Volume Fraction Of Reinforcement Research Articles

Towards high stiffness and ductility-The Mg-Al-Y alloy design through machine learning

In traditional trial-and-error method, enhancing the Young's modulus of magnesium alloys while maintaining a favorable ductility has consistently been a challenge. It is a need to explore more efficient and expedited methods to design magnesium alloys with high modulus and ductility. In this study, machine learning (ML) and assisted microstructure control methods are used to design high modulus magnesium alloys. Six key features that influence stiffness and ductility have been extracted in this ML model based on abundant data from literature sources. As a result, predictive models for Young's modulus and elongation are established, with errors less than 2.4% and 4.5% through XGBoost machine learning model, respectively. Within the given range of six features, the magnesium alloys can be fabricated with the Young's modulus exceeding 50 GPa and an elongation surpassing 6%. As a validation, Mg-Al-Y alloys were experimentally prepared to meet the criteria of six features, achieving Young's modulus of 51.5 GPa, and the elongation of 7%. Moreover, the SHapley Additive exPlanation (SHAP) is introduced to boost the model interpretability. This indicates that balancing the volume fraction of reinforcement, the most important feature, is key to achieve Mg-Al-Y alloys with high Young's modulus and favorable elongation through the two models. Enhancing reinforcement dispersion and reducing the size of reinforcement and grain can further improve the elongation of high-stiffness Mg alloy.

The cruciality of particle size and shape on fracture mechanism of aluminum matrix composites

Metal matrix composites are generally believed to achieve better performance with spherical reinforcements than irregular ones. In this work, through experiments and computational simulations, we have demonstrated that spherical reinforcements do not necessarily enhance the tensile ductility of composites. There exists a critical size for spherical particles. Using an Al2O3-Al2024 composite as an example, we found that when the size of spherical Al2O3 particles is less than 3 µm, they are not fractured during deformation, resulting in enhanced ductility. We elucidated the competitive mechanism between particle and matrix fracture under various reinforcement sizes and volume fractions, and constructed a deformation map that can be utilized to determine fracture mechanisms. This work clarifies the micro-mechanical mechanisms of reinforcements on material fracture behavior, providing guidance for the design and fabrication of strong and ductile metal matrix composites.

Effect of eutectic microstructure on load transfer and creep resistance in Al-Ce alloys

This study investigates the compressive creep response of hypo- and near-eutectic Al-Ce alloys via finite-element modeling (FEM), by considering the composite response of a weak, fast-creeping Al matrix containing slow-creeping Al11Ce3 eutectic reinforcement. In the as-cast microstructure of an eutectic Al-12.5 wt%Ce alloy, the Al11Ce3 eutectic phase is lamellar, regardless of the various cross-sectional geometries (Chinese-script, fish-bone, and comb-like). FEM models based on these various lamellar microstructures investigate the effect of Al11Ce3 reinforcement volume fraction, orientation, and geometry on load transfer performance between matrix and reinforcement during creep deformation. FEM predicts that, when the lamellar Al11Ce3 phase is continuous along the loading direction (where load transfer is most effective), the creep resistance of the alloy is barely affected by cross-sectional geometry of the Al11Ce3 reinforcement or by the solid-solution strengthening of the Al matrix, at constant Al11Ce3 volume fraction. However, alloy creep resistance and load transfer between phases are significantly reduced when applying load parallel to aligned, discontinuous lamellae, and they can be improved by matrix solid-solution strengthening. Furthermore, Al11Ce3 short plates (as created in Al-12.5Ce by coarsening of lamellae upon over-aging at 590 °C/24 h) provide the least creep resistance and load transfer. Lastly, multi-colony FEM models are created by combining colonies with various lamellar orientations to approximate the creep performance of polycrystalline hypo- and near-eutectic alloys which, when compared to experimental data for hypoeutectic Al-7Ce and for near-eutectic Al-(10–13)Ce, provide better predictions than single-colony FEM models or analytical solutions.

Hot deformation behavior of recycled-Be/2024Al composites prepared by pressure infiltration method

It is necessary to confirm the appropriate processing parameters for recycled-Be/2024Al composites before hot processing. Therefore, hot compression experiments were conducted on 40 and 50 vol% recycled-Be/2024Al composites prepared by pressure infiltration method. Meanwhile, the constitutive equations were established. The activation energy increased with the volume fraction of reinforcement, which means the increasing difficulty for composites to deform. However, different from ceramic reinforcements, Be is able to deform with matrix coordinately. This characteristic makes recycled-Be/2024Al composites more prone to deformation than ceramic reinforced Al composites with the same volume fraction of reinforcements. The processing maps of 40 and 50 vol% recycled-Be/2024Al composites have been drawn, and the appropriate processing parameters for 40 and 50 vol% recycled-Be/2024Al composites were determined as 495–525 °C,0.0006–0.0016 s−1 and 500–530 °C,0.016–0.04 s−1, respectively. The microstructures of samples hot compressed with various parameters were observed to identify the accuracy of processing maps.

A multifaceted approach using RVE homogenization methodology for identification of elastoplastic behavior of steel matrix composite: Application to deep-drawing process

The integration of cutting-edge materials and computational methods is now essential in contemporary engineering, especially in sectors where a deep comprehension of the mechanical behavior of reinforced composite materials is crucial. In this context, steel matrix composites, enhanced with reinforcing elements like TiB2, have garnered attention due to their potential for superior mechanical properties and wide-ranging applications. This article explores an innovative computational framework based on the Representative Volume Element (RVE) concept to examine the elastoplastic properties of a ferritic steel matrix reinforced with ceramic particles (TiB2). The finite element analysis (FEA) is performed with periodic boundary conditions (PBCs) to apply the specified loading to the RVE. As a first endeavor, the developed multi-faceted approach provides a broader perspective on shear behavior and the elastoplastic composite’s properties of Fe-TiB2 for various reinforcement volume fractions. Then, the focus of this study lies in its application to the deep-drawing process, a critical manufacturing operation with significant implications in industries such as automotive and aerospace. The established approach for homogenizing elasto-plastic Fe-TiB2 composites is applied to analyze the influence of reinforcement variation on several critical aspects during the deep-drawing process, including formability, forming force, Von Mises stress distribution, and logarithmic strain.

Mechanical behavior of Al /AL2O3p-SiCp hybrid composite fabricated by hot pressing method

Hybrid particulate metal matrix composites with specific strength can be used in various applications. The mechanical properties of these composites can be improved by correctly choosing the type, volume fraction, size, and distribution of reinforcements and metal matrix. In this research, to make Al/Al2O3-SiC hybrid composites, aluminum chips were prepared by machining, and then the chips were coated with Al2O3 and SiC reinforcements by suspension method. For composite making, first, aluminum-coated chips were molded inside a steel mold and after heat treatment at 645 °C for 2 h the chips were hot pressed. The microstructure of the fabricated composites was examined by optical and SEM microscope, and then compression and tensile strength behavior were studied. The microstructural results showed a sound composite without any porosities and cracks. The hybrid composite with 12 wt% reinforcements showed high compressive strength (370 MPa).

Interfacial microstructure of dual-scale SiCp/A356 composites investigated by in situ TEM tensile testing

Silicon carbide particle (SiCp) reinforced Al matrix (SiCp/Al) composites have broad application prospects in high-end equipment manufacturing fields such as aerospace and automotive nowadays. The volume fraction and size of SiCp reinforcement play a decisive role in the physical and mechanical properties of the composites. Herein, we have prepared the dual-scale SiCp/Al composites through the powder metallurgy method. The interfacial microstructure and crystal orientation relationship at the interface was observed and analyzed. And then we have investigated the fracture behavior of the SiCp/Al interface by employing the in situ TEM tensile experiment. The results of the in situ TEM tensile testing show that when there exists a MgAl2O4 interface layer with thickness of 100 nm in the prepared SiC/Al composite, the microcracks are formd preferentially at the MgAl2O4/Al. And the interface bonding strength of the SiC/MgAl2O4 is higher than that of MgAl2O4/Al. Moreover, the microcracks are formed firstly at the sharp corners of micron SiCp and the interface. With the increaing load, the microcracks propagate along the micron SiCp and the interface. With the further increase of the load, connections and mergers will occur between the formed microcracks, which will eventually lead to the breakage of the specimen. Besides, the addition of the dual-scale SiCp can improve the yield strength of the A356 obviously.

Determining the characteristics of representative volume elements in severely deformed aluminum-matrix composite

The accurate evaluation of the effective mechanical properties of composites mainly depends on the characteristics of representative volume elements (RVEs). This paper mainly investigates the RVE size. Additionally, the effect of volume fraction of reinforcement, the edge effect, and RVE types on the critical size are discussed. First, the Al/Ni multilayered composites were processed by nine cycles of the cross-accumulative roll bonding (CARB) method. Then, one type of RVEs was created based on cross-sectional micrographs of composites to consider their inhomogeneities. Another type was generated by using the random sequential adsorption (RSA) procedure. Thereafter, the homogenized effective elastic properties of both types of microstructure-based RVEs and RSA-based RVEs were computed and compared as a function of the volume fraction of Ni and RVE size. The results showed that by increasing the Ni fragments, the RVEs indicated stiffer elastic behavior. By increasing the volume fraction of Ni from 0.2 Vf to 0.8 Vf, the Poisson ratio decreased by 7 % and the elastic modulus increased by 83 % for RSA-based RVE. Regarding the size of microstructure-based RVE of Al/Ni (0.8 Vf), from the largest size (size 1) with a length of 575 μm and a width of 575 μm to the smallest size (size 5) with a length of 287.5 μm and a width of 287.5 μm, the elastic modulus and the Poisson ratio showed 16 % and 0.8 % decrease, respectively.

Thermal Conductivity of AlSi12/Al2O3-Graded Composites Consolidated by Hot Pressing and Spark Plasma Sintering: Experimental Evaluation and Numerical Modeling

Functionally graded metal matrix composites have attracted the attention of various industries as materials with tailorable properties due to spatially varying composition of constituents. This research work was inspired by an application, such as automotive brake disks, which requires advanced materials with improved wear resistance on the outer surface as combined with effective heat flux dissipation of the graded system. To this end, graded AlSi12/Al2O3 composites (FGMs) with a stepwise gradient in the volume fraction of alumina reinforcement were produced by hot pressing and spark plasma sintering techniques. The thermal conductivities of the individual composite layers and the FGMs were evaluated experimentally and simulated numerically using 3D finite element (FE) models based on micro-computed X-ray tomography (micro-XCT) images of actual AlSi12/Al2O3 microstructures. The numerical models incorporated the effects of porosity of the fabricated AlSi12/Al2O3 composites, thermal resistance, and imperfect interfaces between the AlSi12 matrix and the alumina particles. The obtained experimental data and the results of the numerical models are in good agreement, the relative error being in the range of 4 to 6 pct for different compositions and FGM structure. The predictive capability of the proposed micro-XCT-based FE model suggests that this model can be applied to similar types of composites and different composition gradients.

Improving the energy density and flexibility of PMN-0.3PT based piezoelectric generator by composite designing

Ceramics based piezoelectric generators are known for their high energy density and poor flexibility. In this work, 0.7Pb(Mg1/3Nb2/3O3)-0.3PbTiO3 (PMN-0.3PT) and polydimethylsiloxane (PDMS) based 2–2 composite with optimum PMN-0.3PT content (vr) was designed that demonstrated enhanced output energy density and superior mechanical flexibility under dynamic mechanical excitation. vr-PMN-0.3PT/PDMS 2–2 composite with different PMN-PT reinforcement content (vr) and two different reinforcement configurations were fabricated and characterized for effective electro-elastic properties and energy harvesting response. Parallelly, using the finite element method and analytical models, effective electromechanical properties were calculated. Composites with parallel connectivity of the reinforcement phase demonstrated enhanced piezoelectric charge coefficient (d33c) even with low PMN-0.3PT content whereas the relative permittivity (κ33c) and elastic modulus (E33c) exhibited a linearly increasing trend with reinforcement volume fraction. At a compressive load of 50 N and 5 Hz frequency, a piezoelectric generator (PG) based on a vr = 0.2, vr- PMN-0.3PT/PDMS 2–2 composite with parallel connectivity produced a maximum short-circuit current density of 69 nA/cm2 and an open-circuit electric field of 189 V/cm, translating to a maximum output power density of ∼13 μW/cm3 higher than that of pristine PMN-0.3 PT based piezoelectric generator. Estimated mechanical flexibility was found to be ∼53 % higher than that of pristine PMN-0.3PT.

Injection Pultrusion of Glass-Reinforced Epoxy: Cure Kinetics, Rheology, and Force Analysis.

Pultrusion is a highly efficient continuous process to manufacture advanced fiber-reinforced composites. The injection pultrusion variant permits a higher control of the resin flow, enabling the manufacturing of a high reinforcement volume fraction. Moreover, it reduces the emission of volatile compounds that are dangerous for the operators and for the working environment. The present study proposes an experimental analysis of injection pultrusion in three different operative conditions. In particular, the activity focused on the effects of the temperature setup on the thermochemical and rheological behaviors of the resin system and on the interaction between the processed materials and the pultrusion die wall. The setup of the parameters was selected to evidence the behavior of the viscous interaction during the thermoset transition to the solid state, which is particularly challenging due to the localization of high adhesive forces related to the sharp increase in resin viscosity. Microscope observations of the cross-sections were performed to discuss the effects of the process parameters.

Collaborative robust topology optimization of FGMs considering hybrid bounded uncertainties based on the distance to ideal solution

In this article, an efficient collaborative robust topology optimization (CRTO) method is proposed for functionally graded materials (FGMs) considering hybrid bounded uncertainties (HBU). Firstly, to realize the collaborative optimization of the structural topology and volume fraction of reinforcement in FGMs, two sets of design variables are defined following the SIMP framework. Secondly, with the uncertain material properties and external loads mathematically modeled as random and interval uncertain parameters respectively, the objective performance of FGMs are described as the implicit function of two sets of design variables and uncertain parameters. In contrast to the classical method of weighting the mean and standard deviation of objective performance, the robust objective function is constructed based on a novel distance to ideal solution to avoid the manually setting of weight parameters. The sensitivity analysis of the objective and constraint function with regard to the two sets of design variables is derived explicitly and a realization vector set is defined for bounded probabilistic uncertainties to parallelize the sensitivity analysis. In addition, an adaptive density shift algorithm is proposed to produce a clear topological profile and accelerate the convergence of the optimization. The effectiveness of the proposed method is demonstrated by both numerical and engineering examples.

Free vibration analysis of CNT reinforced plates using higher order shear deformation theory

With the stringent requirements of lightweight and high stiffness in space technology and spacecraft, the research on frequency characters of carbon nanotubes (CNTs) reinforced structures is particularly urgent. In this paper, based on the Reissner-Mindlin higher-order shear deformation theory (HSDT), a vibration model for a CNT functionally graded (FG) plate is developed, and influences of the reinforcements distribution form, reinforcement volume fractions, and various boundary conditions of the structure are considered in this established model. Subsequently, the model’s convergence test was presented first with a rectangular plate structure. Finally, the vibration characteristics and modal shapes of the CNT-FG plate structure are carried out by using this model.

Investigation of the effects of volume fraction, aspect ratio and type of fibres on the mechanical properties of short fibre reinforced 3D printed composite materials

AbstractMechanical behaviour of 3D-printed composite parts is affected by the volume fraction, aspect ratio and type of fibre reinforcement. Although in the literature experimental approaches have been used to characterise the effects of the above factors on the mechanical properties of 3D printed parts, time and cost of the manufacturing process as well as the uncertainty associated with a large number of experimental techniques are the key issues. This study aims to address these challenges by developing a methodology based on a multi-scale Finite Element (FE) analysis of representative volume element (RVE) of 3D printed composite parts to predict the effective orthotropic properties. To account for the effects of fibre features, RVEs were modelled considering variables of volume fraction, aspect ratios and type of short fibres. To study the main and interaction effects of the above variables on the mechanical properties of 3D printed composite parts, a structured approach based on the Design of Experiments is used. The FE stress analysis of the RVE provides an understanding about the potential failure modes such as interfacial debonding between fibres and matrix, interlayer and intralayer delamination that may occur in load-bearing 3D printed composite parts. The FE computed mechanical properties are validated against experimental data through a series of mechanical testing of flexure, Iosipescu, and short beam shear which were conducted in conjunction with the Digital Image Correlation technique. As a result, certainty is obtained in using the proposed approach for a fast iterative design of 3D printed composite parts prior to industrial applications.

Analysis of sandwich graphene origami composite plate sandwiched by piezoelectric/piezomagnetic layers: A higher-order electro-magneto-elastic analysis

This work applies a higher order thickness-stretched model for the electro-elastic analysis of the composite graphene origami reinforced square plate sandwiched by the piezoelectric/piezomagnetic layers subjected to the thermal, electric, magnetic and mechanical loads. The plate is manufactured of a copper matrix reinforced with graphene origami where the effective material properties are calculated based on the micromechanical models as a function of volume fraction and folding degree of graphene origami, material properties of matrix, reinforcement, and local temperature. The governing equations are derived using the virtual work principle in terms of the bending, shear and stretching functions, in-plane displacements, electric, and magnetic potentials. The numerical results including various displacement components, maximum electric, and magnetic potentials are presented with changes of volume fraction, folding degree of reinforcement, electrical, magnetic, and thermal loading. A verification investigation is presented for approve of the methodology, and the solution procedure. The main novelty of this work is simultaneous effect of the thickness stretching and the multi-field loading on the electromagnetic bending results of the sandwich plate. Another novelty of this work is usage of graphene origami nano-reinforcement as a controllable material in a sandwich structure subjected to multi-field loadings. The results show an increase in bending, shear, and stretching deflections with an increase in electromagnetic loads, and folding degree as well as a decrease in volume fraction of reinforcement.

Design and preparation of WBX/Al composites for nuclear radiation protection

As the utilization of nuclear energy continues to expand, there is a growing focus on the development of lightweight and efficient nuclear shielding composites. In this paper, novel WBX/Al (x = 1, 2, 4) composites were designed based on shielding performance. The effects of reinforcement type, volume fraction, and material thickness on the 60Co and 137Cs γ-rays, fast and thermal neutron shielding performances were simulated. The results show that WB/Al composites offer better development potential compared to WB2/Al or WB4/Al composites. Additionally, a predictive model for the γ-ray shielding effectiveness of WB/Al composites, based on the areal density of tungsten, was proposed. The fabrication process involved mechanical ball milling and spark plasma sintering to fabricate 30 vol% WB/Al composites, with optimization of ball milling time, sintering temperature, and holding time. As a result, a novel nuclear radiation protection composite with uniform composition, a relative density of 97 %, and flexural strength of 527 MPa was acquired.

Friction surfacing of AA6061 on AA5083 aluminum alloy with adding 316 stainless steel powders: Effect of volume fraction of reinforcements

The present work aims to study the effect of the 316 stainless steel reinforcement volume fraction during friction surfacing of AA6061 on the AA5083 alloy by tool's rotation, traverse speed, and feeding rate of 1000 rpm, 150 mm/min, and 100 mm/min to improve the tribological and mechanical behaviors of deposited layers. It was found that a fully bonded interface without any void or defect at the bonding interface was formed between the deposited layer and substrate. It was also found that an increase in the number of holes from one to two in the tool resulted in the betterment of the strength of the coating layer by about 18% from 219 MPa to 259 MPa that can be attributed to the complete bonding between the deposited layer/substrate and better scattering of 316 stainless steel reinforcements.

Determination of short carbon fiber orientation in zirconium diboride ceramic matrix composites

In fiber-reinforced components, the fiber alignment and orientation have paramount influence on the thermo-mechanical properties of the resulting composite, for both short and continuous fiber. Here we present the case of an ultra-refractory matrix intended for extreme environment applications, ZrB2, reinforced with 20 vol% and 50 vol% short carbon fibers. In both cases, fibers tend to align perpendicular to the uniaxial pressure applied during shaping and sintering of a pellet, although the fiber tilt across the pellet thickness is difficult to determine. Moreover, for high volume fractions of reinforcement, the spatial distribution of the fibers is heterogeneous and tends to have domains of preferential orientations. We compare the information on the fiber distribution as collected by scanning electron microscopy images, X-ray computed tomography and synchrotron X-ray refraction radiography (SXRR). The three techniques prove to be complementary.Importantly, we demonstrate that SXRR yields the most statistically significant information due to the largest field of view, yet with a sensitivity down to the nanometer, and that can be successfully applied also to heavy matrix materials, such as zirconium boride.

Mechanical and interfacial analysis of 3D-printed two-matrix continuous carbon fibre composites for enhanced structural performance

Two-matrix continuous carbon fibre composites are recognized for enhancing structural and mechanical properties. However, a comprehensive investigation into their interfacial behaviour and potential has yet to be undertaken. Based on the 3D printing process, this study uses experimental and simulation techniques to analyse the mechanical and interfacial performance across multiple scales. The flexure properties under different processing parameters are studied at the macro level. Meso and micro-structural characterization are evaluated by scanning electron microscopy, optical microscopy and molecular dynamics simulation. The disparities in simulations and experimental results are attributed to macroscopic defects and reinforcement volume fraction. This yields insights into strategies for optimising performance, culminating in a comprehensive understanding of the fracture mechanism of two-matrix continuous carbon fibre composites. Our study provides an approach to creating and analysing other systems with multiple matrix composites and enabling new engineering applications for composites.

Effect of Milling Time and Reinforcement Volume Fraction on Microstructure and Mechanical Properties of SiCp-Reinforced AA2017 Composite Powder Produced by High-Energy Ball Milling.

The influence of milling time and volume fraction of reinforcement on the morphology, microstructure, and mechanical behaviors of SiCp-reinforced AA2017 composite powder produced by high-energy ball milling (HEBM) was investigated. AA2017 + SiCp composite powder with different amounts of SiC particles (5, 10, and 15 vol%) was successfully prepared from gas-atomized AA2017 aluminum alloy powder with a particle size of <100 μm and silicon carbide (SiC) powder particles with an average particle size of <1 μm. An optical microscope (OM), X-ray diffraction (XRD), and scanning electron microscope (SEM) were utilized to characterize the microstructure of the milled composite powder at different milling periods. The results indicated that the SiC particles were homogeneously distributed in the AA2017 matrix after 5 h of HEBM time. The morphology of the particles transformed from a laminar to a nearly spherical shape, and the size of the milled powder particles reduced with increasing the content of SiC particles. The XRD analysis was carried out to characterize the phase constituents, crystallite size, and lattice strain of the composite powders at different milling periods. It was found that with increasing milling time and SiC volume fraction, the crystallite size of the aluminum alloy matrix decreased while the lattice strain increased. The average crystallite sizes were reduced from >300 nm to 68 nm, 64 nm, and 64 nm after 5 h of milling, corresponding to SiC contents of 5, 10, and 15 vol%, respectively. As a result, the lattice strain increased from 0.15% to 0.5%, which is due to significant plastic deformation during the ball milling process. XRD results showed a rapid decrease in crystallite size during the early milling phase, and the minimum grain size was achieved at a higher volume fraction of SiC particles. Microhardness tests revealed that the milling time has a greater influence on the hardness than the amount of SiC reinforcements. Therefore, the composite powder milled for 5 h showed an average microhardness three times higher than that of the unmilled powder particles.