % composite, consistent with the results of tensile and compressive tests.Highlights Composite material was manufactured by hand lay‐up and vacuum bagging method. Specimens were aged using acid and base solutions. Tensile, compressive, and bending results were obtained depending on particle type and ratio. Tensile, compressive, and bending strengths of composites were compared according to various aging times.

Preparation of Graphite/Ferrite/Resin‐Based Composite High‐Efficiency Wave‐Absorbing Materials by Selective Laser Sintering

Herein, graphite/Fe3O4/resin‐based composite absorbers are prepared by selective laser sintering (SLS) and vacuum impregnation of epoxy resin. The effects of different graphite–Fe3O4 powder compositions on the absorbing and mechanical properties of the composites are investigated. The results show that with the increase of Fe3O4 content, the absorption performance of the composites first increases and then decreases, and the absorption peak gradually moves from high frequency (12–18 GHz) to low frequency (2–8 GHz). The bending strength of composites decreases with the increasing of Fe3O4 content. When the mass ratio of graphite–Fe3O4 is 4:3, the wave absorption performance is the best, the minimum reflection loss is −54.8 dB, the effective absorption bandwidth is 2.8 GHz (8.72–11.52 GHz), and the bending strength is 11 MPa, which is 9 times higher than that of SLS plain billets. This is because the increase of the Fe3O4 content in the hybrid powder increases the number of heterogeneous interfaces, but decreases the number of holes inside the composite, which affects the number of microwave reflections inside the material, resulting in different wave absorption and mechanical properties. The graphite/ferrite/resin matrix composites prepared by SLS technology achieve the synergy of lightweight, high strength, and good wave absorption properties.

Mo2C interface layer: effect on the interface strength and cutting performance of diamond/Fe-Ni-WC composites

The weak interfacial strength between Fe-based matrix and diamonds causes diamond particles to fall off prematurely, significantly affecting the cutting efficiency of diamond composites. This work aimed to optimize the interfacial microstructure and mechanical properties of the diamond/Fe-Ni-WC composites by coating a Mo2C layer on the diamond particles. The Mo2C-coated diamonds were prepared via the molten salt method. Diamond/Fe-Ni-WC composites were sintered by the hot-pressing process under a vacuum. The bending strength of composites with Mo2C-coated diamonds was improved from 804 to 996 MPa with the increased coating time. The energy dispersive spectroscopy scanning indicated that the Mo2C coating layer changed the interfacial composition between the matrix and the diamonds from Fe–C alloy to Mo2C, improving the interface strength. Moreover, the diamond protrusion heights of composites were raised by adding a Mo2C interface, resulting in an improvement in the cutting efficiency of impregnated diamond tools.

The Effect of Fiber Volume Fraction on the Bending Strength of Fiber-Reinforced Composites of Oil Palm Empty Fruit Bunches

In this modern era, the palm oil industry is growing, so the waste is also increasing. If the waste from the palm oil industry is not processed, it will pollute the environment. One way to process palm oil waste is to turn the empty palm fruit bunches (OPEFB) fibers into composite reinforcement. Various natural fibers can be applied to become composite reinforcement, so it is necessary to study the character of OPEFB fibers for composite reinforcement. This study will look at the effect of various volume fractions on the bending strength of the composite. The volume fraction consists of 20%, 30%, and 40% fiber. The composite is then tested for bending to determine the bending strength of the composite. The results of the tests showed that the highest bending strength value was the 30% volume fractional variation with 47.70 MPa. The 40% volume fraction variation has the lowest bending strength value of 29.53 MPa.

The Dependence of the Strength of a Carbon Fiber/Aluminum Matrix Composite on the Interface Shear Strength between the Matrix and Fiber

Taking the example of a composite wire with an Al-25% Sn alloy matrix reinforced with carbon fiber, the dependence of composite bending strength on interface shear strength was determined. Samples of the composite wire with different interface shear strengths were obtained by heat treatment at temperatures from 300 to 600 °C. The highest bending strength of 2450 MPa was observed for composite wire samples with the lowest interface shear strength. With an increase in the shear strength of the interface, a decrease in the strength was observed. The study of the surface of carbon fiber extracted from the composite showed that heat treatment led to the formation of aluminum carbide crystals on the fiber surface, the size and number of which increased with increasing temperature. As a result, there was an increase in the shear strength of the interface. The evaluation of the work of fracture of a composite with different strengths of the interface between the matrix and the fiber demonstrated that as the strength of the interface increases, the work of fracture decreases, due to the premature fracture of the composite through crack propagation in one plane. Based on the experimental data, the refined mixture rule according to the Weibull distribution, and an assessment of the critical stress of crack propagation according to the Griffith–Orowan–Irwin concept, the dependence of composite strength on the shear strength of the interface was estimated. Due to this, the critical shear strength was calculated at which the greatest strength of the composite can be achieved, these values being 107 MPa and 2675 MPa, respectively. It is shown that the contribution of the work of overcoming the friction force to the total work of fracture at relatively small values of shear strength can be several times greater than the total contribution of all other types of energy.

Effects of Preparation Methods on the Microstructure and Mechanical Properties of Graphene-Reinforced Alumina Matrix Composites.

Recent years have witnessed a growing research interest in graphene-reinforced alumina matrix composites (Al2O3-G). In this paper, to better achieve the dispersion of graphene in composites, a ball milling method for adding raw materials step by step, called stepwise feeding ball milling, was proposed. The Al2O3-1.0 wt % graphene composites were prepared by this stepwise feeding ball milling and hot pressing. Then, the effects of sintering temperature and sintering pressure on the microstructure and mechanical properties of composites were studied. Results showed that the bending strength, fracture toughness and Vickers hardness of composites increased firstly and then decreased with increasing sintering temperature. The mechanical properties of composites were all at their maximum with the sintering temperature of 1550 °C. For example, the bending strength of composites reached 754.20 MPa, which was much bigger than 478.03 MPa at 1500 °C and 364.01 MPa at 1600 °C. Analysis suggested that the strength of composites was mainly related to the grain size, microflaw size and porosity.

Toughening and rapid self‐healing for carbon fiber/epoxy composites based on electrospinning thermoplastic polyamide nanofiber

AbstractThis article fabricated toughening and self‐healing carbon/epoxy composites based on electrospinning thermoplastic polyamide nanofiber (PAnf). When the incorporation of PAnf was merely 1.2 wt%, the interlaminar shear and bending strength of composites increased by 17.6% and 14.7%. The two main toughening mechanisms were the entangled porous nanofiber structure with a large specific surface area and the strong interface resulting from the interaction between PAnf and epoxy. Multiple short beam shear cycles generating interlaminar fracture were conducted to evaluate the healing efficiency. The obtained results for three damage‐healing cycles achieved 110.4%, 88.4%, and 70.1%, respectively. The melting thermoplastic PAnf would thermally expand, flow across microcrack, and fill delamination at healing temperature. This process was the inherent characteristic of thermoplastic PAnf, and thus, the composites can heal the damaged region rapidly and repeatedly. Moreover, PAnf with low incorporation showed no adverse effect on the storage modulus and Tg of composites, which maintained their original properties.

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

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

Flexural strength of composite high-density polyurethane foam filled light gauge square steel tubes

The improved flexural strength of composite high-density Polyurethane (PU) foam (Density 150 kg/m3) filled Light Gauge Square Steel (LGSS) tubes is presented in this paper. 4Point bending tests are conducted on Empty and PU Foam filled LGSS Tubes having b/t ratios of 125,100 and 83.33. Numerical study carried out using ABAQUS software to validate experimental results. Using past theoretical models, moment-rotation graphs are prepared for empty and PUFF tubes. The results define the triaxial crushing strength of PU foam in pure bending zone due to confinement by the steel envelope in pre and post buckling regimes and its influence on the composite bending strength (combined flexure and shear). Various types of composite filled tube beams are selected and ratios of their flexural strengths to their own weights are calculated and compared. Observed highest Strength-to-weight ratio for current research composite filled tubes.

Effect of the Hot Deformation Conditions on Structure and Mechanical Properties of AlCr/AlCrSi Powder Composites

Aluminum matrix composites usually contain strengthening particles of refractory compounds (SiC, Al2O3) that do not react with the Al matrix. There is a problem in producing the Al matrix composite with inclusion of metals that can generate intermetallic compounds with aluminum. In this case, a conventional sintering of powder mixtures results in high porosity due to volume growth. That is why some new methods of producing dense Al matrix composites are required. A possibility to create a dense powder Al-based composite containing hard components, such as chromium and silicon, without using the sintering process, is considered. This paper presents study results of structural and mechanical properties of Al-Cr and Al-Cr-Si composites produced by hot compaction of powder mixtures. An analysis of the relationship between mechanical properties and structures of Al-Cr and Al-Cr-Si composites is carried out. Optimal values for thermomechanical processing modes that ensure sufficient strength and plasticity are determined. It is shown that strong bonding of the aluminum particles occurs under hot deformation, and an aluminum matrix is formed that provides acceptable composite bending strength as a result. The presence of chromium and silicon hard inclusions is not a significant obstacle for aluminum plastic flow. Al-Cr and Al-Cr-Si composites produced by hot deformation of the powder mixtures can be used as cathode material for the deposition of wear-resistant nitride coatings on metalworking tools.

Analysis of mechanical strength of weight fraction variation sugar palm fiber as polypropylene-elastomer matrix reinforcement of hybrid composite

Currently, the availability of polypropylene, elastomer and sugar palm fiber (Arenga pinnata) is very abundant, which has a good impact on the potential for the development of new composite materials that have good properties and characteristics. Composites are generally a new material composed of two or more different materials with the aim of producing a new material that has better properties than the constituent material. In this study, polypropylene (PP) plastic and elastomer were used as a composite matrix reinforced with sugar palm fiber (Arenga pinnata). The purpose of this study was to determine the value of tensile strength, impact strength, and bending strength of composites with a weight fraction of 20 % (80:20), 30 % (70:30), and 40 % (60:40). Based on the results of the research on hybrid composites of polypropylene and fiber-reinforced elastomers, composites with a weight fraction of 20 % (80:20) got the lowest tensile strength value of 1.153 MPa, while composites with a weight fraction of 40 % (60:40) obtained the highest tensile strength value of 2.613 MPa. Composites with a weight fraction of 20 % (80:20) got the lowest tensile strain value of 0.0049 and the highest tensile strain value of 0.0067 was found in composites with a weight fraction of 40 % (60:40). For the impact strength, the 40 % (40:60) weight fraction composite got the lowest value of 45248.234 kJ/mm2, while the 20 % (80:20) weight fraction composite got the highest impact strength of 17649.97 kJ/mm2. For bending strength results, the composite with a weight fraction of 20 % (80:20) obtained the lowest bending strength of 1.7778 MPa, while the composite with a weight fraction of 30 % (70:30) obtained the highest bending strength of 4.8867 MPa. The highest bending strain was found in the composite with a weight fraction of 20 % (80:20), which was 0.0207.

The influence of structural parameters of fabrics on the bending strength of T-shaped composites

Fabric-reinforced composites with an assumed cross-sectional shape due to their specific properties and the possibility of their shaping are increasingly used in many industrial sectors. The article presents the results of research on the influence of T-shaped fabric structural parameters on the bending strength of the composites reinforced with this fabric. The composites were reinforced with a designed 3D fabric, which was made in one step on a classic harness loom. The test results showed that the increase in the bending strength of the T-composite was influenced by the increase of the warp and weft density in the web and the reduction of the weft density in the base. The most important cross-sectional element influencing the bending strength of the T-shaped composite is the web element and the distribution of threads in this composite element. In addition, the T-shaped structure was reinforced by using a multilayer fabric in the appropriate cross-sectional elements. There was a three-fold increase in bending strength compared to composites with the fabric without reinforcement. The strength properties of the composite are influenced by the ‘density’ of the structure expressed by the density of threads. By modifying the construction of the reinforced fabric, the bending strength properties can be shaped.

Fabrication and mechanical properties of Ti2AlC/TiAl composites with co-continuous network structure

Ti2AlC/TiAl composites with different volume fractions were prepared by hot pressing technology, and their reinforced structural characteristics and mechanical properties were evaluated. The results showed that when the reinforced phase volume fraction of Ti2AlC was 20%, three-dimensional interpenetrating network structures were formed in the composites. Above 20%, Ti2AlC phase in the composites accumulated and grew to form thick skeletal networks. The microplastic deformation behavior of Ti2AlC phase, such as kink band and delamination, improved the fracture toughness of the composites. Comparative analysis indicated that the uniform and small interconnecting network structures could further reinforce the composites. The bending strengths of composites prepared with 20 vol.% Ti2AlC reached (900.9±45.0) MPa, which was 25.5% higher than that of TiAl matrix. In general, the co-continuous Ti2AlC/TiAl composite with excellent mechanical properties can be prepared by powder metallurgy method.

Вивчення кінетики просочення базальтових, вуглецевих, оксидних волокон розплавами алюмінію та його сплавами

Wetting studies were performed by the sessile drop method using the capillary purification method of melt during the experiment in a vacuum of 2·10-3 Pa in the temperature range of 600–700 oC. The use of a dropper allows separate heating of the melt and the substrate, capillary and thermo vacuum cleaning of the melt, as well as thermo vacuum cleaning of the coatings surface. This is a model scheme of the impregnation process of non-metallic frames with matrix melts in the manufacture of composite materials by spontaneous free impregnation. Vanadium, copper and nickel metals were chosen for the coatings, which were sprayed on the materials by electron beam evaporation of metals in vacuum, and titanium, nickel powders for the coatings were used. The nature of the wetting angle dependence on the film thickness is a linear decrease in the angle with increasing film thickness. Studies have shown the possibility of using double films vanadium–copper, vanadium–nickel for the manufacture of composite materials from basalt fibers. The process of impregnation of basalt, carbon and oxide fibers with aluminum melts and its alloy with silicon in the temperature range 650–700 oC has been studied. The metal titanium, nickel powder coatings and films vanadium–copper, vanadium–nickel for the method of spontaneous free impregnation were used. Speciments of the composite material were obtained and the limit of destruction of these samples was determined. The bend strength of composites (basalt fiber 200 μm) is 270 MPa. Keywords: spontaneous free impregnation, composites, aluminium melts, basalt, carbon, oxide fibers, wetting, metal coatings and coverings.

Physic-Mechanical Properties of Composites Based on Secondary Polypropylene and Dispersed of Plant Waste

The physic-mechanical properties of filled composites based on secondary polypropylene are investigated. As fillers the dispersed wastes of processing of agricultural plants - buckwheat and oat husk, as well as needles flour and wood flour were used. Water absorption, abrasion, impact strength and bending strength of composites were investigated. It has been proven that oat and buckwheat husks can be effectively used in composites based on secondary polypropylene and replace traditional wood fillers. It has been shown that the physic-chemical properties of the filled composites depend on the structure and physicochemical interactions on the phase separation surface, as well as on the surface properties of the filler particles. It is established that for the production of filled composites with improved physic-mechanical characteristics it is necessary to use fillers with small specific surface and concentration of surface functional groups, and the acid-base characteristic of the surface should be closer to neutral. It is shown that these conditions provide for the formation of a uniform structure of the filled composite with less internal stresses.

SHC pressing of TiC + xC composites

Experimental results of the preparation of refractory electrically conductive composites TiC + xC by SHS pressing are presented. The conditions for obtaining composites with a residual porosity of about 20 % are determined. The effect of the composition of the reaction mixture on the phase composition, microstructure, tensile strengths under compression and bending, and the electrical resistivity of SHS composites was studied. It was shown that the compressive and bending strength of composites based on the TiC + xC system is 80-100 and 100-150 MPa, respectively, which is 3-5 times higher than the strength of fine-grained graphite. The electrical resistivity of the composites corresponds to the electrical resistivity of fine-grained graphite (16-18 μ Ohm · m). Ill. 3. Ref. 11. Tab. 3.

Excellent mechanical properties of copper-graphite composites with the addition of tantalum alloying element

In this study, the effect of novel metal tantalum was investigated on the properties of copper-graphite composites. The complete mechanical behavior of copper-tantalum-graphite hybrid composites was examined. The addition of tantalum increased the compressive, tensile and bending strength of composites as well as the hardness and thermal conductivity. The compression, tensile, bending and hardness values for Cu–Ta-GF (0.5) composites are 20.7%, 138%, 69% and 93% higher than pure Cu and these are also far better than Cu-GF composites. The excellent mechanical and thermal properties with good relation of strength-ductility ratio open up a new window to use these materials as heat sinks in thermal packaging system.