Volume Fraction Of Reinforcement Research Articles

Friction Surfacing of Aa6061 on Aa5083 Aluminum Alloy with Adding 316 Stainless Steel Powders: Effect of Volume Fraction of Reinforcements

Friction Surfacing of Aa6061 on Aa5083 Aluminum Alloy with Adding 316 Stainless Steel Powders: Effect of Volume Fraction of Reinforcements

구리/그래핀 복합재의 전기전도도에 미치는 그래핀 입자 및 체적분율의 영향

Cu is most commonly used as a matrix in composites for high electrical and thermal conductivity. Recently, graphene has been researched to improve mechanical and electrical properties as reinforcing materials of composites owing to its excellent physical characteristics. Therefore, the purpose of this study is to evaluate the effects in electrical conductivity according to the shape, structure, and the volume fraction of the graphene reinforcement for Cu/graphene composites. For the evaluation of the variation in electrical conductivity according to the shape and the volume fraction of graphene platelets, RVE was analyzed for models in the location and orientation of graphene which were randomly arranged or not. The change in electrical conductivity of the volume fraction and aspect ratio of graphene platelets was evaluated by using the ABAQUS program. Depending on the angle of graphene platelets, the electrical conductivity was the highest at 0°. In addition, in a relatively high volume fraction model, the electrical conductivity decreased quickly according to increase in the angle, and the variation was changed at angle 45° for the AR.

Mechanical performance of solid and sheet network-based stochastic interpenetrating phase composite materials

Nature-inspired architected materials premise effective property combinations that are well beyond the limits of classical engineering materials. The current study expands the concept of architected, interpenetrating phase composites (IPC) with regular periodic inner phase reinforcements to the realm of stochastic designs. Schoen's Wrapped Package minimal surface (IWP) is used as base reinforcement phase structure, while implicit functions are employed for the creation of stochastic solid and sheet topologies. The study is performed for various reinforcement volume fractions as low as 20 and up to 40%, using a resin-based 3D printer for the specimen fabrication. The strong directional dependence of the uniaxial properties of regular IWP-based designs is highlighted, while their linear and nonlinear material attributes are compared with the ones of stochastic architectures. It is shown that stochastic, sheet-based single phase and IPC material architectures can yield comparable effective mechanical properties or outperform the energy absorption capacity of regular designs at low volume fraction reinforcements. The stochasticity of the strain fields is experimentally verified through digital image correlation (DIC), associating the arising failure modes with the regular or stochastic nature of the inner reinforcement phase. Moreover, functionally graded stochastic architectures are engineered and characterized, establishing a fundamental control of the deformation and resulting stress-strain response along a desired material direction. The high-performing effective material attributes, combined with the directional independence premised by the stochasticity of the IPC metamaterial architectures constitute objectives beyond the performance limits of regular cellular materials, opening new frontiers in the design of advanced structural applications.

Effect of Volume Fraction of Reinforcement on Microstructure and Mechanical Properties of In Situ (Ti, Nb)B/Ti2AlNb Composites with Tailored Three-Dimensional Network Architecture.

The mechanical properties of (Ti, Nb)B/Ti2AlNb composites were expected to improve further by utilizing spark plasma sintering (SPS) and inducing the novel three-dimensional network architecture. In this study, (Ti, Nb)B/Ti2AlNb composites with the novel architecture were successfully fabricated by ball milling the LaB6 and Ti2AlNb mixed powders and subsequent SPS consolidation. The influence of the (Ti, Nb)B content on the microstructure and mechanical properties of the composites was revealed by using the scanning electron microscope (SEM), transmission electron microscopy (TEM) and electronic universal testing machine. The microstructural characterization demonstrated that the boride crystallized into a B27 structure and the α2-precipitated amount increased with the (Ti, Nb)B increasing. When the (Ti, Nb)B content reached 4.9 vol%, both the α2 and reinforcement exhibited a continuous distribution along the prior particle boundaries (PPBs). The tensile test displayed that the tensile strength of the composites presented an increasing trend with the increasing (Ti, Nb)B content followed by a decreasing trend. The composite with a 3.2 vol% reinforcement had the optimal mechanical properties; the yield strengths of the composite at 25 and 650 °C were 998.3 and 774.9 MPa, showing an 11.8% and 9.2% improvement when compared with the Ti2AlNb-based alloy. Overall, (Ti, Nb)B possessed an excellent strengthening effect and inhibited the strength weakening of the PPBs area at high temperatures; the reinforcement content mainly affected the mechanical properties of the (Ti, Nb)B/Ti2AlNb composites by altering the α2-precipitated amount and the morphology of (Ti, Nb)B in the PPBs area. Both the continuous precipitation of the brittle α2 phase and the agglomeration of the (Ti, Nb)B reinforcement dramatically deteriorated the mechanical properties.

In Situ Reactive Printing of Aluminum Matrix Composite with Ultra-High Volume Fraction Reinforcement.

Additive manufacturing (AM) can fabricate intricate structures that are infeasible or uneconomical for conventional manufacturing methods. Its unique capabilities have motivated emergence of several printing technologies and extensive research in material adoption in particular ferrous-, Ti-, and Ni-based alloys. Meanwhile, the large freezing range and high reflectivity of aluminum, a lightweight structural material, greatly reduce aluminum's compatibility with AM. The incompatibility roots from aluminum's unstable behavior in the rapid cyclic thermal conditions in AM and its poor interaction with laser. This hinders the development of laser-based aluminum AM and deteriorates the existing lack of lightweight structural materials in the intermediate temperature range. Aluminum matrix composites (AMCs) have great potential to serve as thermally stable lightweight structural materials, combining lightweight nature of aluminum matrix and strength of reinforcement phases. However, fabrication of AMC largely uses conventional methods, achieving only moderate volume fraction of reinforcement while having limited part complexity compared with AM. To address these challenges, in situ reactive printing (IRP) is adopted as a novel AM method, harnessing the reaction product of dissimilar elemental powder mix to fabricate AMC with an ultra-high volume fraction of intermetallic reinforcement. In this study, the effect of titanium addition to elemental aluminum feedstock powder is systematically studied on different aspects, including material processability, microstructural features, and mechanical performances. The results show that IRP can overcome the incompatibility between AM and aluminum and produce AMC with exceptional volume fraction of reinforcements and outstanding stiffness enhancement when compared with existing AM aluminum alloys and other AMCs.

Fabrication and interface optimization of continuous CF/Al composites with different reinforcement volume fraction

Interface is the key factor to determine the properties of composites. In this work, the Ni coated continuous CF/Al composites were fabricated via twin-roll casting method. After interface optimization, the interfacial bonding strength was enhanced and the dispersion of carbon fibers was improved. The effect of reinforcement volume fraction on microstructure, mechanical properties and strengthening mechanism of CF/Al composites was studied. The microstructural showed that the increase of reinforcement volume fraction was easy to cause more defects in composites. Transmission electron microscopy (TEM) and thermodynamic calculation were used to characterize the interfacial phase composition of composites after interface optimization. The results revealed that the exterior of carbon fibers bundle was mainly composed of Al3Ni intermetallic phase, and there was no obvious Al4C3 phases were found interior of the CFs bundle. In addition, the composites with 13.6 vol% CFs had the best UTS of 218.7 MPa and well dispersion. Furthermore, Vickers hardness test and Nano-indentation results showed that Al-Ni intermetallic compound can enhance the whole hardness of CF/Al composites. Dislocation strengthening in the Al-Ni intermetallic compound region was observed by TEM. The interface evolution mechanism of CF/Al composites were revealed for the first time.

Composite strut-plate lattice: A high-stiffness design of cellular metamaterial having excellent strength and energy absorption ability

Although the 3D-printed plate lattices have higher stiffness and strength than the strut lattices, the difficulty in fabricating the plate microlattices limited their potential application. The plate lattices require holes in the plates to remove the powder trapped inside, but introducing holes in plates in a lattice could reduce stiffness and strength. In general, to enhance the mechanical properties of a specific lattice for a particular mass, the size of the unit cell should be reduced. However, small plate unit cells require tiny holes on plates that may not be sufficiently large enough for post-fabrication powder removal. Thus, as an alternative design strategy, this work proposes a composite strut-plate lattice inspired by fiber-reinforced composite materials to achieve high stiffness, strength and energy absorption ability. Further, this study provides a methodology based on the classical rule of mixture for composite materials to determine the threshold volume fraction of the plate lattice reinforcement in the strut lattice matrix to attain a stiffness value that exceeds the maximum theoretical stiffness limit— the Hashin-Shtrikman upper bound. The finite element simulation results were corroborated by quasi-static compression tests on 3D-printed lattices made of polymer PA12 fabricated using multi jet fusion technique. Notably, the yield strength of the lattice exceeded the maximum theoretical yield strength limit— the Suquet upper bound. Also, the energy absorption ability was remarkably improved compared to the strut lattice and was close to that of the plate lattice. • Combined strut and plate unit cells that solve 3D printing's powder entrapment problem. • Stiffness and yield strength beyond their theoretical limits are achieved. • Mechanical properties are tailored using composite rule of mixture. • The designed composite lattice shows excellent energy absorption ability. • Mechanical properties are predicted by FEM and corroborated with experiments.

Energy-efficient manufacturing of multifunctional vascularized composites

The retention and transport of different fluids inside synthetic microvascular fiber-reinforced polymer (FRP) composites enable environmentally adaptive functions, including thermal regulation, self-healing, and electromagnetic modulation. However, manufacturing of vascularized components involves an energy- and time-intensive multistep process to cure the host matrix (several hours at elevated temperature) and then evacuate the embedded sacrificial template (12–24 h at 200°C under vacuum). Here, we demonstrate rapid (minutes), energy-efficient, and scalable fabrication of vascularized FRP composites at room temperature using the exothermic frontal polymerization of a dicyclopentadiene host matrix. The chemical energy released during frontal curing of the host resin facilitates the endothermic depolymerization of an embedded sacrificial thermoplastic to create structures with high-fidelity microchannels, reducing the thermal energy for fabrication by nearly four orders of magnitude compared to previous methods. The presence of fiber reinforcement in this tandem curing and vascularization strategy presents several challenges related to successful frontal curing and microchannel formation. Increasing the volume fraction of fiber reinforcement ( Vf) decreases the volume of the host resin matrix, generating less energy for sustaining the curing and vascularization processes. Heat retention for several minutes after completion of frontal curing using thermally insulating tooling is crucial for obtaining clear microchannels in composite specimens with Vf = 60%. Simulation of the vascularization process confirms the slower depolymerization of the sacrificial templates in high- Vf composites. A nominal decrease in channel circularity also occurs with an increase in the compaction pressure required for high Vf of composite panels. We leverage this rapid manufacturing strategy to fabricate hybrid composites with vascular networks that span the bulk of the composite and a surface coating for potential self-healing applications.

Experimental investigations of epoxy/boron nitride nanotubes composites prepared by centrifugal mixing and oven curing

Boron nitride nanotubes are reinforced into epoxy to achieve enhanced mechanical properties. BNNTs have high Young’s modulus and tensile strength, thus reinforcing BNNTs uniformly in the epoxy matrix using a centrifugal mixing followed by curing in an oven has enhanced the mechanical properties remarkably. It has been observed that with 1 %, 2 % and 3 % volume fraction of BNNTs reinforcement enhances the mechanical properties like Young’s modulus, tensile stress and fracture toughness by more than 11 % compared to virgin epoxy. With addition of BNNTs to epoxy, Young’s modulus, tensile stress and fracture toughness has increased from 2400 MPa to 2675 MPa, 60 MPa to 67 MPa, and 0.9 MPa-m1/2 to 1.6 MPa-m1/2 respectively. It has also been observed that with addition to BNNTs more than or equal to 4 %, the problem of agglomeration arises. The manufacturing process parameters are optimized for only addition up to 3 % of BNNTs in epoxy.

Thermo-elastodynamic study of the nanocomposite circular sector plates exposed to swift thermal shock

Owing to ruinous effects of thermal shocks on the nanocomposite structures, this study scrutinizes the thermal shock resistance of the poroelastic nanocomposite circular sector plates in the scheme of elasticity theory and application of the harmonic differential quadrature approach (HDQA). Due to the fact that the related studies published priorly were just able to predict the response of the simply-supported plates, the current research would be considered as the first study on the transient thermal shock response of the above-mentioned plates with fully-clamped boundary conditions. To determine the system’s time-dependent response, differential equations are translated to the Laplace domain. Then, the modified declaration of the Dubner and Abate’s technique is exploited to derive the time realization of the system’s response from the Laplace domain. The validation procedure of the current analysis is performed by comparing the outcomes with those claimed in the published researches. In order to clearly assess the system’s shock resistance against the abrupt thermal load, effect of various parameters such as thermal relaxation time (TRT), different scattering models and volume fraction of the nano reinforcement, boundary conditions, intensity of the shock, poroelastic properties of the nanocomposite, and radius to thickness ratio of the sector plate on the thermo-elastodynamic response of the system are investigated. It is revealed that the sensitivity of the system’s response to increase of TRT subsides when TRT is over an upper bond.

Parametric optimization of process parameters during friction stir processing of AA5083/(SiC-Gr) hybrid surface composite

Aluminum alloys are among the most widely used material in the manufacturing industries due to their high strength and lightweight properties. To enhance its surface properties, Friction Stir Processing (FSP) proved itself as an efficient method to enhance its microstructural, mechanical, and tribological properties. However, FSP has many process parameters that can affect the final properties of the material. Therefore, an optimized process parameter is required before the use of FSP to obtain the best results. In this paper, a mathematical model has been developed using Response Surface Methodology to predict the hardness of produced surface composite of AA5083 aluminum alloy by using SiC-Gr hybrid reinforcement. FSP was optimized for its hardness (HRB) property by optimizing the FSP process parameters like Tool rotating speed, Tool Traverse speed, number of FSP passes, and the ratio of hybrid reinforcement volume fraction. It was found that the Tool Rotating speed of 1000 rpm, traverse speed of 80 mm/min, 3 number of FSP passes, and Hybrid reinforcement ratio of 75:25 (SiC:Gr) produced the best result with the hardness of 32.6HRB.

Effect of laser dwell time on pore elimination in powder bed fusion of metal matrix composites: experimentally validated modeling

Many studies have been conducted to better understand the relationship between additive manufacturing (AM) process parameters and the resulting structure and properties of manufactured parts. It is quite clear that defects associated with AM parts are detrimental to part performance and are thus a major concern for a broader application of AM processed parts. In this study, we aim to investigate the influence of process parameters such as laser dwell time in mitigating pore formation during powder bed fusion of AISI 316L austenitic stainless steel (SS316L)-WC composites. Single-track experiments are conducted with varying printing parameters, while discrete element modeling (DEM) is employed for simulating powder-bed packing for composite system. Results show that the filling of the pores between ceramic particles by the molten SS316L is dependent on the laser dwell time, which in turn, depends on the volume fraction of ceramic reinforcement and initial pore sizes between inclusions. Our experiments, in agreement with model analysis, show that with the information of the materials property of the metal phase in a composite system such as viscosity, surface energy and initial pore sizes between ceramic inclusions, the printing parameters can be chosen to yield the appropriate dwell time for pore free composites.

Study of manufacturing and material properties of the hybrid composites with metal matrix as tool materials

Composite materials have many applications in industries and using these composites in deep drawing process is a new trend to obtain high quality drawn products. This study aims to prepare the hybrid Metal Matrix Composites (MMC's) iron-based reinforced with 0, 1, 2, 3 and 4% volume fraction of constant mix (80% Al2O3 and 20% ZrO2) by means of powder metallurgy and investigate the mechanical properties of these hybrid Composites. The powders were compacted at 640 MPa and sintered at 1120 °C in the presence of argon gas. The purity, density, average grain size and shape were measured by Dosimeter, particle size analyzer and SEM. The best mechanical properties were obtained at (97% Fe + 3% (80% Al2O3 + 20% ZrO2) among all reinforcement volume fractions and the composites has properties of 61%, 37% and 7% more than the matrix properties for compression strength, hardness HRC and radial crushing strength respectively.

Corrosion behavior of in situ-synthesized (TiC+TiB)/Ti composites by laser powder-bed fusion: Role of scan strategy

The in-situ TiC and TiB reinforced titanium matrix composites were fabricated by laser powder fusion (LPBF) of B4C/Ti powder mixture, and the influence of scan strategy on the microstructure morphologies and corrosion resistance in NaCl solution were also investigated. The experimental results reveal that anodic dissolution of titanium matrix is accelerated and thus facilitates the formation of the TiO2 passive layer on the surface of the LPBF-produced (TiC+TiB)/Ti composites owing to the in-situ TiC and TiB reinforcements acting as micro-cathode in NaCl aqueous solution. The island scan strategy tends to result in a net-shaped distribution of TiC and TiB reinforcements and pore defects, which causes the inhomogeneity of galvanic couples and resultant TiO2 passive layer. Fortunately, the scan strategies of XY+ 30° and XY+ 67° can alleviate the thermal accumulation and leads to the transformation of refinements distribution to radial-shaped arrangement, which favors for the homogeneity of galvanic couples and resultant TiO2 passive layer. Moreover, the scan strategy of XY+ 90° generates a refinement and increased volume fraction of reinforcements and micro-galvanic couples, which significantly facilitates the formation of a thicker and less-defective TiO2 passive layer, thus leading to better corrosion resistance with a larger value of Rf. Furthermore, the corrosion mechanism of LPBF-produced (TiC+TiB)/Ti composites has also been discussed in detail based on the Electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy results.

Controlling resin flow in Liquid Composite Moulding processes through localized irradiation with ultraviolet light

AbstractA vacuum infusion process was implemented to produce composite specimens from a random glass filament mat and an acrylic modified polyester resin curable upon irradiation with ultraviolet (UV) light. Through localized irradiation with UV light during the reinforcement impregnation, the viscosity of the flowing resin was increased selectively. This allowed converging–diverging flow patterns with defined inclusions to be realized and racetracking along reinforcement edges to be suppressed. The approach is based on radical photopolymerisation. Here, the degree of cure and the viscosity of the resin increase under direct irradiation, such that the resin gels and the flow stalls in a matter of seconds, but remain unchanged in areas covered with an opaque mask. While this study is concerned with the feasibility of the process, potential practical applications are in flow control for Liquid Composite Moulding, that is, compensation for local variations in the fiber volume fraction and permeability of reinforcements.

Effects of the quality of pre-consolidated materials on the mechanical properties and morphology of thermoplastic pultruded flat laminates

Pre-consolidated tapes in thermoplastic pultrusion solve the problem of impregnating a reinforcement with high-viscosity thermoplastic resins. Thermoplastic glass fiber/polypropylene flat laminates (75 mm × 3.5 mm) were fabricated using pre-consolidated tapes from different manufacturers: pre-consolidated tapes by the ApATeCh-Tape Company (Russia) and pre-consolidated sheets by the Zhongji Company (China). In spite of the equal reinforcement volume fraction (38%), the laminates fabricated from the pre-consolidated sheets exhibited higher compressive, tensile, and flexural strengths than those made from the pre-consolidated tapes, differing by 27.1%, 27.3%, and 19.8%, respectively. The observed difference between the strength characteristics of the studied flat laminates was explained by the presence of unimpregnated regions in the fiber bundles and by matrix cracks in the pre-consolidated tapes, absent in the pre-consolidated sheets, as revealed by the scanning electron microscopy analysis. Such defects cannot be corrected during the pultrusion process, resulting in the formation of matrix cracks and debonding, impairing the mechanical performance of the produced pultruded laminates. Pre-consolidated sheets enable pultrusion flat laminates with larger cross-sections, exhibiting better mechanical performance and surface roughness, compared with thermoplastic pultruded composites fabricated from pre-consolidated tapes described in the literature.

Mechanical properties and electrical conductivity of oriented-SiC-whisker-reinforced Al2O3/Cu composites

Oriented SiC whisker-reinforced Al2O3/Cu composites were fabricated by powder metallurgy and hot extrusion. The microstructure of the composites was characterized by scanning electron microscopy. The mechanical properties and electrical conductivity of the composites were measured. The results indicated that the SiC whiskers aligned along the extrusion direction, and the nano Al2O3 particles were uniformly dispersed in the Cu matrix with ideal interfacial bonding. Particle and whisker hybrid reinforcement significantly enhanced the mechanical properties. The yield strength and elongation of (1 vol.%SiCw + Al2O3)/Cu composites were 6% and 15.6% higher than those of the Al2O3/Cu composites, respectively. The experimental yield strength was consistent with the theoretical value associated with different strengthening mechanisms. The main strengthening mechanisms were fine grain strengthening, Orowan strengthening and load transfer strengthening. The electrical conductivity of all the composites was higher than 82.8% IACS; however, the SiC whiskers led to electrical conductivity anisotropy. In general, the electrical conductivity of composites is related to the volume fraction and type of reinforcement. Therefore, the influence of the hybrid composition on the electrical conductivity was studied, and an analytical model for the electrical conductivity of hybrid-reinforced copper matrix composites was established, including the characteristic parameters of the particles and whiskers. The model and presented findings can provide a design basis for hybrid-reinforced composites.

Improving the Young's modulus of Mg via alloying and compositing – A short review

Lightweight, high-modulus structural materials are highly desired in many applications like aerospace, automobile and biomedical instruments. As the lightest metallic structural material, magnesium (Mg) has great potential but is limited by its low intrinsic Young's modulus. This paper reviews the investigations on high-modulus Mg-based materials during the last decades. The nature of elastic modulus is introduced, and typical high-modulus Mg alloys and Mg matrix composites are reviewed. Specifically, Mg alloys enhance Young's modulus of pure Mg mainly by introducing suitable alloying elements to promote the precipitation of high-modulus second phases in the alloy system. Differently, Mg matrix composites improve Young's modulus by incorporating high-modulus particles, whiskers and fibers into the Mg matrix. The modulus strengthening effectiveness brought by the two approaches is compared, and Mg matrix composites stand out as a more promising solution. In addition, two well-accepted modulus prediction models (Halpin-Tsai and Rule of mixtures (ROM)) for different Mg matrix composites are reviewed. The effects of reinforcement type, size, volume fraction and interfacial bonding condition on the modulus of Mg matrix composites are discussed. Finally, the existing challenges and development trends of high-modulus Mg-based materials are proposed and prospected.

Studies on effect of powder metallurgy on the corrosion behaviour of Al-Al2O3p composites

ABSTRACTAluminium metal matrix composites possess better mechanical and corrosion resistance properties in comparison with conventional alloys. The addition of ceramic reinforcement in the matrix material improves the corrosion resistance property of the composite. In this investigation, Al-Al2O3p composites were fabricated through powder metallurgy route with 5%, 10%, 15%, 20%, 25% Al2O3p, and the corrosion rate was evaluated with respect to the effect on volume fraction of reinforcement, the reinforcement particle size, pH and reverse potential. The corrosion test was carried out with 3.5 wt. % Sodium Chloride as a medium to analyse the corrosion behaviour of the composites. The four factors, five levels, central composite rotatable design matrix was used to conduct the optimum number of experiments. An increase in the reinforcement content decreased the corrosion rate. The rate of corrosion is more for the pH value of 1 and less for a pH value of 10. Coarse particles were found to resist corrosion, and samples with fine particles have a tendency to enhance corrosion.

Effect of TiC content on the microstructure and wear performance of in situ synthesized Ni-based composite coatings by laser direct energy deposition

To reveal the effect of content and size of in situ synthesized TiC on phase compositions, microstructure, defects, and mechanical properties of matrix composites in detail, a series of Ni-based composite coatings were fabricated by direct energy deposition. The titanium (Ti) + Ni-coated graphite (C) contents in composite powder are 5, 10, 20, 30, 40, and 50 wt%, respectively. With the increase of Ti and C elements, the phases firstly change from γ–Ni, [Fe–Ni] solid solution, CrB, Cr7C3 to [Fe–Ni] solid solution, CrB, Cr7C3, TiNi2 TiC, TiB2, and finally to TiNi, Cr3C2, Fe2Ti, TiC, TiB2 under the competitive interaction between solute concentration and Gibbs free energy. The volume fraction and relative diameter of the TiC reinforcements are increased gradually to 28.06 % and 2.866 μm, respectively. The dispersed TiC particles are found at the grain boundary and refine the grains. The microhardness is increased from 608.41 ± 6.25 HV0.3 to 1075.11 ± 27.94 HV0.3 due to the combined effect of fine-grain strengthening, solid solution strengthening, and the second phase strengthening. The volume loss was significantly reduced when the relative diameter of TiC is larger than 2.2 μm. Moreover, the wear mechanism was transformed from adhesive wear to abrasive wear and ultimately to fatigue wear. In addition, the transverse and longitudinal cracks were also observed, limiting the application of the fabricated coatings.