Interface In Composite Materials Research Articles

Structure-dependent biomorphology Co3O4-In2O3 nanorods for expired acetone gas sensor

Currently, the detection of acetone in exhaled breath is extensively utilized for the preliminary diagnosis of diabetes and for tracking fat oxidation in exercise. However, semiconductor gas sensors often require enhancement in breath analysis because of their inherent limitations in selectivity and sensitivity to humidity. In this research, we have synthesized an effective and humidity-unaffected acetone sensing material. This was achieved by utilizing the surface induction effect of porous biomass carbon derived from hemp stems to promote the dispersion of Co3O4-In2O3 heterostructure composites, thereby increasing the availability of active sites. This unique structure is achieved by precisely integrating the p-n heterostructure formed by Co3O4-In2O3 nanorods with the hierarchical porous carbon skeleton obtained via the calcination of templates. The p-n heterostructure enhances charge carrier concentration at the interface, thereby augmenting the activation of surface-active oxygen. The composite material's interface barrier improves sensor selectivity, reducing operating temperature (200 °C) and enhancing response rate. In this work, our best sample Coln-3/BC gas sensor exhibits excellent response towards acetone gas (S=Rair/Rgas=56.8 at 100 ppm), low detection limit of 10 ppb, a linear relationship between sensing response and humidity that strikes a balance between irrelevance as well as exceptional selectivity and stability. Therefore, constructing hierarchical structures and gas-sensing materials based on p-n heterojunctions holds promising prospects.

Material Characterization of Glass/Siloxane Interface in Composite Materials

Material Characterization of Glass/Siloxane Interface in Composite Materials

Simulation Analysis of Organic–Inorganic Interface Failure of Scallop under Ultra-High Pressure

Shell is a typical biomineralized inorganic–organic composite material. The essence of scallop deshelling is caused by the fracture failure at the interface of the organic and inorganic–organic matter composites. The constitutive equations were solved so that the stress distributions of the adductor in the radial, circumferential, and axial directions were obtained as σr = σθ = P, σz = 2(2 − ν)P/(2ν − 1), and the shear stress was τzr = 0. Using the method of finite element simulation analysis, the stress distribution laws at different interface states were obtained. The experimental results show that when the amplitude is constant, the undulation period is smaller than the diameter of the adductor or the angle between the bus of the adductor, and the reference horizontal plane gradually decreases, so the interface is more likely to yield. After the analysis, the maximum stress for the yielding of the scallop interface was about 247 MPa, and the whole deshelling process was gradually spread from the outer edge of the interface to the center. The study analyzed the scallop organic–inorganic material interface from the perspective of mechanics, and the mechanical model and simulation analysis results were consistent with the parameter optimization results, which can provide some theoretical basis for the composite material interface failure and in-depth research.

First-principles study on stability, adhesion and fracture properties of ZrO2/W interface in composite materials

Zirconia/tungsten (ZrO2/W) interface is easily formed during the preparation of W-Zr and W-ZrC composites for plasma-facing materials. But there is little information available about the stability, cohesion and bonding of ZrO2/W interface at the atomic scale. Therefore, the thermodynamic stability, mechanical properties and electronic structure of t-ZrO2(001)/W(001) interfaces have been calculated using first-principles calculations. Five kinds of interface bonding structures were considered, and it is found that the two sandwich-like interfaces with one or two stoichimetric ZrO2(001) layers between two W(001) slabs have lower interface energies and better stability than the three precipitate-like interfaces with a ZrO2(001) slab stacked on a W(001) slab, which means that an ultrathin zirconia film tends to form and may promote the grain refinement in W. The analyses of mechanical properties including the work of separation, fracture energy and tensile strengths show that the mechanical failure of the interfaces is inclined to initiate at the interfacial W-O and the O-O bonds, and the ZrO2(001)/W(001) interfaces are less stable against brittle fracture than bulk W and clean W grain boundaries, which implies that the precipitate of ZrO2 particles may act as the crack initiation sites during stretching. Furthermore, the electronic structures analysis indicates that the interfacial W-O bond has some property of covalent and ionic feature. This work could provide a deep understanding of stability, cohesion and fracture properties of ZrO2/W interfaces.

A generalized finite element interface method for mesh reduction of composite materials simulations

This paper proposes interface and polynomial enrichments using the generalized finite element method (IGFEM) for the material interface in composite materials without matching the finite element mesh to the boundaries of different materials. Applications in structural members such as laminated beams and heterogeneous composites (matrix and inclusions) employing coarse and fine meshes are employed. The results were compared with conventional GFEM and analytical solutions. Verification and simulations proved the efficiency of the suggested framework for solving problems with discontinuous gradients resulting from a material interface. The proposed method allows flexibility in mesh generation for composite materials by letting the interface be embedded in an element without the need to match the mesh to the material interface. This improves the computational efficiency over conventional methods.

A Mixed Finite Element-Based Numerical Method for Elastodynamics Considering Adhesive Interface Damage for Dynamic Fracture

The numerical solution of the elastodynamic problem with kinematic boundary conditions is considered using mixed finite elements for the space discretization and a staggered leap-frog scheme for the discretization in time. The stability of the numerical scheme is shown under the usual CFL condition. Using the general form of Robin-type boundary conditions some cases of debonding and the resulting acoustic emission are studied. The methodology presented finds applications to geophysics such as in seismic waves simulation with dynamic rupture and energy release. In this paper, we focus on problems of fracture occurring at the interface of composite materials. Our goal is to study both the mechanism of crack initiation and propagation, as well as the acoustic emission of the released structure-borne energy which may be used in structural health monitoring and prognosis applications.

Using Genetic Algorithm for Investigating the Performance of Carbonbasalt/ Polyester Hybrids Composite Materials

Background:: The composite materials are more efficient and more resistant compared to so-called traditional materials. The application of continuous and variable forces modifies the properties of the materials, and generates the formation of cracks which lead to the rupture of structures. Objective:: The objective of this work is to study the reliability and the origin of the resistance of each fiber-matrix interface of the two hybrid composite materials studied. Methods:: In this study, the genetic algorithm is based on Weibull’s probabilistic approach to calculate the damage to the interface and also on the Cox model to find and initialize the different values used in simulation model. Results:: The results obtained by genetic modeling, have shown that the hybrid Carbon High Modulus (HM)/Basalt/Polyester composite is the most resistant to the mechanical stresses applied comparing with that of Carbon High Strength (HS)/Basalt/Polyester. These results were confirmed by the level of damage to the interface found for the two materials studied and that the interface shear damage of the hybrid Carbon HM/Basalt/Polyester composite is much lower by 13% compared to that of Carbon HS/Basalt/Polyester. Conclusion:: The calculations are in good agreement with the analytical results of Cox, where he demonstrated that Young’s modulus of the fibers has an important influence on the shear strength of the fiber/matrix interface of composite materials.

Process-dependent effects of water on the chemistry of aluminum oxide and aromatic polyimide interface in composite materials

Replacement of Cu wires with Al wires has a significant impact on the overall cable and wire fields. This replacement is particularly important for reducing the weight of hybrid vehicles, significantly improving fuel efficiency, and reducing CO2 emissions. A promising analytical protocol is proposed for investigating the Al and polymer coating interface in samples fabricated by semiconductor-device-manufacturing techniques. The samples were analyzed by time-of-flight secondary ion spectrometry (TOF-SIMS), synchrotron hard-X-ray photoelectron spectroscopy (HAXPES), and electron energy loss spectroscopy with scanning transmission electron microscopy (STEM-EELS). The protocol provides information about the chemistry of interfaces fabricated by (1) Al deposition on a polymer substrate and (2) coating of a polymer precursor on Al. Observation of the Al and pyromellitic-dianhydride-oxydianiline-type polyimide (PMDA-ODA PI) interfaces revealed: For (1), the water adsorbed on the pristine PI surface contributed mainly to formation of the Al hydrate. For (2), at the Al/PI interface, the two events occur in a chain: first, hydrolysis of PAA occurred to form the carboxyl group, followed by acid-base reactions between the carboxyl group and hydroxide/oxide to generate water. Thus, AlOCO bonds form at the interface. The proposed protocol is applicable to the investigation of a wide-ranging combination of metals and polymers.

Measurement of interfacial residual stress in SiC fiber reinforced Ni-Cr-Al alloy composites by Raman spectroscopy

Raman spectroscopy was used to measure Raman spectra of the inner SiC fibers and surface C-rich layers of SiC fibers, composite precursors and SiCf/Ni-Cr-Al composites. The residual stresses of the inner SiC fibers and surface C-rich layers were calculated, and the effect of the (Al + Al2O3) diffusion barrier layer on the interfacial residual stress in the composites was analyzed in combination with the interface microstructure and energy disperse spectroscopy (EDS) elements lining maps. The results show that the existence of (Al + Al2O3) diffusion barrier improves the compatibility of the SiCf/Ni-Cr-Al interface, inhibits the adverse interfacial reaction, and relieves the residual stress inside SiC fibers and at the interface of composite material. Heat treatment can reduce the residual stress at the interface. As the heat treatment time increases, the residual stress at the interface decreases.

First-principles study of adhesion strength and stability of the TiB2/TiC interface in composite materials

The properties of a TiC(0 1 0) surface, a TiB2(0 1 1¯ 0) surface, and TiC(0 1 0)/TiB2(0 1 1¯ 0) interfaces were investigated by first-principles calculations. The work of adhesion (Wad), the interface energy (γint), and the electronic structure of the interfaces were determined. The results show that the C-BS1-B1, C-TS-B2, and Ti-BS1-B1 interfaces are the most stable interfaces. Among all models, the C-TS-B2 interface is most stable and exhibits the highest Wad value (4.77J/m2) and the lowest γint value (1.12J/m2). All three stable interfaces exhibit strong covalent bonding due to the interfacial C-sp and B-sp orbital hybridization; the stable interfaces investigated in this study are as stable as the TiC(1 1 1)/TiB2(0 0 0 1) interface reported in a previous study.

Crystallographic orientations of intermetallic compounds of a multi-pass friction stir processed Al/Mg composite materials

The crystallographic orientation relationships between intermetallic compounds and matrices were investigated in the interface of an overlapped multi-pass friction stir processed Al/Mg composite materials. During the friction stir processing, an Mg rich intermetallic compound (γ-Al12Mg17) was formed close to the bottom Mg alloy and an Al rich intermetallic compound (β-Al3Mg2) was formed close to the top Al alloy. Two new orientation relationships between the Mg matrix and the γ-Al12Mg17 were observed and analyzed. One was identified as 011¯2Mg//1¯01γ, 01¯11Mg//(101)γ, and the other one was identified as 12¯10Mg//[531]γ, (0001)Mg 1.7° form 1¯21¯γ. The stereographic projections of two new orientation relationships were calculated and discussed. Moreover, high resolution transmission electron microscopy studies of the interface between the Mg matrix and the γ-Al12Mg17 indicated that the γ-Al12Mg17 had a coherent interface with the Mg matrix. It was also observed that the β-Al3Mg2 had a cubic-to-cubic orientation relationship with the Al matrix in the Al/Mg composite material interface.

Micromechanical model of the single fiber fragmentation test

A shear-lag model is developed for the analysis of single fiber fragmentation tests for the characterization of the mechanical properties of the fiber/matrix interface in composite materials. The model utilizes the relation for the loss in potential energy of Budiansky, Hutchinson and Evans. The model characterizes the interface in terms of an interfacial fracture energy and a frictional sliding shear stress. Results are obtained in closed analytical form. An experimental approach is proposed for the determination of the interfacial fracture energy and the frictional shear stress from simultaneously obtained data for the applied strain, the opening of a broken fiber and the associated debond length. The residual stresses are obtained as a part of the approach and enables the determination of in-situ fiber strength.

Progress of the Current Interface Research on Carbon Nanotubes Reinforced Aluminum-Matrix Composites

The carbon nanotubes with its stable structure, excellent mechanical properties, become the ideal enhancement phase of composite materials. The enhancement effect is affected by various factors, interface is one of the key factors determine its enhancement effect, also is the research focus of metal matrix composites. Briefly introduced carbon nanotubes reinforced aluminum matrix (CNTs/Al) composite material interface bonding mechanism and interface effect on the properties of composite materials, thermal expansion coefficient and preparation methods were reviewed, purity of carbon nanotubes and other factors impact on CNTs/Alcomposites interface, and puts forward the way to improve interface.

Study on the Application of Silane Coupling Agent in Rice Straw/Poly(butylene Succinate) Composites

Rice straw/Poly(butylene succinate)(PBS) composites were prepared by injection molding machine. The influence of content and particle size of rice straw on the mechanical properties of composites indicated that with the increase of rice straw content the tensile strength and fracture strain of the composites was decreased. With the same content of rice straw, the smaller particle size, the more obvious decreased. The influence of dosage of silane coupling agent(SCA) on the composites was studied, the result indicated that with the increase of SCA content, the interface of composite materials significantly improved, the Young’s modulus increased 362% after rice straw was treated by SCA. Thermal analysis showed that the adding of coupling agent didn’t undermine the thermodynamic stability of the composites.

Effect of interface structure on mechanical properties of advanced composite materials.

This paper deals with the effect of interface structures on the mechanical properties of fiber reinforced composite materials. First, the background of research, development and applications on hybrid composite materials is introduced. Second, metal/polymer composite bonded structures are discussed. Then, the rationale is given for nanostructuring the interface in composite materials and structures by introducing nanoscale features such as nanopores and nanofibers. The effects of modifying matrices and nano-architecturing interfaces on the mechanical properties of nanocomposite materials are examined. A nonlinear damage model for characterizing the deformation behavior of polymeric nanocomposites is presented and the application of this model to carbon nanotube-reinforced and reactive graphite nanotube-reinforced epoxy composite materials is shown.

Numerical simulation of the transient multiphase field during plasma deposition manufacturing composite materials

A solid/liquid/gas unified model has been developed to investigate the gradient composition formation during the plasma deposition manufacturing (PDM) composite materials process. In this model, an enthalpy porosity model was applied to deal with the melting and solidification of the deposited layer, and a level-set approach was introduced to track the evolution of the free surface of the molten pool and the deposited layer. Moreover, complicated physical phenomena occurring at the liquid/gas interface, including forced convection heat loss, heat emission and plasma heat source, have been incorporated into the governing equations by source terms. In this study, the numerical experiment of nickel base alloy powder deposited on the medium steel substrate by PDM technique was implemented based on the staggered grid and SIMPLEC algorithm. Concentration gradient distribution of the solute material at the composite material interface, fluid flow and temperature distribution in the molten pool and the deposited layer have been investigated in detail.

Effect of Glass Fiber Surface Treatments on Mechanical Strength of Epoxy Based Composite Materials

Sizing glass fibers with silane coupling agents enhances the adhesion and the durability of the fiber/polymer matrix interface in composite materials. There are several tests to determine the interfacial strength between a fiber and resin, but all of them present difficulties in interpreting the results and/or sample preparation. In this study, we observed the influence of different aminosilanes fiber coatings on the resistance of epoxy-based composite materials using a very easy fractographic test. In addition, we tried a new fluorescence method to get information on a molecular level precisely at the interface. Strength was taken into account from two standpoints: (i) mechanical strength and (ii) the resistance to hydrolysis of the interface in oriented glass-reinforced epoxy-based composites. Three silanes: γ-aminopropyltriethoxysilane, γ-Aminopropylmethyldiethoxysilane, and γ-Aminopropyldimethylethoxysilane were used to obtain different molecular structures at the interface. It was concluded that: (i) the more accessible amine groups are, the higher the interface rigidity is; (ii) an interpenetrating network mechanism seems to be the most important for adhesion and therefore to the interfacial strength; and (iii) the higher the degree of crosslinking in the silane coupling layer is, the higher the hydrolytic damage rate is.

Experimental procedure to analyse the corrosion mechanisms at the carbon/aluminium interface in composite materials

Aluminium matrix composites reinforced with graphite fibres are of interest for their specific mechanical properties in aeronautical applications. They are also known to have poor resistance to corrosion in aqueous environments, for example in chloride containing solutions. Galvanic coupling between aluminium and graphite is the dominant corrosion mechanism. The corrosion occurs at the fibre–matrix interface and weakens the load transfer from the matrix to the fibre. Galvanic corrosion mechanism has been studied using in situ monitoring by long focal video microscopy and atomic force microscopy. The objective of that study was to find an adequate procedure to analyse the corrosion mechanism at the interface. Quantitative informations on the morphology and the kinetics of the corrosion at the fibre/matrix interface are proposed.

Segmental dynamics of interfacial poly(methyl acrylate)-d(3) in composites by deuterium NMR spectroscopy.

The interface in composite materials containing an ultrathin layer of poly(methyl acrylate)-d(3) (PMA-d(3)) on silica was studied using deuterium NMR. PMA-d(3) was deposited from solution at saturation coverage from toluene onto silica. The samples were dried and composite samples made by hot pressing the PMA-d(3)/silica samples with hydrogenated polystyrene (PS) and high (HMW) and low (LMW) molecular weight hydrogenated poly(methyl acrylate) (PMA) as the overlayer. The interfacial layers of PMA-d(3) were studied at the air-polymer-silica and polymer-polymer-silica interfaces using deuterium solid-state quadrupole-echo NMR and the results compared to those for the bulk polymer. It was found that for samples at the air-polymer-silica interface, some of the polymer segments in the surface sample had segmental mobility higher than that of the corresponding bulk PMA-d(3) sample at the same temperature. When overcoated with unlabeled polymer, the interfacial polymer at the polymer-polymer-silica interface showed reduced mobility due to the presence of the overlayer. The adsorbed PMA-d(3), in the composite samples, decreased in mobility in the order of LMW-PMA > HMW-PMA > PS. The PS sample caused the greatest reduction in the PMA-d(3) interfacial mobility. The order was consistent with the segmental mobilities of the polymers used for the overlayers. The lower the mobility of the polymer used for the overlayer, the more restricted were the polymer segments in the adsorbed PMA-d(3) layer.

462 J積分成分分離法による複合材界面き裂の応力拡大係数評価法(GS-13 き裂(4))

462 J積分成分分離法による複合材界面き裂の応力拡大係数評価法(GS-13 き裂(4))