Three-phase Composites Research Articles

Multiferroic characterization of 3-phase (1-x) (0.7BiFeO3-0.3CoFe2O4)-xPb(Zr,Ti)O3 composites with magnetically driven polarization

Multiferroic materials with magnetoelectric coupling have attracted researchers and scientists as these materials can provide higher freedom to facilitate the functioning of multifunctional devices. The three-phase complex multiferroic composites consisting of rhombohedral BiFeO3, spinel cubic CoFe2O4, and tetragonal Pb(Zr0·52Ti0.48)O3 of the form (1−x) (0.3CoFe2O4-0.7BiFeO3)−xPb(Zr0·52Ti0.48)O3 (x = 0, 0.1, 0.2, and 0.3) were synthesized following a three-step route. The X-ray diffraction analysis confirmed the respective crystalline phases of the BiFeO3, CoFe2O4, and Pb(Zr0·52Ti0.48)O3. The Surface microstructures of the composites were analyzed by the scanning electron microscope (SEM) and elemental stoichiometric contents were confirmed by the energy dispersive X-ray (EDX) analysis. Reversible polarization with the application of an applied magnetic field was observed in the form of ME response for all the samples. The electric and magnetic properties (Dielectric, ferroelectric and ferromagnetic properties) were significantly enhanced in the 0.3CoFe2O4-0.7BiFeO3 system with the addition of piezoelectric Pb(Zr0·52Ti0.48)O3 without suppressing their magnetoelectric coupling coefficient (ME), proving the potential of these multiferroic composites for the fabrication of modern devices with multifunctional applications.

Controlling Binder Adhesion to Impact Electrode Mesostructures and Transport.

The complex three-phase composition of lithium-ion battery electrodes, containing an ion-conducting pore phase, a nanoporous electron-conducting carbon binder domain (CBD) phase, and an active material (AM) phase, provides several avenues of mesostructural engineering to enhance battery performance. We demonstrate a promising strategy for engineering electrode mesostructures by controlling the strength of adhesion between the AM and CBD phases. Using high-fidelity, physics-based colloidal and granular dynamics simulations, we predict that this strategy can provide significant control over electrochemical transport-relevant properties such as ionic conductivity, electronic conductivity, and available AM-electrolyte interface area. Importantly, the proposed strategy could be experimentally realized through surface functionalization of the AM and CBD phases and would be compatible with traditional electrode manufacturing methods.

Interphase effect on the effective magneto-electro-elastic properties for three-phase fiber-reinforced composites by a semi-analytical approach

A semi-analytical approach is proposed to determine the effective magneto-electro-elastic moduli of a fiber-reinforced composite. We especially focus on predicting the effective properties of three-phase periodic composite reinforced with unidirectional, infinitely long and concentric cylindrical fibers with square transversal distribution. The semi-analytical method is developed combining asymptotic homogenization and finite element methods. Asymptotic homogenization method allows the statements of local problems that are solved by finite element method and the associated effective coefficients. Finite element method is implemented via the principle of minimum potential energy. The effect of interphase thickness and the fiber material properties on effective moduli is analyzed. Numerical computations were performed, and an exact agreement is obtained by comparing the semi-analytical approach with asymptotic homogenization method linked to the theory of potential functions of a complex variable.

A probabilistic upscaling of microstructural randomness in modeling mesoscale elastic properties of concrete

We present a modeling framework for propagating the uncertainty, stemming from random heterogeneity of concrete microstructure, to its mesoscale elastic properties at the level of statistical volume element. The microstructure of concrete is modeled as a three-phase composite, consisting of aggregates (inclusions) in mortar (matrix), and interfacial transition zone (ITZ), a thin high porosity zone surrounding aggregates. There is inherent randomness in the composition and mechanical properties of these constituents, which in turn causes spatial heterogeneity in the local material behavior. We present a statistical characterization process to quantify the uncertainty associated with local aggregate volume fraction and aggregate size distribution. We then adopt and test a probabilistic model based on the random matrix theory and maximum entropy principle to construct a stochastic description for bounded apparent elasticity tensors at the mesoscale level, in which the bounds are obtained through a computational calibration process based on the theory of micromechanics and numerical homogenization. The framework provides an efficient way to model and simulate the local statistical fluctuations of material properties that are linked to phenomena occurring at the subscale level of heterogeneity.

Determination of the influence of interfacial thermal resistance in a three phase composite using variational asymptotic based homogenization method

A computational framework based on the Variational Asymptotic Method (VAM) has been developed to determine the effective thermal conductivity of carbon-coated inclusion in the three-phase metal-ceramic composites. In the model, perfect bonding temperature continuity conditions have been assumed between the matrix-interface and interface-inclusion boundaries. Both periodic and random distribution of inclusions have been considered in the study. Simulation results corresponding to homogenized conductivity have been compared with results from various existing analytical models. Results show good agreement between the model predictions and the analytical models. As an application, the framework has been used to investigate the influence of interface thickness, thermal conduction, and shape on the overall homogenized conductivities and the local fields in three-phase composites with coated inclusions.

Dielectric and microwave shielding properties of three-phase composites graphite nanoplatelets/carbonyl iron/epoxy resin

The electrical properties of three-phase composite materials (CMs) graphite nanoplatelets/carbonyl iron/epoxy resin (GNP/Fe/epoxy) with 30 wt% of Fe and (1–5) wt% of GNP were studied by measuring DC conductivity and AC impedance spectra in the frequency range up to 2 MHz. The microwave shielding properties were measured in the frequency range of electromagnetic radiation (EMR) 1–67 GHz. The Nyquist diagrams derived from measured impedance–frequency spectra for GNP/Fe/epoxy CMs were considered within the equivalent circuit model. The significant increase of permittivity was observed for three-phase CMs with the increase of GNP content compared to two-phase GNP/epoxy CMs. For example, the real part of permittivity $$\varepsilon^{\prime}$$ = 700–300 and imaginary part $$\varepsilon^{\prime\prime}$$ = 4 × 105–300 for ternary 5 GNP/Fe/epoxy composite in the frequency range 1 kHz–2 MHz. The observed significant increase of AC conductivity for three-phase composites proved the synergetic role of Fe particles in dispersing of GNP filler in epoxy matrix and formation of micro-capacitor network (for low GNP content) as well as the conductive network for higher GNP content. The observed sufficient increase of EMR shielding ( $${\text{SE}}_{T}$$ in dB) beginning from 30–35 GHz for GNP content of 3–5 wt% correlates with DC electrical conductivity increase. The increase of the sample thickness d leads to the increase of shielding efficiency mainly due to the increase of EMR absorption $${\text{SE}}_{A}$$ term.

Uniform stresses inside a non-elliptical inhomogeneity and a nearby half-plane with locally wavy interface

We develop a two-parameter conformal mapping function for a doubly connected domain to solve the inverse problem in anti-plane and plane elasticity associated with a non-elliptical inhomogeneity with internal uniform stresses embedded in a half-plane bonded to another half-plane also with internal uniform stresses via a locally wavy interface. The internal uniform stresses are found to be independent of the specific shapes of the locally wavy and non-elliptical interfaces. The permissible range of the two parameters in the mapping function for a one-to-one mapping is obtained. Typical geometries corresponding to the three-phase composite are illustrated.

Electrochemical Impedance Characterization of Blood Cell Suspensions-Part 2: Three-Phase Systems With Single-Shelled Particles.

The analyses presented in Part 1 are expanded to three-phase composite materials. The theory developed in Part 1 is used for analytical and numerical calculations of dielectric spectra. In this study, three-phase systems with single-shelled particles were considered. The disordered particle distribution, aligned orientation of particles, and particles placed in different lattice structures are studied. It is shown that both two-phase and three-phase composites exhibit β-dispersion, while three-phase composites additionally exhibit δ-dispersion. This is the fundamental difference in the spectra for two- and three-phase materials. In the case of aligned orientation, the effective permittivity in the direction perpendicular to the spheroid plane exhibits a maximum at a volume fraction of approximately 0.5. Both two- and three-phase materials display this behavior. This may be of interest for the development of new metamaterials. The dielectric properties of composite materials with random distribution and periodic arrangement of particles differ significantly. The dielectric spectrum of erythrocyte suspension in plasma was measured by means of electrochemical impedance spectroscopy. The measurement system consisted of a small chamber with two planar electrodes placed at the bottom and an impedance analyzer. The dielectric properties of erythrocyte cytoplasm and membrane were numerically determined based on experimental data. The measurement of the dielectric properties of whole blood and blood components is very promising for various medical applications.

Electrochemical Impedance Characterization of Blood Cell Suspensions. Part 1: Basic Theory and Application to Two-Phase Systems

Electrochemical impedance spectra of composite materials contain information on the topological arrangement, volume fraction, and shape of particles, as well as the dielectric properties of the matrix and particles. The objective of this study is to investigate how these parameters affect the dielectric spectrum and what reliable information can be extracted from experimental data. The main attention was focused on systems with dielectric behavior similar to that of human blood. Mostly plasma and erythrocytes determine the dielectric properties of whole blood. Erythrocytes suspended in plasma can be considered as three-phase systems with single-shelled particles. A theoretical approach based on the effective medium theory is developed for calculating the effective permittivity and conductivity of three-phase composites at a wide frequency range (from 0 to 1 GHz). A finite-difference method is applied to model three-dimensional periodic structures. A special case of two-phase materials is used to demonstrate the influence of the shape and arrangement of particles on dielectric properties. Theoretical and numerical approaches are applied to two-phase composites with spherical, spheroidal and biconcave particles and are compared with each other and with published data. It is shown that two-phase composites exhibit only β-dispersion. In contrast to the quasi-static limit, the wide-bandwidth impedance spectroscopy makes it possible to distinguish between disordered and regular arrangements of spheroidal and biconcave particles. The results can be used to analyze the dielectric properties of blood, which is very promising for various medical applications. This study of two-phase composites can be further extended to three-phase composites.

Temperature-dependent dynamic response in epoxy-free and epoxy-bonded ME composite: a comparative study

This work presents an experimental comparative study of the frequency-dependent response of the epoxy-free magnetoelectric (ME) composite against epoxy-bonded two-phase and three-phase ME composites of various configurations at varying operating temperatures. Conventionally, ME composites are prepared by bonding the piezoelectric and magnetostrictive material phases by means of an epoxy material. Therefore, the response of the composite becomes a function of the properties of the epoxy used. Since the epoxy properties degrade significantly with increase in temperature, the ME response of the ME composite becomes poor at elevated temperatures. In this work, two-phase and three-phase epoxy-free ME composite has been fabricated by employing a press-fit embedded structure and compared with similar epoxy-bonded embedded structure as well as conventional layered ME composite. Frequency-dependent experiments have been conducted at various temperatures and the responses from the two types of composites have been compared. Magnetostriction measurements at different temperatures have been conducted on individual magnetostrictive constituents to observe the effect of piezomagnetic coefficient on the ME response. It is observed that the ME responses of the epoxy-free composites at room temperature are nearly equivalent to their epoxy-bonded counterparts, whereas at higher temperatures the epoxy-free ring composite offers a much better response. The effect of demagnetizing field on the response of composites of various configurations is studied at different temperatures and a similar result is obtained. The resonant frequency of the ME composite is seen to decrease with an increase in temperature owing to the decrease in the effective Young’s modulus of the composite.

In vitro behavior of silk fibroin-based composite resorbable bone fixation devices

There are between 12 and 15 million bone fractures in the United States annually, and many of them require the implantation of an internal fixation device, which helps anchor severely fractured bones to ensure they heal properly. The current standard for such a device relies on the use of metals like stainless steel or titanium due to their superior mechanical properties and propensity to be bioinert. However, these materials are known to cause stress shielding and metal ion leaching, which often lead to the need for a second surgery to remove the implant. For these reasons, there has been considerable interest in creating a fixation device that would provide mechanical stability during healing, but then safely degrade over time, eventually leaving only the patient's own bone. While there are degradable fixation devices on the market, they are made of polymeric materials and have poor mechanical properties, limiting their use to none- and low-load-bearing applications, such as maxillofacial fracture fixation. The present study investigates the use of silk fibroin, hydroxyapatite, and polylactic acid to make resorbable composites to be used as bone fixation devices for load-bearing applications. Using silk fibroin fibers, hydroxyapatite nanowhiskers, and a polylactic acid matrix, three-phase composites were fabricated that has a flexural modulus and strength up to 21.1 GPa and 536 MPa, respectively. Additionally, in vitro analyses showed that the composites degrade slowly via surface erosion and show good initial biocompatibility. These results show great promise for the use of these composites as load-bearing fracture fixation devices. Statement of SignificanceSilk fibroin fibers and hydroxyapatite nanowhiskers were used to fabricate a three-phase composite material for the purpose of load-bearing bone fracture fixation devices. Currently, the bone fixation market is dominated by metals, which cause stress shielding and metal ion leaching, often requiring a second surgery to remove the implant. There are bioresorbable options, made from polymers like poly(lactic-co-glycolic acid), which safely degrade in vivo, leaving only the patient's natural bone and eliminating the need for a second surgery. This study seeks to bridge the gap, creating a device that supports load-bearing fractures while remaining fully resorbable in vivo. The material in this study exhibits the highest bending modulus and strength of any bioresorbable composite found in literature.

Tribological investigation on nano-graphene and curauá filled three-phase polymer composites

Nano-graphene is one of the recently evolved engineering materials, mainly derived from graphite as graphene oxide. Due to its unusual characteristics, most of the engineered materials get doped with graphene. Especially wear resistant property of nano-graphene is one of the attracting characters found with. Present work investigates the effect of nano-graphene inclusion and various fiber activation on the tribological response of less explored vegetable fiber viz., Curauá/polyester hybrid nanocomposites. Compression molding was employed in composite preparation. Experiments were carried out on a Pin-on-disk wear test rig for varying contact pressures (ranging from 0.1 to 0.3 MPa). Tribological properties like friction and wear are studied as a function of graphene hybridization and fiber activation. Wear mechanism is explored through electron microscopy. Morphology reveals that, the predominant wear mechanism would be the adhesion wear and crazing which alarmed that, additional lubrication to avoid the further wear promoted through the friction.

Three-phase modelling and characterization of elastic behavior of MWCNT reinforced GFRP composites: A combined numerical and experimental study

This paper presents modelling and characterization of the elastic behavior of multi-wall carbon nanotube (MWCNT) reinforced with glass fiber reinforced polymer (GFRP) composites. Firstly, atomistic based finite element modelling of MWCNT is developed using computational software ANSYS® by applying various loading and boundary conditions. The present developed atomistic based FE model of MWCNTs are validated with the available literature in terms of elastic properties. Secondly, a two-phase micromechanics model based on the Mori-Tanaka is used to evaluate the elastic properties of the MWCNT reinforced polymer nanocomposite by replacing MWCNTs with equivalent fibers as micro inclusions. Finally, Chamis model is used to evaluate the elastic properties of the three-phase MWCNT reinforced with GFRP composite. The equivalent elastic properties of the three-phase composite are compared and validated with the experimental results. Further, the detailed parametric study is performed to investigate the influence of tube chirality, weight percentage and agglomeration of MWCNT in terms of the elastic properties. It was concluded that the atomistic based FE modelling of MWCNT combined with Mori–Tanaka and Chamis model is efficient to evaluate the elastic properties of three-phase composites with the confidence on the extracted results compared with experimental results. Further, the presented combined model provides an efficient methodology and comprehensive understanding to analyze elastic behavior of MWCNTs and three-phase fiber/MWCNT/polymer composite. So, the presented combined numerical and experimental study could serve as guidelines in modelling and characterization of elastic behaviour of MWCNT reinforced with GFRP composites.

FE Modeling for Bolted Wood Connection Using a Porous Constitutive Model

According to the facts of localized crushing failure of bolt groove in wood connection with enough end distance and the three‐phase composites of wood with solid (wood substance), water, and gas, a confined compression test for the wood cylinder was conducted for achieving constitutive relation under the complex stress state in wood groove. A porous constitutive model was developed according to the confined compression experiments. Then, the constitutive model was implemented in a finite element modeling of mental dowel‐type fasters in wood‐to‐wood connections to analyse the load‐carrying capacity parallel to the grain. Through changing the thicknesses of centre members and side members of wood connections made of a similar wood species, Pinus Sylvestris var. Mongolica, the effects of thickness combinations of centre members and side members on the failure modes and load‐carrying capacity of bolted wood connection including numerical simulations and experiments were compared. The failure modes, including the yielding of centre member, the yielding of side member, and the yielding of the bolt, as well as the rigid rotation of the bolt, all reappeared by the finite element modeling with the porous constitutive model. The predicted deformation shapes and load‐displacement relations of bolted wood connections were compared with experimental ones, and good correlations were observed. This paper presents a new approach to simulate the local embedment crushing of bolt groove in wood connections.

ЗАКОНОМІРНОСТІ ФОРМУВАННЯ ТРИФАЗНОГО КОМПОЗИТУ ПРИ НАВУГЛЕЦЮВАННІ СПЛАВІВ СИСТЕМИ Fe-W-V-C

Мета. Встановлення закономірностей формування трифазного композиту при навуглецюванні залізних сплавів, легованих декількома карбідоутворюючими елементами, виявлення зв'язку структури поверхневого навуглецьованого шару з його властивостями, обґрунтування теоретичних і практичних основ виготовлення природних композиційних матеріалів з використанням хіміко-термічної обробки є метою даної роботи.Методика. Дослідження проводилися в лабораторних умовах шляхом хіміко-термічної обробки зразків заданого хімічного складу при різних параметрах. Фазові та структурні перетворення, що виникають при обробці, вивчали з використанням методів оптичної металографії та геометричної термодинаміки.Результати. Проведено дослідження закономірностей структуроутворення при навуглецюванні сплавів системи Fе-W-V-С з метою отримання теплостійких економнолегованих матеріалів. Вивчено механізми і природа фазових перетворень, а також взаємозв'язок структури поверхневого навуглецьованого шару з його властивостями. Обґрунтовано теоретичні та практичні основи отримання природних композиційних матеріалів з використанням методів хіміко-термічної обробки з метою виготовлення інструменту з більш високим рівнем теплостійкості та зносостійкості. Виходячи з аналізу структуроутворення, що відбувається при навуглецюванні сплавів системи Fе-W-V-С, встановили оптимальні температурно-концентраційні параметри навуглецьовання сплавів, при яких утворюється трифазний композиційний матеріал, що представляє собою аустенітну матрицю, армовану двома типами карбідів М6С і МС.Наукова новизна. Вперше в роботі встановили оптимальні температурно-концентраційні параметри навуглецюванні сплавів системи Fе-W-V-С, при яких утворюються структури колоніального типу, що представляють собою природний композит.Практична цінність. Можливість отримання металевих матеріалів з якісно вищим рівнем властивостей, які забезпечуються особливим характером структур зміцнюючих фаз, що формуються при хіміко-термічній обробці. Крім цього, розширення досліджень складнолегованих матеріалів, в яких при навуглецюванні в поверхневому шарі утворюється колоніальна аустенітно-карбідна структура, що представляє собою природний композит на базі одного або двох карбідів, вивчення закономірностей процесу кооперативного розпаду з утворенням трифазних колоній зробить певний внесок в теорію багатофазних перетворень.

Infrared spectroscopy in the assessment of the mineral composition of kidney stones

As a result of infrared spectroscopy of kidney stones obtained from 59 patients with urolithiasis, a wide range of chemical compounds were identified in the samples, in which whevellite (calcium oxalate monohydrate), hydroxylapatite and uric acid were presented in the largest quantities. Monophasic stones were found in 8.4 % of patients. The two-phase, three-phase and four-phase composition of the samples was determined in 37.2 %, 42.3 % and 11.8 % of patients respectively. Carrying out infrared spectroscopy of kidney stones obtained as a result of self-passage or due to the use of surgical methods will contribute to the correct choice of an individual program for metaphylaxis of urolithiasis in different patients.

Dynamic modeling of a multi-scale sandwich composite panel containing flexible core and MR smart layer

This is the first research on the nonlinear vibration of a composite sandwich doubly curved shell with a flexible core and MR layers, which we do by employing the Homotopy Perturbation Method (HPM). By using a new higher-order shear deformable theory (TSDT) the face sheets and third-order polynomial theory of the flexible core the strains and stresses are obtained. It is assumed a smart model including a multiscale composite layers shell with a flexible core and magnetorheological layer (MR) that is led up by the nonlinearity of the in-plane and the vertical displacements of the core. Three-phase composites shells with polymer/Carbon nanotube/fiber (PCF) and polymer/Graphene platelet/fiber (PGF) according to the Halpin-Tsai model have been considered. For investigating the effect of pattern distribution versus fundamental frequencies various distributions patterns such as U (uniform), X, A and O are considered. The governing equations of the multiscale shell have been derived by implementing Hamilton's principle and the shell considered to be simply supported. For investigating correctness and accuracy, this paper is validated by other previous researches. Finally, different parameters such as temperature rise, various distributions patterns, magnetic fields and curvature ratio are considered in this article. The results presented that the sandwich multiscale doubly curved shell with flexible core show a complex behavior and the homogeneous composite shells are simpler than the vibration patterns of the multiscale composite panels.

Analysis of porosity influence on the effective moduli of ceramic matrix PZT composite using the simplified finite element model

The problem of determining the effective moduli of a ceramic matrix piezocomposite with respect to multiscale porosity was considered. To solve the homogenization problem, the method of effective moduli in the standard formulation, the finite element method and the ANSYS computational package were used. Various models of two-phase and three-phase composites consisting of a piezoceramic matrix, elastic inclusions of corundum and pores of various sizes have been investigated. Finite element models of representative volumes of 3–0 and 3–0–0 connectivities were developed. The results of computational experiments showed that effective moduli depend quite significantly not only on the volume fractions of inclusions and pores, but also on the structure and size of pores in comparison with the characteristic sizes of inclusions.

Carbon nanotube- and graphene-reinforced multiphase polymeric composites: review on their properties and applications

In this review, recent progress in the mechanical, thermal and interfacial properties of graphene/CNT multiphase polymer composites is examined. Progress in the mechanical and thermal properties of CNT (1D) and graphene (2D) nanostructure materials is also reviewed and compared. Furthermore, this review highlights the improvements in the mechanical, thermal and interfacial properties of two- and three-phase composites, owing to the addition of graphene/CNT. In particular, analysis of several notable papers on hybrid composites (graphene/CNT) provides an intensive review of synergetic effects on the overall properties of the corresponding composites. This holistic review describes an improved interface between fibers and a nanofiller-reinforced matrix. Although the presence of nanofillers even at low loadings confers an overall improvement in composite properties, the exact ratios of individual fillers and combined forms remain to be discussed in depth. Finally, potential applications, current challenges and future perspectives for use of these multiphase composites are discussed with regard to their extraordinary capabilities and promising developments in graphene/CNT family-based composite materials.

Buckling of non-uniformly distributed graphene and fibre reinforced multiscale angle-ply laminates

Present work investigates the biaxial buckling of three-phase, angle-ply laminates reinforced with graphene platelets and carbon or glass fibres. The analysis is based on Classical Plate Theory with the shear effect neglected. The laminate is defined as a three-ply symmetric laminate with simply supported boundary conditions and with different graphene and fibre contents in the surface and middle layers. As such, the laminate has a non-uniform distribution of the reinforcements in the surface and middle layers. Thicknesses of surface and middle layers are also non-uniform, but symmetrical. The objective is to investigate the effect of having a higher content of graphene and fibre in the surface layers as compared to the middle layer and also the effect of the relative thicknesses of the surface and middle layers on the buckling load. The main idea is to produce a cost effective design by concentrating the reinforcements in the surface layers where they are most effective. Thickness of the surface layers can be specified as the minimum required for a given buckling load to reduce the cost and to keep the volume content of the expensive reinforcements to a minimum. Effective properties of the three-phase composite are determined via micromechanical relations. Cost-effective designs using the minimum amount of reinforcements for a given buckling load can be determined from the graphs in the numerical results section. It is observed that relative graphene and fibre contents and thickness ratios of surface and middle layers affect the buckling load at different degrees. It is also observed that higher fibre contents can lead to lower buckling loads if the graphene content exceeds a critical value.