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Sample records for amorphous matrix composite

  1. Amorphous metal matrix composite ribbons

    International Nuclear Information System (INIS)

    Barczy, P.; Szigeti, F.

    1998-01-01

    Composite ribbons with amorphous matrix and ceramic (SiC, WC, MoB) particles were produced by modified planar melt flow casting methods. Weldability, abrasive wear and wood sanding examinations were carried out in order to find optimal material and technology for elevated wear resistance and sanding durability. The correlation between structure and composite properties is discussed. (author)

  2. Correlation of microstructure and compressive properties of amorphous matrix composites reinforced with tungsten continuous fibers or porous foams

    International Nuclear Information System (INIS)

    Son, Chang-Young; Lee, Sang-Bok; Lee, Sang-Kwan; Kim, Choongnyun Paul; Lee, Sunghak

    2010-01-01

    Zr-based amorphous alloy matrix composites reinforced with tungsten continuous fibers or porous foams were fabricated without pores or defects by liquid pressing process, and their microstructures and compressive properties were investigated. About 65-70 vol.% of tungsten reinforcements were homogeneously distributed inside the amorphous matrix. The compressive test results indicated that the tungsten-reinforced composites showed considerable plastic strain as the compressive load was sustained by fibers or foams. Particularly in the tungsten porous foam-reinforced composite, the compressive stress continued to increase according to the work hardening after the yielding, thereby leading to the maximum strength of 2764 MPa and the plastic strain of 39.4%. This dramatic increase in strength and ductility was attributed to the simultaneous and homogeneous deformation at tungsten foams and amorphous matrix since tungsten foams did not show anisotropy and tungsten/matrix interfaces were excellent.

  3. Microstructure and Mechanical Behavior of Microwave Sintered Cu50Ti50 Amorphous Alloy Reinforced Al Metal Matrix Composites

    Science.gov (United States)

    Reddy, M. Penchal; Ubaid, F.; Shakoor, R. A.; Mohamed, A. M. A.

    2018-06-01

    In the present work, Al metal matrix composites reinforced with Cu-based (Cu50Ti50) amorphous alloy particles synthesized by ball milling followed by a microwave sintering process were studied. The amorphous powders of Cu50Ti50 produced by ball milling were used to reinforce the aluminum matrix. They were examined by x-ray diffraction (XRD), scanning electron microscopy (SEM), microhardness and compression testing. The analysis of XRD patterns of the samples containing 5 vol.%, 10 vol.% and 15 vol.% Cu50Ti50 indicates the presence of Al and Cu50Ti50 peaks. SEM images of the sintered composites show the uniform distribution of reinforced particles within the matrix. Mechanical properties of the composites were found to increase with an increasing volume fraction of Cu50Ti50 reinforcement particles. The hardness and compressive strength were enhanced to 89 Hv and 449 MPa, respectively, for the Al-15 vol.% Cu50Ti50 composites.

  4. Amorphous metal composites

    International Nuclear Information System (INIS)

    Byrne, M.A.; Lupinski, J.H.

    1984-01-01

    This patent discloses an improved amorphous metal composite and process of making the composite. The amorphous metal composite comprises amorphous metal (e.g. iron) and a low molecular weight thermosetting polymer binder. The process comprises placing an amorphous metal in particulate form and a thermosetting polymer binder powder into a container, mixing these materials, and applying heat and pressure to convert the mixture into an amorphous metal composite

  5. Atomistic simulation of the thermal conductivity in amorphous SiO2 matrix/Ge nanocrystal composites

    Science.gov (United States)

    Kuryliuk, Vasyl V.; Korotchenkov, Oleg A.

    2017-04-01

    We use nonequilibrium molecular dynamics computer simulations with the Tersoff potential aiming to provide a comprehensive picture of the thermal conductivity of amorphous SiO2 (a-SiO2) matrix with embedded Ge nanocrystals (nc-Ge). The modelling predicts the a-SiO2 matrix thermal conductivity in a temperature range of 50 fair agreement with experiment at around room temperature. It is worth noticing that the predicted room-temperature thermal conductivity in a-SiO2 is in very good agreement with the experimental result, which is in marked contrast with the thermal conductivity calculated employing the widely used van Beest-Kramer-van Santen (BKS) potential. We show that the thermal conductivity of composite nc-Ge/a-SiO2 systems decreases steadily with increasing the volume fraction of Ge inclusions, indicative of enhanced interface scattering of phonons imposed by embedded Ge nanocrystals. We also observe that increasing the volume fractions above a certain threshold value results in a progressively increased thermal conductivity of the nanocomposite, which can be explained by increasing volume fraction of a better thermally conducting Ge. Finally, non-equilibrium molecular dynamics simulations with the Tersoff potential are promising for computing the thermal conductivity of nanocomposites based on amorphous SiO2 and can be readily scaled to more complex composite structures with embedded nanoparticles, which thus help design nanocomposites with desired thermal properties.

  6. Mechanical properties and fracture mechanism of as-cast Mg77TM12Zn5Y6 (TM = Cu, Ni) bulk amorphous matrix composites

    International Nuclear Information System (INIS)

    Qiu, K.Q.; Hu, N.N.; Zhang, H.B.; Jiang, W.H.; Ren, Y.L.; Liaw, P.K.

    2009-01-01

    Comparative investigations on the microstructures, thermal stability and mechanical properties of Mg 77 Cu 12 Zn 5 Y 6 and Mg 77 Ni 12 Zn 5 Y 6 bulk metallic glass matrix composites were carried out by using scanning electron microscopy (SEM), DSC and compressive tester. The results show that the microstructure of as-cast samples with 3 mm in diameter for Cu-containing alloy is consisted of Mg flakes and dotted Mg 2 Cu phase in the amorphous matrix, while the as-cast Ni-containing alloy with the same diameter is mainly consisted of Mg flakes in the amorphous matrix. The glass transition temperature and supercooled liquid region are 413 K and 27 K for the Cu-containing, 443 K and 32 K for the Ni-containing amorphous matrix composites, respectively. The fracture strength, yield strength and plastic strain are 532 MPa, 390 MPa and 2.4% for the Cu-containing alloy, 667 MPa, 412 MPa and 7% for the Ni-containing alloy, respectively. Furthermore, the fracture mechanism for the amorphous matrix composites was discussed according to both the fracture surfaces and the stress-strain curves.

  7. Bulk metallic glass matrix composites

    International Nuclear Information System (INIS)

    Choi-Yim, H.; Johnson, W.L.

    1997-01-01

    Composites with a bulk metallic glass matrix were synthesized and characterized. This was made possible by the recent development of bulk metallic glasses that exhibit high resistance to crystallization in the undercooled liquid state. In this letter, experimental methods for processing metallic glass composites are introduced. Three different bulk metallic glass forming alloys were used as the matrix materials. Both ceramics and metals were introduced as reinforcement into the metallic glass. The metallic glass matrix remained amorphous after adding up to a 30 vol% fraction of particles or short wires. X-ray diffraction patterns of the composites show only peaks from the second phase particles superimposed on the broad diffuse maxima from the amorphous phase. Optical micrographs reveal uniformly distributed particles in the matrix. The glass transition of the amorphous matrix and the crystallization behavior of the composites were studied by calorimetric methods. copyright 1997 American Institute of Physics

  8. Mechanical properties and fracture mechanism of as-cast Mg{sub 77}TM{sub 12}Zn{sub 5}Y{sub 6} (TM = Cu, Ni) bulk amorphous matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, K.Q. [School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110178 (China)], E-mail: kqqiu@yahoo.com.cn; Hu, N.N.; Zhang, H.B. [School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110178 (China); Jiang, W.H. [Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37990 (United States); Ren, Y.L. [School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110178 (China); Liaw, P.K. [Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37990 (United States)

    2009-06-10

    Comparative investigations on the microstructures, thermal stability and mechanical properties of Mg{sub 77}Cu{sub 12}Zn{sub 5}Y{sub 6} and Mg{sub 77}Ni{sub 12}Zn{sub 5}Y{sub 6} bulk metallic glass matrix composites were carried out by using scanning electron microscopy (SEM), DSC and compressive tester. The results show that the microstructure of as-cast samples with 3 mm in diameter for Cu-containing alloy is consisted of Mg flakes and dotted Mg{sub 2}Cu phase in the amorphous matrix, while the as-cast Ni-containing alloy with the same diameter is mainly consisted of Mg flakes in the amorphous matrix. The glass transition temperature and supercooled liquid region are 413 K and 27 K for the Cu-containing, 443 K and 32 K for the Ni-containing amorphous matrix composites, respectively. The fracture strength, yield strength and plastic strain are 532 MPa, 390 MPa and 2.4% for the Cu-containing alloy, 667 MPa, 412 MPa and 7% for the Ni-containing alloy, respectively. Furthermore, the fracture mechanism for the amorphous matrix composites was discussed according to both the fracture surfaces and the stress-strain curves.

  9. Indentation creep behaviors of amorphous Cu-based composite alloys

    Science.gov (United States)

    Song, Defeng; Ma, Xiangdong; Qian, Linfang

    2018-04-01

    This work reports the indentation creep behaviors of two Si2Zr3/amorphous Cu-based composite alloys utilizing nanoindentation technique. By analysis with Kelvin model, the retardation spectra of alloys at different positions, detached and attached regions to the intermetallics, were deduced. For the indentation of detached regions to Si2Zr3 intermetallics in both alloys, very similarity in creep displacement can be observed and retardation spectra show a distinct disparity in the second retardation peak. For the indentation of detached regions, the second retardation spectra also display distinct disparity. At both positions, the retardation spectra suggest that Si elements may lead to the relatively dense structure in the amorphous matrix and to form excessive Si2Zr3 intermetallics which may deteriorate the plastic deformation of current Cu-based composite alloys.

  10. CNTs Modified and Enhanced Cu Matrix Composites

    Directory of Open Access Journals (Sweden)

    ZHANG Wen-zhong

    2016-12-01

    Full Text Available The composite powders of 2%-CNTs were prepared by wet ball milling and hydrogen annealing treatment-cold pressing sintering was used to consolidate the ball milled composite powders with different modifications of the CNTs. The results show that the length of the CNTs is shortened, ports are open, and amorphous carbon content is increased by ball milling. And after a mixed acid purification, the impurity on the surface of the CNTs is completely removed,and a large number of oxygen-containing reactive groups are introduced; the most of CNTs can be embedded in the Cu matrix and the CNTs have a close bonding with the Cu matrix, forming the lamellar composite structure, then, ultrafine-grained composite powders can be obtained by hydrogen annealing treatment. Shortening and purification of the CNTs are both good for dispersion and bonding of CNTs in the Cu matrix, and the tensile strength and hardness of the composites after shortening and purification reaches the highest, and is 296MPa and 139.8HV respectively, compared to the matrix, up to 123.6% in tensile strength and 42.9% in hardness, attributed to the fine grain strengthening and load transferring.

  11. Machining of Metal Matrix Composites

    CERN Document Server

    2012-01-01

    Machining of Metal Matrix Composites provides the fundamentals and recent advances in the study of machining of metal matrix composites (MMCs). Each chapter is written by an international expert in this important field of research. Machining of Metal Matrix Composites gives the reader information on machining of MMCs with a special emphasis on aluminium matrix composites. Chapter 1 provides the mechanics and modelling of chip formation for traditional machining processes. Chapter 2 is dedicated to surface integrity when machining MMCs. Chapter 3 describes the machinability aspects of MMCs. Chapter 4 contains information on traditional machining processes and Chapter 5 is dedicated to the grinding of MMCs. Chapter 6 describes the dry cutting of MMCs with SiC particulate reinforcement. Finally, Chapter 7 is dedicated to computational methods and optimization in the machining of MMCs. Machining of Metal Matrix Composites can serve as a useful reference for academics, manufacturing and materials researchers, manu...

  12. Microstructural and mechanical properties analysis of an aluminium matrix composite reinforced with the amorphous alloy Al{sub 87.5}Ni{sub 4}Sm{sub 8.5} consolidated by hot extrusion; Propriedades mecanicas e microestruturais de um composito com matrix de aluminio e reforco amorfo de Al{sub 87.5}Ni{sub 4}Sm{sub 8.5} consolidado por extrusao a quente por extrusao a quente

    Energy Technology Data Exchange (ETDEWEB)

    Aliaga, L.C.R.; Bolfarini, C.; Kiminami, C.S.; Botta, W.J. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais; Peres, M.M., E-mail: peresmm@yahoo.com.b [Universidade Federal de Itajuba (UNIFEI), Itabira, MG (Brazil)

    2010-07-01

    The aim of this work is the microstructure and the mechanical properties analysis of an aluminium matrix composite reinforced with the Al{sub 87.5}Ni{sub 4}Sm{sub 8.5} amorphous alloy. The amorphous alloy was produced by melt-spinning and fragmented in powder particles by milling. Pure aluminium power was moistured with amorphous powder in a proportion of 80:20 (% weight) and processed by milling using 350 rpm during 30 minutes for the generation of a homogeneous composite powder. This product was consolidated by extrusion at 235 deg C, ram speed of 2mm/min and extrusion ratio of 7/1, generating a compact and cylindrical bar with 3 mm of width. The result sample was characterized by Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC) and by X-Ray Diffraction (XRD). Microhardness and compression tests show an improvement on the mechanical properties. (author)

  13. Fracture of Carbon Nanotube - Amorphous Carbon Composites: Molecular Modeling

    Science.gov (United States)

    Jensen, Benjamin D.; Wise, Kristopher E.; Odegard, Gregory M.

    2015-01-01

    Carbon nanotubes (CNTs) are promising candidates for use as reinforcements in next generation structural composite materials because of their extremely high specific stiffness and strength. They cannot, however, be viewed as simple replacements for carbon fibers because there are key differences between these materials in areas such as handling, processing, and matrix design. It is impossible to know for certain that CNT composites will represent a significant advance over carbon fiber composites before these various factors have been optimized, which is an extremely costly and time intensive process. This work attempts to place an upper bound on CNT composite mechanical properties by performing molecular dynamics simulations on idealized model systems with a reactive forcefield that permits modeling of both elastic deformations and fracture. Amorphous carbon (AC) was chosen for the matrix material in this work because of its structural simplicity and physical compatibility with the CNT fillers. It is also much stiffer and stronger than typical engineering polymer matrices. Three different arrangements of CNTs in the simulation cell have been investigated: a single-wall nanotube (SWNT) array, a multi-wall nanotube (MWNT) array, and a SWNT bundle system. The SWNT and MWNT array systems are clearly idealizations, but the SWNT bundle system is a step closer to real systems in which individual tubes aggregate into large assemblies. The effect of chemical crosslinking on composite properties is modeled by adding bonds between the CNTs and AC. The balance between weakening the CNTs and improving fiber-matrix load transfer is explored by systematically varying the extent of crosslinking. It is, of course, impossible to capture the full range of deformation and fracture processes that occur in real materials with even the largest atomistic molecular dynamics simulations. With this limitation in mind, the simulation results reported here provide a plausible upper limit on

  14. Ceramic matrix composite article and process of fabricating a ceramic matrix composite article

    Science.gov (United States)

    Cairo, Ronald Robert; DiMascio, Paul Stephen; Parolini, Jason Robert

    2016-01-12

    A ceramic matrix composite article and a process of fabricating a ceramic matrix composite are disclosed. The ceramic matrix composite article includes a matrix distribution pattern formed by a manifold and ceramic matrix composite plies laid up on the matrix distribution pattern, includes the manifold, or a combination thereof. The manifold includes one or more matrix distribution channels operably connected to a delivery interface, the delivery interface configured for providing matrix material to one or more of the ceramic matrix composite plies. The process includes providing the manifold, forming the matrix distribution pattern by transporting the matrix material through the manifold, and contacting the ceramic matrix composite plies with the matrix material.

  15. The structure of the "amorphous" matrix of keratins.

    Science.gov (United States)

    Kadir, Murat; Wang, Xinwei; Zhu, Bowen; Liu, Jing; Harland, Duane; Popescu, Crisan

    2017-05-01

    Various keratin fibers, particularly human hairs, were investigated by transmission electron microscopy, TEM, solid-state 1 H NMR and Transient Electro-Thermal Technique, TET. The results converge to suggest that the matrix of keratin fiber cortex, far from being amorphous, has a well-defined nano-scale grainy structure, the size of these grains being around 2-4nm. The size of the grains appears to strongly depend on the chemical treatment of the fiber, on the temperature and on the relative humidity of the environment, as well as on the physiological factors at the level of fiber production in follicle. By suggesting an organization at the nano-scale of the protein chains in these grains, likely to be Keratin Associated Proteins, the results challenge the view of matrix as a homogeneous glassy material. Moreover, they indicate the potential of further investigating the purpose of this structure that appears to reflect not only chemical treatments of keratins but also biological processes at the level of the follicle. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Titanium Matrix Composite Pressure Vessel, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — For over 15 years, FMW Composite Systems has developed Metal Matrix Composite manufacturing methodologies for fabricating silicon-carbide-fiber-reinforced titanium...

  17. Structure-Composition-Property Relationships in Polymeric Amorphous Calcium Phosphate-Based Dental Composites

    Directory of Open Access Journals (Sweden)

    Drago Skrtic

    2009-11-01

    Full Text Available Our studies of amorphous calcium phosphate (ACP-based materials over the last decade have yielded bioactive polymeric composites capable of protecting teeth from demineralization or even regenerating lost tooth mineral. The anti-cariogenic/remineralizing potential of these ACP composites originates from their propensity, when exposed to the oral environment, to release in a sustained manner sufficient levels of mineral-forming calcium and phosphate ions to promote formation of stable apatitic tooth mineral. However, the less than optimal ACP filler/resin matrix cohesion, excessive polymerization shrinkage and water sorption of these experimental materials can adversely affect their physicochemical and mechanical properties, and, ultimately, limit their lifespan. This study demonstrates the effects of chemical structure and composition of the methacrylate monomers used to form the matrix phase of composites on degree of vinyl conversion (DVC and water sorption of both copolymers and composites and the release of mineral ions from the composites. Modification of ACP surface via introducing cations and/or polymers ab initio during filler synthesis failed to yield mechanically improved composites. However, moderate improvement in composite’s mechanical stability without compromising its remineralization potential was achieved by silanization and/or milling of ACP filler. Using ethoxylated bisphenol A dimethacrylate or urethane dimethacrylate as base monomers and adding moderate amounts of hydrophilic 2-hydroxyethyl methacrylate or its isomer ethyl-α-hydroxymethacrylate appears to be a promising route to maximize the remineralizing ability of the filler while maintaining high DVC. Exploration of the structure/composition/property relationships of ACP fillers and polymer matrices is complex but essential for achieving a better understanding of the fundamental mechanisms that govern dissolution/re-precipitation of bioactive ACP fillers, and

  18. Formation of soft magnetic high entropy amorphous alloys composites containing in situ solid solution phase

    Science.gov (United States)

    Wei, Ran; Sun, Huan; Chen, Chen; Tao, Juan; Li, Fushan

    2018-03-01

    Fe-Co-Ni-Si-B high entropy amorphous alloys composites (HEAACs), which containing high entropy solid solution phase in amorphous matrix, show good soft magnetic properties and bending ductility even in optimal annealed state, were successfully developed by melt spinning method. The crystallization phase of the HEAACs is solid solution phase with body centered cubic (BCC) structure instead of brittle intermetallic phase. In addition, the BCC phase can transformed into face centered cubic (FCC) phase with temperature rise. Accordingly, Fe-Co-Ni-Si-B high entropy alloys (HEAs) with FCC structure and a small amount of BCC phase was prepared by copper mold casting method. The HEAs exhibit high yield strength (about 1200 MPa) and good plastic strain (about 18%). Meanwhile, soft magnetic characteristics of the HEAs are largely reserved from HEAACs. This work provides a new strategy to overcome the annealing induced brittleness of amorphous alloys and design new advanced materials with excellent comprehensive properties.

  19. Ceramic matrix and resin matrix composites - A comparison

    Science.gov (United States)

    Hurwitz, Frances I.

    1987-01-01

    The underlying theory of continuous fiber reinforcement of ceramic matrix and resin matrix composites, their fabrication, microstructure, physical and mechanical properties are contrasted. The growing use of organometallic polymers as precursors to ceramic matrices is discussed as a means of providing low temperature processing capability without the fiber degradation encountered with more conventional ceramic processing techniques. Examples of ceramic matrix composites derived from particulate-filled, high char yield polymers and silsesquioxane precursors are provided.

  20. Ceramic matrix and resin matrix composites: A comparison

    Science.gov (United States)

    Hurwitz, Frances I.

    1987-01-01

    The underlying theory of continuous fiber reinforcement of ceramic matrix and resin matrix composites, their fabrication, microstructure, physical and mechanical properties are contrasted. The growing use of organometallic polymers as precursors to ceramic matrices is discussed as a means of providing low temperature processing capability without the fiber degradation encountered with more conventional ceramic processing techniques. Examples of ceramic matrix composites derived from particulate-filled, high char yield polymers and silsesquioxane precursors are provided.

  1. Amorphous Metals and Composites as Mirrors and Mirror Assemblies

    Science.gov (United States)

    Hofmann, Douglas C. (Inventor); Davis, Gregory L. (Inventor); Agnes, Gregory S. (Inventor); Shapiro, Andrew A. (Inventor)

    2016-01-01

    A mirror or mirror assembly fabricated by molding, pressing, assembling, or depositing one or more bulk metal glass (BMG), bulk metal glass composite (BMGMC), or amorphous metal (AM) parts and where the optical surface and backing of the mirror can be fabricated without machining or polishing by utilizing the unique molding capabilities of this class of materials.

  2. Dielectric breakdown in silica-amorphous polymer nanocomposite films: the role of the polymer matrix.

    Science.gov (United States)

    Grabowski, Christopher A; Fillery, Scott P; Westing, Nicholas M; Chi, Changzai; Meth, Jeffrey S; Durstock, Michael F; Vaia, Richard A

    2013-06-26

    The ultimate energy storage performance of an electrostatic capacitor is determined by the dielectric characteristics of the material separating its conductive electrodes. Polymers are commonly employed due to their processability and high breakdown strength; however, demands for higher energy storage have encouraged investigations of ceramic-polymer composites. Maintaining dielectric strength, and thus minimizing flaw size and heterogeneities, has focused development toward nanocomposite (NC) films; but results lack consistency, potentially due to variations in polymer purity, nanoparticle surface treatments, nanoparticle size, and film morphology. To experimentally establish the dominant factors in broad structure-performance relationships, we compare the dielectric properties for four high-purity amorphous polymer films (polymethyl methacrylate, polystyrene, polyimide, and poly-4-vinylpyridine) incorporating uniformly dispersed silica colloids (up to 45% v/v). Factors known to contribute to premature breakdown-field exclusion and agglomeration-have been mitigated in this experiment to focus on what impact the polymer and polymer-nanoparticle interactions have on breakdown. Our findings indicate that adding colloidal silica to higher breakdown strength amorphous polymers (polymethyl methacrylate and polyimide) causes a reduction in dielectric strength as compared to the neat polymer. Alternatively, low breakdown strength amorphous polymers (poly-4-vinylpyridine and especially polystyrene) with comparable silica dispersion show similar or even improved breakdown strength for 7.5-15% v/v silica. At ∼15% v/v or greater silica content, all the polymer NC films exhibit breakdown at similar electric fields, implying that at these loadings failure becomes independent of polymer matrix and is dominated by silica.

  3. Magnetoimpedance of cobalt-based amorphous ribbons/polymer composites

    Energy Technology Data Exchange (ETDEWEB)

    Semirov, A.V., E-mail: semirov@mail.ru [Irkutsk State University, Irkutsk (Russian Federation); Derevyanko, M.S.; Bukreev, D.A.; Moiseev, A.A.; Kudryavtsev, V.O. [Irkutsk State University, Irkutsk (Russian Federation); Safronov, A.P. [Ural Federal University, Yekaterinburg (Russian Federation)

    2016-10-01

    The combined influence of the temperature, the elastic tensile stress and the external magnetic field on the total impedance and impedance components were studied for rapidly quenched amorphous Co{sub 75}Fe{sub 5}Si{sub 4}B{sub 16} ribbons. Both as-cast amorphous ribbons and Co{sub 75}Fe{sub 5}Si{sub 4}B{sub 16}/polymer amorphous ribbon based composites were considered. Following polymer coverings were studied: modified rubber solution in o-xylene, solution of butyl methacrylate and methacrylic acid copolymer in isopropanol and solution of polymethylphenylsiloxane resin in toluene. All selected composites showed very good adhesion of the coverings and allowed to provide temperature measurements from 163 K up to 383 K under the applied deforming tensile force up to 30 N. The dependence of the modulus of the impedance and its components on the external magnetic field was influenced by the elastic tensile stresses and was affected by the temperature of the samples. It was shown that maximal sensitivity of the impedance and its components to the external magnetic field was observed at minimal temperature and maximal deforming force depended on the frequency of an alternating current. - Highlights: • Impedance and its components of amorphous Co{sub 75}Fe{sub 5}Si{sub 4}B{sub 16} ribbons were studied. • MI sensitivity to the magnetic field depends on a temperature and a deforming force. • Polymer covering can affect the functional properties of the composite.

  4. Microstructure of Matrix in UHTC Composites

    Science.gov (United States)

    Johnson, Sylvia; Stackpoole, Margaret; Gusman, Michael I.; Chavez-Garia Jose; Doxtad, Evan

    2011-01-01

    Approaches to controlling the microstructure of Ultra High Temperature Ceramics (UHTCs) are described.. One matrix material has been infiltrated into carbon weaves to make composite materials. The microstructure of these composites is described.

  5. Kinetic Monte Carlo simulation of growth of Ge quantum dot multilayers with amorphous matrix

    Energy Technology Data Exchange (ETDEWEB)

    Endres, Jan, E-mail: endres.jan@gmail.com; Holý, Václav; Daniš, Stanislav [Charles University, Faculty of Mathematics and Physics (Czech Republic); Buljan, Maja [Ruđer Bošković Institute (Croatia)

    2017-04-15

    Kinetic Monte Carlo method is used to simulate the growth of germanium quantum dot multilayers with amorphous matrix. We modified a model for self-assembled growth of quantum dots in crystalline matrix for the case of the amorphous one. The surface morphology given as hills above the buried dots is the main driving force for the ordering of the quantum dots. In the simulations, we observed a short-range self-ordering in the lateral direction. The ordering in lateral and vertical direction depends strongly on the surface morphology, mostly on the strength how the deposited material replicates previous surfaces.

  6. Experimental and modelling studies of the shape memory properties of amorphous polymer network composites

    International Nuclear Information System (INIS)

    Arrieta, J S; Diani, J; Gilormini, P

    2014-01-01

    Shape memory polymer composites (SMPCs) have become an important way to leverage improvements in the development of applications featuring shape memory polymers (SMPs). In this study, an amorphous SMP matrix has been filled with different types of reinforcements. An experimental set of results is presented and then compared to three-dimensional (3D) finite-element simulations. Thermomechanical shape memory cycles were performed in uniaxial tension. The fillers effect was studied in stress-free and constrained-strain recoveries. Experimental observations indicate complete shape recovery and put in evidence the increased sensitivity of constrained length stress recoveries to the heating ramp on the tested composites. The simulations reproduced a simplified periodic reinforced composite and used a model for the matrix material that has been previously tested on regular SMPs. The latter combines viscoelasticity at finite strain and time-temperature superposition. The simulations easily allow representation of the recovery properties of a reinforced SMP. (paper)

  7. Multiscale Modeling of Ceramic Matrix Composites

    Science.gov (United States)

    Bednarcyk, Brett A.; Mital, Subodh K.; Pineda, Evan J.; Arnold, Steven M.

    2015-01-01

    Results of multiscale modeling simulations of the nonlinear response of SiC/SiC ceramic matrix composites are reported, wherein the microstructure of the ceramic matrix is captured. This micro scale architecture, which contains free Si material as well as the SiC ceramic, is responsible for residual stresses that play an important role in the subsequent thermo-mechanical behavior of the SiC/SiC composite. Using the novel Multiscale Generalized Method of Cells recursive micromechanics theory, the microstructure of the matrix, as well as the microstructure of the composite (fiber and matrix) can be captured.

  8. Suspension plasma sprayed composite coating using amorphous powder feedstock

    International Nuclear Information System (INIS)

    Chen Dianying; Jordan, Eric H.; Gell, Maurice

    2009-01-01

    Al 2 O 3 -ZrO 2 composite coatings were deposited by the suspension plasma spray process using molecularly mixed amorphous powders. X-ray diffraction (XRD) analysis shows that the as-sprayed coating is composed of α-Al 2 O 3 and tetragonal ZrO 2 phases with grain sizes of 26 nm and 18 nm, respectively. The as-sprayed coating has 93% density with a hardness of 9.9 GPa. Heat treatment of the as-sprayed coating reveals that the Al 2 O 3 and ZrO 2 phases are homogeneously distributed in the composite coating

  9. Celsian Glass-Ceramic Matrix Composites

    Science.gov (United States)

    Bansal, Narottam P.; Dicarlo, James A.

    1996-01-01

    Glass-ceramic matrix reinforced fiber composite materials developed for use in low dielectric applications, such as radomes. Materials strong and tough, exhibit low dielectric properties, and endure high temperatures.

  10. Silver Matrix Composites - Structure and Properties

    Directory of Open Access Journals (Sweden)

    Wieczorek J.

    2016-03-01

    Full Text Available Phase compositions of composite materials determine their performance as well as physical and mechanical properties. Depending on the type of applied matrix and the kind, amount and morphology of the matrix reinforcement, it is possible to shape the material properties so that they meet specific operational requirements. In the paper, results of investigations on silver alloy matrix composites reinforced with ceramic particles are presented. The investigations enabled evaluation of hardness, tribological and mechanical properties as well as the structure of produced materials. The matrix of composite material was an alloy of silver and aluminium, magnesium and silicon. As the reinforcing phase, 20-60 μm ceramic particles (SiC, SiO2, Al2O3 and Cs were applied. The volume fraction of the reinforcing phase in the composites was 10%. The composites were produced using the liquid phase (casting technology, followed by plastic work (the KOBO method. The mechanical and tribological properties were analysed for plastic work-subjected composites. The mechanical properties were assessed based on a static tensile and hardness tests. The tribological properties were investigated under dry sliding conditions. The analysis of results led to determination of effects of the composite production technology on their performance. Moreover, a relationship between the type of reinforcing phase and the mechanical and tribological properties was established.

  11. COMPOSITION OF FOWLPOX VIRUS AND INCLUSION MATRIX.

    Science.gov (United States)

    RANDALL, C C; GAFFORD, L G; DARLINGTON, R W; HYDE, J

    1964-04-01

    Randall, Charles C. (University of Mississippi School of Medicine, Jackson), Lanelle G. Gafford, Robert W. Darlington, and James M. Hyde. Composition of fowlpox virus and inclusion matrix. J. Bacteriol. 87:939-944. 1964.-Inclusion bodies of fowlpox virus infection are especially favorable starting material for the isolation of virus and inclusion matrix. Electron micrographs of viral particles and matrix indicated a high degree of purification. Density-gradient centrifugation of virus in cesium chloride and potassium tartrate was unsatisfactory because of inactivation, and clumping or disintegration. Chemical analyses of virus and matrix revealed significant amounts of lipid, protein, and deoxyribonucleic acid, but no ribonucleic acid or carbohydrate. Approximately 47% of the weight of the virus and 83% of the matrix were extractable in chloroform-methanol. The lipid partitions of the petroleum ether extracts were similar, except that the phospholipid content of the matrix was 2.2 times that of the virus. Viral particles were sensitive to diethyl ether and chloroform.

  12. Nanophosphor composite scintillators comprising a polymer matrix

    Science.gov (United States)

    Muenchausen, Ross Edward; Mckigney, Edward Allen; Gilbertson, Robert David

    2010-11-16

    An improved nanophosphor composite comprises surface modified nanophosphor particles in a solid matrix. The nanophosphor particle surface is modified with an organic ligand, or by covalently bonding a polymeric or polymeric precursor material. The surface modified nanophosphor particle is essentially charge neutral, thereby preventing agglomeration of the nanophosphor particles during formation of the composite material. The improved nanophosphor composite may be used in any conventional scintillator application, including in a radiation detector.

  13. Crystalline and Amorphous Phosphorus – Carbon Nanotube Composites as Promising Anodes for Lithium-Ion Batteries

    KAUST Repository

    Smajic, Jasmin

    2016-05-04

    Battery research has been going full steam and with that the search for alternative anodes. Among many proposed electrode materials, little attention has been given to phosphorus. Phosphorus boasts the third highest gravimetric charge capacity and the highest volumetric charge capacity of all elements. Because of that, it would be an attractive battery anode material were it not for its poor cyclability with significant capacity loss immediately after the first cycle. This is known to be the consequence of considerable volume changes of phosphorus during charge/discharge cycles. In this work, we propose circumventing this issue by mixing amorphous red phosphorus with carbon nanotubes. By employing a non-destructive sublimation-deposition method, we have synthesized composites where the synergetic effect between phosphorus and carbon nanotubes allow for an improvement in the electrochemical performance of battery anodes. In fact, it has been shown that carbon nanotubes can act as an effective buffer to phosphorus volumetric expansions and contractions during charging and discharging of the half-cells [1]. By modifying the synthesis parameters, we have also been able to change the degree of crystallinity of the phosphorus matrix in the composites. In fact, the less common phase of red phosphorus, named fibrous phosphorus, was obtained, and that explains some of the varying electrochemical performances observed in the composites. Overall, it is found that a higher surface area of amorphous phosphorus allows for a better anode material when using single-walled carbon nanotubes as fillers.

  14. Piezoelectric ceramic-reinforced metal matrix composites

    OpenAIRE

    2004-01-01

    Composite materials comprising piezoelectric ceramic particulates dispersed in a metal matrix are capable of vibration damping. When the piezoelectric ceramic particulates are subjected to strain, such as the strain experienced during vibration of the material, they generate an electrical voltage that is converted into Joule heat in the surrounding metal matrix, thereby dissipating the vibrational energy. The piezoelectric ceramic particulates may also act as reinforcements to improve the mec...

  15. Solidification processing of monotectic alloy matrix composites

    Science.gov (United States)

    Frier, Nancy L.; Shiohara, Yuh; Russell, Kenneth C.

    1989-01-01

    Directionally solidified aluminum-indium alloys of the monotectic composition were found to form an in situ rod composite which obeys a lambda exp 2 R = constant relation. The experimental data shows good agreement with previously reported results. A theoretical boundary between cellular and dendritic growth conditions was derived and compared with experiments. The unique wetting characteristics of the monotectic alloys can be utilized to tailor the interface structure in metal matrix composites. Metal matrix composites with monotectic and hypermonotectic Al-In matrices were made by pressure infiltration, remelted and directionally solidified to observe the wetting characteristics of the alloys as well as the effect on structure of solidification in the constrained field of the fiber interstices. Models for monotectic growth are modified to take into account solidification in these constrained fields.

  16. Processable polyimide adhesive and matrix composite resin

    Science.gov (United States)

    Pratt, J. Richard (Inventor); St.clair, Terry L. (Inventor); Progar, Donald J. (Inventor)

    1990-01-01

    A high temperature polyimide composition prepared by reacting 4,4'-isophthaloyldiphthalic anhydride with metaphenylenediamine is employed to prepare matrix resins, adhesives, films, coatings, moldings, and laminates, especially those showing enhanced flow with retention of mechanical and adhesive properties. It can be used in the aerospace industry, for example, in joining metals to metals or metals to composite structures. One area of application is in the manufacture of lighter and stronger aircraft and spacecraft structures.

  17. Corrosion of Graphite Aluminum Metal Matrix Composites

    Science.gov (United States)

    1991-02-01

    cathodic protection of G/AI MMCs resulted in overprotection 13. Overprotection resulted from a local increase in pH near cathodic sites during...34Cathodic Overprotection of SiC/6061-T6 and G/6061- T6 Aluminum Alloy Metal Matrix Composites," Scripta Metallurgica, 22 (1988) 413-418. 14. R

  18. Ceramic matrix composites by microwave assisted CVI

    International Nuclear Information System (INIS)

    Currier, R.P.; Devlin, D.J.

    1993-01-01

    Chemical vapor infiltration (CVI) processes for producing continuously reinforced ceramic composites are reviewed. Potential advantages of microwave assisted CVI are noted and numerical studies of microwave assisted CVI are reviewed. The models predict inverted thermal gradients in fibrous ceramic preforms subjected to microwave radiation and suggest processing strategies for achieving uniformly dense composites. Comparisons are made to experimental results on silicon-based composite systems. The role played by the relative ability of fiber and matrix to dissipate microwave energy is noted. Results suggest that microwave induced inverted gradients can be exploited to promote inside-out densification. 10 refs., 2 figs

  19. Thermal stress effects in intermetallic matrix composites

    Science.gov (United States)

    Wright, P. K.; Sensmeier, M. D.; Kupperman, D. S.; Wadley, H. N. G.

    1993-01-01

    Intermetallic matrix composites develop residual stresses from the large thermal expansion mismatch (delta-alpha) between the fibers and matrix. This work was undertaken to: establish improved techniques to measure these thermal stresses in IMC's; determine residual stresses in a variety of IMC systems by experiments and modeling; and, determine the effect of residual stresses on selected mechanical properties of an IMC. X ray diffraction (XRD), neutron diffraction (ND), synchrotron XRD (SXRD), and ultrasonics (US) techniques for measuring thermal stresses in IMC were examined and ND was selected as the most promising technique. ND was demonstrated on a variety of IMC systems encompassing Ti- and Ni-base matrices, SiC, W, and Al2O3 fibers, and different fiber fractions (Vf). Experimental results on these systems agreed with predictions of a concentric cylinder model. In SiC/Ti-base systems, little yielding was found and stresses were controlled primarily by delta-alpha and Vf. In Ni-base matrix systems, yield strength of the matrix and Vf controlled stress levels. The longitudinal residual stresses in SCS-6/Ti-24Al-llNb composite were modified by thermomechanical processing. Increasing residual stress decreased ultimate tensile strength in agreement with model predictions. Fiber pushout strength showed an unexpected inverse correlation with residual stress. In-plane shear yield strength showed no dependence on residual stress. Higher levels of residual tension led to higher fatigue crack growth rates, as suggested by matrix mean stress effects.

  20. Hybrid Ceramic Matrix Fibrous Composites: an Overview

    Science.gov (United States)

    Naslain, R.

    2011-10-01

    Ceramic-Matrix Composites (CMCs) consist of a ceramic fiber architecture in a ceramic matrix, bonded together through a thin interphase. The present contribution is limited to non-oxide CMCs. Their constituents being oxidation-prone, they are protected by external coatings. We state here that CMCs display a hybrid feature, when at least one of their components is not homogeneous from a chemical or microstructural standpoint. Hybrid fiber architectures are used to tailor the mechanical or thermal CMC-properties whereas hybrid interphases, matrices and coatings to improve CMC resistance to aggressive environments.

  1. Hybrid Ceramic Matrix Fibrous Composites: an Overview

    International Nuclear Information System (INIS)

    Naslain, R

    2011-01-01

    Ceramic-Matrix Composites (CMCs) consist of a ceramic fiber architecture in a ceramic matrix, bonded together through a thin interphase. The present contribution is limited to non-oxide CMCs. Their constituents being oxidation-prone, they are protected by external coatings. We state here that CMCs display a hybrid feature, when at least one of their components is not homogeneous from a chemical or microstructural standpoint. Hybrid fiber architectures are used to tailor the mechanical or thermal CMC-properties whereas hybrid interphases, matrices and coatings to improve CMC resistance to aggressive environments.

  2. Ceramic Matrix Composite (CMC) Materials Characterization

    Science.gov (United States)

    Calomino, Anthony

    2001-01-01

    Under the former NASA EPM Program, much initial progress was made in identifying constituent materials and processes for SiC/SiC ceramic composite hot-section components. This presentation discusses the performance benefits of these approaches and elaborates on further constituent and property improvements made under NASA UEET. These include specific treatments at NASA that significantly improve the creep and environmental resistance of the Sylramic(TM) SiC fiber as well as the thermal conductivity and creep resistance of the CVI Sic matrix. Also discussed are recent findings concerning the beneficial effects of certain 2D-fabric architectures and carbon between the BN interphase coating and Sic matrix.

  3. Ceramic Matrix Composite (CMC) Materials Development

    Science.gov (United States)

    DiCarlo, James

    2001-01-01

    Under the former NASA EPM Program, much initial progress was made in identifying constituent materials and processes for SiC/SiC ceramic composite hot-section components. This presentation discusses the performance benefits of these approaches and elaborates on further constituent and property improvements made under NASA UEET. These include specific treatments at NASA that significantly improve the creep and environmental resistance of the Sylramic(TM) Sic fiber as well as the thermal conductivity and creep resistance of the CVI Sic matrix. Also discussed are recent findings concerning the beneficial effects of certain 2D-fabric architectures and carbon between the BN interphase coating and Sic matrix.

  4. Influence of in situ synthesized TiC on thermal stability and corrosion behavior of Zr60Cu10Al15Ni15 amorphous composites

    International Nuclear Information System (INIS)

    Geng, Jiwei; Teng, Xinying; Zhou, Guorong; Leng, Jinfeng; Zhao, Degang

    2014-01-01

    In situ synthesized TiC particles were prepared by a thermal explosion method. Adding “in situ synthesized” TiC into Zr 60 Cu 10 Al 15 Ni 15 glass matrix to obtain amorphous matrix composites was achieved. The corrosion behavior of Zr 60 Cu 10 Al 15 Ni 15 amorphous composites was evaluated using potentiodynamic polarization measurements in 3.5 wt% NaCl solution at room temperature. The results show that the microhardness and thermal stability are improved apparently, while the TiC (≤0.6 wt%) does not significantly affect the supercooled liquid behavior. Moreover, the corrosion resistance is improved apparently because the nanocrystals accelerate the diffusion of passive elements for faster formation of the protective passive film at nanocrystals/amorphous interfaces. However, when the TiC content is more than 0.6 wt%, both glass forming ability and corrosion resistance are reduced significantly

  5. Ferroelastic ceramic-reinforced metal matrix composites

    OpenAIRE

    2006-01-01

    Composite materials comprising ferroelastic ceramic particulates dispersed in a metal matrix are capable of vibration damping. When the ferroelastic ceramic particulates are subjected to stress, such as the cyclic stress experienced during vibration of the material, internal stresses in the ceramic cause the material to deform via twinning, domain rotation or domain motion thereby dissipating the vibrational energy. The ferroelastic ceramic particulates may also act as reinforcements to impro...

  6. Composites having an intermetallic containing matrix

    International Nuclear Information System (INIS)

    Nagle, D.C.; Brupbacher, J.M.; Christodoulou, L.

    1990-01-01

    This paper describes a composite material. It comprises: a dispersion of in-situ precipitated second phase particles selected from the group consisting of borides, carbides, nitrides, and sulfides, in an intermetallic containing matrix selected from the group consisting of the aluminides, silicides, and beryllides of nickel, copper, titanium, cobalt, iron, platinum, gold, silver, niobium, tantalum, zinc, molybdenum, hafnium, tin, tungsten, lithium, magnesium, thorium, chromium, vanadium, zirconium, and manganese

  7. Creep of plain weave polymer matrix composites

    Science.gov (United States)

    Gupta, Abhishek

    Polymer matrix composites are increasingly used in various industrial sectors to reduce structural weight and improve performance. Woven (also known as textile) composites are one class of polymer matrix composites with increasing market share mostly due to their lightweight, their flexibility to form into desired shape, their mechanical properties and toughness. Due to the viscoelasticity of the polymer matrix, time-dependent degradation in modulus (creep) and strength (creep rupture) are two of the major mechanical properties required by engineers to design a structure reliably when using these materials. Unfortunately, creep and creep rupture of woven composites have received little attention by the research community and thus, there is a dire need to generate additional knowledge and prediction models, given the increasing market share of woven composites in load bearing structural applications. Currently, available creep models are limited in scope and have not been validated for any loading orientation and time period beyond the experimental time window. In this thesis, an analytical creep model, namely the Modified Equivalent Laminate Model (MELM), was developed to predict tensile creep of plain weave composites for any orientation of the load with respect to the orientation of the fill and warp fibers, using creep of unidirectional composites. The ability of the model to predict creep for any orientation of the load is a "first" in this area. The model was validated using an extensive experimental involving the tensile creep of plain weave composites under varying loading orientation and service conditions. Plain weave epoxy (F263)/ carbon fiber (T300) composite, currently used in aerospace applications, was procured as fabrics from Hexcel Corporation. Creep tests were conducted under two loading conditions: on-axis loading (0°) and off-axis loading (45°). Constant load creep, in the temperature range of 80-240°C and stress range of 1-70% UTS of the

  8. Dielectric Cure Monitoring of Thermosetting Matrix Composites

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyoung Geun [Agency for Defense Development, Daejeon (Korea, Republic of); Lee, Dae Gil [KAIST, Daejeon (Korea, Republic of)

    2003-10-15

    Cure monitoring can be used to improve the quality and productivity of thermosetting resin matrix composite products during their manufacturing process. In this work, the sensitivity of dielectrometry was improved by adequate separation the efforts of sensor and externals on the measured signal. A new algorithm to obtain the degree of cure during dielectric cure monitoring of glass/polyester and glass/epoxy composites was developed by employing a function of both temperature and dissipation factor, in which five cure monitoring parameters were used to calculate the degree of cure. The decreasing pattern of dissipation factor was compared with the relationships between the degree of cure and the resin viscosity. The developed algorithm might be employed for the in situ cure monitoring of thermosetting resin composites

  9. Dielectric Cure Monitoring of Thermosetting Matrix Composites

    International Nuclear Information System (INIS)

    Kim, Hyoung Geun; Lee, Dae Gil

    2003-01-01

    Cure monitoring can be used to improve the quality and productivity of thermosetting resin matrix composite products during their manufacturing process. In this work, the sensitivity of dielectrometry was improved by adequate separation the efforts of sensor and externals on the measured signal. A new algorithm to obtain the degree of cure during dielectric cure monitoring of glass/polyester and glass/epoxy composites was developed by employing a function of both temperature and dissipation factor, in which five cure monitoring parameters were used to calculate the degree of cure. The decreasing pattern of dissipation factor was compared with the relationships between the degree of cure and the resin viscosity. The developed algorithm might be employed for the in situ cure monitoring of thermosetting resin composites

  10. In-situ ductile metal/bulk metallic glass matrix composites formed by chemical partitioning

    Science.gov (United States)

    Kim, Choong Paul; Hays, Charles C.; Johnson, William L.

    2004-03-23

    A composite metal object comprises ductile crystalline metal particles in an amorphous metal matrix. An alloy is heated above its liquidus temperature. Upon cooling from the high temperature melt, the alloy chemically partitions, forming dendrites in the melt. Upon cooling the remaining liquid below the glass transition temperature it freezes to the amorphous state, producing a two-phase microstructure containing crystalline particles in an amorphous metal matrix. The ductile metal particles have a size in the range of from 0.1 to 15 micrometers and spacing in the range of from 0.1 to 20 micrometers. Preferably, the particle size is in the range of from 0.5 to 8 micrometers and spacing is in the range of from 1 to 10 micrometers. The volume proportion of particles is in the range of from 5 to 50% and preferably 15 to 35%. Differential cooling can produce oriented dendrites of ductile metal phase in an amorphous matrix. Examples are given in the Zr--Ti--Cu--Ni--Be alloy bulk glass forming system with added niobium.

  11. Cooled Ceramic Matrix Composite Propulsion Structures Demonstrated

    Science.gov (United States)

    Jaskowiak, Martha H.; Dickens, Kevin W.

    2005-01-01

    NASA's Next Generation Launch Technology (NGLT) Program has successfully demonstrated cooled ceramic matrix composite (CMC) technology in a scramjet engine test. This demonstration represented the world s largest cooled nonmetallic matrix composite panel fabricated for a scramjet engine and the first cooled nonmetallic composite to be tested in a scramjet facility. Lightweight, high-temperature, actively cooled structures have been identified as a key technology for enabling reliable and low-cost space access. Tradeoff studies have shown this to be the case for a variety of launch platforms, including rockets and hypersonic cruise vehicles. Actively cooled carbon and CMC structures may meet high-performance goals at significantly lower weight, while improving safety by operating with a higher margin between the design temperature and material upper-use temperature. Studies have shown that using actively cooled CMCs can reduce the weight of the cooled flow-path component from 4.5 to 1.6 lb/sq ft and the weight of the propulsion system s cooled surface area by more than 50 percent. This weight savings enables advanced concepts, increased payload, and increased range. The ability of the cooled CMC flow-path components to operate over 1000 F hotter than the state-of-the-art metallic concept adds system design flexibility to space-access vehicle concepts. Other potential system-level benefits include smaller fuel pumps, lower part count, lower cost, and increased operating margin.

  12. Fracture behaviour of brittle (glass) matrix composites

    Czech Academy of Sciences Publication Activity Database

    Dlouhý, Ivo; Chlup, Zdeněk; Boccaccini, A. R.

    2005-01-01

    Roč. 482, - (2005), s. 115-122 ISSN 0255-5476. [International Conference on Materials Structure and Micromechanics of Fracture /4./. Brno, 23.06.2004-25.06.2004] R&D Projects: GA AV ČR(CZ) IAA2041003; GA ČR(CZ) GA101/02/0683 Institutional research plan: CEZ:AV0Z2041904 Keywords : Ceramic matrix composites * fracture toughness * toughening effects Subject RIV: JH - Ceramic s, Fire-Resistant Materials and Glass Impact factor: 0.399, year: 2005

  13. Magnetic properties of Mn-oxide nanoparticles dispersed in an amorphous SiO2 matrix

    Science.gov (United States)

    Milivojević, D.; Babić-Stojić, B.; Jokanović, V.; Jagličić, Z.; Makovec, D.

    2011-03-01

    Samples of Mn-oxide nanoparticles dispersed in an amorphous SiO2 matrix with manganese concentration 0.7 and 3 at% have been synthesized by a sol-gel method. Transmission electron microscopy analysis has shown that the samples contain agglomerates of amorphous silica particles 10-20 nm in size. In silica matrix two types of Mn-rich particles are dispersed, smaller nanoparticles with dimensions between 3 and 10 nm, and larger crystalline areas consisting of aggregates of the smaller nanoparticles. High-temperature magnetic susceptibility study reveals that dominant magnetic phase at higher temperatures is λ-MnO2. At temperatures below TC=43 K strong ferrimagnetism originating from the minor Mn3O4 phase masks the relatively weak magnetism of λ-MnO2 with antiferromagnetic interactions. Magnetic field dependence of the maximum in the zero-field-cooled magnetization for both the samples in the vicinity of 40 K, and a frequency shift of the real component of the ac magnetic susceptibility in the sample with 3 at% Mn suggest that the magnetic moments of the smaller Mn3O4 nanoparticles with dimensions below 10 nm are exposed to thermally activated blocking process just below the Curie temperature TC. Appearance of a maximum in the zero-field-cooled magnetization for both the samples below 10 K indicates possible spin glass freezing of the magnetic moments at low temperatures which might occur in the geometrically frustrated Mn sublattice of the λ-MnO2 crystal structure.

  14. Encapsulated Vanadium-Based Hybrids in Amorphous N-Doped Carbon Matrix as Anode Materials for Lithium-Ion Batteries.

    Science.gov (United States)

    Long, Bei; Balogun, Muhammad-Sadeeq; Luo, Lei; Luo, Yang; Qiu, Weitao; Song, Shuqin; Zhang, Lei; Tong, Yexiang

    2017-11-01

    Recently, researchers have made significant advancement in employing transition metal compound hybrids as anode material for lithium-ion batteries and developing simple preparation of these hybrids. To this end, this study reports a facile and scalable method for fabricating a vanadium oxide-nitride composite encapsulated in amorphous carbon matrix by simply mixing ammonium metavanadate and melamine as anode materials for lithium-ion batteries. By tuning the annealing temperature of the mixture, different hybrids of vanadium oxide-nitride compounds are synthesized. The electrode material prepared at 700 °C, i.e., VM-700, exhibits excellent cyclic stability retaining 92% of its reversible capacity after 200 cycles at a current density of 0.5 A g -1 and attractive rate performance (220 mAh g -1 ) under the current density of up to 2 A g -1 . The outstanding electrochemical properties can be attributed to the synergistic effect from heterojunction form by the vanadium compound hybrids, the improved ability of the excellent conductive carbon for electron transfer, and restraining the expansion and aggregation of vanadium oxide-nitride in cycling. These interesting findings will provide a reference for the preparation of transition metal oxide and nitride composites as well. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Miedema model based methodology to predict amorphous-forming-composition range in binary and ternary systems

    Energy Technology Data Exchange (ETDEWEB)

    Das, N., E-mail: nirupamd@barc.gov.in [Materials Science Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Mittra, J. [Materials Science Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Murty, B.S. [Department of Metallurgical and Materials Engineering, IIT Madras, Chennai 600 036 (India); Pabi, S.K. [Department of Metallurgical and Materials Engineering, IIT Kharagpur, Kharagpur 721 302 (India); Kulkarni, U.D.; Dey, G.K. [Materials Science Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2013-02-15

    Highlights: Black-Right-Pointing-Pointer A methodology was proposed to predict amorphous forming compositions (AFCs). Black-Right-Pointing-Pointer Chemical contribution to enthalpy of mixing {proportional_to} enthalpy of amorphous for AFCs. Black-Right-Pointing-Pointer Accuracy in the prediction of AFC-range was noticed in Al-Ni-Ti system. Black-Right-Pointing-Pointer Mechanical alloying (MA) results of Al-Ni-Ti followed the predicted AFC-range. Black-Right-Pointing-Pointer Earlier MA results of Al-Ni-Ti also conformed to the predicted AFC-range. - Abstract: From the earlier works on the prediction of amorphous forming composition range (AFCR) using Miedema based model and also, on mechanical alloying experiments it has been observed that all amorphous forming compositions of a given alloy system falls within a linear band when the chemical contribution to enthalpy of the solid solution ({Delta}H{sup ss}) is plotted against the enthalpy of mixing in the amorphous phase ({Delta}H{sup amor}). On the basis of this observation, a methodology has been proposed in this article to identify the AFCR of a ternary system that is likely to be more precise than what can be obtained using {Delta}H{sup amor} - {Delta}H{sup ss} < 0 criterion. MA experiments on various compositions of Al-Ni-Ti system, producing amorphous, crystalline, and mixture of amorphous plus crystalline phases have been carried out and the phases have been characterized using X-ray diffraction and transmission electron microscopy techniques. Data from the present MA experiments and, also, from the literature have been used to validate the proposed approach. Also, the proximity of compositions, producing a mixture of amorphous and crystalline phases to the boundary of AFCR in the Al-Ni-Ti ternary has been found useful to validate the effectiveness of the prediction.

  16. Influence of Solvent Composition on the Performance of Spray-Dried Co-Amorphous Formulations

    Directory of Open Access Journals (Sweden)

    Jaya Mishra

    2018-04-01

    Full Text Available Ball-milling is usually used to prepare co-amorphous drug–amino acid (AA mixtures. In this study, co-amorphous drug–AA mixtures were produced using spray-drying, a scalable industrially preferred preparation method. The influence of the solvent type and solvent composition was investigated. Mixtures of indomethacin (IND and each of the three AAs arginine, histidine, and lysine were ball-milled and spray-dried at a 1:1 molar ratio, respectively. Spray-drying was performed at different solvent ratios in (a ethanol and water mixtures and (b acetone and water mixtures. Different ratios of these solvents were chosen to study the effect of solvent mixtures on co-amorphous formulation. Residual crystallinity, thermal properties, salt/partial salt formation, and powder dissolution profiles of the IND–AA mixtures were investigated and compared to pure crystalline and amorphous IND. It was found that using spray-drying as a preparation method, all IND–AA mixtures could be successfully converted into the respective co-amorphous forms, irrespective of the type of solvent used, but depending on the solvent mixture ratios. Both ball-milled and spray-dried co-amorphous samples showed an enhanced dissolution rate and maintained supersaturation compared to the crystalline and amorphous IND itself. The spray-dried samples resulting in co-amorphous samples were stable for at least seven months of storage.

  17. Finite size effects in a model for platicity of amorphous composites

    DEFF Research Database (Denmark)

    Tyukodi, Botond; Lemarchand, Claire A.; Hansen, Jesper Schmidt

    2016-01-01

    We discuss the plastic behavior of an amorphous matrix reinforced by hard particles. A mesoscopic depinning-like model accounting for Eshelby elastic interactions is implemented. Only the effect of a plastic disorder is considered. Numerical results show a complex size dependence of the effective...

  18. Fracture toughness in metal matrix composites

    Directory of Open Access Journals (Sweden)

    Perez Ipiña J.E.

    2000-01-01

    Full Text Available Evaluations of the fracture toughness in metal matrix composites (Duralcan reinforced with 15% of Al(20(3 and SiC are presented in this work. The application of Elastic Plastic Fracture Mechanics is discussed and the obtained values are compared with the ones obtained by means of Linear Elastic Fracture Mechanics. Results show that J IC derived K JC values are higher than the corresponding values obtained by direct application of the linear elastic methodology. The effect of a heat treatment on the material fracture toughness was also evaluated in which the analyzed approaches showed, not only different toughness values, but also opposite tendencies. A second comparison of the J IC and K JC values obtained in this work with toughness values reported in the literature is presented and discussed.

  19. Mechanical spectroscopy study on the Cu54Zr40Al6 amorphous matrix alloy at low temperature

    International Nuclear Information System (INIS)

    Marques, P.W.B.; Chaves, J.M.; Silva, P.S.; Florêncio, O.; Moreno-Gobbi, A.; Aliaga, L.C.R.; Botta, W.J.

    2015-01-01

    Highlights: • Cu 54 Zr 40 Al 6 alloy was characterized by mechanical spectroscopy at low temperature. • Flexural and ultrasonic methods showed peaks associated to rearrangement of clusters. • The peaks less stable were associated with annihilation of Zr or Cu clusters. • MHz range can be favors the formation of Cu an Al-centered icosahedral structures. • TEM images show an increase in the size and number of crystal in amorphous matrix. - Abstract: A mechanical spectroscopy study of Cu 54 Zr 40 Al 6 bulk metallic glasses composites was carried out in the kHz and MHz frequency ranges, by means of flexural and ultrasonic methods, respectively, in the temperature interval 150–300 K. In internal friction and attenuation curves at low temperature were observed peaks which were associated with distortions in the configuration of atomic clusters, which absorbed different quantities of energy due to short and medium order rearrangements. Changes within the clusters or atomic jumps between clusters occurring in the specimen induced the onset of polyamorphic peaks, since electronic interactions and bonding changed abruptly

  20. Synthesis and densification of Cu-coated Ni-based amorphous composite powders

    International Nuclear Information System (INIS)

    Kim, Yong-Jin; Kim, Byoung-Kee; Kim, Jin-Chun

    2007-01-01

    Spherical Ni 57 Zr 20 Ti 16 Si 2 Sn 3 (numbers indicate at.%) amorphous powders were produced by the gas atomization process, and ductile Cu phase was coated on the Ni-based amorphous powders by the spray drying process in order to increase the ductility of the consolidated amorphous alloy. The characteristics of the as-prepared powders and the consolidation behaviors of Cu-coated Ni-based amorphous composite powders were investigated. The atomization was conducted at 1450 deg. C under the vacuum of 10 -2 mbar. The Ni-based amorphous powders and Cu nitrate solution were mixed and sprayed at temperature of 130 deg. C. After spray drying and reduction treatment, the sub-micron size Cu powders were coated successfully on the surface of the atomized Ni amorphous powders. The spark plasma sintering process was applied to study the densification behavior of the Cu-coated composite powders. Thickness of the Cu layer was less than 1 μm. The compacts obtained by SPS showed high relative density of over 98% and its hardness was over 800 Hv

  1. Fine-Tuning of Polymeric Resins and their Interfaces with Amorphous Calcium Phosphate. A Strategy for Designing Effective Remineralizing Dental Composites

    Directory of Open Access Journals (Sweden)

    Drago Skrtic

    2010-09-01

    Full Text Available For over a decade our group has been designing, preparing and evaluating bioactive, remineralizing composites based on amorphous calcium phosphate (ACP fillers embedded in polymerized methacrylate resin matrices. In these studies a major focus has been on exploring structure-property relationships of the matrix phase of these composites on their anti-cariogenic potential. The main challenges were to gain a better understanding of polymer matrix/filler interfacial properties through controlling the surface properties of the fillers or through fine-tuning of the resin matrix. In this work, we describe the effect of chemical structure and composition of the resin matrices on some of the critical physicochemical properties of the copolymers and their ACP composites. Such structure-property studies are essential in formulating clinically effective products, and this knowledge base is likely to have strong impact on the future design of therapeutic materials, appropriate for mineral restoration in defective tooth structures.

  2. Influence of Solvent Composition on the Performance of Spray-Dried Co-Amorphous Formulations

    DEFF Research Database (Denmark)

    Mishra, Jaya; Rades, Thomas; Löbmann, Korbinian

    2018-01-01

    Ball-milling is usually used to prepare co-amorphous drug–amino acid (AA) mixtures. In this study, co-amorphous drug–AA mixtures were produced using spray-drying, a scalable industrially preferred preparation method. The influence of the solvent type and solvent composition was investigated....... Mixtures of indomethacin (IND) and each of the three AAs arginine, histidine, and lysine were ball-milled and spray-dried at a 1:1 molar ratio, respectively. Spray-drying was performed at different solvent ratios in (a) ethanol and water mixtures and (b) acetone and water mixtures. Different ratios...... that using spray-drying as a preparation method, all IND–AA mixtures could be successfully converted into the respective co-amorphous forms, irrespective of the type of solvent used, but depending on the solvent mixture ratios. Both ball-milled and spray-dried co-amorphous samples showed an enhanced...

  3. Method of forming a ceramic matrix composite and a ceramic matrix component

    Science.gov (United States)

    de Diego, Peter; Zhang, James

    2017-05-30

    A method of forming a ceramic matrix composite component includes providing a formed ceramic member having a cavity, filling at least a portion of the cavity with a ceramic foam. The ceramic foam is deposited on a barrier layer covering at least one internal passage of the cavity. The method includes processing the formed ceramic member and ceramic foam to obtain a ceramic matrix composite component. Also provided is a method of forming a ceramic matrix composite blade and a ceramic matrix composite component.

  4. Performance of dielectric nanocomposites: matrix-free, hairy nanoparticle assemblies and amorphous polymer-nanoparticle blends.

    Science.gov (United States)

    Grabowski, Christopher A; Koerner, Hilmar; Meth, Jeffrey S; Dang, Alei; Hui, Chin Ming; Matyjaszewski, Krzysztof; Bockstaller, Michael R; Durstock, Michael F; Vaia, Richard A

    2014-12-10

    Demands to increase the stored energy density of electrostatic capacitors have spurred the development of materials with enhanced dielectric breakdown, improved permittivity, and reduced dielectric loss. Polymer nanocomposites (PNCs), consisting of a blend of amorphous polymer and dielectric nanofillers, have been studied intensely to satisfy these goals; however, nanoparticle aggregates, field localization due to dielectric mismatch between particle and matrix, and the poorly understood role of interface compatibilization have challenged progress. To expand the understanding of the inter-relation between these factors and, thus, enable rational optimization of low and high contrast PNC dielectrics, we compare the dielectric performance of matrix-free hairy nanoparticle assemblies (aHNPs) to blended PNCs in the regime of low dielectric contrast to establish how morphology and interface impact energy storage and breakdown across different polymer matrices (polystyrene, PS, and poly(methyl methacrylate), PMMA) and nanoparticle loadings (0-50% (v/v) silica). The findings indicate that the route (aHNP versus blending) to well-dispersed morphology has, at most, a minor impact on breakdown strength trends with nanoparticle volume fraction; the only exception being at intermediate loadings of silica in PMMA (15% (v/v)). Conversely, aHNPs show substantial improvements in reducing dielectric loss and maintaining charge/discharge efficiency. For example, low-frequency dielectric loss (1 Hz-1 kHz) of PS and PMMA aHNP films was essentially unchanged up to a silica content of 50% (v/v), whereas traditional blends showed a monotonically increasing loss with silica loading. Similar benefits are seen via high-field polarization loop measurements where energy storage for ∼15% (v/v) silica loaded PMMA and PS aHNPs were 50% and 200% greater than respective comparable PNC blends. Overall, these findings on low dielectric contrast PNCs clearly point to the performance benefits of

  5. Compositions of corrosion-resistant Fe-based amorphous metals suitable for producing thermal spray coatings

    Science.gov (United States)

    Farmer, Joseph C; Wong, Frank M.G.; Haslam, Jeffery J; Ji, Xiaoyan; Day, Sumner D; Blue, Craig A; Rivard, John D.K.; Aprigliano, Louis F; Kohler, Leslie K; Bayles, Robert; Lemieux, Edward J; Yang, Nancy; Perepezko, John H; Kaufman, Larry; Heuer, Arthur; Lavernia, Enrique J

    2013-09-03

    A method of coating a surface comprising providing a source of amorphous metal that contains manganese (1 to 3 atomic %), yttrium (0.1 to 10 atomic %), and silicon (0.3 to 3.1 atomic %) in the range of composition given in parentheses; and that contains the following elements in the specified range of composition given in parentheses: chromium (15 to 20 atomic %), molybdenum (2 to 15 atomic %), tungsten (1 to 3 atomic %), boron (5 to 16 atomic %), carbon (3 to 16 atomic %), and the balance iron; and applying said amorphous metal to the surface by a spray.

  6. Development of novel Mg–Ni60Nb40 amorphous particle reinforced composites with enhanced hardness and compressive response

    International Nuclear Information System (INIS)

    Jayalakshmi, S.; Sahu, Shreyasi; Sankaranarayanan, S.; Gupta, Sujasha; Gupta, M.

    2014-01-01

    Development of amorphous alloy/glassy particle reinforced light metal composites is an emerging research field. In this investigation, we have synthesized and characterized Ni 60 Nb 40 amorphous alloy particle reinforced Mg-composites with varying volume fractions. Microwave-assisted two-directional rapid sintering technique followed by hot extrusion was used to produce these pure Mg-based composites. The structural and mechanical properties of the developed composites were investigated, and are discussed using structure–property relationship. Structural analysis indicated the retention of amorphous structure of the reinforcement in all the composites. It was found that the distribution of the reinforcement was strongly dependent on the volume fraction (V f ). The addition of Ni 60 Nb 40 amorphous alloy particles modified the preferred crystal orientation of Mg, as was observed from X-ray diffraction (XRD) analysis. The composites showed significant improvement in hardness (increment up to 120%) and compressive strength (∼85% increase at 5% V f ). Comparison of mechanical properties of the developed composites with those of conventional Mg-composites having ceramic/metallic reinforcements, highlight the effectiveness of using amorphous particles as promising reinforcement materials. - Highlights: • Novel Mg-composites reinforced with Ni 60 Nb 40 amorphous particles were developed . • Microwave sintering and hot extrusion were used to synthesize the composites. • Reinforcements retained the amorphous structure, and changed Mg-crystal orientation. • Composites showed significant enhancement in hardness and compressive properties. • Performance of developed composites are superior/competitive to conventional MMCs

  7. Metal Matrix Composite Solar Cell Metallization

    Directory of Open Access Journals (Sweden)

    Wilt David M.

    2017-01-01

    Full Text Available Advanced solar cells are moving to ever thinner formats in order to save mass and in some cases improve performance. As cells are thinned, the possibility that they may fracture or cleave due to mechanical stresses is increased. Fractures of the cell can degrade the overall device performance if the fracture propagates through the contact metallization, which frequently occurs. To address this problem, a novel semiconductor metallization system based on multi-walled carbon nanotube (CNT reinforcement, termed metal matrix composite (MMC metallization is under investigation. Electro-mechanical characterization of MMC films demonstrate their ability to provide electrical conductivity over >40 micron wide cracks in the underlying semiconductor, with the carbon nanotubes bridging the gap. In addition, these materials show a “self-healing” behaviour, electrically reconnecting at ~30 microns when strained past failure. Triple junction (TJ space cells with MMC metallization demonstrated no loss in Jsc after intentional fracture, whereas TJ cells with conventional metallization suffer up to 50% Jsc loss.

  8. Microstructure and property of Fe–Co–B–Si–C–Nb amorphous composite coating fabricated by laser cladding process

    International Nuclear Information System (INIS)

    Zhu, Y.Y.; Li, Z.G.; Li, R.F.; Li, M.; Daze, X.L.; Feng, K.; Wu, Y.X.

    2013-01-01

    Laser cladding of Fe 34 Co 34 B 20 Si 5 C 3 Nb 4 on a low carbon steel substrate was conducted using coaxial powder feeding method. Microstructure, phase and microhardness were investigated by scanning electronic microscopy, transmission electron microscopy, X-ray diffraction, electron probe micro-analysis and microhardness tester. Amorphous coating with NbC particles embedded in the matrix was formed. Differential scanning calorimetry curve showed that the glass transition temperature (T g ) and the onset crystallization temperature (T x ) were 799 K and 850 K, respectively. The supercooled liquid region (ΔT x = T x − T g ) was as large as 51 K, which implied the high thermal stability of the supercooled liquid against crystallization. Due to the NbC particles embedded in the amorphous matrix, the mean value of the microhardness of the coating prepared by laser cladding was higher than that of the bulk metallic glass formed by the copper mold casting method. The contribution of NbC particles to the total microhardness was theoretically estimated. The estimated hardness of the composite coating agreed well with the tested value.

  9. Thermal conductivity of microPCMs-filled epoxy matrix composites

    OpenAIRE

    Su, J.F.; Wang, X.Y; Huang, Z.; Zhao, Y.H.; Yuan, X.Y.

    2011-01-01

    Microencapsulated phase change materials (microPCMs) have been widely applied in solid matrix as thermal-storage or temperature-controlling functional composites. The thermal conductivity of these microPCMs/matrix composites is an important property need to be considered. In this study, a series of microPCMs have been fabricated using the in situ polymerization with various core/shell ratio and average diameter; the thermal conductivity of microPCMs/epoxy composites were investigated in detai...

  10. Graphene-Reinforced Metal and Polymer Matrix Composites

    Science.gov (United States)

    Kasar, Ashish K.; Xiong, Guoping; Menezes, Pradeep L.

    2018-06-01

    Composites have tremendous applicability due to their excellent capabilities. The performance of composites mainly depends on the reinforcing material applied. Graphene is successful as an efficient reinforcing material due to its versatile as well as superior properties. Even at very low content, graphene can dramatically improve the properties of polymer and metal matrix composites. This article reviews the fabrication followed by mechanical and tribological properties of metal and polymer matrix composites filled with different kinds of graphene, including single-layer, multilayer, and functionalized graphene. Results reported to date in literature indicate that functionalized graphene or graphene oxide-polymer composites are promising materials offering significantly improved strength and frictional properties. A similar trend of improved properties has been observed in case of graphene-metal matrix composites. However, achieving higher graphene loading with uniform dispersion in metal matrix composites remains a challenge. Although graphene-reinforced composites face some challenges, such as understanding the graphene-matrix interaction or fabrication techniques, graphene-reinforced polymer and metal matrix composites have great potential for application in various fields due to their outstanding properties.

  11. Infiltration processing of metal matrix composites using coated ceramic particulates

    Science.gov (United States)

    Leon-Patino, Carlos Alberto

    2001-07-01

    A new process was developed to fabricate particulate metal matrix composites (MMCs). The process involves three steps: (1) modifying the particulate surface by metal coating, (2) forming a particulate porous compact; and (3) introducing metal into the channel network by vacuum infiltration. MMCs with different reinforcements, volume fractions, and sizes can be produced by this technique. Powders of alumina and silicon carbide were successfully coated with nickel and copper in preparation for infiltration with molten aluminum. Electroless Ni and Cu deposition was used since it enhances the wettability of the reinforcements for composite fabrication. While Cu deposits were polycrystalline, traces of phosphorous co-deposited from the electroless bath gave an amorphous Ni-P coating. The effect of metal coating on wetting behavior was evaluated at 800°C on plain and metal-coated ceramic plates using a sessile drop technique. The metallic films eliminated the non-wetting behavior of the uncoated ceramics, leading to equilibrium contact angles in the order of 12° and below 58° for Ni and Cu coated ceramics, respectively. The spreading data indicated that local diffusion at the triple junction was the governing mechanism of the wetting process. Precipitation of intermetallic phases in the drop/ceramic interface delayed the formation of Al4C3. Infiltration with molten Al showed that the coated-particulates are suitable as reinforcing materials for fabricating MMCs, giving porosity-free components with a homogeneously distributed reinforcing phase. The coating promoted easy metal flow through the preform, compared to the non-infiltration behavior of the uncoated counterparts. Liquid state diffusion kinetics due to temperature dependent viscosity forces controlled the infiltration process. Microstructural analysis indicated the formation of intermetallic phases such as CuAl 2, in the case of Cu coating, and Ni2Al3 and NiAl 3 when Ni-coated powders were infiltrated. The

  12. Corrosion behavior and pitting susceptibility of in-situ Ti-based metallic glass matrix composites in 3.5 wt.% NaCl solutions

    Science.gov (United States)

    Xu, K. K.; Lan, A. D.; Yang, H. J.; Han, P. D.; Qiao, J. W.

    2017-11-01

    The Ti62Zr12V13Cu4Be9, Ti58Zr16V10Cu4Be12, Ti46Zr20V12Cu5Be17, and Ti40Zr24V12Cu5Be19 metallic glass matrix composites (MGMCs) were prepared by copper mould casting. The corrosion resistance and the pitting susceptibility of Ti-based MGMCs were tested on their cross-sectional areas in 3.5 wt.% NaCl solutions by potentiodynamic polarization measurements. The composites with lower Ti contents (Ti40Zr24V12Cu5Be19 and Ti46Zr20V12Cu5Be17) exhibit a low resistance to the chloride induced pitting and local corrosion. The preferential dissolution of amorphous matrix is explained by the high chemical reactivity of beryllium element compared to that of stable dendrites and by the detected lower Ti and V contents. However, fairly good passivity was found in the composite with higher Ti contents (Ti62Zr12V13Cu4Be9). XPS measurements revealed that protective Ti-enriched oxide film was formed on the composite surface, additionally, lower content of beryllium element in amorphous matrix hinder the selective corrosion of amorphous matrix. The assessment of experimental observation leads to a proposed corrosion mechanism involving selective dissolution of amorphous matrix and chloride induced pitting process.

  13. Preparation of magnesium metal matrix composites by powder metallurgy process

    Science.gov (United States)

    Satish, J.; Satish, K. G., Dr.

    2018-02-01

    Magnesium is the lightest metal used as the source for constructional alloys. Today Magnesium based metal matrix composites are widely used in aerospace, structural, oceanic and automobile applications for its light weight, low density(two thirds that of aluminium), good high temperature mechanical properties and good to excellent corrosion resistance. The reason of designing metal matrix composite is to put in the attractive attributes of metals and ceramics to the base metal. In this study magnesium metal matrix hybrid composite are developed by reinforcing pure magnesium with silicon carbide (SiC) and aluminium oxide by method of powder metallurgy. This method is less expensive and very efficient. The Hardness test was performed on the specimens prepared by powder metallurgy method. The results revealed that the micro hardness of composites was increased with the addition of silicon carbide and alumina particles in magnesium metal matrix composites.

  14. Synthesis of Fe-based amorphous composite coatings with low purity materials by laser cladding

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Qingjun [School of Materials Science and Engineering, Shandong University, Jinan 250061 (China)]. E-mail: sduzhu@yahoo.com.cn; Qu Shiyao [School of Materials Science and Engineering, Shandong University, Jinan 250061 (China); Wang Xinhong [School of Materials Science and Engineering, Shandong University, Jinan 250061 (China); Zou Zengda [School of Materials Science and Engineering, Shandong University, Jinan 250061 (China)

    2007-06-30

    Amorphous composite coatings Fe{sub 38}Ni{sub 30-X}Si{sub 16}B{sub 14}V{sub 2}M {sub X} (X = 0, 1, 2) (M contains Al, Ti, Mo, and C) were prepared with low purity of raw materials by laser cladding. X-ray diffraction and transmission electron microscopy results show that the coating have an amorphous structure with a few crystalline phase on it. The amorphous phase is the primary phase. The glass forming ability as well as the microhardness of the Fe-based alloy made from low purity raw materials can be much enhanced by adding small amount of multi-components. However, the elements addition has its optimal quantity. When X is equal to 1, the microstructure of the coating contains 97.93% amorphous phase and 2.07% crystalline phase on it. As a result, the microhardness of the coating reaches maximum. With further increasing of the additions, the amorphous phase in the coating lessens instead of augment and the crystalline phase begins to accumulate, which result in the decrease of the microhardness.

  15. Microstructural Characterization of Cast Magnesium Matrix Composites by Raman Microscopy

    Directory of Open Access Journals (Sweden)

    M.A. Malik

    2013-01-01

    Full Text Available Cast magnesium matrix composites reinforced with silicon carbide particles were investigated by using Raman microscopy. 3C, 4H and6H polytypes of SiC particles were identified in the investigated composites. Additionally, Mg2Si compound was detected by Ramanmicroscopy in the composites microstructure.

  16. Microstructural Characterization of Cast Magnesium Matrix Composites by Raman Microscopy

    OpenAIRE

    Malika M.A.; Majchrzak K.; Braszczyńska-Malik K.N.

    2013-01-01

    Cast magnesium matrix composites reinforced with silicon carbide particles were investigated by using Raman microscopy. 3C, 4H and 6H polytypes of SiC particles were identified in the investigated composites. Additionally, Mg2Si compound was detected by Raman microscopy in the composites microstructure.

  17. Microstructural Characterization of Cast Magnesium Matrix Composites by Raman Microscopy

    Directory of Open Access Journals (Sweden)

    Malika M.A.

    2013-03-01

    Full Text Available Cast magnesium matrix composites reinforced with silicon carbide particles were investigated by using Raman microscopy. 3C, 4H and 6H polytypes of SiC particles were identified in the investigated composites. Additionally, Mg2Si compound was detected by Raman microscopy in the composites microstructure.

  18. Nanophosphor composite scintillator with a liquid matrix

    Science.gov (United States)

    McKigney, Edward Allen; Burrell, Anthony Keiran; Bennett, Bryan L.; Cooke, David Wayne; Ott, Kevin Curtis; Bacrania, Minesh Kantilal; Del Sesto, Rico Emilio; Gilbertson, Robert David; Muenchausen, Ross Edward; McCleskey, Thomas Mark

    2010-03-16

    An improved nanophosphor scintillator liquid comprises nanophosphor particles in a liquid matrix. The nanophosphor particles are optionally surface modified with an organic ligand. The surface modified nanophosphor particle is essentially surface charge neutral, thereby preventing agglomeration of the nanophosphor particles during dispersion in a liquid scintillator matrix. The improved nanophosphor scintillator liquid may be used in any conventional liquid scintillator application, including in a radiation detector.

  19. Optical and vibrational properties of sulfur and selenium versus halogens in hydrogenated amorphous silicon matrix

    International Nuclear Information System (INIS)

    Al-Alawi, S.M.; Al-Dallal, S.

    1999-01-01

    The infrared spectra of a compositional variation series of alpha-Si,S:H; alpha-Si,Se:H, alpha-Si:Cl, H and alpha-Si:F,H thin films were deposited by r.f. glow discharge were compared. It was shown that S, Se, Cl and F can be bonded to the silicon matrix. The stretching mode bands at 2000 cm/sup -1/. and 2100 cm/sup -1/ in the infrared spectra of the above alloys shifts systematically to higher wave numbers when incorporated S,Se or halogen atoms are increases. This observation was attributed to the larger electronegativity of these atoms with respect to the host matrix. Optical transmission spectroscopy and photothermal deflection experiments reveal an increase in the band gap when the content of any of the above elements is increased. However, the highest band gap was obtained for sulfur alloys. This result was interpreted in terms of the S-Si bond strength as compared to other elements. It was found that alpha-Si, S:H was interpreted in terms of the S-Si alloys exhibit the highest structural stability among the four alloys for moderate amount of incorporated sulfur atoms. (author)

  20. Pseudomonas biofilm matrix composition and niche biology

    Science.gov (United States)

    Mann, Ethan E.; Wozniak, Daniel J.

    2014-01-01

    Biofilms are a predominant form of growth for bacteria in the environment and in the clinic. Critical for biofilm development are adherence, proliferation, and dispersion phases. Each of these stages includes reinforcement by, or modulation of, the extracellular matrix. Pseudomonas aeruginosa has been a model organism for the study of biofilm formation. Additionally, other Pseudomonas species utilize biofilm formation during plant colonization and environmental persistence. Pseudomonads produce several biofilm matrix molecules, including polysaccharides, nucleic acids, and proteins. Accessory matrix components shown to aid biofilm formation and adaptability under varying conditions are also produced by pseudomonads. Adaptation facilitated by biofilm formation allows for selection of genetic variants with unique and distinguishable colony morphology. Examples include rugose small-colony variants and wrinkly spreaders (WS), which over produce Psl/Pel or cellulose, respectively, and mucoid bacteria that over produce alginate. The well-documented emergence of these variants suggests that pseudomonads take advantage of matrix-building subpopulations conferring specific benefits for the entire population. This review will focus on various polysaccharides as well as additional Pseudomonas biofilm matrix components. Discussions will center on structure–function relationships, regulation, and the role of individual matrix molecules in niche biology. PMID:22212072

  1. Thermal and mechanical behavior of metal matrix and ceramic matrix composites

    Science.gov (United States)

    Kennedy, John M. (Editor); Moeller, Helen H. (Editor); Johnson, W. S. (Editor)

    1990-01-01

    The present conference discusses local stresses in metal-matrix composites (MMCs) subjected to thermal and mechanical loads, the computational simulation of high-temperature MMCs' cyclic behavior, an analysis of a ceramic-matrix composite (CMC) flexure specimen, and a plasticity analysis of fibrous composite laminates under thermomechanical loads. Also discussed are a comparison of methods for determining the fiber-matrix interface frictional stresses of CMCs, the monotonic and cyclic behavior of an SiC/calcium aluminosilicate CMC, the mechanical and thermal properties of an SiC particle-reinforced Al alloy MMC, the temperature-dependent tensile and shear response of a graphite-reinforced 6061 Al-alloy MMC, the fiber/matrix interface bonding strength of MMCs, and fatigue crack growth in an Al2O3 short fiber-reinforced Al-2Mg matrix MMC.

  2. Modern Nondestructive Test Methods for Army Ceramic Matrix Composites

    National Research Council Canada - National Science Library

    Strand, Douglas J

    2008-01-01

    .... Ceramic matrix composites (CMC) are potentially good high-temperature structural materials because of their low density, high elastic moduli, high strength, and for those with weak interfaces, surprisingly good damage tolerance...

  3. Diffraction measurements of residual stress in titanium matrix composites

    International Nuclear Information System (INIS)

    James, M.R.; Bourke, M.A.; Goldstone, J.A.; Lawson, A.C.

    1993-01-01

    Metal matrix composites develop residual strains after consolidation due to the thermal expansion mismatch between the reinforcement fiber and the matrix. X-ray and neutron diffraction measured values for the longitudinal residual stress in the matrix of four titanium MMCs are reported. For thick composites (> 6 plies) the surface stress measured by x-ray diffraction matches that determined by neutron diffraction and therefore represents the stress in the bulk region consisting of the fibers and matrix. For thin sheet composites, the surface values are lower than in the interior and increase as the outer rows of fibers are approached. While a rationale for the behavior in the thin sheet has yet to be developed, accounting for composite thickness is important when using x-ray measured values to validate analytic and finite element calculations of the residual stress state

  4. Exploration the extrudability of aluminum matrix composite (LM6/TIC ...

    African Journals Online (AJOL)

    Aluminum matrix composites (LM6/TiC) is a mix of excellent properties of aluminum ... ABAQUS/CAE software has been successfully employed for Modeling and ... Experimental results show that, many mechanical properties are improved and ...

  5. Transverse thermal expansion of carbon fiber/epoxy matrix composites

    Science.gov (United States)

    Helmer, J. F.; Diefendorf, R. J.

    1983-01-01

    Thermal expansion coefficients and moduli of elasticity have been determined experimentally for a series of epoxy-matrix composites reinforced with carbon and Kevlar fibers. It is found that in the transverse direction the difference between the properties of the fiber and the matrix is not as pronounced as in the longitudinal direction, where the composite properties are fiber-dominated. Therefore, the pattern of fiber packing tends to affect transverse composite properties. The transverse properties of the composites tested are examined from the standpoint of the concept of homogeneity defined as the variation of packing (or lack thereof) throughout a sample.

  6. Review on preparation techniques of particle reinforced metal matrix composites

    Directory of Open Access Journals (Sweden)

    HAO Bin

    2006-02-01

    Full Text Available This paper reviews the investigation status of the techniques for preparation of metal matrix composites and the research outcomes achieved recently. The mechanisms, characteristics, application ranges and levels of development of these preparation techniques are analyzed. The advantages and the disadvantages of each technique are synthetically evaluated. Lastly, the future directions of research and the prospects for the preparation techniques of metal matrix composites are forecasted.

  7. Uniaxial in-plane magnetization of iron nanolayers grown within an amorphous matrix

    Energy Technology Data Exchange (ETDEWEB)

    Ghafari, M., E-mail: mohammad.ghafari@kit.edu; Hahn, H. [Herbert Gleiter Institute of Nanoscience, Nanjing University of Science and Technology, Nanjing 210094 (China); Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Mattheis, R. [Leibniz Institute for Photonic Technology IPHT, Jena (Germany); McCord, J. [Institute for Materials Science, Kiel University Kiel, Kaiserstraße 2, 24143 Kiel (Germany); Brand, R. A. [Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Macedo, W. A. A. [Laboratório de Física Aplicada, Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), 31270-901 Belo Horizonte, MG (Brazil)

    2014-08-18

    Conversion electron Mössbauer spectroscopy is used to determine the magnetic ground state at zero magnetic field of four-monolayer thick amorphous iron layers as part of a CoFeB-Fe multilayer stack. By comparing the intensities of the magnetic hyperfine field, an easy in-plane axis of the amorphous embedded Fe layer is verified, which is collinear to the uniaxial anisotropy axis of the neighboring amorphous CoFeB. Despite the soft magnetic character of the Fe layers, external fields up to 4 T perpendicular to the film plane are insufficient to completely align the embedded Fe moments parallel to the magnetic field due to a local disorder of the magnetic moments of the Fe atoms.

  8. Reactive synthesis of NbAl3 matrix composites

    International Nuclear Information System (INIS)

    Lu, L.; Kim, Y.S.; Gokhale, A.B.; Abbaschian, R.

    1990-01-01

    NbAl 3 matrix composites were synthesized in-situ via reactive hot compaction (RHC) of elemental powders. It was found that the simultaneous application of pressure during synthesis was effective in attaining a near-theoretical density matrix at relatively low temperatures and pressures. Using this technique, two types of composites were produced: matrices containing a uniform dispersion of second phase particles (either Nb 3 Al or Nb 2 Al with an Nb core or Nb 2 Al) and matrices reinforced with coated or uncoated ductile Nb filaments. It was found that a limited amount of toughening is obtained using the first approach, while composites containing coated Nb filaments exhibited a significant increase in the ambient temperature fracture toughness. In this paper, various aspects of RHC processing of NbAl 3 matrix composites, the effect of initial stoichiometry and powder size on the microstructure, as well as the mechanical behavior of the composites are discussed

  9. Effect of matrix cracking and material uncertainty on composite plates

    International Nuclear Information System (INIS)

    Gayathri, P.; Umesh, K.; Ganguli, R.

    2010-01-01

    A laminated composite plate model based on first order shear deformation theory is implemented using the finite element method. Matrix cracks are introduced into the finite element model by considering changes in the A, B and D matrices of composites. The effects of different boundary conditions, laminate types and ply angles on the behavior of composite plates with matrix cracks are studied. Finally, the effect of material property uncertainty, which is important for composite material on the composite plate, is investigated using Monte Carlo simulations. Probabilistic estimates of damage detection reliability in composite plates are made for static and dynamic measurements. It is found that the effect of uncertainty must be considered for accurate damage detection in composite structures. The estimates of variance obtained for observable system properties due to uncertainty can be used for developing more robust damage detection algorithms.

  10. The Candida albicans Biofilm Matrix: Composition, Structure and Function.

    Science.gov (United States)

    Pierce, Christopher G; Vila, Taissa; Romo, Jesus A; Montelongo-Jauregui, Daniel; Wall, Gina; Ramasubramanian, Anand; Lopez-Ribot, Jose L

    2017-03-01

    A majority of infections caused by Candida albicans -the most frequent fungal pathogen-are associated with biofilm formation. A salient feature of C. albicans biofilms is the presence of the biofilm matrix. This matrix is composed of exopolymeric materials secreted by sessile cells within the biofilm, in which all classes of macromolecules are represented, and provides protection against environmental challenges. In this review, we summarize the knowledge accumulated during the last two decades on the composition, structure, and function of the C. albicans biofilm matrix. Knowledge of the matrix components, its structure, and function will help pave the way to novel strategies to combat C. albicans biofilm infections.

  11. Shock Wave Response of Iron-based In Situ Metallic Glass Matrix Composites.

    Science.gov (United States)

    Khanolkar, Gauri R; Rauls, Michael B; Kelly, James P; Graeve, Olivia A; Hodge, Andrea M; Eliasson, Veronica

    2016-03-02

    The response of amorphous steels to shock wave compression has been explored for the first time. Further, the effect of partial devitrification on the shock response of bulk metallic glasses is examined by conducting experiments on two iron-based in situ metallic glass matrix composites, containing varying amounts of crystalline precipitates, both with initial composition Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4. The samples, designated SAM2X5-600 and SAM2X5-630, are X-ray amorphous and partially crystalline, respectively, due to differences in sintering parameters during sample preparation. Shock response is determined by making velocity measurements using interferometry techniques at the rear free surface of the samples, which have been subjected to impact from a high-velocity projectile launched from a powder gun. Experiments have yielded results indicating a Hugoniot Elastic Limit (HEL) to be 8.58 ± 0.53 GPa for SAM2X5-600 and 11.76 ± 1.26 GPa for SAM2X5-630. The latter HEL result is higher than elastic limits for any BMG reported in the literature thus far. SAM2X5-600 catastrophically loses post-yield strength whereas SAM2X5-630, while showing some strain-softening, retains strength beyond the HEL. The presence of crystallinity within the amorphous matrix is thus seen to significantly aid in strengthening the material as well as preserving material strength beyond yielding.

  12. Aluminum matrix composites reinforced with alumina nanoparticles

    CERN Document Server

    Casati, Riccardo

    2016-01-01

    This book describes the latest efforts to develop aluminum nanocomposites with enhanced damping and mechanical properties and good workability. The nanocomposites exhibited high strength, improved damping behavior and good ductility, making them suitable for use as wires. Since the production of metal matrix nanocomposites by conventional melting processes is considered extremely problematic (because of the poor wettability of the nanoparticles), different powder metallurgy routes were investigated, including high-energy ball milling and unconventional compaction methods. Special attention was paid to the structural characterization at the micro- and nanoscale, as uniform nanoparticle dispersion in metal matrix is of prime importance. The aluminum nanocomposites displayed an ultrafine microstructure reinforced with alumina nanoparticles produced in situ or added ex situ. The physical, mechanical and functional characteristics of the materials produced were evaluated using different mechanical tests and micros...

  13. Experimental study on mechanical behavior of fiber/matrix interface in metal matrix composite

    International Nuclear Information System (INIS)

    Wang, Q.; Chiang, F.P.

    1994-01-01

    The technique SIEM(Speckle Interferometry with Electron Microscopy) was employed to quantitatively measure the deformation on the fiber/matrix interface in SCS-6/Ti-6-4 composite at a microscale level. The displacement field within the fiber/matrix interphase zone was determined by in-situ observation with sensitivity of 0.003(microm). The macro-mechanical properties were compared with micro-mechanical behavior. It is shown that the strength in the interphase zone is weaker than the matrix tensile strength. The deformation process can be characterized by the uniform deformation, interface strain concentration and debond, and matrix plastic deformation

  14. A Matrix Splitting Method for Composite Function Minimization

    KAUST Repository

    Yuan, Ganzhao

    2016-12-07

    Composite function minimization captures a wide spectrum of applications in both computer vision and machine learning. It includes bound constrained optimization and cardinality regularized optimization as special cases. This paper proposes and analyzes a new Matrix Splitting Method (MSM) for minimizing composite functions. It can be viewed as a generalization of the classical Gauss-Seidel method and the Successive Over-Relaxation method for solving linear systems in the literature. Incorporating a new Gaussian elimination procedure, the matrix splitting method achieves state-of-the-art performance. For convex problems, we establish the global convergence, convergence rate, and iteration complexity of MSM, while for non-convex problems, we prove its global convergence. Finally, we validate the performance of our matrix splitting method on two particular applications: nonnegative matrix factorization and cardinality regularized sparse coding. Extensive experiments show that our method outperforms existing composite function minimization techniques in term of both efficiency and efficacy.

  15. A Matrix Splitting Method for Composite Function Minimization

    KAUST Repository

    Yuan, Ganzhao; Zheng, Wei-Shi; Ghanem, Bernard

    2016-01-01

    Composite function minimization captures a wide spectrum of applications in both computer vision and machine learning. It includes bound constrained optimization and cardinality regularized optimization as special cases. This paper proposes and analyzes a new Matrix Splitting Method (MSM) for minimizing composite functions. It can be viewed as a generalization of the classical Gauss-Seidel method and the Successive Over-Relaxation method for solving linear systems in the literature. Incorporating a new Gaussian elimination procedure, the matrix splitting method achieves state-of-the-art performance. For convex problems, we establish the global convergence, convergence rate, and iteration complexity of MSM, while for non-convex problems, we prove its global convergence. Finally, we validate the performance of our matrix splitting method on two particular applications: nonnegative matrix factorization and cardinality regularized sparse coding. Extensive experiments show that our method outperforms existing composite function minimization techniques in term of both efficiency and efficacy.

  16. Cavitation instabilities between fibres in a metal matrix composite

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2016-01-01

    induced by bonding to the ceramics that only show elastic deformation. In an MMC the stress state in the metal matrix is highly non-uniform, varying between regions where shear stresses are dominant and regions where hydrostatic tension is strong. An Al–SiC whisker composite with a periodic pattern......Short fibre reinforced metal matrix composites (MMC) are studied here to investigate the possibility that a cavitation instability can develop in the metal matrix. The high stress levels needed for a cavitation instability may occur in metal–ceramic systems due to the constraint on plastic flow...... of transversely staggered fibres is here modelled by using an axisymmetric cell model analysis. First the critical stress level is determined for a cavitation instability in an infinite solid made of the Al matrix material. By studying composites with different distributions and aspect ratios of the fibres...

  17. Micromechanics of deformation of metallic-glass-matrix composites from in situ synchrotron strain measurements and finite element modeling

    International Nuclear Information System (INIS)

    Ott, R.T.; Sansoz, F.; Molinari, J.F.; Almer, J.; Ramesh, K.T.; Hufunagel, T.C.

    2005-01-01

    In situ X-ray scattering and finite element modeling (FEM) were used to examine the micromechanics of deformation of in situ formed metallic-glass-matrix composites consisting of Ta-rich particles dispersed in an amorphous matrix. The strain measurements show that under uniaxial compression the second-phase particles yield at an applied stress of approx. 325 MPa. After yielding, the particles do not strain harden significantly; we show that this is due to an increasingly hydrostatic stress state arising from the lateral constraint on deformation of the particles imposed by the elastic matrix. Shear band initiation in the matrix is not due to the difference in elastic properties between the matrix and the particles. Rather, the development of a plastic misfit strain causes stress concentrations around the particles, resulting in localized yielding of the matrix by shear band formation at an applied stress of approx. 1450 MPa, considerably lower than the macroscopic yield stress of the composite (approx. 1725 MPa). Shear bands do not propagate at the lower stress because the yield criterion of the matrix is only satisfied in the region immediately around the particles. At the higher stresses, the yield criterion is satisfied in large regions of the matrix, allowing extensive shear band propagation and significant macroscopic plastic deformation. However, the presence of the particles makes the stress state highly inhomogeneous, which may partially explain why fracture is suppressed in the composite, allowing the development of large plastic strains

  18. exploration the extrudability of aluminum matrix composite (lm6/tic)

    African Journals Online (AJOL)

    lanez

    2017-11-24

    Nov 24, 2017 ... Aluminum matrix composites (LM6/TiC) is a mix of excellent properties of aluminum casting alloy (LM6), and particles of (TiC) which make it the first choice in many applications like airplane and marine industries. During this research the extrudability and mechanical specifications of this composite ...

  19. Compositional dependence of Young's moduli for amorphous FeCo-SiO2 thin films

    International Nuclear Information System (INIS)

    Zhang, L.; Xie, J. L.; Deng, L. J.; Guo, Q.; Zhu, Z. W.; Bi, L.

    2011-01-01

    Systematic force-deflection measurements with microcantilevers and a combinatorial-deposition method have been used to investigate the Young's moduli of amorphous composite FeCo-SiO 2 thin films as a function of film composition, with high compositional resolution. It is found that the modulus decreases monotonically with increasing FeCo content. Such a trend can be explained in terms of the metalloid atoms having a significant effect on the Young's moduli of metal-metalloid composites, which is associated with the strong chemical interaction between the metalloid and themetallic atoms rather than that between the metallic components themselves. This work provides an efficient and effective method to study the moduli of magnetic thin films over a largecomposition coverage, and to compare the relative magnitudes of moduli for differentcompositions at high compositional resolution.

  20. Bulk metallic glass matrix composite for good biocompatibility

    International Nuclear Information System (INIS)

    Hadjoub, F; Metiri, W; Doghmane, A; Hadjoub, Z

    2012-01-01

    Reinforcement volume fraction effects on acoustical parameters of Zr 41.2 Ti 13.8 Cu 12.5 Ni 10 Be 22.5 matrix composites reinforced by Mg, Ag and Cd metals have been studied via a simulation program based on acoustic microscopy technique. Moreover, acoustical parameters of human bone were compared to those of BMGs in both monolithic and reinforced case. It was found that elastic behavior of BMGs matrix composites in high reinforcement volume fraction is similar of that of human bone. This behavior leads to high biocompatibility and good transfer of stress between composite material and human system.

  1. Advanced Ceramic Matrix Composites with Multifunctional and Hybrid Structures

    Science.gov (United States)

    Singh, Mrityunjay; Morscher, Gregory N.

    2004-01-01

    Ceramic matrix composites are leading candidate materials for a number of applications in aeronautics, space, energy, and nuclear industries. Potential composite applications differ in their requirements for thickness. For example, many space applications such as "nozzle ramps" or "heat exchangers" require very thin (structures whereas turbine blades would require very thick parts (> or = 1 cm). Little is known about the effect of thickness on stress-strain behavior or the elevated temperature tensile properties controlled by oxidation diffusion. In this study, composites consisting of woven Hi-Nicalon (trademark) fibers a carbon interphase and CVI SiC matrix were fabricated with different numbers of plies and thicknesses. The effect of thickness on matrix crack formation, matrix crack growth and diffusion kinetics will be discussed. In another approach, hybrid fiber-lay up concepts have been utilized to "alloy" desirable properties of different fiber types for mechanical properties, thermal stress management, and oxidation resistance. Such an approach has potential for the C(sub I)-SiC and SiC(sub f)-SiC composite systems. CVI SiC matrix composites with different stacking sequences of woven C fiber (T300) layers and woven SiC fiber (Hi-Nicalon (trademark)) layers were fabricated. The results will be compared to standard C fiber reinforced CVI SiC matrix and Hi-Nicalon reinforced CVI SiC matrix composites. In addition, shear properties of these composites at different temperatures will also be presented. Other design and implementation issues will be discussed along with advantages and benefits of using these materials for various components in high temperature applications.

  2. Mechanisms of de cohesion in cutting aluminium matrix composites

    International Nuclear Information System (INIS)

    Cichosz, Piotr; Karolczak, Pawel; Kuzinovski, Mikolaj

    2008-01-01

    In this paper properties and applications of aluminium matrix composites are presented with a composite reinforced with saffil fibres selected for topical study. Behavior of matrix and reinforcement during machining with a cutting tool is analyzed. The paper presents an explosive quick-stop device designed to obtain undisturbed machined surface for examination. Meso hardness measurements of deformed structure, resultant chips and built-up-edge were carried out. Scanning micrographs of machined surface are presented with morphology and types of chips analysed. Values of the fibrousness angle ψ and thickening index k h of chip are evaluated. The research performed has enabled the authors to define mechanisms of e cohesion during cutting aluminium matrix composites. The results received for composite material are compared with those pertinent to aluminum alloys.

  3. Standard Guide for Testing Polymer Matrix Composite Materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This guide summarizes the application of ASTM standard test methods (and other supporting standards) to continuous-fiber reinforced polymer matrix composite materials. The most commonly used or most applicable ASTM standards are included, emphasizing use of standards of Committee D30 on Composite Materials. 1.2 This guide does not cover all possible standards that could apply to polymer matrix composites and restricts discussion to the documented scope. Commonly used but non-standard industry extensions of test method scopes, such as application of static test methods to fatigue testing, are not discussed. A more complete summary of general composite testing standards, including non-ASTM test methods, is included in the Composite Materials Handbook (MIL-HDBK-17). Additional specific recommendations for testing textile (fabric, braided) composites are contained in Guide D6856. 1.3 This guide does not specify a system of measurement; the systems specified within each of the referenced standards shall appl...

  4. Interfacial reactions in intermetallic matrix composites

    International Nuclear Information System (INIS)

    Cantrell, L.B.; Clevenger, E.M.; Perepezko, J.H.

    1993-01-01

    The thermal stability of advanced composites is dominated by the behavior of internal interfaces. Analysis of these internal interfaces often involves consideration of at least ternary order phase equilibria. Limited thermodynamic data exists for ternary and higher order systems. However, a combined approach based upon the use of binary data to estimate ternary phase equilibria and experimentally determined reaction pathways is effective in the analysis of interface reactions in composite systems. In blended powder samples, thermal analysis was used to find possible reaction temperatures, while X-ray analysis, EDS, and EPMA of diffusion couples were used to assess interdiffusion reaction pathways. The approach is illustrated by compatibility studies between TiAl and TiSi 2 at 1,100 C, and in-situ reactions between B 4 C and TiAl at 1300 C where multiple reaction sequences have been analyzed to provide guidance for the design of in-situ reaction processing of composites

  5. Modeling the curing process of thermosetting resin matrix composites

    Science.gov (United States)

    Loos, A. C.

    1986-01-01

    A model is presented for simulating the curing process of a thermosetting resin matrix composite. The model relates the cure temperature, the cure pressure, and the properties of the prepreg to the thermal, chemical, and rheological processes occurring in the composite during cure. The results calculated with the computer code developed on the basis of the model were compared with the experimental data obtained from autoclave-curved composite laminates. Good agreement between the two sets of results was obtained.

  6. Interfacial reaction effects on erosion of aluminum matrix composites

    International Nuclear Information System (INIS)

    Tu, J.P.; Hiroshima Univ., Higashi-Hiroshima; Matsumura, M.

    1999-01-01

    Alumina borate (A 18 B 4 O 33 ) whisker reinforced aluminum composites have attracted interest because of their high specific strength, high modulus and low cost. An obvious feature of the microstructure in A 18 B 4 O 33 /Al composite is that an interfacial reaction exists between the whisker and the aluminum alloy. In order to discuss the influence of interface interaction between the whisker and matrix on the erosion resistance of composites, two reaction treatments are conducted. From the results of the treated composites, it can be obtained about the erosion characteristics of the composite materials under steady-state conditions

  7. The chemical composition and band gap of amorphous Si:C:N:H layers

    Energy Technology Data Exchange (ETDEWEB)

    Swatowska, Barbara, E-mail: swatow@agh.edu.pl [AGH University of Science and Technology, Department of Electronics, Mickiewicza Av. 30, 30-059 Krakow (Poland); Kluska, Stanislawa; Jurzecka-Szymacha, Maria [AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Mickiewicza Av. 30, 30-059 Krakow (Poland); Stapinski, Tomasz [AGH University of Science and Technology, Department of Electronics, Mickiewicza Av. 30, 30-059 Krakow (Poland); Tkacz-Smiech, Katarzyna [AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Mickiewicza Av. 30, 30-059 Krakow (Poland)

    2016-05-15

    Highlights: • Six type of amorphous hydrogenated films were obtained and analysed. • Investigated chemical bondings strongly influenced energy gap values. • Analysed layers could be applied as semiconductors and also as dielectrics. - Abstract: In this work we presented the correlation between the chemical composition of amorphous Si:C:N:H layers of various content of silicon, carbon and nitrogen, and their band gap. The series of amorphous Si:C:N:H layers were obtained by plasma assisted chemical vapour deposition method in which plasma was generated by RF (13.56 MHz, 300 W) and MW (2.45 GHz, 2 kW) onto monocrystalline silicon Si(001) and borosilicate glass. Structural studies were based on FTIR transmission spectrum registered within wavenumbers 400–4000 cm{sup −1}. The presence of Si−C, Si−N, C−N, C=N, C=C, C≡N, Si−H and C−H bonds was shown. The values band gap of the layers have been determined from spectrophotometric and ellipsometric measurements. The respective values are contained in the range between 1.64 eV – characteristic for typical semiconductor and 4.21 eV – for good dielectric, depending on the chemical composition and atomic structure of the layers.

  8. Electromagnetic wave absorption properties of composites with micro-sized magnetic particles dispersed in amorphous carbon

    Energy Technology Data Exchange (ETDEWEB)

    Li, Bin Peng [Research Center of Carbon Fiber, Key Laboratory for Liquid–Solid Structural Evolution and Processing of Materials of Ministry of Education, Shandong University, Jinan 250061 (China); Tianjin Binhai New Area Finance Bureau, Tianjin 300450 (China); Wang, Cheng Guo, E-mail: sduwangchg@gmail.com [Research Center of Carbon Fiber, Key Laboratory for Liquid–Solid Structural Evolution and Processing of Materials of Ministry of Education, Shandong University, Jinan 250061 (China); Wang, Wen [Norinco Group China North Material Science and Engineering Technology Group Corporation, Jinan 250031 (China); Yu, Mei Jie; Gao, Rui; Chen, Yang; Xiang Wang, Yan [Research Center of Carbon Fiber, Key Laboratory for Liquid–Solid Structural Evolution and Processing of Materials of Ministry of Education, Shandong University, Jinan 250061 (China)

    2014-09-01

    Composites with micro-sized magnetic particles dispersed in amorphous carbon were fabricated conveniently and economically by carbonizing polyacrylonitrile (PAN) fibers mixed with micro-sized iron particles under different temperatures. The composites were characterized by X-ray diffraction (XRD) and scanning electric microscope (SEM). The electromagnetic (EM) properties were measured by a vector network analyzer in the frequency range of 2–18 GHz based on which analog computations of EM wave absorption properties were carried out. The influences of temperature on phase composition and EM wave absorption properties were also investigated, indicating that the composites had good electromagnetic absorption properties with both electrical loss and magnetic loss. Effective reflection loss (RL<−10 dB) was observed in a large frequency range of 7.5–18 GHz with the absorber thickness of 2.0–3.0 mm for the paraffin samples with composite powders heated up to 750 °C and the minimum absorption peak around −40 dB appeared at approximately 10 GHz with matching thickness of 2.0 mm for the paraffin sample with composite powders heated up to 800 °C. - Highlights: • High-performance electromagnetic wave absorption materials were fabricated conveniently and economically. • The materials are composites with micro-sized magnetic particles dispersed in porous amorphous carbon. • The influences of temperature on phase composition and electromagnetic wave absorption properties were investigated. • The composites heated up to 750 °C and 800 °C had good electromagnetic wave absorption property.

  9. Acoustic emission as a screening tool for ceramic matrix composites

    Science.gov (United States)

    Ojard, Greg; Goberman, Dan; Holowczak, John

    2017-02-01

    Ceramic matrix composites are composite materials with ceramic fibers in a high temperature matrix of ceramic or glass-ceramic. This emerging class of materials is viewed as enabling for efficiency improvements in many energy conversion systems. The key controlling property of ceramic matrix composites is a relatively weak interface between the matrix and the fiber that aids crack deflection and fiber pullout resulting in greatly increased toughness over monolithic ceramics. United Technologies Research Center has been investigating glass-ceramic composite systems as a tool to understand processing effects on material performance related to the performance of the weak interface. Changes in the interface have been shown to affect the mechanical performance observed in flexural testing and subsequent microstructural investigations have confirmed the performance (or lack thereof) of the interface coating. Recently, the addition of acoustic emission testing during flexural testing has aided the understanding of the characteristics of the interface and its performance. The acoustic emission onset stress changes with strength and toughness and this could be a quality tool in screening the material before further development and use. The results of testing and analysis will be shown and additional material from other ceramic matrix composite systems may be included to show trends.

  10. Metal Matrix Composites Reinforced by Nano-Particles—A Review

    Directory of Open Access Journals (Sweden)

    Riccardo Casati

    2014-03-01

    Full Text Available Metal matrix composites reinforced by nano-particles are very promising materials, suitable for a large number of applications. These composites consist of a metal matrix filled with nano-particles featuring physical and mechanical properties very different from those of the matrix. The nano-particles can improve the base material in terms of wear resistance, damping properties and mechanical strength. Different kinds of metals, predominantly Al, Mg and Cu, have been employed for the production of composites reinforced by nano-ceramic particles such as carbides, nitrides, oxides as well as carbon nanotubes. The main issue of concern for the synthesis of these materials consists in the low wettability of the reinforcement phase by the molten metal, which does not allow the synthesis by conventional casting methods. Several alternative routes have been presented in literature for the production of nano-composites. This work is aimed at reviewing the most important manufacturing techniques used for the synthesis of bulk metal matrix nanocomposites. Moreover, the strengthening mechanisms responsible for the improvement of mechanical properties of nano-reinforced metal matrix composites have been reviewed and the main potential applications of this new class of materials are envisaged.

  11. Fabrication of metal matrix composites by powder metallurgy: A review

    Science.gov (United States)

    Manohar, Guttikonda; Dey, Abhijit; Pandey, K. M.; Maity, S. R.

    2018-04-01

    Now a day's metal matrix components are used in may industries and it finds the applications in many fields so, to make it as better performable materials. So, the need to increase the mechanical properties of the composites is there. As seen from previous studies major problem faced by the MMC's are wetting, interface bonding between reinforcement and matrix material while they are prepared by conventional methods like stir casting, squeeze casting and other techniques which uses liquid molten metals. So many researchers adopt PM to eliminate these defects and to increase the mechanical properties of the composites. Powder metallurgy is one of the better ways to prepare composites and Nano composites. And the major problem faced by the conventional methods are uniform distribution of the reinforcement particles in the matrix alloy, many researchers tried to homogeneously dispersion of reinforcements in matrix but they find it difficult through conventional methods, among all they find ultrasonic dispersion is efficient. This review article is mainly concentrated on importance of powder metallurgy in homogeneous distribution of reinforcement in matrix by ball milling or mechanical milling and how powder metallurgy improves the mechanical properties of the composites.

  12. Modeling the Mechanical Behavior of Ceramic Matrix Composite Materials

    Science.gov (United States)

    Jordan, William

    1998-01-01

    Ceramic matrix composites are ceramic materials, such as SiC, that have been reinforced by high strength fibers, such as carbon. Designers are interested in using ceramic matrix composites because they have the capability of withstanding significant loads while at relatively high temperatures (in excess of 1,000 C). Ceramic matrix composites retain the ceramic materials ability to withstand high temperatures, but also possess a much greater ductility and toughness. Their high strength and medium toughness is what makes them of so much interest to the aerospace community. This work concentrated on two different tasks. The first task was to do an extensive literature search into the mechanical behavior of ceramic matrix composite materials. This report contains the results of this task. The second task was to use this understanding to help interpret the ceramic matrix composite mechanical test results that had already been obtained by NASA. Since the specific details of these test results are subject to the International Traffic in Arms Regulations (ITAR), they are reported in a separate document (Jordan, 1997).

  13. Effect of Sb on physical properties and microstructures of laser nano/amorphous-composite film

    International Nuclear Information System (INIS)

    Li, Jia-Ning; Gong, Shui-Li; Sun, Mei; Shan, Fei-Hu; Wang, Xi-Chang; Jiang, Shuai

    2013-01-01

    A nano/amorphous-composite film was fabricated by laser cladding (LC) of the Co–Ti–B 4 C–Sb mixed powders on a TA15 alloy. Such film mainly consisted of Ti–Al, Co–Ti, Co–Sb intermetallics, TiC, TiB 2 , TiB, and the amorphous phases. Experimental results indicated that the crystal systems of TiB 2 (hexagonal)/TiC (cubic) and Sb (rhombohedral) played important role on the formation of such film. Due to the mismatch of these crystals systems and mutual immiscibility of the metallic components, Sb was not incorporated in TiB 2 /TiC, but formed separate nuclei during the film growth. Thus, the growth of TiB 2 /TiC was stopped by the Sb nucleus in such LC molten pool, so as to form the nanoscale particles

  14. Effect of Sb on physical properties and microstructures of laser nano/amorphous-composite film

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jia-Ning, E-mail: jn2369@163.com [Science and Technology on Power Beam Processes Laboratory, Beijing (China); Aviation Industry Corporation of China, Beijing Institute of Aeronautical Materials, Beijing 100095 (China); Beijing Aeronautical Manufacturing Technology Research Institute, Beijing 100024 (China); Gong, Shui-Li, E-mail: gongshuili@sina.com [Science and Technology on Power Beam Processes Laboratory, Beijing (China); Beijing Aeronautical Manufacturing Technology Research Institute, Beijing 100024 (China); Sun, Mei; Shan, Fei-Hu; Wang, Xi-Chang [Science and Technology on Power Beam Processes Laboratory, Beijing (China); Beijing Aeronautical Manufacturing Technology Research Institute, Beijing 100024 (China); Jiang, Shuai [Science and Technology on Power Beam Processes Laboratory, Beijing (China); Beijing Aeronautical Manufacturing Technology Research Institute, Beijing 100024 (China); Department of Materials Science and Engineering, China University of Petroleum, Qingdao 266580 (China)

    2013-11-01

    A nano/amorphous-composite film was fabricated by laser cladding (LC) of the Co–Ti–B{sub 4}C–Sb mixed powders on a TA15 alloy. Such film mainly consisted of Ti–Al, Co–Ti, Co–Sb intermetallics, TiC, TiB{sub 2}, TiB, and the amorphous phases. Experimental results indicated that the crystal systems of TiB{sub 2} (hexagonal)/TiC (cubic) and Sb (rhombohedral) played important role on the formation of such film. Due to the mismatch of these crystals systems and mutual immiscibility of the metallic components, Sb was not incorporated in TiB{sub 2}/TiC, but formed separate nuclei during the film growth. Thus, the growth of TiB{sub 2}/TiC was stopped by the Sb nucleus in such LC molten pool, so as to form the nanoscale particles.

  15. Improving Turbine Performance with Ceramic Matrix Composites

    Science.gov (United States)

    DiCarlo, James A.

    2007-01-01

    Under the new NASA Fundamental Aeronautics Program, efforts are on-going within the Supersonics Project aimed at the implementation of advanced SiC/SiC ceramic composites into hot section components of future gas turbine engines. Due to recent NASA advancements in SiC-based fibers and matrices, these composites are lighter and capable of much higher service temperatures than current metallic superalloys, which in turn will allow the engines to operate at higher efficiencies and reduced emissions. This presentation briefly reviews studies within Task 6.3.3 that are primarily aimed at developing physics-based concepts, tools, and process/property models for micro- and macro-structural design, fabrication, and lifing of SiC/SiC turbine components in general and airfoils in particular. Particular emphasis is currently being placed on understanding and modeling (1) creep effects on residual stress development within the component, (2) fiber architecture effects on key composite properties such as design strength, and (3) preform formation processes so that the optimum architectures can be implemented into complex-shaped components, such as turbine vanes and blades.

  16. Ceramic matrix composites using polymer pyrolysis and liquid densification processing

    International Nuclear Information System (INIS)

    Davis, H.O.; Petrak, D.R.

    1995-01-01

    The polymer precursor approach for manufacture of ceramic matrix composites (CMCs) is both flexible and tailorable to shape and engineering requirements. The tailorability includes a wide range of reinforcements, polymer matrix precursors and fillers. Processing is selected based on cure/pressure requirements to best produce the required shape, radii, fiber volume and fiber orientation. Combinations of tooling used for cure/pressure applications are discussed and fabricated components are shown. ((orig.))

  17. Microstructure, Friction and Wear of Aluminum Matrix Composites

    Science.gov (United States)

    Florea, R. M.

    2018-06-01

    MMCs are made by dispersing a reinforcing material into a metal matrix. They are prepared by casting, although several technical challenges exist with casting technology. Achieving a homogeneous distribution of reinforcement within the matrix is one such challenge, and this affects directly on the properties and quality of composite. The aluminum alloy composite materials consist of high strength, high stiffness, more thermal stability, more corrosion and wear resistance, and more fatigue life. Aluminum alloy materials found to be the best alternative with its unique capacity of designing the materials to give required properties. In this work a composite is developed by adding silicon carbide in Aluminum metal matrix by mass ratio 5%, 10% and 15%. Mechanical tests such as hardness test and microstructure test are conducted.

  18. Fatigue and frictional heating in ceramic matrix composites

    DEFF Research Database (Denmark)

    Jacobsen, T.K.; Sørensen, B.F.; Brøndsted, P.

    1997-01-01

    This paper describes an experimental technique for monitoring the damage evolution in ceramic matrix composites during cyclic testing. The damage is related to heat dissipation, which may be measured as radiated heat from the surface of the test specimen. In the present experimental set-up an iso......This paper describes an experimental technique for monitoring the damage evolution in ceramic matrix composites during cyclic testing. The damage is related to heat dissipation, which may be measured as radiated heat from the surface of the test specimen. In the present experimental set...... with a high spatial and temperature resolution and changes in the heat dissipation can be measured almost instantaneously. The technique has been tested on uni-directional ceramic matrix composites. Experimental results are shown and the possibilities and the limitations of the technique are discussed....

  19. 4TH International Conference on High-Temperature Ceramic Matrix Composites

    National Research Council Canada - National Science Library

    2001-01-01

    .... Topic to be covered include fibers, interfaces, interphases, non-oxide ceramic matrix composites, oxide/oxide ceramic matrix composites, coatings, and applications of high-temperature ceramic matrix...

  20. Matrix densification of SiC composites by sintering process

    International Nuclear Information System (INIS)

    Kim, Young-Wook; Jang, Doo-Hee; Eom, Jung-Hye; Chun, Yong-Seong

    2007-02-01

    The objectives of this research are to develop a process for dense SiC fiber-SiC composites with a porosity of 5% or less and to develop high-strength SiC fiber-SiC composites with a strength of 500 MPa or higher. To meet the above objectives, the following research topics were investigated ; new process development for the densification of SiC fiber-SiC composites, effect of processing parameters on densification of SiC fiber-SiC composites, effect of additive composition on matrix microstructure, effects of additive composition and content on densification of SiC fiber-SiC composites, mechanical properties of SiC fiber-SiC composites, effect of fiber coating on densification and strength of SiC fiber-SiC composites, development of new additive composition. There has been a great deal of progress in the development of technologies for the processing and densification of SiC fiber-SiC composites and in better understanding of additive-densification-mechanical property relations as results of this project. Based on the progress, dense SiC fiber-SiC composites (≥97%) and high strength SiC fiber-SiC composites (≥600 MPa) have been developed. Development of 2D SiC fiber-SiC composites with a relative density of ≥97% and a strength of ≥600 MPa can be counted as a notable achievement

  1. Progressive delamination in polymer matrix composite laminates: A new approach

    Science.gov (United States)

    Chamis, C. C.; Murthy, P. L. N.; Minnetyan, L.

    1992-01-01

    A new approach independent of stress intensity factors and fracture toughness parameters has been developed and is described for the computational simulation of progressive delamination in polymer matrix composite laminates. The damage stages are quantified based on physics via composite mechanics while the degradation of the laminate behavior is quantified via the finite element method. The approach accounts for all types of composite behavior, laminate configuration, load conditions, and delamination processes starting from damage initiation, to unstable propagation, and to laminate fracture. Results of laminate fracture in composite beams, panels, plates, and shells are presented to demonstrate the effectiveness and versatility of this new approach.

  2. Ceramic matrix composites -- Advanced high-temperature structural materials

    International Nuclear Information System (INIS)

    Lowden, R.A.; Ferber, M.K.; DiPietro, S.G.

    1995-01-01

    This symposium on Ceramic Matrix Composites: Advanced High-Temperature Structural Materials was held at the 1994 MRS Fall Meeting in Boston, Massachusetts on November 28--December 2. The symposium was sponsored by the Department of Energy's Office of Industrial Technology's Continuous Fiber Ceramic Composites Program, the Air Force Office of Scientific Research, and NASA Lewis Research Center. Among the competing materials for advanced, high-temperature applications, ceramic matrix composites are leading candidates. The symposium was organized such that papers concerning constituents--fibers and matrices--were presented first, followed by composite processing, modeling of mechanical behavior, and thermomechanical testing. More stable reinforcements are necessary to enhance the performance and life of fiber-reinforced ceramic composites, and to ensure final acceptance of these materials for high-temperature applications. Encouraging results in the areas of polymer-derived SiC fibers and single crystal oxide filaments were given, suggesting composites with improved thermomechanical properties and stability will be realized in the near future. The significance of the fiber-matrix interface in the design and performance of these materials is evident. Numerous mechanical models to relate interface properties to composite behavior, and interpret test methods and data, were enthusiastically discussed. One issue of great concern for any advanced material for use in extreme environments is stability. This theme arose frequently throughout the symposium and was the topic of focus on the final day. Fifty nine papers have been processed separately for inclusion on the data base

  3. Composite Matrix Regenerator for Stirling Engines

    Science.gov (United States)

    Knowles, Timothy R.

    1997-01-01

    This project concerns the design, fabrication and testing of carbon regenerators for use in Stirling power convertors. Radial fiber design with nonmetallic components offers a number of potential advantages over conventional steel regenerators: reduced conduction and pressure drop losses, and the capability for higher temperature, higher frequency operation. Diverse composite fabrication methods are explored and lessons learned are summarized. A pulsed single-blow test rig has been developed that has been used for generating thermal effectiveness data for different flow velocities. Carbon regenerators have been fabricated by carbon vapor infiltration of electroflocked preforms. Performance data in a small Stirling engine are obtained. Prototype regenerators designed for the BP-1000 power convertor were fabricated and delivered to NASA-Lewis.

  4. Electron beam curing of polymer matrix composites

    International Nuclear Information System (INIS)

    Janke, C.J.; Wheeler, D.; Saunders, C.

    1998-01-01

    The purpose of the CRADA was to conduct research and development activities to better understand and utilize the electron beam PMC curing technology. This technology will be used to replace or supplement existing PMC thermal curing processes in Department of Energy (DOE) Defense Programs (DP) projects and American aircraft and aerospace industries. This effort involved Lockheed Martin Energy Systems, Inc./Lockheed Martin Energy Research Corp. (Contractor), Sandia National Laboratories, and ten industrial Participants including four major aircraft and aerospace companies, three advanced materials companies, and three electron beam processing organizations. The technical objective of the CRADA was to synthesize and/or modify high performance, electron beam curable materials that meet specific end-use application requirements. There were six tasks in this CRADA including: Electron beam materials development; Electron beam database development; Economic analysis; Low-cost Electron Beam tooling development; Electron beam curing systems integration; and Demonstration articles/prototype structures development. The contractor managed, participated and integrated all the tasks, and optimized the project efforts through the coordination, exchange, and dissemination of information to the project participants. Members of the Contractor team were also the principal inventors on several electron beam related patents and a 1997 R and D 100 Award winner on Electron-Beam-Curable Cationic Epoxy Resins. The CRADA achieved a major breakthrough for the composites industry by having successfully developed high-performance electron beam curable cationic epoxy resins for use in composites, adhesives, tooling compounds, potting compounds, syntactic foams, etc. UCB Chemicals, the world's largest supplier of radiation-curable polymers, has acquired a license to produce and sell these resins worldwide

  5. Drilling of metal matrix composites: cutting forces and chip formation

    International Nuclear Information System (INIS)

    Songmene, V.; Balout, B.; Masounave, J.

    2002-01-01

    Particulate metal matrix composites (MMCs) are known for their low weight and their high wear resistance, but also for the difficulties encountered during their machining. New aluminium MMCs containing with both soft lubricating graphite particles and hard particles (silicon carbide or alumina) with improved machinability were developed. This study investigates the drilling of these composites as compared to non-reinforced aluminium. The microstructure of chip, the cutting forces, the shear angles and the friction at tool-chip interface are used to compare the machinability of these composites. It was found that, during drilling of this new family of composites, the feed rate, and the nature of reinforcing particles govern the cutting forces. The mathematical models established by previous researchers for predicting the cutting forces when drilling metals were validated for these composites. The reinforcing particles within the composite help for chip segmentation, making the composite more brittle and easy to shear during the cutting process. (author)

  6. Influence of surface modified nanoilmenite/amorphous silica composite particles on the thermal stability of cold galvanizing coating

    Directory of Open Access Journals (Sweden)

    A.M. Al-Sabagh

    2018-03-01

    Full Text Available The present approach investigates the use of novel nanoilmenite/amorphous silica composite (NI/AS particles fabricated from ilmenite nanoparticles (FeTiO3 NPs and synthesized amorphous silica grains to improve thermal stability of the cold galvanizing coating. Transmission electron microscopic (TEM images demonstrated that both nanoilmenite and nanocomposite particles were of flaky-like nature and the average diameter of the particles is 20 nm. The lamellar shape of the nanocomposite and spherical nature of Zn-dust particles were illustrated by scanning electron microscopy (SEM micrographs. Different alkyd-based cold galvanizing coating formulations were modified using uniformly dispersing various amounts of the processed nanocomposite particles as a modifier to form some engineering nanocomposite coatings. Thermal stability of the nanocomposite and Zn-dust particles was determined by thermo-gravimetric analysis (TGA. From the obtained results it could be observed that the weight loss (% as a feature of the thermal stability in case of the nanocomposite particles was 2.9 compared to 85.9 for Zn-dust powder grains. Derivative thermo-gravimetric (DTG measurements were done under nitrogen atmosphere for the cured cold galvanizing coating samples heated from room temperature to 1000 °C. The obtained results revealed that the maximum decomposition temperature point in the third degradation step for 6% nanocomposite surface modified cured sample (CG-F was detected at 693 °C and was less value for unmodified conventional cold galvanizing coating (CG-A at 612 °C. The increase in thermal stability with increasing the concentration of nanocomposite particles could be mainly attributed to the interface surface interaction between the nanocomposite particles and alkyd resin matrix in which enhancing the inorganic-organic network stiffness by causing a reduction in the total free spaces and enhancement in the cross-linking density of the cured film

  7. Radiation amorphization of materials

    International Nuclear Information System (INIS)

    Neklyudov, I.M.; Chernyaeva, T.P.

    1993-01-01

    The results of experimental and theoretical research on radiation amorphization are presented in this analytical review. Mechanism and driving forces of radiation amorphization are described, kinetic and thermodynamic conditions of amorphization are formulated. Compositional criteria of radiation amorphization are presented, that allow to predict irradiation behaviour of materials, their tendency to radiation amorphization. Mechanism of transition from crystalline state to amorphous state are considered depending on dose, temperature, structure of primary radiation damage and flux level. (author). 134 refs., 4 tab., 25 fig

  8. Rapid, room-temperature synthesis of amorphous selenium/protein composites using Capsicum annuum L extract

    Science.gov (United States)

    Li, Shikuo; Shen, Yuhua; Xie, Anjian; Yu, Xuerong; Zhang, Xiuzhen; Yang, Liangbao; Li, Chuanhao

    2007-10-01

    We describe the formation of amorphous selenium (α-Se)/protein composites using Capsicum annuum L extract to reduce selenium ions (SeO32-) at room temperature. The reaction occurs rapidly and the process is simple and easy to handle. A protein with a molecular weight of 30 kDa extracted from Capsicum annuum L not only reduces the SeO32- ions to Se0, but also controls the nucleation and growth of Se0, and even participates in the formation of α-Se/protein composites. The size and shell thickness of the α-Se/protein composites increases with high Capsicum annuum L extract concentration, and decreases with low reaction solution pH. The results suggest that this eco-friendly, biogenic synthesis strategy could be widely used for preparing inorganic/organic biocomposites. In addition, we also discuss the possible mechanism of the reduction of SeO32- ions by Capsicum annuum L extract.

  9. Compressive behavior of wire reinforced bulk metallic glass matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung-Yub [Department of Materials Science, M/C 138-78, California Institute of Technology, Pasadena, CA 91125 (United States); Clausen, Bjorn [Lujan Neutron Science Center, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Uestuendag, Ersan [Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011 (United States)]. E-mail: ustundag@iastate.edu; Choi-Yim, Haein [Department of Materials Science, M/C 138-78, California Institute of Technology, Pasadena, CA 91125 (United States); Aydiner, C. Can [Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011 (United States); Bourke, Mark A.M. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2005-06-15

    Bulk metallic glasses (BMGs) possess a unique set of mechanical properties that make them attractive structural materials. However, when loaded without constraint, BMGs fracture catastrophically due to formation of macroscopic shear bands and this behavior reduces their reliability. To address this issue, BMG matrix composites have been developed. In this investigation, neutron diffraction was used during uniaxial compressive loading to measure the internal strains in the second phases of various BMG composites reinforced with Ta, Mo, or stainless steel wires. The diffraction data were then employed to develop a finite element model that deduced the in situ constitutive behavior of each phase. It was found that the reinforcements yielded first and started transferring load to the matrix, which remained elastic during the whole experiment. While the present composites exhibited enhanced ductility, largely due to their ductile reinforcements, they yielded at applied stresses lower than those found in W reinforced composites.

  10. Ceramic fiber reinforced glass-ceramic matrix composite

    Science.gov (United States)

    Bansal, Narottam P. (Inventor)

    1993-01-01

    A slurry of BSAS glass powders is cast into tapes which are cut to predetermined sizes. Mats of continuous chemical vapor deposition (CVD)-SiC fibers are alternately stacked with these matrix tapes. This tape-mat stack is warm-pressed to produce a 'green' composite which is heated to burn out organic constituents. The remaining interim material is then hot-pressed to form a BSAS glass-ceramic fiber-reinforced composite.

  11. Metallic-fibre-reinforced ceramic-matrix composite

    International Nuclear Information System (INIS)

    Prevost, F.; Schnedecker, G.; Boncoeur, M.

    1994-01-01

    A refractory metal wire cloth is embedded in an oxide ceramic matrix, using a plasma spraying technology, in order to elaborate composite plates. When mechanically tested, the composite fails with a pseudo-ductile fracture mode whereas the ceramic alone is originally brittle. It exhibits a higher fracture strength, and remains in the form of a single piece even when straining is important. No further heat treatment is needed after the original processing to reach these characteristics. (authors). 2 figs., 2 refs

  12. Thermosetting Polymer-Matrix Composites for Strucutral Repair Applications

    Energy Technology Data Exchange (ETDEWEB)

    Goertzen, William Kirby [Iowa State Univ., Ames, IA (United States)

    2007-12-01

    Several classes of thermosetting polymer matrix composites were evaluated for use in structural repair applications. Initial work involved the characterization and evaluation of woven carbon fiber/epoxy matrix composites for structural pipeline repair. Cyanate ester resins were evaluated as a replacement for epoxy in composites for high-temperature pipe repair applications, and as the basis for adhesives for resin infusion repair of high-temperature composite materials. Carbon fiber/cyanate ester matrix composites and fumed silica/cyanate ester nanocomposites were evaluated for their thermal, mechanical, viscoelastic, and rheological properties as they relate to their structure, chemistry, and processing characteristics. The bisphenol E cyanate ester under investigation possesses a high glass transition temperature, excellent mechanical properties, and unique ambient temperature processability. The incorporate of fumed silica served to enhance the mechanical and rheological properties of the polymer and reduce thermal expansion without sacrificing glass transition or drastically altering curing kinetics. Characterization of the composites included dynamic mechanical analysis, thermomechanical analysis, differential scanning calorimetry, thermogravimetric analysis, rheological and rheokinetic evaluation, and transmission electron microscopy.

  13. Load transfer in short fibre reinforced metal matrix composites

    International Nuclear Information System (INIS)

    Garces, Gerardo; Bruno, Giovanni; Wanner, Alexander

    2007-01-01

    The internal load transfer and the deformation behaviour of aluminium-matrix composites reinforced with 2D-random alumina (Saffil) short fibres was studied for different loading modes. The evolution of stress in the metallic matrix was measured by neutron diffraction during in situ uniaxial deformation tests. Tensile and compressive tests were performed with loading axis parallel or perpendicular to the 2D-reinforcement plane. The fibre stresses were computed based on force equilibrium considerations. The results are discussed in light of a model recently established by the co-authors for composites with visco-plastic matrix behaviour and extended to the case of plastic deformation in the present study. Based on that model, the evolution of internal stresses and the macroscopic stress-strain were simulated. Comparison between the experimental and computational results shows a qualitative agreement in all relevant aspects

  14. Metal matrix composites: History, status, factors and future

    Science.gov (United States)

    Cyriac, Ajith James

    The history, status, and future of metal matrix composites are presented by evaluating the progression of available literature through time. The trends that existed and issues that still prevail are discussed and a prediction of the future for MMCs is presented. The factors that govern the performance of metal matrix composites are also discussed. In many developed countries and in several developing countries there exists continued interest in MMCs. Researchers tried numerous combinations of matrices and reinforcements since work strictly on MMCs began in the 1950s. This led to developments for aerospace and defense applications, but resultant commercial applications were limited. The introduction of ceramic whiskers as reinforcement and the development of 'in-situ' eutectics in the 1960s aided high temperature applications in aircraft engines. In the late 1970s the automobile industries started to take MMCs seriously. In the last 20 years, MMCs evolved from laboratories to a class of materials with numerous applications and commercial markets. After the collapse of the Berlin Wall, prevailing order in the world changed drastically. This effect was evident in the progression of metal matrix composites. The internet connected the world like never before and tremendous information was available for researchers around the world. Globalization and the internet resulted in the transformation of the world to a more level playing field, and this effect is evident in the nature and source of research on metal matrix composites happening around the world.

  15. Metal matrix composites. Part 1. Types, properties, applications

    International Nuclear Information System (INIS)

    Edil da Costa, C.; Velasco Lopez, F.; Torralba Castello, M.

    2000-01-01

    An overview on the state of the art of metal matrix composites used in the automotive and aerospace industries is made. These materials usually are based on light alloys (Al, Ti and Mg) and reinforced with fibres or particles. In this review, it is presented a general scope on the different MMCs families, about their properties and their main applications. (Author) 61 refs

  16. Analysis of Damage in a Ceramic Matrix Composite

    DEFF Research Database (Denmark)

    Sørensen, Bent F.; Talreja, Ramesh

    1993-01-01

    Mechanisms of damage and the associated mechanical response are stud ied for a unidirectionally fiber-reinforced ceramic matrix composite subjected to uniaxial tensile loading parallel to fibers. A multi-stage development of damage is identified, and for each stage the governing mechanisms...

  17. Demineralized dentin matrix composite collagen material for bone tissue regeneration.

    Science.gov (United States)

    Li, Jianan; Yang, Juan; Zhong, Xiaozhong; He, Fengrong; Wu, Xiongwen; Shen, Guanxin

    2013-01-01

    Demineralized dentin matrix (DDM) had been successfully used in clinics as bone repair biomaterial for many years. However, particle morphology of DDM limited it further applications. In this study, DDM and collagen were prepared to DDM composite collagen material. The surface morphology of the material was studied by scanning electron microscope (SEM). MC3T3-E1 cells responses in vitro and tissue responses in vivo by implantation of DDM composite collagen material in bone defect of rabbits were also investigated. SEM analysis showed that DDM composite collagen material evenly distributed and formed a porous scaffold. Cell culture and animal models results indicated that DDM composite collagen material was biocompatible and could support cell proliferation and differentiation. Histological evaluation showed that DDM composite collagen material exhibited good biocompatibility, biodegradability and osteoconductivity with host bone in vivo. The results suggested that DDM composite collagen material might have a significant clinical advantage and potential to be applied in bone and orthopedic surgery.

  18. Characterization and control of the fiber-matrix interface in ceramic matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Lowden, R.A.

    1989-03-01

    Fiber-reinforced SiC composites fabricated by thermal-gradient forced-flow chemical-vapor infiltration (FCVI) have exhibited both composite (toughened) and brittle behavior during mechanical property evaluation. Detailed analysis of the fiber-matrix interface revealed that a silica layer on the surface of Nicalon Si-C-O fibers tightly bonds the fiber to the matrix. The strongly bonded fiber and matrix, combined with the reduction in the strength of the fibers that occurs during processing, resulted in the observed brittle behavior. The mechanical behavior of Nicalon/SiC composites has been improved by applying thin coatings (silicon carbide, boron, boron nitride, molybdenum, carbon) to the fibers, prior to densification, to control the interfacial bond. Varying degrees of bonding have been achieved with different coating materials and film thicknesses. Fiber-matrix bond strengths have been quantitatively evaluated using an indentation method and a simple tensile test. The effects of bonding and friction on the mechanical behavior of this composite system have been investigated. 167 refs., 59 figs., 18 tabs.

  19. Residual stresses and mechanical properties of metal matrix composites

    International Nuclear Information System (INIS)

    Persson, Christer.

    1993-01-01

    The large difference in coefficient of thermal expansion of the matrix and particles in a metal matrix composite will introduce residual stresses during cooling from process temperature. These stresses are locally very high, and are known to influence the mechanical behaviour of the material. Changes in the stress state will occur during heat treatments and when the material is loaded due to different elastic, plastic, and creep properties of the constituents. The change of residual stresses in an Al-SiC particulate composite after different degree of plastic straining has been studied. The effect of plastic straining was modelled by an Eshelby model. The model and the measurements both show that the stress in the loading direction decreases for a tensile plastic strain and increases for a compressive plastic strain. By x-ray diffraction the stress response in the matrix and particles can be measured independently. This has been used to determine the stress state under and after heat treatments and under mechanical loading in two Al 15% SiC metal matrix composites. By analysing the line width from x-ray experiment the changes in the microstrains in the material were studied. A finite element model was used to model the generation of thermal residual stresses, stress relaxation during heat treatments, and load sharing during the first load cycle. Calculated stresses and microstrains were found to be in good agreement with the measured values. The elastic behaviour of the composite can be understood largely in terms of elastic load transfer between matrix and particles. However, at higher loads when the matrix becomes plastic residual stresses also become important. 21 refs

  20. Dual-nanoparticulate-reinforced aluminum matrix composite materials

    International Nuclear Information System (INIS)

    Kwon, Hansang; Cho, Seungchan; Kawasaki, Akira; Leparoux, Marc

    2012-01-01

    Aluminum (Al) matrix composite materials reinforced with carbon nanotubes (CNT) and silicon carbide nanoparticles (nano-SiC) were fabricated by mechanical ball milling, followed by hot-pressing. Nano-SiC was used as an active mixing agent for dispersing the CNTs in the Al powder. The hardness of the produced composites was dramatically increased, up to eight times higher than bulk pure Al, by increasing the amount of nano-SiC particles. A small quantity of aluminum carbide (Al 4 C 3 ) was observed by TEM analysis and quantified using x-ray diffraction. The composite with the highest hardness values contained some nanosized Al 4 C 3 . Along with the CNT and the nano-SiC, Al 4 C 3 also seemed to play a role in the enhanced hardness of the composites. The high energy milling process seems to lead to a homogeneous dispersion of the high aspect ratio CNTs, and of the nearly spherical nano-SiC particles in the Al matrix. This powder metallurgical approach could also be applied to other nanoreinforced composites, such as ceramics or complex matrix materials. (paper)

  1. Carbide-reinforced metal matrix composite by direct metal deposition

    Science.gov (United States)

    Novichenko, D.; Thivillon, L.; Bertrand, Ph.; Smurov, I.

    Direct metal deposition (DMD) is an automated 3D laser cladding technology with co-axial powder injection for industrial applications. The actual objective is to demonstrate the possibility to produce metal matrix composite objects in a single-step process. Powders of Fe-based alloy (16NCD13) and titanium carbide (TiC) are premixed before cladding. Volume content of the carbide-reinforced phase is varied. Relationships between the main laser cladding parameters and the geometry of the built-up objects (single track, 2D coating) are discussed. On the base of parametric study, a laser cladding process map for the deposition of individual tracks was established. Microstructure and composition of the laser-fabricated metal matrix composite objects are examined. Two different types of structures: (a) with the presence of undissolved and (b) precipitated titanium carbides are observed. Mechanism of formation of diverse precipitated titanium carbides is studied.

  2. Cellular Magnesium Matrix Foam Composites for Mechanical Damping Applications

    Science.gov (United States)

    Shunmugasamy, Vasanth Chakravarthy; Mansoor, Bilal; Gupta, Nikhil

    2016-01-01

    The damping characteristics of metal alloys and metal matrix composites are relevant to the automotive, aerospace, and marine structures. Use of lightweight materials can help in increasing payload capacity and in decreasing fuel consumption. Lightweight composite materials possessing high damping capabilities that can be designed as structural members can greatly benefit in addressing these needs. In this context, the damping properties of lightweight metals such as aluminum and magnesium and their respective composites have been studied in the existing literature. This review focuses on analyzing the damping properties of aluminum and magnesium alloys and their cellular composites. The damping properties of various lightweight alloys and composites are compared on the basis of their density to understand the potential for weight saving in structural applications. Magnesium alloys are observed to possess better damping properties in comparison to aluminum. However, aluminum matrix syntactic foams reinforced with silicon carbide hollow particles possess a damping capacity and density comparable to magnesium alloy. By using the data presented in the study, composites with specific compositions and properties can be selected for a given application. In addition, the comparison of the results helps in identifying the areas where attention needs to be focused to address the future needs.

  3. Stochastic-Strength-Based Damage Simulation Tool for Ceramic Matrix and Polymer Matrix Composite Structures

    Science.gov (United States)

    Nemeth, Noel N.; Bednarcyk, Brett A.; Pineda, Evan J.; Walton, Owen J.; Arnold, Steven M.

    2016-01-01

    Stochastic-based, discrete-event progressive damage simulations of ceramic-matrix composite and polymer matrix composite material structures have been enabled through the development of a unique multiscale modeling tool. This effort involves coupling three independently developed software programs: (1) the Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC), (2) the Ceramics Analysis and Reliability Evaluation of Structures Life Prediction Program (CARES/ Life), and (3) the Abaqus finite element analysis (FEA) program. MAC/GMC contributes multiscale modeling capabilities and micromechanics relations to determine stresses and deformations at the microscale of the composite material repeating unit cell (RUC). CARES/Life contributes statistical multiaxial failure criteria that can be applied to the individual brittle-material constituents of the RUC. Abaqus is used at the global scale to model the overall composite structure. An Abaqus user-defined material (UMAT) interface, referred to here as "FEAMAC/CARES," was developed that enables MAC/GMC and CARES/Life to operate seamlessly with the Abaqus FEA code. For each FEAMAC/CARES simulation trial, the stochastic nature of brittle material strength results in random, discrete damage events, which incrementally progress and lead to ultimate structural failure. This report describes the FEAMAC/CARES methodology and discusses examples that illustrate the performance of the tool. A comprehensive example problem, simulating the progressive damage of laminated ceramic matrix composites under various off-axis loading conditions and including a double notched tensile specimen geometry, is described in a separate report.

  4. Fibre-matrix bond strength studies of glass, ceramic, and metal matrix composites

    Science.gov (United States)

    Grande, D. H.; Mandell, J. F.; Hong, K. C. C.

    1988-01-01

    An indentation test technique for compressively loading the ends of individual fibers to produce debonding has been applied to metal, glass, and glass-ceramic matrix composites; bond strength values at debond initiation are calculated using a finite-element model. Results are correlated with composite longitudinal and interlaminar shear behavior for carbon and Nicalon fiber-reinforced glasses and glass-ceramics including the effects of matrix modifications, processing conditions, and high-temperature oxidation embrittlement. The data indicate that significant bonding to improve off-axis and shear properties can be tolerated before the longitudinal behavior becomes brittle. Residual stress and other mechanical bonding effects are important, but improved analyses and multiaxial interfacial failure criteria are needed to adequately interpret bond strength data in terms of composite performance.

  5. Carbon fibre reinforced copper matrix composites: processing routes and properties

    Energy Technology Data Exchange (ETDEWEB)

    Le Petitcorps, Y. [Bordeaux-1 Univ., 33 - Pessac (France). ICMCB; Poueylaud, J.M. [Bordeaux-1 Univ., 33 - Pessac (France). ICMCB; Albingre, L. [Bordeaux-1 Univ., 33 - Pessac (France). ICMCB; Berdeu, B. [L`Electrolyse, 33 - Latresne (France); Lobstein, P. [L`Electrolyse, 33 - Latresne (France); Silvain, J.F. [Bordeaux-1 Univ., 33 - Pessac (France). ICMCB

    1997-06-01

    Copper matrix composites are of interest for applications in the electronic field which requires materials with high thermal conductivity properties. The use of carbon fibres can (1) decrease the density and the coefficient of thermal expansion of the material and (2) increase the stiffness and strength to rupture of the resulting composite. In order to produce cheap materials, chemical plating and uniaxial hot pressing processing routes were chosen. 1D-C{sub (P55Thornel)} / Cu prepregs were hot pressed in an argon atmosphere at 750 C during 30 min. The volume fraction of the fibres within the composite was in the range of 10-35%. Physical (density and thermal expansion coefficient) and thermal conductivity properties of the composite were in good agreement with the predictions. However this material exhibits very poor mechanical properties (Young`s modulus and tensile strength). Scanning electron microscopy (SEM) observations of the surfaces of ruptures have shown that (1) a very weak bonding between the graphite fibres and the copper matrix was formed and (2) the rupture of the composite was initiated in the matrix at the copper grain boundaries. In order to overcome these two difficulties, the carbon fibres were pre-coated with a thin layer (100 nm) of cobalt. The aim of the cobalt was to react with the carbon to form carbide compounds and as a consequence to increase the bonding between the metal and the fibre. The tensile properties ({sigma}{sub c}{sup R} and E{sub c}) of this composite were then increased by 50% in comparison with the former material; however the strain to rupture was still too weak ({epsilon}{sub c}{sup R} = 0.5%). In order to explain the role of each constituents, X-ray profiles and TEM analyses were done at the fibre/matrix interface and at the grain boundaries. Some modifications of the chemical plating steps were done to improve the purity of the copper. (orig.)

  6. Single walled carbon nanotube network—Tetrahedral amorphous carbon composite film

    Energy Technology Data Exchange (ETDEWEB)

    Iyer, Ajai, E-mail: ajai.iyer@aalto.fi; Liu, Xuwen; Koskinen, Jari [Department of Materials Science and Engineering, School of Chemical Technology, Aalto University, POB 16200, 00076 Espoo (Finland); Kaskela, Antti; Kauppinen, Esko I. [NanoMaterials Group, Department of Applied Physics, School of Science, Aalto University, POB 15100, 00076 Espoo (Finland); Johansson, Leena-Sisko [Department of Forest Products Technology, School of Chemical Technology, Aalto University, POB 16400, 00076 Espoo (Finland)

    2015-06-14

    Single walled carbon nanotube network (SWCNTN) was coated by tetrahedral amorphous carbon (ta-C) using a pulsed Filtered Cathodic Vacuum Arc system to form a SWCNTN—ta-C composite film. The effects of SWCNTN areal coverage density and ta-C coating thickness on the composite film properties were investigated. X-Ray photoelectron spectroscopy measurements prove the presence of high quality sp{sup 3} bonded ta-C coating on the SWCNTN. Raman spectroscopy suggests that the single wall carbon nanotubes (SWCNTs) forming the network survived encapsulation in the ta-C coating. Nano-mechanical testing suggests that the ta-C coated SWCNTN has superior wear performance compared to uncoated SWCNTN.

  7. Colon-specific pulsatile drug release provided by electrospun shellac nanocoating on hydrophilic amorphous composites.

    Science.gov (United States)

    Yang, Yao-Yao; Liu, Zhe-Peng; Yu, Deng-Guang; Wang, Ke; Liu, Ping; Chen, Xiaohong

    2018-01-01

    Colon-specific pulsatile drug release, as a combined drug controlled-release model, is a useful drug delivery manner for a series of diseases. New nanomedicines and related preparation methods are highly desired. With diclofenac sodium (DS) as a model drug, a new type of structural nanocomposite (SC), in which composite polyvinylpyrrolidone (PVP)-DS core was coated by shellac, was fabricated via modified coaxial electrospinning. For comparison, traditional PVP-DS monolithic hydrophilic nanocomposites (HCs) were generated using a traditional blending process. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR-FTIR), water contact angle (WCA), and in vitro dissolution and ex vivo permeation tests were conducted to characterize the composites. SEM images demonstrated that both composites were linear nanofibers with smooth surface morphology and cross sections. TEM disclosed that the SCs had a thin shellac sheath layer of approximately 12 nm. XRD and ATR-FTIR results demonstrated that the crystalline DS was converted into amorphous composites with PVP because of favorable secondary interactions. WCA and in vitro dissolution tests demonstrated that the sheath shellac layers in SC could resist acid conditions and provide typical colon-specific pulsatile release, rather than a pulsatile release of HC under acid conditions. Ex vivo permeation results demonstrated that the SCs were able to furnish a tenfold drug permeation rate than the DS particles on the colon membrane. A new SC with a shellac coating on hydrophilic amorphous nanocomposites could furnish a colon-specific pulsatile drug release profile. The modified coaxial process can be exploited as a useful tool to create nanocoatings.

  8. Research Progress on Carbon Nanotubes Reinforced Cu-matrix Composites

    Directory of Open Access Journals (Sweden)

    TAO Jing-mei

    2017-04-01

    Full Text Available The critical issues of CNTs/Cu composites were reviewed. The preparation techniques of the composites were classified, and the research progress on powder metallurgic methods, electrochemical methods and other methods was summarized, with an emphasis on the relationship between preparation methods and properties. The interfacial characteristic of the CNTs/Cu composites was analyzed, and the research progress and existing problems of mechanical properties, electrical properties, thermal properties and wear and friction properties of the composites were also summarized. It was pointed out that the key to increase the comprehensive properties of the composites is to obtain the homogeneous distribution of CNTs and good interfacial bonding between CNTs and the Cu matrix by improving the preparation methods.

  9. Internal friction in a new kind of metal matrix composites

    International Nuclear Information System (INIS)

    San Juan, J.; No, M.L.

    2006-01-01

    We have developed a new kind of metal matrix composites, based on powders of Cu-Al-Ni shape memory alloys (SMAs) surrounded by an indium matrix, specifically designed to exhibit high mechanical damping. The damping properties have been characterized by mechanical spectroscopy as a function of temperature between 150 and 400 K, frequency between 3 x 10 -3 and 3 Hz, and strain amplitude between 5 x 10 -6 and 10 -4 . The material exhibits, in some range of temperature, internal friction as high as 0.54. The extremely high damping is discussed in the light of the microstructure of the material, which has been characterized in parallel

  10. Laser cladding of wear resistant metal matrix composite coatings

    International Nuclear Information System (INIS)

    Yakovlev, A.; Bertrand, Ph.; Smurov, I.

    2004-01-01

    A number of coatings with wear-resistant properties as well as with a low friction coefficient are produced by laser cladding. The structure of these coatings is determined by required performance and realized as metal matrix composite (MMC), where solid lubricant serves as a ductile matrix (e.g. CuSn), reinforced by appropriate ceramic phase (e.g. WC/Co). One of the engineered coating with functionally graded material (FGM) structure has a dry friction coefficient 0.12. Coatings were produced by coaxial injection of powder blend into the zone of laser beam action. Metallographic and tribological examinations were carried out confirming the advanced performance of engineered coatings

  11. Metal matrix composite fabrication processes for high performance aerospace structures

    Science.gov (United States)

    Ponzi, C.

    A survey is conducted of extant methods of metal matrix composite (MMC) production in order to serve as a basis for prospective MMC users' selection of a matrix/reinforcement combination, cost-effective primary fabrication methods, and secondary fabrication techniques for the achievement of desired performance levels. Attention is given to the illustrative cases of structural fittings, control-surface connecting rods, hypersonic aircraft air inlet ramps, helicopter swash plates, and turbine rotor disks. Methods for technical and cost analysis modeling useful in process optimization are noted.

  12. Characterization of selected LDEF polymer matrix resin composite materials

    Science.gov (United States)

    Young, Philip R.; Slemp, Wayne S.; Witte, William G., Jr.; Shen, James Y.

    1991-01-01

    The characterization of selected graphite fiber reinforced epoxy (934 and 5208) and polysulfone (P1700) matrix resin composite materials which received 5 years and 10 months of exposure to the LEO environment on the Long Duration Exposure Facility is reported. Resin loss and a decrease in mechanical performance as well as dramatic visual effects were observed. However, chemical characterization including infrared, thermal, and selected solution property measurements showed that the molecular structure of the polymeric matrix had not changed significantly in response to this exposure. The potential effect of a silicon-containing molecular contamination of these specimens is addressed.

  13. Poly(borosiloxanes as precursors for carbon fiber ceramic matrix composites

    Directory of Open Access Journals (Sweden)

    Renato Luiz Siqueira

    2007-06-01

    Full Text Available Ceramic matrix composites (CMCs, constituted of a silicon boron oxycarbide (SiBCO matrix and unidirectional carbon fiber rods as a reinforcement phase, were prepared by pyrolysis of carbon fiber rods wrapped in polysiloxane (PS or poly(borosiloxane (PBS matrices. The preparation of the polymeric precursors involved hydrolysis/condensation reactions of alkoxysilanes in the presence and absence of boric acid, with B/Si atomic ratios of 0.2 and 0.5. Infrared spectra of PBS showed evidence of Si-O-B bonds at 880 cm-1, due to the incorporation of the crosslinker trigonal units of BO3 in the polymeric network. X ray diffraction analyses exhibited an amorphous character of the resulting polymer-derived ceramics obtained by pyrolysis up to 1000 °C under inert atmosphere. The C/SiBCO composites showed better thermal stability than the C/SiOC materials. In addition, good adhesion between the carbon fiber and the ceramic phase was observed by SEM microscopy

  14. Intermetallic matrix composites; Proceedings of the MRS Symposium, San Francisco, CA, Apr. 18-20, 1990

    International Nuclear Information System (INIS)

    Anton, D.L.; Martin, P.L.; Miracle, D.B.; Mcmeeking, R.

    1990-01-01

    The present volume on intermetallic matrix composites discusses the modeling, processing, microstructure/property relationships, and compatibility of intermetallic matrix composites. Attention is given to models for the strength of ductile matrix composites, innovative processing techniques for intermetallic matrix composites, ductile phase toughening of brittle intermetallics, and reactive synthesis of NbAl3 matrix composites. Topics addressed include solidification processing of NbCr2 alloys, Ta and Nb reinforced MoSi2, the microstructure and mechanical behavior of Ni3Al-matrix composites, and ductile-phase toughening of Cr3Si with chromium. Also discussed are dislocation morphologies in TiB2/NiAl, the development of highly impact resistant NiAl matrix composites, the effect of notches on the fatigue life of the SCS-6Ti3Al composite, and the chemical stability of fiber-metal matrix composites

  15. Inorganic Polymer Matrix Composite Strength Related to Interface Condition

    Directory of Open Access Journals (Sweden)

    John Bridge

    2009-12-01

    Full Text Available Resin transfer molding of an inorganic polymer binder was successfully demonstrated in the preparation of ceramic fiber reinforced engine exhaust valves. Unfortunately, in the preliminary processing trials, the resulting composite valves were too brittle for in-engine evaluation. To address this limited toughness, the effectiveness of a modified fiber-matrix interface is investigated through the use of carbon as a model material fiber coating. After sequential heat treatments composites molded from uncoated and carbon coated fibers are compared using room temperature 3-point bend testing. Carbon coated Nextel fiber reinforced geopolymer composites demonstrated a 50% improvement in strength, versus that of the uncoated fiber reinforced composites, after the 250 °C postcure.

  16. Progressive fracture of polymer matrix composite structures: A new approach

    Science.gov (United States)

    Chamis, C. C.; Murthy, P. L. N.; Minnetyan, L.

    1992-01-01

    A new approach independent of stress intensity factors and fracture toughness parameters has been developed and is described for the computational simulation of progressive fracture of polymer matrix composite structures. The damage stages are quantified based on physics via composite mechanics while the degradation of the structural behavior is quantified via the finite element method. The approach account for all types of composite behavior, structures, load conditions, and fracture processes starting from damage initiation, to unstable propagation and to global structural collapse. Results of structural fracture in composite beams, panels, plates, and shells are presented to demonstrate the effectiveness and versatility of this new approach. Parameters and guidelines are identified which can be used as criteria for structural fracture, inspection intervals, and retirement for cause. Generalization to structures made of monolithic metallic materials are outlined and lessons learned in undertaking the development of new approaches, in general, are summarized.

  17. Mechanical properties of aluminium matrix composites reinforced with intermetallics

    International Nuclear Information System (INIS)

    Torres, B.; Garcia-Escorial, A.; Ibanez, J.; Lieblich, M.

    2001-01-01

    In this work 2124 aluminium matrix composites reinforced with Ni 3 Al, NiAl, MoSi 2 and Cr 3 Si intermetallic powder particles have been investigated. For comparison purposes, un reinforced 2124 and reinforced with SiC have also been studied. In all cases, the same powder metallurgy route was used, i. e. the 2124 alloy was obtained by rapid solidification and the intermetallic particles by self-propagating high-temperature synthesis (SHS). The matrix and the intermetallics were mechanically blended, cold compacted and finally hot extruded. Tensile tests were carried out in T1 and T4 treatments. Results indicate that mechanical properties depend strongly on the tendency to form new phases at the matrix-intermetallic interface during processing and/or further thermal treatments. The materials which present better properties are those that present less reaction between matrix and intermetallic reinforcement, i. e. MoSi 2 and SiC reinforced composites. (Author) 9 refs

  18. Preparation and characterization of aluminium-silica metal matrix composite

    Science.gov (United States)

    Mallikarjuna, G. B.; Basavaraj, E.

    2018-04-01

    Aluminum alloys are widely used in aerospace and automobile industries due to their low density and good mechanical properties, better corrosion resistance and wear, low thermal coefficient of expansion as compared to conventional metals and alloys. The excellent properties of these materials and relatively low production cost make them a very attractive for a variety of applications. In this present work, Al alloy LM13-SiO2 composites were produced by stir casting method. The reinforcement SiO2 particle size used for preparation of composites are 106 µm, 150 µm, 250 µm and 355 µm with varying amount of 3 to 12 wt% in steps of 3. The prepared composite specimens were machined as per test standards. Effects of weight percentage of SiO2 particles on wear, tensile strength of Al alloy LM13-SiO2 composites have been investigated. The microstructures of the composites were studied to know the dispersion of the SiO2 particles in matrix. Experimental results shows that there is enhanced mechanical properties, when silica weighing 9% was added to the base aluminium alloy and also similar trend exists in all four different micron size of silica and also it has been observed that addition of SiO2 particles significantly improves wear resistance properties as compared with that of unreinforced matrix.

  19. Silver matrix composites reinforced with galvanically silvered particles

    OpenAIRE

    J. Śleziona; J. Wieczorek,

    2007-01-01

    Purpose: The paper presents the possibility of the application of metalic layers drifted with the use of the galvanic methods on the ceramic particles surface. The application of the layers was aimed at obtaining the rewetting of the reinforcing particles with the liquid silver in the course of the producing of silver matrix composites with the use of mechanical stirring method. To enable introducing of the iron powder and glass carbon powder to liquid silver the solution of covering the powd...

  20. Fracture Resistance Evaluation of Fibre Reinforced Brittle Matrix Composites

    Czech Academy of Sciences Publication Activity Database

    Dlouhý, Ivo; Chlup, Zdeněk

    2005-01-01

    Roč. 290, - (2005), s. 167-174 ISSN 1013-9826. [Fractography of Advanced Ceramic s /2./. Stará Lesná, 03.10.2004-06.10.2004] R&D Projects: GA AV ČR(CZ) IAA2041003; GA ČR(CZ) GA101/02/0683 Keywords : fibre-reinforced ceramic s * glass matrix composites * chevron notch Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 0.224, year: 2005

  1. Electron Beam Curing of Polymer Matrix Composites - CRADA Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Janke, C. J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howell, Dave [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Norris, Robert E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    1997-05-01

    The major cost driver in manufacturing polymer matrix composite (PMC) parts and structures, and one of the elements having the greatest effect on their quality and performance, is the standard thermal cure process. Thermal curing of PMCs requires long cure times and high energy consumption, creates residual thermal stresses in the part, produces volatile toxic by-products, and requires expensive tooling that is tolerant of the high cure temperatures.

  2. Matrix-reinforcement reactivity in P/M titanium matrix composites

    International Nuclear Information System (INIS)

    Amigo, V.; Romero, F.; Salvador, M. D.; Busquets, D.

    2007-01-01

    The high reactivity of titanium and the facility of the same one to form intermetallics makes difficult obtaining composites with this material and brings the need in any case of covering the principal fibres used as reinforcement. To obtain composites of titanium reinforced with ceramic particles ins proposed in this paper, for this reason it turns out to be fundamental to evaluate the reactivity between the matrix and reinforcement. Both titanium nitride and carbide (TiN and TiC) are investigated as materials of low reactivity whereas titanium silicide (TiSi 2 ) is also studied as materials of major reactivity, already stated by the scientific community. This reactivity will be analysed by means of scanning electron microscopy (SEM) there being obtained distribution maps of the elements that allow to establish the possible influence of the sintering temperature and time. Hereby the matrix-reinforcement interactions are optimized to obtain suitable mechanical properties. (Author) 39 refs

  3. Mechanical spectroscopy study on the Cu{sub 54}Zr{sub 40}Al{sub 6} amorphous matrix alloy at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Marques, P.W.B., E-mail: paulowilmar@df.ufscar.br [Departamento de Física, Universidade Federal de São Carlos, CP-676, São Carlos, SP (Brazil); Chaves, J.M.; Silva, P.S.; Florêncio, O. [Departamento de Física, Universidade Federal de São Carlos, CP-676, São Carlos, SP (Brazil); Moreno-Gobbi, A. [Instituto de Física, Facultad de Ciencias (UDELAR), Iguá 4225, CEP 11400 Montevideo (Uruguay); Aliaga, L.C.R.; Botta, W.J. [Departamento de Engenharia de Materiais, Universidade Federal de São Carlos, CP-676, São Carlos, SP (Brazil)

    2015-02-05

    Highlights: • Cu{sub 54}Zr{sub 40}Al{sub 6} alloy was characterized by mechanical spectroscopy at low temperature. • Flexural and ultrasonic methods showed peaks associated to rearrangement of clusters. • The peaks less stable were associated with annihilation of Zr or Cu clusters. • MHz range can be favors the formation of Cu an Al-centered icosahedral structures. • TEM images show an increase in the size and number of crystal in amorphous matrix. - Abstract: A mechanical spectroscopy study of Cu{sub 54}Zr{sub 40}Al{sub 6} bulk metallic glasses composites was carried out in the kHz and MHz frequency ranges, by means of flexural and ultrasonic methods, respectively, in the temperature interval 150–300 K. In internal friction and attenuation curves at low temperature were observed peaks which were associated with distortions in the configuration of atomic clusters, which absorbed different quantities of energy due to short and medium order rearrangements. Changes within the clusters or atomic jumps between clusters occurring in the specimen induced the onset of polyamorphic peaks, since electronic interactions and bonding changed abruptly.

  4. Processing of aluminum matrix composites by electroless plating and melt infiltration

    International Nuclear Information System (INIS)

    Leon, C.A.; Bourassa, A.-M.; Drew, R.A.L.

    2000-01-01

    Reduction of the SiC/ Al interaction and enhancement of wetting between reinforcements and molten aluminum was obtained by modifying the ceramic surface with deposition of nickel and copper coatings. The preparation of nickel- and copper-coated ceramic particles as precursors for MMC fabrication was studied. Al 2 O 3 and SiC powders were successfully coated with Ni and Cu using electroless metal plating. Uniform and continuous metal films were deposited on both, alumina and silicon carbide powders XRD showed that the Ni-P deposit was predominantly amorphous, while the copper deposit was essentially polycrystalline. Infiltration results showed that the use of the coated powders enhances the wettability between the matrix and ceramic phase when processing particulate MMCs by a vacuum infiltration technique, giving a porosity-free composite with a homogeneously distributed reinforcing phase. The coating promoted easy metal flow through the preform, compared to the non-infiltration behavior of the uncoated counterpart samples XRD microstructural analysis of the composites indicates the formation of intermetallic phases such as CuAl 2 , in the case of copper coating, and NiAl and NiAl 3 when nickel-coated powders are infiltrated. Metallization of the ceramics minimizes the interfacial reaction of the SiC/Al composites and promotes wetting of Al 2 O 3 reinforcements with liquid aluminum. Copyright (2000) AD-TECH - International Foundation for the Advancement of Technology Ltd

  5. High temperature resin matrix composites for aerospace structures

    Science.gov (United States)

    Davis, J. G., Jr.

    1980-01-01

    Accomplishments and the outlook for graphite-polyimide composite structures are briefly outlined. Laminates, skin-stiffened and honeycomb sandwich panels, chopped fiber moldings, and structural components were fabricated with Celion/LARC-160 and Celion/PMR-15 composite materials. Interlaminar shear and flexure strength data obtained on as-fabricated specimens and specimens that were exposed for 125 hours at 589 K indicate that epoxy sized and polyimide sized Celion graphite fibers exhibit essentially the same behavior in a PMR-15 matrix composite. Analyses and tests of graphite-polyimide compression and shear panels indicate that utilization in moderately loaded applications offers the potential for achieving a 30 to 50 percent reduction in structural mass compared to conventional aluminum panels. Data on effects of moisture, temperature, thermal cycling, and shuttle fluids on mechanical properties indicate that both LARC-160 and PMR-15 are suitable matrix materials for a graphite-polyimide aft body flap. No technical road blocks to building a graphite-polyimide composite aft body flap are identified.

  6. Assessment of hyaline cartilage matrix composition using near infrared spectroscopy.

    Science.gov (United States)

    Palukuru, Uday P; McGoverin, Cushla M; Pleshko, Nancy

    2014-09-01

    Changes in the composition of the extracellular matrix (ECM) are characteristic of injury or disease in cartilage tissue. Various imaging modalities and biochemical techniques have been used to assess the changes in cartilage tissue but lack adequate sensitivity, or in the case of biochemical techniques, result in destruction of the sample. Fourier transform near infrared (FT-NIR) spectroscopy has shown promise for the study of cartilage composition. In the current study NIR spectroscopy was used to identify the contributions of individual components of cartilage in the NIR spectra by assessment of the major cartilage components, collagen and chondroitin sulfate, in pure component mixtures. The NIR spectra were obtained using homogenous pellets made by dilution with potassium bromide. A partial least squares (PLS) model was calculated to predict composition in bovine cartilage samples. Characteristic absorbance peaks between 4000 and 5000 cm(-1) could be attributed to components of cartilage, i.e. collagen and chondroitin sulfate. Prediction of the amount of collagen and chondroitin sulfate in tissues was possible within 8% (w/dw) of values obtained by gold standard biochemical assessment. These results support the use of NIR spectroscopy for in vitro and in vivo applications to assess matrix composition of cartilage tissues, especially when tissue destruction should be avoided. Copyright © 2014. Published by Elsevier B.V.

  7. Characterization and processing of heat treated aluminium matrix composite

    Science.gov (United States)

    Doifode, Yogesh; Kulkarni, S. G.

    2018-05-01

    The present study is carried out to determine density and porosity of Aluminium bagasse ash reinforced composite produced by powder metallurgy method. Bagasse ash is used as reinforcement material having high silica and alumina contents and varied from 5 weight % to 40 weight%. The manufactured composite is heat treated, the main objective of heat treatment is to prepare the material structurally and physically fit for engineering application. The results showed that the density decreases with percentage increase in reinforcement of bagasse ash from 2.6618 gm/cm3 to 1.9830 gm/cm3 with the minimum value at 40 weight% bagasse ash without heat treatment whereas after heat treatment density of composite increases due filling up of voids and porous holes. Heat treatment processing is the key to this improvement, with the T6 heat treated composite to convene the reduced porosity of composite. Consequently aluminium metal matrix composite combines the strength of the reinforcement to achieve a combination of desirable properties not available in any single material. It may observe that porosity in case of powder metallurgy samples showed more porosity portions compare to the casting samples. In order to achieve optimality in structure and properties of Bagasse ash-reinforcement heat treatment techniques have evolved. Generally, the ceramic reinforcements increase the density of the base alloy during fabrication of composites. However, the addition of lightweight reinforcements reduces the density of the hybrid composites. The results also showed that, the density varies from to with minimum value at 40 wt. % BA. The results of the statistical analysis showed that there are significant differences among the means of each property of the composites at various levels of BA replacement .It was concluded that bagasse ash can be used as reinforcement and the produced composites have low density and heat treatment reduces porosity which could be used in automobile industry for

  8. Rapid, room-temperature synthesis of amorphous selenium/protein composites using Capsicum annuum L extract

    Energy Technology Data Exchange (ETDEWEB)

    Li Shikuo; Shen Yuhua; Xie Anjian; Yu Xuerong; Zhang Xiuzhen; Yang Liangbao; Li Chuanhao [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China)

    2007-10-10

    We describe the formation of amorphous selenium ({alpha}-Se)/protein composites using Capsicum annuum L extract to reduce selenium ions (SeO{sub 3}{sup 2-}) at room temperature. The reaction occurs rapidly and the process is simple and easy to handle. A protein with a molecular weight of 30 kDa extracted from Capsicum annuum L not only reduces the SeO{sub 3}{sup 2-} ions to Se{sup 0}, but also controls the nucleation and growth of Se{sup 0}, and even participates in the formation of {alpha}-Se/protein composites. The size and shell thickness of the {alpha}-Se/protein composites increases with high Capsicum annuum L extract concentration, and decreases with low reaction solution pH. The results suggest that this eco-friendly, biogenic synthesis strategy could be widely used for preparing inorganic/organic biocomposites. In addition, we also discuss the possible mechanism of the reduction of SeO{sub 3}{sup 2-} ions by Capsicum annuum L extract.

  9. Rapid, room-temperature synthesis of amorphous selenium/protein composites using Capsicum annuum L extract

    International Nuclear Information System (INIS)

    Li Shikuo; Shen Yuhua; Xie Anjian; Yu Xuerong; Zhang Xiuzhen; Yang Liangbao; Li Chuanhao

    2007-01-01

    We describe the formation of amorphous selenium (α-Se)/protein composites using Capsicum annuum L extract to reduce selenium ions (SeO 3 2- ) at room temperature. The reaction occurs rapidly and the process is simple and easy to handle. A protein with a molecular weight of 30 kDa extracted from Capsicum annuum L not only reduces the SeO 3 2- ions to Se 0 , but also controls the nucleation and growth of Se 0 , and even participates in the formation of α-Se/protein composites. The size and shell thickness of the α-Se/protein composites increases with high Capsicum annuum L extract concentration, and decreases with low reaction solution pH. The results suggest that this eco-friendly, biogenic synthesis strategy could be widely used for preparing inorganic/organic biocomposites. In addition, we also discuss the possible mechanism of the reduction of SeO 3 2- ions by Capsicum annuum L extract

  10. Electrochemical process for the manufacturing of titanium alloy matrix composites

    Directory of Open Access Journals (Sweden)

    V. Soare

    2009-07-01

    Full Text Available The paper presents a new method for precursors’ synthesis of titanium alloys matrix composites through an electrochemical process in molten calcium chloride. The cathode of the cell was made from metallic oxides powders and reinforcement ceramic particles, which were pressed and sintered into disk form and the anode from graphite. The process occurred at 850 °C, in two stages, at 2,7 / 3,2 V: the ionization of the oxygen in oxides and the reduction with calcium formed by electrolysis of calcium oxide fed in the electrolyte. The obtained composite precursors, in a form of metallic sponge, were consolidated by pressing and sintering. Chemical and structural analyses on composites samples were performed.

  11. Matrix resin effects in composite delamination - Mode I fracture aspects

    Science.gov (United States)

    Hunston, Donald L.; Moulton, Richard J.; Johnston, Norman J.; Bascom, Willard D.

    1987-01-01

    A number of thermoset, toughened thermoset, and thermoplastic resin matrix systems were characterized for Mode I critical strain energy release rates, and their composites were tested for interlaminar critical strain energy release rates using the double cantilever beam method. A clear correlation is found between the two sets of data. With brittle resins, the interlaminar critical strain energy release rates are somewhat larger than the neat resin values due to a full transfer of the neat resin toughness to the composite and toughening mechanisms associated with crack growth. With tougher matrices, the higher critical strain energy release rates are only partially transferred to the composites, presumably because the fibers restrict the crack-tip deformation zones.

  12. Mathematical model for choosing the nuclear safe matrix compositions for fissile material immobilization

    International Nuclear Information System (INIS)

    Gorshtein, A.I.; Matyunin, Yu.I.; Poluehktov, P.P.

    2000-01-01

    A mathematical model is proposed for preliminary choice of the nuclear safe matrix compositions for fissile material immobilization. The IBM PC computer software for nuclear safe matrix composition calculations is developed. The limiting concentration of fissile materials in the some used and perspective nuclear safe matrix compositions for radioactive waste immobilization is calculated [ru

  13. Nondestructive characterization of metal-matrix-composites by ultrasonic technique

    International Nuclear Information System (INIS)

    Lee, Joon Hyun

    1992-01-01

    Nondestructive characterizations using ultrasonic technique were conducted systematically on Al 2 O 3 short fiber reinforced pure Al and AC8A aluminium metal-matrix composites. In order to determine the elastic moduli of metal-matrix composites(MMCs), Al 2 O 3 /AC8A composites with volume fraction of Al 2 O 3 short fiber varying up to 30% were fabricated by squeeze casting technique. Pure Al and AC8A reinforced with Al 2 O 3 short fiber were also fabricated by changing the fabrication parameters such as the applied pressure, the volume fraction of fiber. The Influences of texture change associated with change of fabrication parameters were investigated using the sophisticated LFB acoustic microscope with the frequency of 225 MHz. Ultrasonic velocities of longitudinal, shear and Rayleigh waves of the composites were measured by pulse-echo method and line-focus-beam(LBF) acoustic microscope. Ultrasonic velocities of the longitudinal, the shear and Rayleigh waves were found to correlate primarily with the volume fraction of Al 2 O 3 . The elastic constants of composites including Young's Modulus, Shear Modulus, Bulk Modulus and Poisson's ratio were determined on the basis of the longitudinal and the shear wave velocities measured by an ultrasonic pulse-echo method. The Young's Modulus of the composites obtained by ultrasonic technique were slightly lower than those measured by 4-point-bend test and also showed relatively good agreements with the calculated results derived from the equal stress condition. The applicability of LFB acoustic microscope on material characterization of the MMCs was discussed on the basis of the relationships between Rayleigh wave velocity as a function of rotated angle of specimen and fabrication parameters of the MMCs.

  14. Effective utilizations of palm oil mill fly ash for synthetic amorphous silica and carbon zeolite composite synthesis

    Science.gov (United States)

    Utama, P. S.; Saputra, E.; Khairat

    2018-04-01

    Palm Oil Mill Fly Ash (POMFA) the solid waste of palm oil industry was used as a raw material for synthetic amorphous silica and carbon zeolite composite synthesis in order to minimize the wastes of palm oil industry. The alkaline extraction combine with the sol-gel precipitation and mechanical fragmentation was applied to produce synthetic amorphous silica. The byproduct, extracted POMFA was rich in carbon and silica content in a significant amount. The microwave heated hydrothermal process used to synthesize carbon zeolite composite from the byproduct. The obtained silica had chemical composition, specific surface area and the micrograph similar to commercial precipitated silica for rubber filler. The microwave heated hydrothermal process has a great potential for synthesizing carbon zeolite composite. The process only needs one-step and shorter time compare to conventional hydrothermal process.

  15. Aspects of fabrication aluminium matrix heterophase composites by suspension method

    Science.gov (United States)

    Dolata, A. J.; Dyzia, M.

    2012-05-01

    Composites with an aluminium alloy matrix (AlMMC) exhibit several advantageous properties such as good strength, stiffness, low density, resistance and dimensional stability to elevated temperatures, good thermal expansion coefficient and particularly high resistance to friction wear. Therefore such composites are more and more used in modern engineering constructions. Composites reinforced with hard ceramic particles (Al2O3, SiC) are gradually being implemented into production in automotive or aircraft industries. Another application of AlMMC is in the electronics industry, where the dimensional stability and capacity to absorb and remove heat is used in radiators. However the main problems are still: a reduction of production costs, developing methods of composite material tests and final product quality assessment, standardisation, development of recycling and mechanical processing methods. AlMMC production technologies, based on liquid-phase methods, and the shaping of products by casting methods, belong to the cheapest production methods. Application of a suspension method for the production of composites with heterophase reinforcement may turn out to be a new material and technological solution. The article presents the material and technological aspects of the transfer procedures for the production of composite suspensions from laboratory scale to a semi-industrial scale.

  16. Aspects of fabrication aluminium matrix heterophase composites by suspension method

    International Nuclear Information System (INIS)

    Dolata, A J; Dyzia, M

    2012-01-01

    Composites with an aluminium alloy matrix (AlMMC) exhibit several advantageous properties such as good strength, stiffness, low density, resistance and dimensional stability to elevated temperatures, good thermal expansion coefficient and particularly high resistance to friction wear. Therefore such composites are more and more used in modern engineering constructions. Composites reinforced with hard ceramic particles (Al 2 O 3 , SiC) are gradually being implemented into production in automotive or aircraft industries. Another application of AlMMC is in the electronics industry, where the dimensional stability and capacity to absorb and remove heat is used in radiators. However the main problems are still: a reduction of production costs, developing methods of composite material tests and final product quality assessment, standardisation, development of recycling and mechanical processing methods. AlMMC production technologies, based on liquid-phase methods, and the shaping of products by casting methods, belong to the cheapest production methods. Application of a suspension method for the production of composites with heterophase reinforcement may turn out to be a new material and technological solution. The article presents the material and technological aspects of the transfer procedures for the production of composite suspensions from laboratory scale to a semi-industrial scale.

  17. Aluminium matrix heterophase composites for air compressor pistons

    Directory of Open Access Journals (Sweden)

    M.Dyzia

    2011-04-01

    Full Text Available The article presents the results of surface test of composite shaped in the permanent mould casting process. As part of the research anddevelopment project realized in the Department of Materials Technology at the Silesian University of Technology, a pilot plant scale stand was built to manufacture of more than 50 kg suspensions in a single technological cycle. Made in industrial conditions castings to form in the five inner core mould mounted in GM110 permanent mould casting machine confirmed the possibility of the shaping the composite pistons. Castings made from composite suspension AlSi7Mg/SiC and AlSi7Mg/SiC + Cg according to the technology procedure were classified as correct and devoted to the proper machining forming working surfaces of the piston to the air compressor. Comparative tests were performed for the casting of unreinforced AlSi7Mg alloy and composite castings. To assess the ability to fill the mold cavity and the accuracy of mapping used in contour shape FRT analysis of the distance between the grooves on the surface of the piston skirt. Studies have confirmed the differences in the fluidity of alloy matrix and composites suspensions. The difference in the accuracy of the dimensional mapping mould does not disqualify of composite materials, all castings are classified as correct and used for machining.

  18. Surface modification of aluminum nitride by polysilazane and its polymer-derived amorphous silicon oxycarbide ceramic for the enhancement of thermal conductivity in silicone rubber composite

    Science.gov (United States)

    Chiu, Hsien Tang; Sukachonmakul, Tanapon; Kuo, Ming Tai; Wang, Yu Hsiang; Wattanakul, Karnthidaporn

    2014-02-01

    Polysilazane (PSZ) and its polymer-derived amorphous silicon oxycarbide (SiOC) ceramic were coated on aluminum nitride (AlN) by using a dip-coating method to allow moisture-crosslinking of PSZ on AlN, followed by heat treatment at 700 °C in air to convert PSZ into SiOC on AlN. The results from FTIR, XPS and SEM indicated that the surface of AlN was successfully coated by PSZ and SiOC film. It was found that the introduction of PSZ and SiOC film help improve in the interfacial adhesion between the modified AlN (PSZ/AlN and SiOC/AlN) and silicone rubber lead to the increase in the thermal conductivity of the composites since the thermal boundary resistance at the filler-matrix interface was decreased. However, the introduction of SiOC as an intermediate layer between AlN and silicone rubber could help increase the thermal energy transport at the filler-matrix interface rather than using PSZ. This result was due to the decrease in the surface roughness and thickness of SiOC film after heat treatment at 700 °C in air. Thus, in the present work, a SiOC ceramic coating could provide a new surface modification for the improvement of the interfacial adhesion between the thermally conductive filler and the matrix in which can enhance the thermal conductivity of the composites.

  19. Laser Surface Treatment and Modification of Aluminum Alloy Matrix Composites

    Science.gov (United States)

    Abbass, Muna Khethier

    2018-02-01

    The present work aimed to study the laser surface treatment and modification of Al-4.0%Cu-1.0%Mg alloy matrix composite reinforced with 10%SiC particles produced by stir casting. The specimens of the base alloy and composite were irradiated with an Nd:YAG laser of 1000 mJ, 1064 nm and 3 Hz . Dry wear test using the pin-on -disc technique at different sliding times (5-30 min) at a constant applied load and sliding speed were performed before and after laser treatment. Micro hardness and wear resistance were increased for all samples after laser hardening treatment. The improvement of these properties is explained by microstructural homogenization and grain refinement of the laser treated surface. Modification and refinement of SiC particles and grain refinement in the microstructure of the aluminum alloy matrix (α-Al) were observed by optical and SEM micrographs. The highest increase in hardness was 21.4% and 26.2% for the base alloy and composite sample respectively.

  20. Wear and impact resistance of HVOF sprayedceramic matrix composites coating

    Science.gov (United States)

    Prawara, B.; Martides, E.; Priyono, B.; Ardy, H.; Rikardo, N.

    2016-02-01

    Ceramic coating has the mechanical properties of high hardness and it is well known for application on wear resistance, but on the other hand the resistance to impact load is low. Therefore its use is limited to applications that have no impact loading. The aim of this research was to obtain ceramic-metallic composite coating which has improved impact resistance compared to conventional ceramic coating. The high impact resistance of ceramic-metallic composite coating is obtained from dispersed metallic alloy phase in ceramic matrix. Ceramic Matrix Composites (CMC) powder with chrome carbide (Cr3C2) base and ceramic-metal NiAl-Al2O3 with various particle sizes as reinforced particle was deposited on mild steel substrate with High Velocity Oxygen Fuel (HVOF) thermal spray coating. Repeated impact test showed that reinforced metallic phase size influenced impact resistance of CMC coating. The ability of CMC coating to absorb impact energy has improved eight times and ten times compared with original Cr3C2 and hard chrome plating respectively. On the other hand the high temperature corrosion resistance of CMC coating showed up to 31 cycles of heating at 800°C and water quenching cooling.

  1. Discontinuously reinforced titanium matrix composites for fusion applications

    International Nuclear Information System (INIS)

    Castro, V.; Leguey, T.; Monge, M.A.; Munoz, A.; Pareja, R.; Victoria, M.

    2002-01-01

    We have reinforced α-Ti with different contents of TiC particles using the in situ technique and conventional casting. Compositional and microstructural characterization of the TiC/Ti composite material was made by XRD and SEM-EDS. Tensile tests at RT, 723 and 973 K have been performed on samples heat treated at 1000 K for 30 min which were prepared from cold rolled material. The effect of the content, size and morphology of the TiC particles on the tensile properties has been investigated. The results indicate that the expected improvement in the mechanical characteristics of TiC/Ti composites is inhibited by the detrimental presence of coarse dendritic particles of TiC. The premature failure of these composites at RT is due to cracking of the coarse TiC particles. Local softening due to inhomogeneous plastic deformation of the Ti matrix appears to contribute to the tensile failure of the TiC/Ti composites deformed at 723 and 973 K.

  2. Discontinuously reinforced titanium matrix composites for fusion applications

    Energy Technology Data Exchange (ETDEWEB)

    Castro, V. E-mail: mvcastro@fis.uc3m.es; Leguey, T.; Monge, M.A.; Munoz, A.; Pareja, R.; Victoria, M

    2002-12-01

    We have reinforced {alpha}-Ti with different contents of TiC particles using the in situ technique and conventional casting. Compositional and microstructural characterization of the TiC/Ti composite material was made by XRD and SEM-EDS. Tensile tests at RT, 723 and 973 K have been performed on samples heat treated at 1000 K for 30 min which were prepared from cold rolled material. The effect of the content, size and morphology of the TiC particles on the tensile properties has been investigated. The results indicate that the expected improvement in the mechanical characteristics of TiC/Ti composites is inhibited by the detrimental presence of coarse dendritic particles of TiC. The premature failure of these composites at RT is due to cracking of the coarse TiC particles. Local softening due to inhomogeneous plastic deformation of the Ti matrix appears to contribute to the tensile failure of the TiC/Ti composites deformed at 723 and 973 K.

  3. Double Vacuum Bag Process for Resin Matrix Composite Manufacturing

    Science.gov (United States)

    Hou, Tan-Hung (Inventor); Jensen, Brian J. (Inventor)

    2007-01-01

    A double vacuum bag molding assembly with improved void management and laminate net shape control which provides a double vacuum enviromnent for use in fabricating composites from prepregs containing air and/or volatiles such as reactive resin matrix composites or composites from solvent containing prepregs with non-reactive resins matrices. By using two vacuum environments during the curing process, a vacuum can be drawn during a B-stage of a two-step cycle without placing the composite under significant relative pressure. During the final cure stage, a significant pressure can be applied by releasing the vacuum in one of the two environments. Inner and outer bags are useful for creating the two vacuum environments with a perforated tool intermediate the two. The composite is placed intermediate a tool plate and a caul plate in the first environment with the inner bag and tool plate defining the first environment. The second environment is characterized by the outer bag which is placed over the inner bag and the tool plate.

  4. Table-like magnetocaloric effect in Gd–Ni–Al amorphous/nanocrystalline composites

    International Nuclear Information System (INIS)

    Zheng, Qiang; Zhang, Linlin; Du, Juan

    2017-01-01

    In this work, Gd–Ni–Al amorphous/nanocrystalline composites produced by melt-spinning method with double magnetocaloric effect (MCE) plateaus have been developed. Two MCE plateaus, ∼4.7 J kg −1 K −1 (90–120 K) and ∼3.60 J kg −1 K −1 (250–275 K), were discovered in Gd 80 Ni 11.6 Al 8.4 for a magnetic field change of 0 to 5 T. For Gd 90 Ni 5.8 Al 4.2 , the plateau values are ∼3.90 J kg −1 K −1 (85–120 K) and ∼6.70 J kg −1 K −1 (265–280 K) for a magnetic field change of 0–5 T. The reason why MCE plateau formation was investigated and discussed. These composites having two MCE plateaus are competitive candidates for the ideal Ericsson cycle. (paper)

  5. High Dehumidification Performance of Amorphous Cellulose Composite Membranes prepared from Trimethylsilyl Cellulose

    KAUST Repository

    Puspasari, Tiara

    2018-04-11

    Cellulose is widely regarded as an environmentally friendly, natural and low cost material which can significantly contribute the sustainable economic growth. In this study, cellulose composite membranes were prepared via regeneration of trimethylsilyl cellulose (TMSC), an easily synthesized cellulose derivative. The amorphous hydrophilic feature of the regenerated cellulose enabled fast permeation of water vapour. The pore-free cellulose layer thickness was adjustable by the initial TMSC concentration and acted as an efficient gas barrier. As a result, a 5,000 GPU water vapour transmission rate (WVTR) at the highest ideal selectivity of 1.1 x 106 was achieved by the membranes spin coated from a 7% (w/w) TMSC solution. The membranes maintained a 4,000 GPU WVTR with selectivity of 1.1 x 104 in the mixed-gas experiments, surpassing the performances of the previously reported composite membranes. This study provides a simple way to not only produce high performance membranes but also to advance cellulose as a low-cost and sustainable membrane material for dehumidification applications.

  6. Metal Matrix Composite Material by Direct Metal Deposition

    Science.gov (United States)

    Novichenko, D.; Marants, A.; Thivillon, L.; Bertrand, P. H.; Smurov, I.

    Direct Metal Deposition (DMD) is a laser cladding process for producing a protective coating on the surface of a metallic part or manufacturing layer-by-layer parts in a single-step process. The objective of this work is to demonstrate the possibility to create carbide-reinforced metal matrix composite objects. Powders of steel 16NCD13 with different volume contents of titanium carbide are tested. On the base of statistical analysis, a laser cladding processing map is constructed. Relationships between the different content of titanium carbide in a powder mixture and the material microstructure are found. Mechanism of formation of various precipitated titanium carbides is investigated.

  7. Baseplates in metallic matrix composites for power and microwave applications

    International Nuclear Information System (INIS)

    Massiot, P.

    1997-01-01

    Baseplates for microelectronic devices in fields where transform environments are encountered, such as automotive or airborne must have some fundamental characteristics such as: high thermal conductivity, low density, good mechanical properties and a coefficient of thermal expansion (CTE) nearly equal to the microelectronic substrates and the components installed on the baseplates. Metallic matrix composites are very good candidates because they perfectly answer to those requirements. In this presentation, with some examples of electronic devices in power and microwave applications we will show the big interest to use this kind of material. (author)

  8. Steel-SiC Metal Matrix Composite Development. Final report

    International Nuclear Information System (INIS)

    Smith, Don D.

    2005-01-01

    One of the key materials challenges for Generation IV reactor technology is to improve the strength and resistance to corrosion and radiation damage in the metal cladding of the fuel pins during high-temperature operation. Various candidate Gen IV designs call for increasing core temperature to improve efficiency and facilitate hydrogen production, operation with molten lead moderator to use fast neutrons. Fuel pin lifetime against swelling and fracture is a significant limit in both respects. The goal of this project is to develop a method for fabricating SiC-reinforced high-strength steel. We are developing a metal-matrix composite (MMC) in which SiC fibers are be embedded within a metal matrix of steel, with adequate interfacial bonding to deliver the full benefit of the tensile strength of the SiC fibers in the composite. In the context of the mission of the SBIR program, this Phase I grant has been successful. The development of a means to attain interfacial bonding between metal and ceramic has been a pacing challenge in materials science and technology for a century. It entails matching or grading of thermal expansion across the interface and attaining a graded chemical composition so that impurities do not concentrate at the boundary to create a slip layer. To date these challenges have been solved in only a modest number of pairings of compatible materials, e.g. Kovar and glass, titanium and ceramic, and aluminum and ceramic. The latter two cases have given rise to the only presently available MMC materials, developed for aerospace applications. Those materials have been possible because the matrix metal is highly reactive at elevated temperature so that graded composition and intimate bonding happens naturally at the fiber-matrix interface. For metals that are not highly reactive at processing temperature, however, successful bonding is much more difficult. Recent success has been made with copper MMCs for cooling channels in first-wall designs for fusion

  9. Metal matrix composites synthesis, wear characteristics, machinability study of MMC brake drum

    CERN Document Server

    Natarajan, Nanjappan; Davim, J Paulo

    2015-01-01

    This book is dedicated to composite materials, presenting different synthesis processes, composite properties and their machining behaviour. The book describes also the problems on manufacturing of metal matrix composite components. Among others, it provides procedures for manufacturing of metal matrix composites and case studies.

  10. Discontinuously reinforced intermetallic matrix composites via XD synthesis. [exothermal dispersion

    Science.gov (United States)

    Kumar, K. S.; Whittenberger, J. D.

    1992-01-01

    A review is given of recent results obtained for discontinuously reinforced intermetallic matrix composites produced using the XD process. Intermetallic matrices investigated include NiAl, multiphase NiAl + Ni2AlTi, CoAl, near-gamma titanium aluminides, and Ll2 trialuminides containing minor amounts of second phase. Such mechanical properties as low and high temperature strength, compressive and tensile creep, elastic modulus, ambient ductility, and fracture toughness are discussed as functions of reinforcement size, shape, and volume fraction. Microstructures before and after deformation are examined and correlated with measured properties. An observation of interest in many of the systems examined is 'dispersion weakening' at high temperatures and high strain rates. This behavior is not specific to the XD process; rather similar observations have been reported in other discontinuous composites. Proposed mechanisms for this behavior are presented.

  11. Polarization Behavior of Squeeze Cast Al2O3 Fiber Reinforced Aluminum Matrix Composites

    International Nuclear Information System (INIS)

    Ham, S. H.; Kang, Y. C.; Cho, K. M.; Park, I. M.

    1992-01-01

    Electrochemical polarization behavior of squeeze cast Al 2 O 3 short fiber reinforced Al alloy matrix composites was investigated for the basic understanding of the corrosion properties of the composites. The composites were fabricated with variations of fiber volume fraction and matrix alloys. It was found that the reinforced composites are more susceptible to corrosion attack than the unreinforced matrix alloys in general. Corrosion resistance shows decreasing tendency with increasing Al 2 O 3 fiber volume fraction in AC8A matrix. Effect of the matrix alloys revealed that the AC8A Al matrix composite is less susceptible to corrosion attack than the 2024 and 7075 Al matrix composites. Effect of plastic deformation on electrochemical polarization behavior of the squeeze cast Al/Al 2 O 3 composites was examined after extrusion of AC8A-10v/o Al 2 O 3 . Result shows that corrosion resistance is deteriorated after plastic deformation

  12. Life Modeling and Design Analysis for Ceramic Matrix Composite Materials

    Science.gov (United States)

    2005-01-01

    The primary research efforts focused on characterizing and modeling static failure, environmental durability, and creep-rupture behavior of two classes of ceramic matrix composites (CMC), silicon carbide fibers in a silicon carbide matrix (SiC/SiC) and carbon fibers in a silicon carbide matrix (C/SiC). An engineering life prediction model (Probabilistic Residual Strength model) has been developed specifically for CMCs. The model uses residual strength as the damage metric for evaluating remaining life and is posed probabilistically in order to account for the stochastic nature of the material s response. In support of the modeling effort, extensive testing of C/SiC in partial pressures of oxygen has been performed. This includes creep testing, tensile testing, half life and residual tensile strength testing. C/SiC is proposed for airframe and propulsion applications in advanced reusable launch vehicles. Figures 1 and 2 illustrate the models predictive capabilities as well as the manner in which experimental tests are being selected in such a manner as to ensure sufficient data is available to aid in model validation.

  13. Effect of Fiber Poisson Contraction on Matrix Multicracking Evolution of Fiber-Reinforced Ceramic-Matrix Composites

    Science.gov (United States)

    Longbiao, Li

    2015-12-01

    An analytical methodology has been developed to investigate the effect of fiber Poisson contraction on matrix multicracking evolution of fiber-reinforced ceramic-matrix composites (CMCs). The modified shear-lag model incorporated with the Coulomb friction law is adopted to solve the stress distribution in the interface slip region and intact region of the damaged composite. The critical matrix strain energy criterion which presupposes the existence of an ultimate or critical strain energy limit beyond which the matrix fails has been adopted to describe matrix multicracking of CMCs. As more energy is placed into the composite, matrix fractures and the interface debonding occurs to dissipate the extra energy. The interface debonded length under the process of matrix multicracking is obtained by treating the interface debonding as a particular crack propagation problem along the fiber/matrix interface. The effects of the interfacial frictional coefficient, fiber Poisson ratio, fiber volume fraction, interface debonded energy and cycle number on the interface debonding and matrix multicracking evolution have been analyzed. The theoretical results are compared with experimental data of unidirectional SiC/CAS, SiC/CAS-II and SiC/Borosilicate composites.

  14. Machinability study of Al-TiC metal matrix composite

    Directory of Open Access Journals (Sweden)

    Siddappa P. N.

    2018-01-01

    Full Text Available Aluminum Metal Matrix Composites have emerged as an advanced class of structural materials have a combination of different, superior properties compared to an unreinforced matrix, which can result in a number of service benefits such as increased strength, higher elastic moduli, higher service temperature, low CTE, improved wear resistance, high toughness, etc. The excellent mechanical properties of these materials together with weight saving makes them very attractive for a variety of engineering applications in aerospace, automotive, electronic industries, etc. Hence, these materials provide as alternative substitutes for conventional engineering materials when specific mechanical properties necessary for required applications. In this work an attempt is made to study the machining parameters of Al6061/TiC MMC. The composite is developed by reinforcing TiC particles in varying proportions of 3, 6, 9 and 12 % weight fractions to the Al6061 matric alloy through stir casting technique. Cutting forces were measured by varying cutting speed and feed rate with constant depth of cut for different % weight fractions. The results showed that the cutting force increases with the increase of feed rate and decreases with the increase of cutting speed for all the weight fractions. Cutting parameters were optimized using Taguchi technique.

  15. Thermal expansion behaviour of high performance PEEK matrix composites

    International Nuclear Information System (INIS)

    Goyal, R K; Mulik, U P; Tiwari, A N; Negi, Y S

    2008-01-01

    The thermal expansion behaviour of high performance poly(ether-ether-ketone) (PEEK) composites reinforced with micro- (8 μm) and nano- (39 nm) sized Al 2 O 3 particles was studied. The distribution of Al 2 O 3 in the PEEK matrix was studied by scanning electron microscopy and transmission electron microscopy. The coefficient of thermal expansion (CTE) was reduced from 58 x 10 -6 deg. C -1 for pure PEEK to 22 x 10 -6 deg. C -1 at 43 vol% micro-Al 2 O 3 and to 23 x 10 -6 deg. C -1 at 12 vol% nano-Al 2 O 3 composites. For a given volume fraction, nano-Al 2 O 3 particles are more effective in reducing the CTE of composites than that of micro-Al 2 O 3 particles. This may be attributed to the much higher interfacial area or volume of nanocomposites than that of microcomposites. The upper limit and lower limit of the Schapery model separately fit closely the CTE of the micro- and nano-composites, respectively. Other models such as the rule of mixture and Kerner and Turner models were also correlated with the data

  16. Structural and functional polymer-matrix composites for electromagnetic applications

    Science.gov (United States)

    Wu, Junhua

    This dissertation addresses the science and technology of functional and structural polymer-matrix composite materials for electromagnetic applications, which include electromagnetic interference (EMI) shielding and low observability (Stealth). The structural composites are continuous carbon fiber epoxy-matrix composites, which are widely used for airframes. The functional composites are composites with discontinuous fillers and in both bulk and coating forms. Through composite structure variation, attractive electromagnetic properties have been achieved. With no degradation of the tensile strength or modulus, the shielding effectiveness of the structural composites has been improved by enhancing multiple reflections through light activation of the carbon fiber. The multiple reflections loss of the electromagnetic wave increases from 1.1 to 10.2 dB at 1.0 GHz due to the activation. Such a large effect of multiple reflections has not been previously reported in any material. The observability of these composites has been lowered by decreasing the electrical conductivity (and hence decreasing the reflection loss) through carbon fiber coating. The incorporation of mumetal, a magnetic alloy particulate filler (28-40 mum size), in a latex paint has been found to be effective for enhancing the shielding only if the electrical resistivity of the resulting composite coating is below 10 O.cm, as rendered by a conductive particulate filler, such as nickel flake (14-20 mum size). This effectiveness (39 dB at 1.0 GHz) is attributed to the absorption of the electromagnetic wave by the mumetal and the nickel flake, with the high conductivity rendered by the presence of the nickel flake resulting in a relatively high reflection loss of 15.5 dB. Without the nickel flake, the mumetal gives only 3 dB of shielding and 1.5 dB of reflection loss at 1.0 GHz. Nickel powder (0.3-0.5 mum size) has been found to be an effective filler for improving the shielding of polyethersulfone (PES

  17. Fabrication of metal-matrix composites and adaptive composites using ultrasonic consolidation process

    International Nuclear Information System (INIS)

    Kong, C.Y.; Soar, R.C.

    2005-01-01

    Ultrasonic consolidation (UC) has been used to embed thermally sensitive and damage intolerant fibres within aluminium matrix structures using high frequency, low amplitude, mechanical vibrations. The UC process can induce plastic flow in the metal foils being bonded, to allow the embedding of fibres at typically 25% of the melting temperature of the base metal and at a fraction of the clamping force when compared to fusion processes. To date, the UC process has successfully embedded Sigma silicon carbide (SiC) fibres, shape memory alloy wires and optical fibres, which are presented in this paper. The eventual aim of this research is targeted at the fabrication of adaptive composite structures having the ability to measure external stimuli and respond by adapting their structure accordingly, through the action of embedded active and passive functional fibres within a freeform fabricated metal-matrix structure. This paper presents the fundamental studies of this research to identify embedding methods and working range for the fabrication of adaptive composite structures. The methods considered have produced embedded fibre specimens in which large amounts of plastic flow have been observed, within the matrix, as it is deformed around the fibres, resulting in fully consolidated specimens without damage to the fibres. The microscopic observation techniques and macroscopic functionality tests confirms that the UC process could be applied to the fabrication of metal-matrix composites and adaptive composites, where fusion techniques are not feasible and where a 'cold' process is necessary

  18. Deformation behavior of an electrodeposited nano-Ni/amorphous Fe78Si9B13 laminated composite sheet

    Directory of Open Access Journals (Sweden)

    Zhang Kaifeng

    2015-01-01

    Full Text Available A nano-Ni/amorphous Fe78Si9B13 composite sheet was prepared in the form of three-ply (Ni-Fe78Si9B13-Ni laminated structure by an electrodeposition method. The average grain size of Ni layers is about 50 nm. The interface of laminated composite was investigated with SEM equipped with energy dispersive scanning (EDS and line analysis technique. The laminated composite has a good interfacial bonding between amorphous layer and nano-Ni layers due to the mutual diffusion of atoms in Fe78Si9B13 and Ni layers during the process of electrodeposition. A maximum elongation of 115.5% was obtained when the volume fraction of nano-Ni layers (VNi was 0.77, which is greatly higher than that of monolithic amorphous Fe78Si9B13 ribbon (36.3% tested under the same conditions. Bulging tests were carried out to evaluate plastic forming properties of the Fe78Si9B13/Ni laminated composite. Under the condition of 450 °C, 4.0 MPa and 30 min, a good bulging part with the relative bulging height (RBH of 0.4 was obtained.

  19. Influence of tool pin in friction stir welding on activated carbon reinforced aluminium metal matrix composite

    Science.gov (United States)

    DijuSamuel, G.; Raja Dhas, J. Edwin

    2017-10-01

    This paper focus on impact of tool pin in friction stir welding on activated carbon reinforced aluminium metal matrix composite. For fabrication of metal matrix composite AA6061 is used as matrix and activated carbon is used as reinforcement and it is casted using modified stir casting technique. After casting metal matrix composite has undergone various microstructure tests like SEM,EDAX and XRD. FSW is carried out in this metal matrix composite by choosing various tool pin profile like square,round,Threaded round, hexagon and taper. The quality of welded plates is measured in terms of ultimate tensile strength and hardness.

  20. Fabrication of Ceramic Matrix Composite Tubes Using a Porous Mullite/Alumina Matrix and Alumina/Mullite Fiber

    National Research Council Canada - National Science Library

    Radsick, Timothy

    2001-01-01

    ... or from inadequate oxide-based ones. A porous mullite/alumina matrix combined with alumina/mullite fiber reinforcement eliminates the need for an interface coating while producing a strong, tough and oxidation resistant composite...

  1. Kinetics of transformation of deformation processed gold-matrix composite

    Science.gov (United States)

    Wongpreedee, Kageeporn

    Gold matrix Ḏeformation-processed M&barbelow;etal M&barbelow;etal C&barbelow;omposites (DMMC) have been developed that have better strength and conductivity than conventional gold alloys. However, DMMC possess metastable two-phase microstructures, and their strength and conductivity decrease after prolonged exposure to elevated temperatures. The kinetics of the transformation from the metastable two-phase microstructure to the equilibrium single-phase solid solution is of interest. This document describes a study of the elevated temperature stability of Au DMMC's and the relationship between microstructure and resistivity of three compositions: Au-7 vol %Ag, Au-14 vol %Ag, and Au-vol 7%Pt. DMMC samples were prepared by a powder metallurgy technique and mechanical processes. The smallest final diameter of these wires was 120 mum. Avrami and Arrhenius relations were used to evaluate the kinetic transformation. The extensive deformation used to produce these composites reshaped the initially equi-axed powder particles into a nanofilamentary composite. Electrical resistivity measurements were used to determine the degree of transformation from the initial metastable nano-filamentary composite to the equilibrium solid solution condition. These measurements indicated that this transformation in Au-14 at%Ag, Au-7 at %Ag Au and Au-7 at %Pt DMMC wires proceeded with activation energies of 141, 156, and 167 kJ/mol, respectively. It is thought that these empirically determined activation energies differ from those determined in single crystal, planar interface Au-Ag and Au-Pt diffusion couples due to chemical potential, surface curvature, and strain effects. The DMMC systems reach the equilibrium solid solution condition faster than single crystal, planar interface systems for two reasons: (1) far more defects (dislocations, grain boundaries, vacancies from non-conservative dislocation motion, etc.) are present in the Au-Ag and Au-Pt DMMC composites, and (2) the small

  2. Effects of hydrogenation on thermal conductivity of ultrananocrystalline diamond/amorphous carbon composite films prepared via coaxial arc plasma deposition

    Science.gov (United States)

    Takeichi, Satoshi; Nishiyama, Takashi; Tabara, Mitsuru; Kawawaki, Shuichi; Kohno, Masamichi; Takahashi, Koji; Yoshitake, Tsuyoshi

    2018-06-01

    Ultrananocrystalline diamond (UNCD)/hydrogenated amorphous carbon (a-C:H) composite (UNCD/a-C:H) and UNCD/non-hydrogenated amorphous carbon (a-C) composite (UNCD/a-C) films were prepared via coaxial arc plasma deposition, and their thermal conductivity and interfacial conductance in grain boundaries were measured using a time-domain thermoreflectance method. The interfacial conductance was estimated to be 1,010 and 4,892 MW/(m2·K) for UNCD/a-C:H and UNCD/a-C films, respectively. The reasons for the hydrogenated film having lower interfacial conductance than the non-hydrogenated film are 1) the reduced number of carriers that contribute to heat transport and 2) the hydrogen atoms, which are preferentially located at the grain boundaries and enhance phonon scattering.

  3. Nonleachable Imidazolium-Incorporated Composite for Disruption of Bacterial Clustering, Exopolysaccharide-Matrix Assembly, and Enhanced Biofilm Removal.

    Science.gov (United States)

    Hwang, Geelsu; Koltisko, Bernard; Jin, Xiaoming; Koo, Hyun

    2017-11-08

    Surface-grown bacteria and production of an extracellular polymeric matrix modulate the assembly of highly cohesive and firmly attached biofilms, making them difficult to remove from solid surfaces. Inhibition of cell growth and inactivation of matrix-producing bacteria can impair biofilm formation and facilitate removal. Here, we developed a novel nonleachable antibacterial composite with potent antibiofilm activity by directly incorporating polymerizable imidazolium-containing resin (antibacterial resin with carbonate linkage; ABR-C) into a methacrylate-based scaffold (ABR-modified composite; ABR-MC) using an efficient yet simplified chemistry. Low-dose inclusion of imidazolium moiety (∼2 wt %) resulted in bioactivity with minimal cytotoxicity without compromising mechanical integrity of the restorative material. The antibiofilm properties of ABR-MC were assessed using an exopolysaccharide-matrix-producing (EPS-matrix-producing) oral pathogen (Streptococcus mutans) in an experimental biofilm model. Using high-resolution confocal fluorescence imaging and biophysical methods, we observed remarkable disruption of bacterial accumulation and defective 3D matrix structure on the surface of ABR-MC. Specifically, the antibacterial composite impaired the ability of S. mutans to form organized bacterial clusters on the surface, resulting in altered biofilm architecture with sparse cell accumulation and reduced amounts of EPS matrix (versus control composite). Biofilm topology analyses on the control composite revealed a highly organized and weblike EPS structure that tethers the bacterial clusters to each other and to the surface, forming a highly cohesive unit. In contrast, such a structured matrix was absent on the surface of ABR-MC with mostly sparse and amorphous EPS, indicating disruption in the biofilm physical stability. Consistent with lack of structural organization, the defective biofilm on the surface of ABR-MC was readily detached when subjected to low shear

  4. Advanced composite structures. [metal matrix composites - structural design criteria for spacecraft construction materials

    Science.gov (United States)

    1974-01-01

    A monograph is presented which establishes structural design criteria and recommends practices to ensure the design of sound composite structures, including composite-reinforced metal structures. (It does not discuss design criteria for fiber-glass composites and such advanced composite materials as beryllium wire or sapphire whiskers in a matrix material.) Although the criteria were developed for aircraft applications, they are general enough to be applicable to space vehicles and missiles as well. The monograph covers four broad areas: (1) materials, (2) design, (3) fracture control, and (4) design verification. The materials portion deals with such subjects as material system design, material design levels, and material characterization. The design portion includes panel, shell, and joint design, applied loads, internal loads, design factors, reliability, and maintainability. Fracture control includes such items as stress concentrations, service-life philosophy, and the management plan for control of fracture-related aspects of structural design using composite materials. Design verification discusses ways to prove flightworthiness.

  5. Composites of amorphous and nanocrystalline Zr–Cu–Al–Nb bulk materials synthesized by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Drescher, P., E-mail: philipp.drescher@uni-rostock.de [Fluidic Technology and Microfluidics, Faculty of Mechanical Engineering and Marine Technology, University of Rostock, 18059 Rostock (Germany); Witte, K. [Physics of New Materials, Institute of Physics, University of Rostock, 18051 Rostock (Germany); Yang, B. [Polymer Physics, Institute of Physics, University of Rostock, 18051 Rostock (Germany); Steuer, R.; Kessler, O. [Chair of Materials Science, Faculty of Mechanical Engineering and Marine Technology, University of Rostock, 18059 Rostock (Germany); Burkel, E. [Physics of New Materials, Institute of Physics, University of Rostock, 18051 Rostock (Germany); Schick, C. [Polymer Physics, Institute of Physics, University of Rostock, 18051 Rostock (Germany); Seitz, H. [Fluidic Technology and Microfluidics, Faculty of Mechanical Engineering and Marine Technology, University of Rostock, 18059 Rostock (Germany)

    2016-05-15

    The fabrication of Zr{sub 70}Cu{sub 24}Al{sub 4}Nb{sub 2} bulk metallic glass composite samples by spark plasma sintering (SPS) process has been successfully realized. The unique characteristics of bulk metallic glasses could lead to the possibility of future applications as new structural and functional materials. The densification of an amorphous Zr{sub 70}Cu{sub 24}Al{sub 4}Nb{sub 2} powder was realized in a systematic study changing the sintering temperature in the SPS process leading to stable composites characteristic of amorphous and nanocrystalline structures. X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) analysis, transmission electron microscopy (TEM) as well as hardness tests were applied to determine the structural and mechanical properties of the sintered materials. A stable amorphous bulk metallic glass based on Zr{sub 70}Cu{sub 24}Al{sub 4}Nb{sub 2} with a low fraction of crystallites could be fabricated applying a nominal sintering temperature of 400 °C. Higher sintering temperatures lead to composites with high fractions of nanocrystalline material with porosities below 0.5%.

  6. Friction stir welding of Aluminium matrix composites – A Review

    Directory of Open Access Journals (Sweden)

    Subramanya Prabhu

    2018-01-01

    Full Text Available Friction stir welding (FSW is established as one of the prominent welding techniques to join aluminium matrix composites (AMCs. It is a solid state welding process, takes place well below the melting temperature of the material, eliminates the detrimental effects of conventional fusion welding process. Although the process is capable to join AMCs, challenges are still open that need to be fulfill to widen its applications. This paper gives the outline of the friction stir welding technique used to join AMCs. Effect of process variables on the microstructure and mechanical properties of the joints, behavior of reinforcing materials during welding, effect of tool profiles on the joint strength are discussed in detail. Few improvements and direction for future research are also proposed.

  7. Design Concepts for Cooled Ceramic Matrix Composite Turbine Vanes

    Science.gov (United States)

    Boyle, Robert

    2014-01-01

    This project demonstrated that higher temperature capabilities of ceramic matrix composites (CMCs) can be used to reduce emissions and improve fuel consumption in gas turbine engines. The work involved closely coupling aerothermal and structural analyses for the first-stage vane of a high-pressure turbine (HPT). These vanes are actively cooled, typically using film cooling. Ceramic materials have structural and thermal properties different from conventional metals used for the first-stage HPT vane. This project identified vane configurations that satisfy CMC structural strength and life constraints while maintaining vane aerodynamic efficiency and reducing vane cooling to improve engine performance and reduce emissions. The project examined modifications to vane internal configurations to achieve the desired objectives. Thermal and pressure stresses are equally important, and both were analyzed using an ANSYS® structural analysis. Three-dimensional fluid and heat transfer analyses were used to determine vane aerodynamic performance and heat load distributions.

  8. Nondestructive Damage Evaluation in Ceramic Matrix Composites for Aerospace Applications

    Directory of Open Access Journals (Sweden)

    Konstantinos G. Dassios

    2013-01-01

    Full Text Available Infrared thermography (IRT and acoustic emission (AE are the two major nondestructive methodologies for evaluating damage in ceramic matrix composites (CMCs for aerospace applications. The two techniques are applied herein to assess and monitor damage formation and evolution in a SiC-fiber reinforced CMC loaded under cyclic and fatigue loading. The paper explains how IRT and AE can be used for the assessment of the material’s performance under fatigue. IRT and AE parameters are specifically used for the characterization of the complex damage mechanisms that occur during CMC fracture, and they enable the identification of the micromechanical processes that control material failure, mainly crack formation and propagation. Additionally, these nondestructive parameters help in early prediction of the residual life of the material and in establishing the fatigue limit of materials rapidly and accurately.

  9. Wear and Reactivity Studies of Melt infiltrated Ceramic Matrix Composite

    Science.gov (United States)

    Jarmon, David C.; Ojard, Greg; Brewer, David N.

    2013-01-01

    As interest grows in the use of ceramic matrix composites (CMCs) for critical gas turbine engine components, the effects of the CMCs interaction with the adjoining structure needs to be understood. A series of CMC/material couples were wear tested in a custom elevated temperature test rig and tested as diffusion couples, to identify interactions. Specifically, melt infiltrated silicon carbide/silicon carbide (MI SiC/SiC) CMC was tested in combination with a nickel-based super alloy, Waspaloy, a thermal barrier coating, Yttria Stabilized Zirconia (YSZ), and a monolithic ceramic, silicon nitride (Si3N4). To make the tests more representative of actual hardware, the surface of the CMC was kept in the as-received state (not machined) with the full surface features/roughness present. Test results include: scanning electron microscope characterization of the surfaces, micro-structural characterization, and microprobe analysis.

  10. Oxidation resistant coatings for ceramic matrix composite components

    Energy Technology Data Exchange (ETDEWEB)

    Vaubert, V.M.; Stinton, D.P. [Oak Ridge National Lab., TN (United States); Hirschfeld, D.A. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States). Dept. of Materials and Metallurgical Engineering

    1998-11-01

    Corrosion resistant Ca{sub 0.6}Mg{sub 0.4}Zr{sub 4}(PO{sub 4}){sub 6} (CMZP) and Ca{sub 0.5}Sr{sub 0.5}Zr{sub 4}(PO{sub 4}){sub 6} (CS-50) coatings for fiber-reinforced SiC-matrix composite heat exchanger tubes have been developed. Aqueous slurries of both oxides were prepared with high solids loading. One coating process consisted of dipping the samples in a slip. A tape casting process has also been created that produced relatively thin and dense coatings covering a large area. A processing technique was developed, utilizing a pre-sintering step, which produced coatings with minimal cracking.

  11. Composite superconductors with copper-aluminum stabilizing matrix

    International Nuclear Information System (INIS)

    Keilin, V.E.; Anashkin, O.P.; Krivikh, A.V.; Kiriya, I.V.; Kovalev, I.A.; Dolgosheev, P.I.; Rychagov, A.V.; Sytnikov, V.E.

    1992-01-01

    A new type of composite superconductors has been developed. They consist of one or several (cabled) multifilamentary wires with low Cu-to-Sc ratio which are embedded and soldered into grooves made in matrix of rectangular cross-section. The latter consists of aluminum core metallurgically plated with a thin copper sheath. Such conductors combine the advantages of both aluminum and copper as stabilizing materials. They have low density, exhibit almost not magnetoresistance, are relatively cheap and can be produced in very long pieces. Copper plating offers the possibility of soft soldering thus ensuring good electrical and thermal contact between superconducting wires and stabilizing matrix, and helping to join pieces to each other. the properties of two Nb-Ti conductors (3.5 x 2 mm 2 and 7x4 mm 2 ) are described in more detail. The first is used in SC coils for whole-body magnetoresonance tomography, and the second will be used in a open-quotes thinclose quotes coil for charged particles detector. The influence of aluminum purity on SC magnet behavior is also briefly discussed

  12. Poling of PVDF matrix composites for integrated structural load sensing

    Science.gov (United States)

    Haghiashtiani, Ghazaleh; Greminger, Michael A.; Zhao, Ping

    2014-03-01

    The purpose of this study is to create and evaluate a smart composite structure that can be used for integrated load sensing and structural health monitoring. In this structure, PVDF films are used as the matrix material instead of epoxy resin or other thermoplastics. The reinforcements are two layers of carbon fiber with one layer of Kevlar separating them. Due to the electrical conductivity properties of carbon fiber and the dielectric effect of Kevlar, the structure acts as a capacitor. Furthermore, the piezoelectric properties of the PVDF matrix can be used to monitor the response of the structure under applied loads. In order to exploit the piezoelectric properties of PVDF, the PVDF material must be polarized to align the dipole moments of its crystalline structure. The optimal condition for poling the structure was found by performing a 23 factorial design of experiment (DoE). The factors that were studied in DoE were temperature, voltage, and duration of poling. Finally, the response of the poled structure was monitored by exposing the samples to an applied load.

  13. Advanced Measurements of Silicon Carbide Ceramic Matrix Composites

    Energy Technology Data Exchange (ETDEWEB)

    Farhad Farzbod; Stephen J. Reese; Zilong Hua; Marat Khafizov; David H. Hurley

    2012-08-01

    Silicon carbide (SiC) is being considered as a fuel cladding material for accident tolerant fuel under the Light Water Reactor Sustainability (LWRS) Program sponsored by the Nuclear Energy Division of the Department of Energy. Silicon carbide has many potential advantages over traditional zirconium based cladding systems. These include high melting point, low susceptibility to corrosion, and low degradation of mechanical properties under neutron irradiation. In addition, ceramic matrix composites (CMCs) made from SiC have high mechanical toughness enabling these materials to withstand thermal and mechanical shock loading. However, many of the fundamental mechanical and thermal properties of SiC CMCs depend strongly on the fabrication process. As a result, extrapolating current materials science databases for these materials to nuclear applications is not possible. The “Advanced Measurements” work package under the LWRS fuels pathway is tasked with the development of measurement techniques that can characterize fundamental thermal and mechanical properties of SiC CMCs. An emphasis is being placed on development of characterization tools that can used for examination of fresh as well as irradiated samples. The work discuss in this report can be divided into two broad categories. The first involves the development of laser ultrasonic techniques to measure the elastic and yield properties and the second involves the development of laser-based techniques to measurement thermal transport properties. Emphasis has been placed on understanding the anisotropic and heterogeneous nature of SiC CMCs in regards to thermal and mechanical properties. The material properties characterized within this work package will be used as validation of advanced materials physics models of SiC CMCs developed under the LWRS fuels pathway. In addition, it is envisioned that similar measurement techniques can be used to provide process control and quality assurance as well as measurement of

  14. Development of antifriction composites based on polypyromellitimide matrix

    Energy Technology Data Exchange (ETDEWEB)

    Olifirov, L.K., E-mail: M80786@yandex.ru [National University of Science and Technology «MISIS» (Russian Federation); Kaloshkin, S.D.; Tcherdyntsev, V.V. [National University of Science and Technology «MISIS» (Russian Federation); Danilov, V.D. [Blagonravov Institute of Machines Science of Russian Academy of Sciences (Russian Federation)

    2014-02-15

    Highlights: • Polypyromellitimide powder from waste of production polyimide films were obtained. • Structure of polypyromellitimide strongly changes after high energy ball milling. • Addition of commercial polyimide powder improve moldability of polypyromellitimide. • Polypyromellitimide based composites show good tribological properties in dry friction mode. -- Abstract: A method of polypyromellitimide powder production from PM-A film was proposed and a possibility of fabricating bulk composites based on polypyromellitimide matrix was investigated. The powders were prepared by the treatment of PM-A films in a planetary ball mill. The compositions based on polypyromellitimide containing additives of Al{sub 65}Cu{sub 23}Fe{sub 12} quasicrystals, graphite, polytetrafluoroethylene and PI-PR-20 polyimide were prepared by the solid-state mixing in an IKA M20 batch mill. The bulk samples were fabricated by the compression molding technique. Thus produced materials were characterized by using the methods of sieve analysis, scanning electron microscopy, Fourier-transform infrared spectroscopy, dynamo-mechanical analysis and tribological tests. It was found that the PM-A polypyromellitimide powder had a low sinterability and, therefore, the bulk samples of unfilled PM-A and also the composites based on PM-A containing additives of Al{sub 65}Cu{sub 23}Fe{sub 12} quasicrystals, graphite and polytetrafluoroethylene exhibited a high brittleness and show unstable behavior in the tribological tests. It was found that an addition of 15 wt.% PI-PR-20 polyimide improved the sinterability of PM-A and also provides excellent antifriction properties.

  15. Multivariate Quantification of the Solid State Phase Composition of Co-Amorphous Naproxen-Indomethacin

    DEFF Research Database (Denmark)

    Beyer, Andreas; Grohganz, Holger; Löbmann, Korbinian

    2015-01-01

    To benefit from the optimized dissolution properties of active pharmaceutical ingredients in their amorphous forms, co-amorphisation as a viable tool to stabilize these amorphous phases is of both academic and industrial interest. Reports dealing with the physical stability and recrystallization...... components was prepared and analyzed by XRPD. In order to test the model performances, leave-one-out cross validation was performed and revealed root mean square errors of validation between 3.11% and 3.45% for the crystalline molar fractions and 5.57% for the co-amorphous molar fraction. In summary, even...

  16. Metal matrix coated fiber composites and the methods of manufacturing such composites

    Science.gov (United States)

    Weeks, J.K. Jr.; Gensse, C.

    1993-09-14

    A fiber coating which allows ceramic or metal fibers to be wetted by molten metals is disclosed. The coating inhibits degradation of the physical properties caused by chemical reaction between the fiber and the coating itself or between the fiber and the metal matrix. The fiber coating preferably includes at least a wetting layer, and in some applications, a wetting layer and a barrier layer between the fiber and the wetting layer. The wetting layer promotes fiber wetting by the metal matrix. The barrier layer inhibits fiber degradation. The fiber coating permits the fibers to be infiltrated with the metal matrix resulting in composites having unique properties not obtainable in pure materials. 8 figures.

  17. Wear mechanisms in powder metallurgy high speed steels matrix composites

    International Nuclear Information System (INIS)

    Gordo, E.; Martinez, M. A.; Torralba, J. M.; Jimenez, J. A.

    2001-01-01

    The development of metal matrix composites has a major interest for automotive and cutting tools industries since they possess better mechanical properties and wear resistance than corresponding base materials. One of the manufacturing methods for these materials includes processing by powder metallurgy techniques. in this case, blending of both, base material and reinforcement powders constitute the most important process in order to achieve a homogeneous distribution of second phase particles. in the present work, composite materials of M3/2 tool steel reinforced with 2.5,5 and 8 vol% of niobium carbide have been prepared. In order to ensure a homogeneous mix, powders of both materials were mixed by dry high-energy mechanical milling at 200 r.p.m. for 40 h. After a recovering annealing, two routes for consolidate were followed die pressing and vacuum sintering, and hot isostatic pressing (HIP). Pin-on-disc tests were carried out to evaluate wear behaviour in all the materials. Results show that ceramic particles additions improve wear resistance of base material. (Author) 9 refs

  18. Weibull modeling of particle cracking in metal matrix composites

    International Nuclear Information System (INIS)

    Lewis, C.A.; Withers, P.J.

    1995-01-01

    An investigation into the occurrence of reinforcement cracking within a particulate ZrO 2 /2618 Al alloy metal matrix composite under tensile plastic straining has been carried out, special attention being paid to the dependence of fracture on particle size and shape. The probability of particle cracking has been modeled using a Weibull approach, giving good agreement with the experimental data. Values for the Weibull modulus and the stress required to crack the particles were found to be within the range expected for the cracking of ceramic particles. Additional information regarding the fracture behavior of the particles was provided by in-situ neutron diffraction monitoring of the internal strains, measurement of the variation in the composite Young's modulus with straining and by direct observation of the cracked particles. The values of the particle stress required for the initiation of particle cracking deduced from these supplementary experiments were found to be in good agreement with each other and with the results from the Weibull analysis. Further, it is shown that while both the current experiments, as well as the previous work of others, can be well described by the Weibull approach, the exact values of the Weibull parameters do deduced are very sensitive to the approximations and the assumptions made in constructing the model

  19. The influence of matrix composition and reinforcement type on the properties of polysialate composites

    Science.gov (United States)

    Hammell, James A.

    There is a critical need for the development of materials for eliminating fire as a cause of death in aircraft accidents. Currently available composites that use organic matrices not only deteriorate at temperatures above 300°C but also emit toxic fumes. The results presented in this dissertation focus on the development of an inorganic matrix that does not burn or emit toxic fumes. The matrix, known as polysialate, can withstand temperatures in excess of 1000°C. The matrix behaves like a ceramic, but does not need high curing temperatures, so it can be processed like many common organic matrices. The major parameters evaluated in this dissertation are: (i) Influence of reinforcement type, (ii) Matrix formulation for both wet-dry durability and high temperature resistance, (iii) Influence of processing variables such as moisture reduction and storage, (iv) Tensile strain capacity of modified matrices and matrices reinforced with ceramic microfibers and discrete carbon fibers, and (v) analytical modeling of mechanical properties. For the reinforcement type; carbon, glass, and stainless steel wire fabrics were investigated. Carbon fabrics with 1, 3, 12, and 50k tows were used. A matrix chemical formulation that can withstand wetting and drying was developed. This formulation was tested at high temperatures to ascertain its stability above 400°C. On the topic of processing, shelf life of prepregged fabric layers and efficient moisture removal methods were studied. An analytical model based on layered reinforcement was developed for analyzing flexural specimens. It is shown that the new inorganic matrix can withstand wetting and drying, and also high temperature. The layered reinforcement concept provides accurate prediction of strength and stiffness for composites reinforced with 1k and 3k tows. The prepregged fabric layers can be stored for 14 days at -15°C without losing strength.

  20. Multivariate Quantification of the Solid State Phase Composition of Co-Amorphous Naproxen-Indomethacin

    Directory of Open Access Journals (Sweden)

    Andreas Beyer

    2015-10-01

    Full Text Available To benefit from the optimized dissolution properties of active pharmaceutical ingredients in their amorphous forms, co-amorphisation as a viable tool to stabilize these amorphous phases is of both academic and industrial interest. Reports dealing with the physical stability and recrystallization behavior of co-amorphous systems are however limited to qualitative evaluations based on the corresponding X-ray powder diffractograms. Therefore, the objective of the study was to develop a quantification model based on X-ray powder diffractometry (XRPD, followed by a multivariate partial least squares regression approach that enables the simultaneous determination of up to four solid state fractions: crystalline naproxen, γ-indomethacin, α-indomethacin as well as co-amorphous naproxen-indomethacin. For this purpose, a calibration set that covers the whole range of possible combinations of the four components was prepared and analyzed by XRPD. In order to test the model performances, leave-one-out cross validation was performed and revealed root mean square errors of validation between 3.11% and 3.45% for the crystalline molar fractions and 5.57% for the co-amorphous molar fraction. In summary, even four solid state phases, involving one co-amorphous phase, can be quantified with this XRPD data-based approach.

  1. Adjusting shape-memory properties of amorphous polyether urethanes and radio-opaque composites thereof by variation of physical parameters during programming

    International Nuclear Information System (INIS)

    Cui, J; Kratz, K; Lendlein, A

    2010-01-01

    Various composites have been prepared to improve the mechanical properties of shape-memory polymers (SMPs) or to incorporate new functionalities (e.g. magneto-sensitivity) in polymer matrices. In this paper, we systematically investigated the influence of the programming temperature T prog and the applied strain ε m as parameters of the shape-memory creation procedure (SMCP) on the shape-memory properties of an amorphous polyether urethane and radio-opaque composites thereof. Recovery under stress-free conditions was quantified by the shape recovery rate R r and the switching temperature T sw , while the maximum recovery stress σ max was determined at the characteristic temperature T σ,max under constant strain conditions. Excellent shape-memory properties were achieved in all experiments with R r values in between 80 and 98%. σ max could be tailored from 0.4 to 3.7 MPa. T sw and T σ,max could be systematically adjusted from 33 to 71 °C by variation of T prog for each investigated sample. The investigated radio-opaque shape-memory composites will form the material basis for mechanically active scaffolds, which could serve as an intelligent substitute for the extracellular matrix to study the influence of mechanical stimulation of tissue development

  2. Strength and fracture behavior of aluminide matrix composites with ceramic fibers

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, M.; Suganuma, K.; Niihara, K.

    1999-07-01

    This paper investigates the fracture behavior of FeAl and Ni{sub 3}Al matrix composites with ceramic continuous fibers 8.5--10 {micro}m in diameter. When stress is applied to these composites, multiple-fracture of fibers predominantly occurs before matrix cracking, because the load carried by the fibers reaches their fracture strength. Fragments which remain longer than the critical length can provide significant strengthening through load bearing even though fiber breaking has occurred. The ultimate fracture strength of the composites also depends on stress relaxation by plastic deformation of the matrix at a crack tip in the multiple-fractured fibers. Ductilizing of the matrix by B doping improves the ultimate strength at ambient temperatures in both composites. However, their mechanical properties at elevated temperatures are quite different. In the case of Ni{sub 3}Al matrix composites, embrittlement of the matrix is undesirable for high strength and reliability at 873--973 K.

  3. Long-Term Stability of New Co-Amorphous Drug Binary Systems: Study of Glass Transitions as a Function of Composition and Shelf Time

    Directory of Open Access Journals (Sweden)

    Luz María Martínez

    2016-12-01

    Full Text Available The amorphous state is of particular interest in the pharmaceutical industry due to the higher solubility that amorphous active pharmaceutical ingredients show compared to their respective crystalline forms. Due to their thermodynamic instability, drugs in the amorphous state tend to recrystallize; in order to avoid crystallization, it has been a common strategy to add a second component to hinder the crystalline state and form a thermally stable co-amorphous system, that is to say, an amorphous binary system which retains its amorphous structure. The second component can be a small molecule excipient (such as a sugar or an aminoacid or a second drug, with the advantage that a second active pharmaceutical ingredient could be used for complementary or combined therapeutic purposes. In most cases, the compositions studied are limited to 1:1, 2:1 and 1:2 molar ratios, leaving a gap of information about phase transitions and stability on the amorphous state in a wider range of compositions. In the present work, a study of novel co–amorphous formulations in which the selection of the active pharmaceutical ingredients was made according to the therapeutic effect is presented. Resistance against crystallization and behavior of glass transition temperature ( T g were studied through calorimetric measurements as a function of composition and shelf time. It was found that binary formulations with T g temperatures higher than those of pure components presented long-term thermal stability. In addition, significant increments of T g values, of as much as 15 ∘ C, were detected as a result of glass relaxation at room temperature during storage time; this behavior of glass transition has not been previously reported for co-amorphous drugs. Based on these results, it can be concluded that monitoring behavior of T g and relaxation processes during the first weeks of storage leads to a more objective evaluation of the thermomechanical stability of an amorphous

  4. Economical Fabrication of Thick-Section Ceramic Matrix Composites

    Science.gov (United States)

    Babcock, Jason; Ramachandran, Gautham; Williams, Brian; Benander, Robert

    2010-01-01

    A method was developed for producing thick-section [>2 in. (approx.5 cm)], continuous fiber-reinforced ceramic matrix composites (CMCs). Ultramet-modified fiber interface coating and melt infiltration processing, developed previously for thin-section components, were used for the fabrication of CMCs that were an order of magnitude greater in thickness [up to 2.5 in. (approx.6.4 cm)]. Melt processing first involves infiltration of a fiber preform with the desired interface coating, and then with carbon to partially densify the preform. A molten refractory metal is then infiltrated and reacts with the excess carbon to form the carbide matrix without damaging the fiber reinforcement. Infiltration occurs from the inside out as the molten metal fills virtually all the available void space. Densification to thick-section components required modification of the conventional process conditions, and the means by which the large amount of molten metal is introduced into the fiber preform. Modification of the low-temperature, ultraviolet-enhanced chemical vapor deposition process used to apply interface coatings to the fiber preform was also required to accommodate the high preform thickness. The thick-section CMC processing developed in this work proved to be invaluable for component development, fabrication, and testing in two complementary efforts. In a project for the Army, involving SiC/SiC blisk development, nominally 0.8 in. thick x 8 in. diameter (approx. 2 cm thick x 20 cm diameter) components were successfully infiltrated. Blisk hubs were machined using diamond-embedded cutting tools and successfully spin-tested. Good ply uniformity and extremely low residual porosity (41 ksi (approx. 283 MPa) flexural strength.

  5. Magnetoresistance in amorphous NdFeB/FeB compositionally modulated multilayers

    International Nuclear Information System (INIS)

    Peral, G.; Briones, F.; Vicent, J.L.

    1991-01-01

    Resistance measurements have been done in amorphous Nd 12 Fe 80 B 8 sputtered films and in amorphous sputtered Nd 26 Fe 68 B 6 /Fe 92 B 8 multilayers between 6 and 150 K with applied magnetic field parallel (LMR) and perpendicular (TMR) up to 7 T. The samples were grown by dc triode sputtering, with nominal unequal (2:1) layer thicknesses. The layered character of the samples have been tested by x-ray diffraction. Longitudinal magnetoresistance (LMR) is positive and transverse magnetoresistance (TMR) is negative. The magnetoresistance values are higher than in amorphous ferromagnets, and multilayering of these alloys produces much larger magnetoresistance values than either alloy alone and there is a strong dependence on the multilayer wavelength. The MR shows a weak temperature dependence in the temperature interval that was investigated

  6. Creep Forming of Carbon-Reinforced Ceramic-Matrix Composites

    Science.gov (United States)

    Vaughn, Wallace L.; Scotti, Stephan J.; Ashe, Melissa P.; Connolly, Liz

    2007-01-01

    A set of lecture slides describes an investigation of creep forming as a means of imparting desired curvatures to initially flat stock plates of carbon-reinforced ceramic-matrix composite (C-CMC) materials. The investigation is apparently part of a continuing effort to develop improved means of applying small CCMC repair patches to reinforced carbon-carbon leading edges of aerospace vehicles (e.g., space shuttles) prior to re-entry into the atmosphere of the Earth. According to one of the slides, creep forming would be an intermediate step in a process that would yield a fully densified, finished C-CMC part having a desired size and shape (the other steps would include preliminary machining, finish machining, densification by chemical vapor infiltration, and final coating). The investigation included experiments in which C-CMC disks were creep-formed by heating them to unspecified high temperatures for time intervals of the order of 1 hour while they were clamped into single- and double-curvature graphite molds. The creep-formed disks were coated with an oxidation- protection material, then subjected to arc-jet tests, in which the disks exhibited no deterioration after exposure to high-temperature test conditions lasting 490 seconds.

  7. Environmental Barrier Coatings for Ceramic Matrix Composites - An Overview

    Science.gov (United States)

    Lee, Kang; van Roode, Mark; Kashyap, Tania; Zhu, Dongming; Wiesner, Valerie

    2017-01-01

    SiC/SiC Ceramic Matrix Composites (CMCs) are increasingly being considered as structural materials for advanced power generation equipment because of their light weight, higher temperature capability, and oxidation resistance. Limitations of SiC/SiC CMCs include surface recession and component cracking and associated chemical changes in the CMC. The solutions pursued to improve the life of SiC/SiC CMCs include the incorporation of coating systems that provide surface protection, which has become known as an Environmental Barrier Coating (EBC). The development of EBCs for the protection of gas turbine hot section CMC components was a continuation of coating development work for corrosion protection of silicon-based monolithics. Work on EBC development for SiC/SiC CMCs has been ongoing at several national laboratories and the original gas turbine equipment manufacturers. The work includes extensive laboratory, rig and engine testing, including testing of EBC coated SiC/SiC CMCs in actual field applications. Another EBC degradation issue which is especially critical for CMC components used in aircraft engines is the degradation from glassy deposits of calcium-magnesium-aluminosilicate (CMAS) with other minor oxides. This paper addresses the need for and properties of external coatings on SiC/SiC CMCs to extend their useful life in service and the retention of their properties.

  8. Milling of Nanoparticles Reinforced Al-Based Metal Matrix Composites

    Directory of Open Access Journals (Sweden)

    Alokesh Pramanik

    2018-03-01

    Full Text Available This study investigated the face milling of nanoparticles reinforced Al-based metal matrix composites (nano-MMCs using a single insert milling tool. The effects of feed and speed on machined surfaces in terms of surface roughness, surface profile, surface appearance, chip surface, chip ratio, machining forces, and force signals were analyzed. It was found that surface roughness of machined surfaces increased with the increase of feed up to the speed of 60 mm/min. However, at the higher speed (100–140 mm/min, the variation of surface roughness was minor with the increase of feed. The machined surfaces contained the marks of cutting tools, lobes of material flow in layers, pits and craters. The chip ratio increased with the increase of feed at all speeds. The top chip surfaces were full of wrinkles in all cases, though the bottom surfaces carried the evidence of friction, adhesion, and deformed material layers. The effect of feed on machining forces was evident at all speeds. The machining speed was found not to affect machining forces noticeably at a lower feed, but those decreased with the increase of speed for the high feed scenario.

  9. Mechanical and corrosion behaviors of developed copper-based metal matrix composites

    Science.gov (United States)

    Singh, Manvandra Kumar; Gautam, Rakesh Kumar; Prakash, Rajiv; Ji, Gopal

    2018-03-01

    This work investigates mechanical properties and corrosion resistances of cast copper-tungsten carbide (WC) metal matrix composites (MMCs). Copper matrix composites have been developed by stir casting technique. Different sizes of micro and nano particles of WC particles are utilized as reinforcement to prepare two copper-based composites, however, nano size of WC particles are prepared by high-energy ball milling. XRD (X-rays diffraction) characterize the materials for involvement of different phases. The mechanical behavior of composites has been studied by Vickers hardness test and compression test; while the corrosion behavior of developed composites is investigated by electrochemical impedance spectroscopy in 0.5 M H2SO4 solutions. The results show that hardness, compressive strength and corrosion resistance of copper matrix composites are very high in comparison to that of copper matrix, which attributed to the microstructural changes occurred during composite formation. SEM (Scanning electron microscopy) reveals the morphology of the corroded surfaces.

  10. Fundamental studies of low velocity impact resistance of graphite fiber reinforced polymer matrix composites

    International Nuclear Information System (INIS)

    Bowles, K.J.

    1985-01-01

    A study was conducted to relate the impact resistance of graphite fiber reinforced composites with matrix properties through gaining an understanding of the basic mechanics involved in the deformation and fracture process, and the effect of the polymer matrix structure on these mechanisms. It was found that the resin matrix structure influences the composite impact resistance in at least two ways. The integration of flexibilizers into the polymer chain structure tends to reduce the T/sub G/ and the mechanical properties of the polymer. The reduction in the mechanical properties of the matrix does not enhance the composite impact resistance because it allows matrix controlled failure to initiate impact damage. Linear polymers, which contain no active groups for cross-linking, do not toughen composites because the fiber-matrix interfacial bond is not of sufficient strength to prevent interfacial failure from occurring. Toughness must be built into the basic polymer backbone and cross-linking structure

  11. Wear Characterization of Aluminium/Basalt Fiber Reinforced Metal Matrix Composites - A Novel Material

    Directory of Open Access Journals (Sweden)

    P. Amuthakkannan

    2017-06-01

    Full Text Available Aluminum alloy based metal matrix composite participate have a wider applications in wear resistance applications. Attempt made in current study is that, basalt fiber reinforced aluminum metal matrix composite have been prepared using stir casting method. Different weight percentage of basalt fiber reinforced with Al (6061 metal matrix composites are used to study the wear resistance of the composites. For wear study, percentage of reinforcement, normal load and sliding velocity are the considered as important parameters. To study the effect of basalt fiber reinforcement on the dry sliding wear of Al6061 alloy composites the Pin On wear tester is used. Initially hardness of the composites was tested, it was found that increasing reinforcement in the composite hardness value of the composites also increased. Based on the Grey relation analysis (GRA the effects of wear resistance of the composites were studied.

  12. Interactions between tungsten carbide (WC) particulates and metal matrix in WC-reinforced composites

    International Nuclear Information System (INIS)

    Lou, D.; Hellman, J.; Luhulima, D.; Liimatainen, J.; Lindroos, V.K.

    2003-01-01

    A variety of experimental techniques have been used to investigate the interactions between tungsten carbide (WC-Co 88/12) particulates and the matrix in some new wear resistant cobalt-based superalloy and steel matrix composites produced by hot isostatic pressing. The results show that the chemical composition of the matrix has a strong influence on the interface reaction between WC and matrix and the structural stability of the WC particulates in the composite. Some characteristics of the interaction between matrix and reinforcement are explained by the calculation of diffusion kinetics. The three-body abrasion wear resistance of the composites has been examined based on the ASTM G65-91 standard procedure. The wear behavior of the best composites of this study shows great potential for wear protection applications

  13. Machinability of titanium metal matrix composites (Ti-MMCs)

    Science.gov (United States)

    Aramesh, Maryam

    Titanium metal matrix composites (Ti-MMCs), as a new generation of materials, have various potential applications in aerospace and automotive industries. The presence of ceramic particles enhances the physical and mechanical properties of the alloy matrix. However, the hard and abrasive nature of these particles causes various issues in the field of their machinability. Severe tool wear and short tool life are the most important drawbacks of machining this class of materials. There is very limited work in the literature regarding the machinability of this class of materials especially in the area of tool life estimation and tool wear. By far, polycrystalline diamond (PCD) tools appear to be the best choice for machining MMCs from researchers' point of view. However, due to their high cost, economical alternatives are sought. Cubic boron nitride (CBN) inserts, as the second hardest available tools, show superior characteristics such as great wear resistance, high hardness at elevated temperatures, a low coefficient of friction and a high melting point. Yet, so far CBN tools have not been studied during machining of Ti-MMCs. In this study, a comprehensive study has been performed to explore the tool wear mechanisms of CBN inserts during turning of Ti-MMCs. The unique morphology of the worn faces of the tools was investigated for the first time, which led to new insights in the identification of chemical wear mechanisms during machining of Ti-MMCs. Utilizing the full tool life capacity of cutting tools is also very crucial, due to the considerable costs associated with suboptimal replacement of tools. This strongly motivates development of a reliable model for tool life estimation under any cutting conditions. In this study, a novel model based on the survival analysis methodology is developed to estimate the progressive states of tool wear under any cutting conditions during machining of Ti-MMCs. This statistical model takes into account the machining time in

  14. Evaluation of dry sliding wear behavior of silicon particles reinforced aluminum matrix composites

    International Nuclear Information System (INIS)

    Sun Zhiqiang; Zhang Di; Li Guobin

    2005-01-01

    This paper reports a study on the wear property of powder metallurgy aluminum matrix composites 9Si/Al-Cu-Mg. A on rock wear-testing machine is used to evaluate the wear property of the composites, in which a GCrl5 steel ring is used as the counter face material. The wear behavior of the composites under different conditions is studied. The optical microscope and scanning electron microscope are used to analyze the worn surfaces and the subsurface of the composites in order to research the wear mechanism of the composites. Results indicate that the weight loss of the composite were lower than that of the matrix alloy

  15. Research and Development Progress of National Key Laboratory of Advanced Composites on Advanced Aeronautical Resin Matrix Composites

    Directory of Open Access Journals (Sweden)

    LI Bintai

    2016-06-01

    Full Text Available Applications and research progress in advanced aeronautical resin matrix composites by National Key Laboratory of Advanced Composites (LAC were summarized. A novel interlaminar toughening technology employing ultra-thin TP non-woven fabric was developed in LAC, which significantly improved the compression after impact (CAI performances of composite laminates.Newly designed multilayer sandwich stealth composite structures exhibited a good broadband radar absorbing properties at 1-18 GHz.There were remarkable developments in high toughness and high temperature resin matrix composites, covering major composite processing technologies such as prepreg-autoclave procedure, liquid composite molding and automation manufacture, etc. Finally, numerical simulation and optimization methods were deliberately utilized in the study of composites curing behavior, resin flow and curing deformation. A composite material database was also established.In conclusion, LAC has been a great support for the development of aeronautical equipment, playing such roles as innovation leading, system dominating, foundation supporting and application ensuring of aerocomposites.

  16. Fracture Toughness of Carbon Nanotube-Reinforced Metal- and Ceramic-Matrix Composites

    International Nuclear Information System (INIS)

    Chen, Y.L.; Liu, B.; Hwang, K.C.; Chen, Y.L.; Huang, Y.

    2011-01-01

    Hierarchical analysis of the fracture toughness enhancement of carbon nanotube- (CNT-) reinforced hard matrix composites is carried out on the basis of shear-lag theory and fracture mechanics. It is found that stronger CNT/matrix interfaces cannot definitely lead to the better fracture toughness of these composites, and the optimal interfacial chemical bond density is that making the failure mode just in the transition from CNT pull-out to CNT break. For hard matrix composites, the fracture toughness of composites with weak interfaces can be improved effectively by increasing the CNT length. However, for soft matrix composite, the fracture toughness improvement due to the reinforcing CNTs quickly becomes saturated with an increase in CNT length. The proposed theoretical model is also applicable to short fiber-reinforced composites.

  17. Fracture Toughness of Carbon Nanotube-Reinforced Metal- and Ceramic-Matrix Composites

    Directory of Open Access Journals (Sweden)

    Y. L. Chen

    2011-01-01

    Full Text Available Hierarchical analysis of the fracture toughness enhancement of carbon nanotube- (CNT- reinforced hard matrix composites is carried out on the basis of shear-lag theory and facture mechanics. It is found that stronger CNT/matrix interfaces cannot definitely lead to the better fracture toughness of these composites, and the optimal interfacial chemical bond density is that making the failure mode just in the transition from CNT pull-out to CNT break. For hard matrix composites, the fracture toughness of composites with weak interfaces can be improved effectively by increasing the CNT length. However, for soft matrix composite, the fracture toughness improvement due to the reinforcing CNTs quickly becomes saturated with an increase in CNT length. The proposed theoretical model is also applicable to short fiber-reinforced composites.

  18. On Poisson's ratio for metal matrix composite laminates. [aluminum boron composites

    Science.gov (United States)

    Herakovich, C. T.; Shuart, M. J.

    1978-01-01

    The definition of Poisson's ratio for nonlinear behavior of metal matrix composite laminates is discussed and experimental results for tensile and compressive loading of five different boron-aluminum laminates are presented. It is shown that there may be considerable difference in the value of Poisson's ratio as defined by a total strain or an incremental strain definition. It is argued that the incremental definition is more appropriate for nonlinear material behavior. Results from a (0) laminate indicate that the incremental definition provides a precursor to failure which is not evident if the total strain definition is used.

  19. High Temperature Degradation Mechanisms in Polymer Matrix Composites

    Science.gov (United States)

    Cunningham, Ronan A.

    1996-01-01

    Polymer matrix composites are increasingly used in demanding structural applications in which they may be exposed to harsh environments. The durability of such materials is a major concern, potentially limiting both the integrity of the structures and their useful lifetimes. The goal of the current investigation is to develop a mechanism-based model of the chemical degradation which occurs, such that given the external chemical environment and temperatures throughout the laminate, laminate geometry, and ply and/or constituent material properties, we can calculate the concentration of diffusing substances and extent of chemical degradation as functions of time and position throughout the laminate. This objective is met through the development and use of analytical models, coupled to an analysis-driven experimental program which offers both quantitative and qualitative information on the degradation mechanism. Preliminary analyses using a coupled diffusion/reaction model are used to gain insight into the physics of the degradation mechanisms and to identify crucial material parameters. An experimental program is defined based on the results of the preliminary analysis which allows the determination of the necessary material coefficients. Thermogravimetric analyses are carried out in nitrogen, air, and oxygen to provide quantitative information on thermal and oxidative reactions. Powdered samples are used to eliminate diffusion effects. Tests in both inert and oxidative environments allow the separation of thermal and oxidative contributions to specimen mass loss. The concentration dependency of the oxidative reactions is determined from the tests in pure oxygen. Short term isothermal tests at different temperatures are carried out on neat resin and unidirectional macroscopic specimens to identify diffusion effects. Mass loss, specimen shrinkage, the formation of degraded surface layers and surface cracking are recorded as functions of exposure time. Geometry effects

  20. Strain evolution after fiber failure in a single-fiber metal matrix composite under cyclic loading

    Energy Technology Data Exchange (ETDEWEB)

    Hanan, Jay C. [Department of Materials Science, California Institute of Technology, Pasadena, CA 91125 (United States)]. E-mail: jay.hanan@okstate.edu; Mahesh, Sivasambu [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Uestuendag, Ersan [Department of Materials Science, California Institute of Technology, Pasadena, CA 91125 (United States)]. E-mail: ersan@caltech.edu; Beyerlein, Irene J. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Swift, Geoffrey A. [Department of Materials Science, California Institute of Technology, Pasadena, CA 91125 (United States); Clausen, Bjorn [Department of Materials Science, California Institute of Technology, Pasadena, CA 91125 (United States); Brown, Donald W. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Bourke, Mark A.M. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2005-06-15

    The evolution of in situ elastic strain with cyclic tensile loading in each phase of a single Al{sub 2}O{sub 3}-fiber/aluminum-matrix composite was studied using neutron diffraction (ND). An analytical model appropriate for metal matrix composites (MMCs) was developed to connect the measured axial strain evolution in each phase with the possible micromechanical events that could occur during loading at room temperature: fiber fracture, interfacial slipping, and matrix plastic deformation. Model interpretation showed that the elastic strain evolution in the fiber and matrix was governed by fiber fracture and interface slipping and not by plastic deformation of the matrix, whereas the macroscopic stress-strain response of the composite was influenced by all three. The combined single-fiber composite model and ND experiment introduces a new and quick engineering approach for qualifying the micromechanical response in MMCs due to cyclic loading and fiber fracture.

  1. Strain evolution after fiber failure in a single-fiber metal matrix composite under cyclic loading

    International Nuclear Information System (INIS)

    Hanan, Jay C.; Mahesh, Sivasambu; Uestuendag, Ersan; Beyerlein, Irene J.; Swift, Geoffrey A.; Clausen, Bjorn; Brown, Donald W.; Bourke, Mark A.M.

    2005-01-01

    The evolution of in situ elastic strain with cyclic tensile loading in each phase of a single Al 2 O 3 -fiber/aluminum-matrix composite was studied using neutron diffraction (ND). An analytical model appropriate for metal matrix composites (MMCs) was developed to connect the measured axial strain evolution in each phase with the possible micromechanical events that could occur during loading at room temperature: fiber fracture, interfacial slipping, and matrix plastic deformation. Model interpretation showed that the elastic strain evolution in the fiber and matrix was governed by fiber fracture and interface slipping and not by plastic deformation of the matrix, whereas the macroscopic stress-strain response of the composite was influenced by all three. The combined single-fiber composite model and ND experiment introduces a new and quick engineering approach for qualifying the micromechanical response in MMCs due to cyclic loading and fiber fracture

  2. Application of ceramic short fiber reinforced Al alloy matrix composite on piston for internal combustion engines

    Directory of Open Access Journals (Sweden)

    Wu Shenqing

    2010-11-01

    Full Text Available The preparation and properties of ceramic short fiber reinforced Al-Si alloy matrix composite and it’s application on the piston for internal combustion engines are presented. Alumina or aluminosilicate fibers reinforced Al-Si alloy matrix composite has more excellent synthetical properties at elevated temperature than the matrix alloys. A partially reinforced Al-Si alloy matrix composite piston produced by squeeze casting technique has a firm interface between reinforced and unreinforced areas, low reject rate and good technical tolerance. As a new kind of piston material, it has been used for mass production of about 400,000 pieces of automobile engines piston. China has become one of a few countries in which aluminum alloy matrix composite materials have been used in automobile industry and attained industrialization.

  3. Synthesis and high temperature stability of amorphous Si(B)CN-MWCNT composite nanowires

    Science.gov (United States)

    Bhandavat, Romil; Singh, Gurpreet

    2012-02-01

    We demonstrate synthesis of a hybrid nanowire structure consisting of an amorphous polymer-derived silicon boron-carbonitride (Si-B-C-N) shell with a multiwalled carbon nanotube core. This was achieved through a novel process involving preparation of a boron-modified liquid polymeric precursor through a reaction of trimethyl borate and polyureasilazane under atmospheric conditions; followed by conversion of polymer to glass-ceramic on carbon nanotube surfaces through controlled heating. Chemical structure of the polymer was studied by liquid-NMR while evolution of various ceramic phases was studied by Raman spectroscopy, solid-NMR, Fourier transform infrared and X-ray photoelectron spectroscopy. Electron microscopy and X-ray diffraction confirms presence of amorphous Si(B)CN coating on individual nanotubes for all specimen processed below 1400 degree C. Thermogravimetric analysis, followed by TEM revealed high temperature stability of the carbon nanotube core in flowing air up to 1300 degree C.

  4. Effect of the type of radiation on the degradation behavior of polymer matrix composites

    International Nuclear Information System (INIS)

    Egusa, Shigenori

    1992-01-01

    Four kinds of polymer matrix composites (filler: E-glass or carbon fiber cloth; matrix; epoxy or polyimide resin) were irradiated with neutrons and 60 Co γ-rays at room temperature or at 5 K. Three-point bend tests were then carried out at 77 K. Comparison of the neutron and γ-ray irradiation effects shows that the radiation sensitivity of the glass/epoxy and glass/polyimide composites is 1.8-2.6 times higher to neutrons than to γ-rays, indicating a higher sensitivity of the epoxy and polyimide matrix resins to recoil protons than to γ-rays. Absorbed dose calculations, on the other hand, show that the spatial distribution of the microscopic energy deposition in polymer matrix composites is inhomogeneous for neutrons, although almost homogeneous for γ-rays. In addition, the neutron irradiation of boron-containing E-glass fiber composites produces additional radiation damage due to a 10 B(n,α) 7 Li reaction in the glass fibers, thus significantly enhancing a decrease in the composite strength. These facts indicate that as far as polymer matrix composites are concerned, the irradiation effects of neutrons will be rather difficult to simulate with different types of radiation such as protons and carbon ions from an ion accelerator. Thus, it may be prudent that such simulation irradiation be carried out mainly for pure resins to be used as matrix in polymer matrix composites. (author)

  5. Mechanism of radiation-induced degradation in mechanical properties of polymer matrix composites

    International Nuclear Information System (INIS)

    Egusa, Shigenori

    1988-01-01

    Four kinds of polymer matrix composites (filler, E-glass or carbon fibre cloth; matrix, epoxy or polyimide resin) and pure epoxy and polyimide resins were irradiated with 60 Co γ-rays or 2 MeV electrons at room temperature. Mechanical tests were then carried out at 77K and at room temperature. Following irradiation, the Young's (tensile) modulus of these composites and pure resins remains practically unchanged even at 170 MGy for both test temperatures. The ultimate strength, however, decreases appreciably with increasing dose. The dose dependence of the composite strength depends not only on the combination of fibre and matrix in the composite but also on the test temperature. A relationship is found between the composite ultimate strain and the matrix ultimate strain, thus indicating that the dose dependence of the composite strength is virtually determined by a change in the matrix ultimate strain due to irradiation. Based on this finding, we propose a mechanism of radiation-induced degradation of a polymer matrix composite in order to explain the dose dependence of the composite strength measured at 77 K and at room temperature. (author)

  6. Numerical Modeling of Macroscopic Behavior of Particulate Composite with Crosslinked Polymer Matrix

    Czech Academy of Sciences Publication Activity Database

    Náhlík, Luboš; Máša, B.; Hutař, Pavel

    2011-01-01

    Roč. 465, - (2011), s. 129-132 ISSN 1013-9826 R&D Projects: GA ČR GA106/08/1409 Institutional research plan: CEZ:AV0Z20410507 Keywords : Particle reinforced composites * polymer matrix composite * mechanical response Subject RIV: JI - Composite Materials

  7. NewIn-situ synthesis method of magnesium matrix composites reinforced with TiC particulates

    Directory of Open Access Journals (Sweden)

    Zhang Xiuqing

    2006-12-01

    Full Text Available Magnesium matrix composites reinforced with TiC particulates was prepared using a new in-situ synthesis method of remelting and dilution technique. And measurements were performed on the composites. The results of x ray diffraction (XRD analysis confirmed that TiC particulates were synthesized during the sintering process, and they retained in magnesium matrix composites after the remelting and dilution processing. From the microstructure characterization and electron probe microanalysis (EPMA, we could see that fine TiC particulates distributed uniformly in the matrix material.

  8. Environmental Barrier Coatings for Ceramic Matrix Composites - An Overview

    Science.gov (United States)

    Lee, Kang; Zhu, Dongming; Wiesner, Valerie Lynn; van Roode, Mark; Kashyap, Tania; Zhu, Dongming; Wiesner, Valerie

    2016-01-01

    Ceramic Matrix Composites (CMCs) are increasingly being considered as structural materials for advanced power generation equipment. Broadly speaking the two classes of materials are oxide-based CMCs and non-oxide based CMCs. The non-oxide CMCs are primarily silicon-based. Under conditions prevalent in the gas turbine hot section the water vapor formed in the combustion of gaseous or liquid hydrocarbons reacts with the surface-SiO2 to form volatile products. Progressive surface recession of the SiC-SiC CMC component, strength loss as a result of wall thinning and chemical changes in the component occur, which leads to the loss of structural integrity and mechanical strength and becomes life limiting to the equipment in service. The solutions pursued to improve the life of SiC-SiC CMCs include the incorporation of an external barrier coating to provide surface protection to the CMC substrate. The coating system has become known as an Environmental Barrier Coating (EBC). The relevant early coatings work was focused on coatings for corrosion protection of silicon-based monolithic ceramics operating under severely corrosive conditions. The development of EBCs for gas turbine hot section components was built on the early work for silicon-based monolithics. The first generation EBC is a three-layer coating, which in its simplest configuration consists of a silicon (Si) base coat applied on top of the CMC, a barium-strontium-aluminosilicate (BSAS) surface coat resistant to water vapor attack, and a mullite-based intermediate coating layer between the Si base coat and BSAS top coat. This system can be represented as Si-Mullite-BSAS. While this baseline EBC presented a significant improvement over the uncoated SiC-SiC CMC, for the very long durations of 3-4 years or more expected for industrial operation further improvements in coating durability are desirable. Also, for very demanding applications with higher component temperatures but shorter service lives more rugged EBCs

  9. Electrochemical synthesis, structure and phase composition of nano structured amorphous thin layers of NiW and Ni-Mo

    International Nuclear Information System (INIS)

    Vitina, I.; Lubane, M.; Belmane, V.; Rubene, V.; Krumina, A.

    2006-01-01

    Full text: Nano structured Ni-W thin layers containing W 6-37 wt.% were electrodeposited on a copper substratum. The W content in the layer changes, and it is determined by the electrolyte pH in the range 8.0-9.6 and the cathode current density in the range 1.0-10.0 A/dm 2 . The atomic composition and thermal stability of structure of the electrodeposited thin layers depend for the most part on the conditions of the electrodeposition and less on the W content in the layer. Cracking of the Ni-W layers electrodeposited at the electrolyte pH 8.5 and containing 34-37 wt.% W and 8.5 wt.% W was observed. The cracking increases at heating at 400 deg C for 50 h. On the contrary, no cracking of the Ni-W layer electrodeposited at the electrolyte pH 9.0 and containing 25 wt.% W was observed. The atomic composition of the layer remains practically unchanged at heating at 400 deg C for 50 h. The layer binds oxygen up to 7 wt.%. According to X-ray diffraction, in spite of the W content 35-37 wt.% in the layer, nano structured layers rather than amorphous layers were obtained which at heating at 400 deg C depending on the W content crystallises as Ni or intermetallic compounds Ni x W y if the W content is approx. 25 wt.%. Amorphous Ni-Mo alloys containing 35-52 wt.% Mo was electrodeposited on copper substratum at the cathode current densities of 0.5-1.5 A/dm2 and the electrolyte pH 6.8-8.6. Formation of thin layer (∼1-2μm) of X-ray amorphous Ni-Mo alloy, the Mo content, the characteristics of structure depend on the electrodeposition process, the electrolyte pH, and the cathode current density. The Ni-Mo layer deposited at the electrolyte pH above 8.6 and below average 6.8 had a nanocrystalline structure rather than characteristics of amorphous structure. Ni- W and Ni-Mo alloys were electrodeposited from citrate electrolyte not containing ammonium ions

  10. Electrical features of an amorphous indium-gallium-zinc-oxide film transistor using a double active matrix with different oxygen contents

    International Nuclear Information System (INIS)

    Koo, Ja Hyun; Kang, Tae Sung; Hong, Jin Pyo

    2012-01-01

    The electrical characteristics of amorphous indium-gallium-zinc-oxide (a-IGZO) thin film transistor (TFTs) are systematically studied using a double a-IGZO active layer that is composed of a-IGZO x (oxygen-ion-poor region) and a-IGZO y (oxygen-ion-rich-region). An active layer is designed to have a serially-stacked bi-layer matrix with different oxygen contents, providing the formation of different electron conduction channels. Two different oxygen contents in the active layer are obtained by varying the O 2 partial pressure during sputtering. The a-IGZO TFT based on a double active layer exhibits a high mobility of 9.1 cm 2 /Vsec, a threshold voltage (V T ) of 16.5 V, and ΔV T shifts of less than 1.5 V under gate voltage stress. A possible electrical sketch for the double active layer channel is also discussed.

  11. Morphological, structural and magnetic properties of α-Fe2O3 nanoparticles in an amorphous alumina matrix obtained by aqueous combustion method

    International Nuclear Information System (INIS)

    Tadic, Marin; Kusigerski, Vladan; Markovic, Dragana; Citakovic, Nada; Remskar, Maja; Spasojevic, Vojislav

    2009-01-01

    We report on morphological, structural and magnetic properties of α-Fe 2 O 3 nanoparticles in an amorphous alumina matrix synthesized by aqueous combustion method. The sample was characterized by X-ray powder diffraction (XRPD), high-resolution electron microscopy (HREM) and SQUID magnetometry. XRPD study reveals the phase purity of α-Fe 2 O 3 whereas HREM images show an unusual spongy structure and well-crystallized nanoparticles with a size of about 25 nm. Magnetic measurements show a high irreversibility temperature T irr ∼ 350 K, Morin transition at T M ∼ 210 K, increase of the magnetization below T ∼ 45 K and hysteretic behavior below T M at 5 K and 200 K.

  12. 3-D FEM Modeling of fiber/matrix interface debonding in UD composites including surface effects

    International Nuclear Information System (INIS)

    Pupurs, A; Varna, J

    2012-01-01

    Fiber/matrix interface debond growth is one of the main mechanisms of damage evolution in unidirectional (UD) polymer composites. Because for polymer composites the fiber strain to failure is smaller than for the matrix multiple fiber breaks occur at random positions when high mechanical stress is applied to the composite. The energy released due to each fiber break is usually larger than necessary for the creation of a fiber break therefore a partial debonding of fiber/matrix interface is typically observed. Thus the stiffness reduction of UD composite is contributed both from the fiber breaks and from the interface debonds. The aim of this paper is to analyze the debond growth in carbon fiber/epoxy and glass fiber/epoxy UD composites using fracture mechanics principles by calculation of energy release rate G II . A 3-D FEM model is developed for calculation of energy release rate for fiber/matrix interface debonds at different locations in the composite including the composite surface region where the stress state differs from the one in the bulk composite. In the model individual partially debonded fiber is surrounded by matrix region and embedded in a homogenized composite.

  13. An Amorphous Carbon Nitride Composite Derived from ZIF-8 as Anode Material for Sodium-Ion Batteries.

    Science.gov (United States)

    Fan, Jing-Min; Chen, Jia-Jia; Zhang, Qian; Chen, Bin-Bin; Zang, Jun; Zheng, Ming-Sen; Dong, Quan-Feng

    2015-06-08

    An composite comprising amorphous carbon nitride (ACN) and zinc oxide is derived from ZIF-8 by pyrolysis. The composite is a promising anode material for sodium-ion batteries. The nitrogen content of the ACN composite is as high as 20.4 %, and the bonding state of nitrogen is mostly pyridinic, as determined by X-ray photoelectron spectroscopy (XPS). The composite exhibits an excellent Na(+) storage performance with a reversible capacity of 430 mA h g(-1) and 146 mA h g(-1) at current densities of 83 mA g(-1) and 8.33 A g(-1) , respectively. A specific capacity of 175 mA h g(-1) was maintained after 2000 cycles at 1.67 A g(-1) , with only 0.016 % capacity degradation per cycle. Moreover, an accelerating rate calorimetry (ARC) test demonstrates the excellent thermal stability of the composite, with a low self heating rate and high onset temperature (210 °C). These results shows its promise as a candidate material for high-capacity, high-rate anodes for sodium-ion batteries. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Effects of High-Temperature Annealing in Air on Hi-Nicalon Fiber-Reinforced Celsian Matrix Composites

    Science.gov (United States)

    Bansal, Narottam P.

    2008-01-01

    BN/SiC-coated Hi-Nicalon fiber-reinforced celsian matrix composites (CMC) were annealed for 100 h in air at various temperatures to 1200 C, followed by flexural strength measurements at room temperature. Values of yield stress and strain, ultimate strength, and composite modulus remain almost unchanged for samples annealed up to 1100 C. A thin porous layer formed on the surface of the 1100 C annealed sample and its density decreased from 3.09 to 2.90 g/cu cm. The specimen annealed at 1200 C gained 0.43 wt%, was severely deformed, and was covered with a porous layer of thick shiny glaze which could be easily peeled off. Some gas bubbles were also present on the surface. This surface layer consisted of elongated crystals of monoclinic celsian and some amorphous phase(s). The fibers in this surface ply of the CMC had broken into small pieces. The fiber-matrix interface strength was characterized through fiber push-in technique. Values of debond stress, alpha(sub d), and frictional sliding stress, tau(sub f), for the as-fabricated CMC were 0.31+/-0.14 GPa and 10.4+/-3.1 MPa, respectively. These values compared with 0.53+/-0.47 GPa and 8.33+/-1.72 MPa for the fibers in the interior of the 1200 C annealed sample, indicating hardly any change in fiber-matrix interface strength. The effects of thermal aging on microstructure were investigated using scanning electron microscopy. Only the surface ply of the 1200 C annealed specimens had degraded from oxidation whereas the bulk interior part of the CMC was unaffected. A mechanism is proposed explaining the various steps involved during the degradation of the CMC on annealing in air at 1200 C.

  15. Microstructural evolution and strengthening behavior in in-situ magnesium matrix composites fabricated by solidification processing

    Energy Technology Data Exchange (ETDEWEB)

    Chelliah, Nagaraj M., E-mail: cmnraj.7@gmail.com [Department of Mechanical Engineering, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab (India); Singh, Harpreet, E-mail: harpreetsingh@iitrpr.ac.in [Department of Mechanical Engineering, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab (India); Surappa, M.K., E-mail: mirle@materials.iisc.ac.in [Department of Materials Engineering, Indian Institute of Science, Bengaluru 560012, Karnataka (India)

    2017-06-15

    In-situ magnesium matrix composites with three different matrix materials (including Mg, AZ91 and AE44 Mg-alloys) were fabricated by injecting cross-linked polymer directly into the molten Mg/Mg-alloys, and having it convert to the 2.5 vol% SiCNO ceramic phase using liquid stir-casting method. In-situ chemical reaction took place within the molten slurry tending to produce 42 and 18 vol% Mg{sub 2}Si crystals in Mg and AE44 matrix composites, respectively but not in AZ91 matrix composite. Microstructural evolution of Mg{sub 2}Si crystals was discussed on the basis of availability of heterogeneous nucleation sites and amount of Al-atoms in the molten slurry. The observed micro-hardness and yield strengths are enhanced by factor of four to three as compared to their unreinforced counterparts, and Taylor strengthening was found to be the predominant strengthening mechanism in magnesium and AE44 matrix composites. Summation model predicted the yield strengths of the fabricated composites more preciously when compared to Zhang and Chen, and modified Clyne models. - Highlights: • In-situ magnesium composites were fabricated using liquid stir-casting method. • In-situ pyrolysis of cross-linked polymer has been utilized to obtain ceramic phases. • Mg{sub 2}Si crystals were formed in magnesium and AE44 matrix composites but not in AZ91 matrix composites. • The variation in size and morphology of Mg{sub 2}Si crystals with matrix materials are discussed. • Strengthening mechanisms in in-situ composites are analyzed and discussed.

  16. Stress and Damage in Polymer Matrix Composite Materials Due to Material Degradation at High Temperatures

    Science.gov (United States)

    McManus, Hugh L.; Chamis, Christos C.

    1996-01-01

    This report describes analytical methods for calculating stresses and damage caused by degradation of the matrix constituent in polymer matrix composite materials. Laminate geometry, material properties, and matrix degradation states are specified as functions of position and time. Matrix shrinkage and property changes are modeled as functions of the degradation states. The model is incorporated into an existing composite mechanics computer code. Stresses, strains, and deformations at the laminate, ply, and micro levels are calculated, and from these calculations it is determined if there is failure of any kind. The rationale for the model (based on published experimental work) is presented, its integration into the laminate analysis code is outlined, and example results are given, with comparisons to existing material and structural data. The mechanisms behind the changes in properties and in surface cracking during long-term aging of polyimide matrix composites are clarified. High-temperature-material test methods are also evaluated.

  17. ASTM and VAMAS activities in titanium matrix composites test methods development

    Science.gov (United States)

    Johnson, W. S.; Harmon, D. M.; Bartolotta, P. A.; Russ, S. M.

    1994-01-01

    Titanium matrix composites (TMC's) are being considered for a number of aerospace applications ranging from high performance engine components to airframe structures in areas that require high stiffness to weight ratios at temperatures up to 400 C. TMC's exhibit unique mechanical behavior due to fiber-matrix interface failures, matrix cracks bridged by fibers, thermo-viscoplastic behavior of the matrix at elevated temperatures, and the development of significant thermal residual stresses in the composite due to fabrication. Standard testing methodology must be developed to reflect the uniqueness of this type of material systems. The purpose of this paper is to review the current activities in ASTM and Versailles Project on Advanced Materials and Standards (VAMAS) that are directed toward the development of standard test methodology for titanium matrix composites.

  18. THE STRUCTURE AND PROPERTIES OF COMPOSITE LASER CLAD COATINGS WITH Ni BASED MATRIX WITH WC PARTICLES

    Directory of Open Access Journals (Sweden)

    Zita Iždinská

    2010-09-01

    Full Text Available In this work, the influence of the processing conditions on the microstructure and abrasive wear behavior of composite laser clad coatings with Ni based matrix reinforced with 50% WC particles is analyzed. Composite powder was applied in the form of coatings onto a mild steel substrate (Fe–0.17% C by different laser powers and cladding speeds. The microstructure of the coatings was analyzed by scanning electron microscopy (SEM. Tribological properties of coatings were evaluated by pin-on-disc wear test. It appeared that the hardness of the matrix of composite coatings decreases with increasing cladding speed. However, wear resistance of composite coatings with decreasing hardness of Ni based matrix increases. Significantly enhanced wear resistance of WC composite coatings in comparison with Ni based coatings is attributed to the hard phase structures in composite coatings.

  19. Prediction of the creep properties of discontinuous fibre composites from the matrix creep law

    International Nuclear Information System (INIS)

    Bilde-Soerensen, J.B.; Boecker Pedersen, O.; Lilholt, H.

    1975-02-01

    Existing theories for predicting the creep properties of discontinuous fibre composites with non-creeping fibres from matrix creep properties, originally based on a power law, are extended to include an exponential law, and in principle a general matrixlaw. An analysis shows that the composite creep curve can be obtained by a simple displacement of the matrix creep curve in a log sigma vs. log epsilon diagram. This principle, that each point on the matrix curve has a corresponding point on the composite curve,is given a physical interpretation. The direction of displacement is such that the transition from a power law toan exponential law occurs at a lower strain rate for the composite than for the unreinforced matrix. This emphasizes the importance of the exponential creep range in the creep of fibre composites. The combined use of matrix and composite data may allow the creep phenomenon to be studied over a larger range of strain rates than otherwise possible. A method for constructing generalized composite creep diagrams is suggested. Creep properties predicted from matrix data by the present analysis are compared with experimental data from the literature. (author)

  20. Improving the corrosion wear resistance of AISI 316L stainless steel by particulate reinforced Ni matrix composite alloying layer

    Science.gov (United States)

    Xu, Jiang; Zhuo, Chengzhi; Tao, Jie; Jiang, Shuyun; Liu, Linlin

    2009-01-01

    In order to overcome the problem of corrosion wear of AISI 316L stainless steel (SS), two kinds of composite alloying layers were prepared by a duplex treatment, consisting of Ni/nano-SiC and Ni/nano-SiO2 predeposited by brush plating, respectively, and subsequent surface alloying with Ni-Cr-Mo-Cu by a double glow process. The microstructure of the two kinds of nanoparticle reinforced Ni-based composite alloying layers was investigated by means of SEM and TEM. The electrochemical corrosion behaviour of composite alloying layers compared with the Ni-based alloying layer and 316L SS under different conditions was characterized by potentiodynamic polarization test and electrochemical impedance spectroscopy. Results showed that under alloying temperature (1000 °C) conditions, amorphous nano-SiO2 particles still retained the amorphous structure, whereas nano-SiC particles were decomposed and Ni, Cr reacted with SiC to form Cr6.5Ni2.5Si and Cr23C6. In static acidic solution, the corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiO2 particles interlayer is lower than that of the Ni-based alloying layer. However, the corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiO2 particles interlayer is prominently superior to that of the Ni-based alloying layer under acidic flow medium condition and acidic slurry flow condition. The corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiC particles interlayer is evidently lower than that of the Ni-based alloying layer, but higher than that of 316L SS under all test conditions. The results show that the highly dispersive nano-SiO2 particles are helpful in improving the corrosion wear resistance of the Ni-based alloying layer, whereas carbides and silicide phase are deleterious to that of the Ni-based alloying layer due to the fact that the preferential removal of the matrix around the precipitated phase takes place by the chemical

  1. Design Concepts for Cooled Ceramic Matrix Composite Turbine Vanes, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The work proposed herein is to demonstrate that the higher temperature capabilities of Ceramic Matrix Composites (CMC) can be fully utilized to reduce emissions and...

  2. Polyvinylpyrrolidone Matrix as an Effective Reducing Agent and Stabilizer during Reception of Silver Nanoparticles in Composites

    OpenAIRE

    Semenyuk, Nataliya; Kostiv, Ulyana; Dudok, Galyna; Nechay, Jaroslav; Skorokhoda, Volodymyr

    2013-01-01

    The use of polyvinylpyrrolidone matrix as an effective reducing agent and stabilizer during reception of silver nanoparticles in composites is substantiated. The influence of various factors on patterns of obtaining silver nanoparticles and their size.

  3. Carbon dioxide selective mixed matrix composite membrane containing ZIF-7 nano-fillers

    KAUST Repository

    Li, Tao; Pan, Yichang; Peinemann, Klaus-Viktor; Lai, Zhiping

    2013-01-01

    Mixed matrix materials made from selective inorganic fillers and polymers are very attractive for the manufacturing of gas separation membranes. But only few of these materials could be manufactured into high-performance asymmetric or composite

  4. Theoretical and experimental investigation of wear characteristics of aluminum based metal matrix composites using RSM

    International Nuclear Information System (INIS)

    Selvi, S.; Rajasekar, E.

    2015-01-01

    The tribological properties such as wear rate, hardness of the aluminum-fly ash composite synthesized by stir casting were investigated by varying the weight % of fly ash from 5 to 20 with constant weight % of zinc and magnesium metal powder. A mathematical model was developed to predict the wear rate of aluminum metal matrix composites and the adequacy of the model was verified using analysis of variance. Scanning electron microscopy was used for the microstructure analysis which showed a uniform distribution of fly ash in the metal matrix. Energy - dispersive X-ray spectroscopy was used for the elemental analysis or chemical characterization of a sample. The results showed that addition of fly ash to aluminum based metal matrix improved both the mechanical and tribological properties of the composites. The fly ash particles improved the wear resistance of the metal matrix composites because the hardness of the samples taken increased as the fly ash content was increased.

  5. The Micromechanics of Deformation and Failure in Metal-Matrix Composites

    National Research Council Canada - National Science Library

    Needleman, Alan

    1997-01-01

    .... However, metal-matrix composites often have low ductility and low fracture toughness. An improved understanding of the basic deformation and failure mechanisms is needed to overcome these problems...

  6. Composite Armor Performance Enhancement by Tethered Polymer Chains at the Fiber-Matrix Interface

    National Research Council Canada - National Science Library

    Kalika, D

    1998-01-01

    ... properties of fiber composites. The governing strategy was to tailor the discontinuous fiber-matrix interface so as to introduce a volume of interaction capable of providing additional, molecular-level energy dissipation mechanisms...

  7. Thermodynamic assessment and the composition prediction of amorphous alloy in the Fe–B–Er alloy system

    International Nuclear Information System (INIS)

    Wang, S.L.; Han, J.J.; Wang, C.P.; Kou, S.Z.; Liu, X.J.

    2012-01-01

    Highlights: ► The thermodynamic parameters of each phase in the Fe–Er and B–Er binary systems were obtained. ► An agreement between the calculated results and experimental data was obtained in each binary system. ► The liquidus surface of Fe–B–Er system has been calculated by means of CALPHAD. ► The investigation of GFA in Fe-rich alloys in the context of Fe–B–Er liquidus surface proves the significance of calculated phase diagram in the composition design of Fe-based metallic glass. - Abstract: The phase diagrams and thermodynamic properties in the Fe–Er and B–Er binary systems have been assessed by using the CALPHAD (Calculation of Phase Diagrams) method on the basis of the experimental data including the thermodynamic properties and phase equilibria. The thermodynamic parameters of each phase in the Fe–Er and B–Er binary systems were obtained, and an agreement between the calculated results and experimental data was obtained in each binary system. The isothermal sections at different temperatures and liquidus surface in the Fe–B–Er system have been calculated based on the binary thermodynamic data assessed in the present work. In addition, by considering that the glass formation composition of amorphous alloy is closely relative to the eutectic point in corresponding phase diagram, the investigation of glass-forming ability (GFA) in Fe-rich alloys in the Fe–B–Er liquidus surface has also been implemented in this work. The experimental result indicates that the GFA of a certain alloy is intimately relative to its location in the phase diagram, which proves that the phase diagram is an efficient tool for the composition design of Fe-based amorphous alloy.

  8. Anisotropic thermal expansion behaviors of copper matrix in β-eucryptite/copper composite

    International Nuclear Information System (INIS)

    Wang Lidong; Xue Zongwei; Qiao Yingjie; Fei, W.D.

    2012-01-01

    Highlights: ► The thermal expansion behaviors of Cu matrix were studied by in situ XRD. ► The expansion of Cu{1 1 1} plane is linear, that of Cu{2 0 0} is nonlinear. ► The anisotropic thermal expansion of Cu is related to the twinning of Cu matrix. ► The twinning of Cu matrix makes the CTE of the composite increasing. - Abstract: A β-eucryptite/copper composite was fabricated by spark plasma sintering process. The thermal expansion behaviors of Cu matrix of the composite were studied by in situ X-ray diffraction during heating process. The results show that Cu matrix exhibits anisotropic thermal expansion behaviors for different crystallographic directions, the expansion of Cu{1 1 1} plane is linear in the temperature range from 20 °C to 300 °C and the expansion of Cu{2 0 0} is nonlinear with a inflection at about 180 °C. The microstructures of Cu matrix before and after thermal expansion testing were investigated using transmission electronic microscope. The anisotropic thermal expansion behavior is related to the deformation twinning formed in the matrix during heating process. At the same time, the deformation twinning of Cu matrix makes the average coefficient of thermal expansion of the composite increase.

  9. Tensile Stress Rupture Behavior of a Woven Ceramic Matrix Composite in Humid Environments at Intermediate Temperature

    National Research Council Canada - National Science Library

    LaRochelle, Kevin J

    2005-01-01

    Stress rupture tests on the Sylramic(TM) fiber with an in-situ layer of boron nitride, boron nitride interphase, and SiC matrix ceramic matrix composite were performed at 550 degrees C and 750 degrees C with 0.0, 0.2...

  10. Ceramic fiber-reinforced monoclinic celsian phase glass-ceramic matrix composite material

    Science.gov (United States)

    Bansal, Narottam P. (Inventor); Dicarlo, James A. (Inventor)

    1994-01-01

    A hyridopolysilazane-derived ceramic fiber reinforced monoclinic celsian phase barium aluminum silicate glass-ceramic matrix composite material is prepared by ball-milling an aqueous slurry of BAS glass powder and fine monoclinic celsian seeds. The fibers improve the mechanical strength and fracture toughness and with the matrix provide superior dielectric properties.

  11. Structure, composition and function of interfaces in ceramic fibre/matrix composites

    International Nuclear Information System (INIS)

    Pippel, E.

    1993-01-01

    Improving the properties of fibre reinforced ceramics and glasses by optimizing their microstructure requires the knowledge of this structure down to the atomic level. In these materials energy-dissipative processes during fracture particularly act within an interface layer or layer system between fibre and matrix which can either be produced by fibre coating, or which develops during the processing of the composites. Examples are presented of the microstructural phenomena of such layers revealed by HVEM and HREM and complemented by microchemical information via a nanoscale EDXS equipment. The investigations are carried out on Nicalon fibres in Duran glass as well as on Tyranno, Nicalon and carbon fibres in different SiC-matrices. Finally, a process is discussed which may control the important interface parameters. (orig.)

  12. Modelling of polypropylene fibre-matrix composites using finite element analysis

    Directory of Open Access Journals (Sweden)

    2009-01-01

    Full Text Available Polypropylene (PP fibre-matrix composites previously prepared and studied experimentally were modelled using finite element analysis (FEA in this work. FEA confirmed that fibre content and composition controlled stress distribution in all-PP composites. The stress concentration at the fibre-matrix interface became greater with less fibre content. Variations in fibre composition were more significant in higher stress regions of the composites. When fibre modulus increased, the stress concentration at the fibres decreased and the shear stress at the fibre-matrix interface became more intense. The ratio between matrix modulus and fibre modulus was important, as was the interfacial stress in reducing premature interfacial failure and increasing mechanical properties. The model demonstrated that with low fibre concentration, there were insufficient fibres to distribute the applied stress. Under these conditions the matrix yielded when the applied stress reached the matrix yield stress, resulting in increased fibre axial stress. When the fibre content was high, there was matrix depletion and stress transfer was inefficient. The predictions of the FEA model were consistent with experimental and published data.

  13. A Review on Artificial Aging Behaviors of Fiber Reinforced Polymer-matrix Composites

    OpenAIRE

    Meng Jiangyan; Wang Yunying

    2016-01-01

    As is known, factors in climate environment such as hygrothermal effect and UV may have a negative effect on the mechanical properties of fiber reinforced polymer-matrix composites, resulting in their strength and stiffness degraded. In this review, we summarize all the recent studies on the artificial climate aging, hygrothermal aging, and thermal-oxidation aging of fiber reinforced polymer-matrix composites, as well as their artificial accelerated aging and natural aging. In addition, studi...

  14. Composite properties for S-2 glass in a room-temperature-curable epoxy matrix

    Science.gov (United States)

    Clements, L. L.; Moore, R. L.

    1979-01-01

    The authors have measured thermal and mechanical properties of several composites of S-2 glass fiber in a room-temperature-curable epoxy matrix. The filament-wound composites ranged from 50 to 70 vol% fiber. The composites had generally good to excellent mechanical properties, particularly in view of the moderate cost of the material. However, the composites showed rapid increases in transverse thermal expansion above 50 C, and this property must be carefully considered if any use above that temperature is contemplated.

  15. Measurement and Analysis of Composition and Depth Profile of H in Amorphous Si1−xCx:H Films

    International Nuclear Information System (INIS)

    Wei, Hua; Shu-De, Yao; Kun, Wang; Zhi-Bo, Ding

    2008-01-01

    Composition in amorphous Si 1−X C x :H heteroepitaxial thin films on Si (100) by plasma enhanced chemical vapour deposition (PECVD) is analysed. The unknown x (0.45–0.57) and the depth profile of hydrogen in the thin films are characterized by Rutherford backscattering spectrum (RBS), resonance-nuclear reaction analysis (R-NRA) and elastic recoil detection (ERD), respectively. In addition, the depth profile of hydrogen in the unannealed thin films is compared to that of the annealed thin films with rapid thermal annealing (RTA) or laser spike annealing (LSA) in nitrogen atmosphere. The results indicate that the stoichiometric amorphous SiC can be produced by PECVD when the ratio of CH 4 /SiH 4 is approximately equal to 25. The content of hydrogen decreases suddenly from 35% to 1% after 1150° C annealing. RTA can reduce hydrogen in SiC films effectively than LSA. (cross-disciplinary physics and related areas of science and technology)

  16. Pseudocapacitance of amorphous TiO2@nitrogen doped graphene composite for high rate lithium storage

    International Nuclear Information System (INIS)

    Li, Sheng; Xue, Pan; Lai, Chao; Qiu, Jingxia; Ling, Min; Zhang, Shanqing

    2015-01-01

    The high rate applications such as electric vehicles of the traditional lithium ion batteries (LIBs) are commonly limited by their insufficient electron conductivity and slow mass transport of lithium ions in bulk electrode materials. In order to address these issues, in this work, a simple and up-scalable wet-mechanochemical (wet-ball milling) route has been developed for fabrication of amorphous porous TiO 2 @nitrogen doped graphene (TiO 2 @N-G) nanocomposites. The amorphous phase, unique porous structure of TiO 2 and the surface defects from nitrogen doping to graphene planes have incurred surface controlled reactions, contributing pseudocapacitance to the total capacity of the battery. It plays a dominant role in producing outstanding high rate electrochemical performance, e.g., 182.7 mAh/g (at 3.36 A/g) after 100 cycles. The design and synthesis of electrode materials with enhanced conductivity and surface pseudocapacitance can be a promising way for high rate LIBs.

  17. Rapid synthesis of graphene/amorphous α-MnO2 composite with enhanced electrochemical performance for electrochemical capacitor

    International Nuclear Information System (INIS)

    Pang, Mingjun; Long, Guohui; Jiang, Shang; Ji, Yuan; Han, Wei; Wang, Biao; Liu, Xilong; Xi, Yunlong

    2015-01-01

    Highlights: • Graphene/MnO 2 is successfully fabricated by a facile co-precipitation method. • The graphene/MnO 2 electrode reaches 367 Fg −1 in 1 M KOH electrolyte. • The electrode exhibits good cycling performance of 73.9% retention after 1000 cycles. - Abstract: Nanostructured graphene/amorphous α-MnO 2 composites have been synthesized by a facile co-precipitation method under the alkaline condition, in which graphene nanosheets as a supporting substrate to grow MnO 2 . Characterizations of prepared samples’ morphology and microstructures indicate MnO 2 is successfully formed on the surface of graphene by electrostatic interaction. Moreover, the electrochemical properties of the synthesized electrode materials for supercapacitors are studied in a three-electrode experimental setup using a 1 M KOH aqueous solution as the electrolyte. As a result, the specific capacitance of graphene/MnO 2 composite (weight ratio of graphene to MnO 2 is 1:1) determined by a galvanostatic charge–discharge method at a current density of 1 Ag −1 reaches 367 Fg −1 , which is 1.8 and 4.6 fold higher than that of pure graphene and MnO 2 . The capacity retention of the graphene/MnO 2 composite is 73.9% of the original capacitance after 1000 cycles, indicating graphene/MnO 2 composite is a promising electrode material for supercapacitors

  18. Unified continuum damage model for matrix cracking in composite rotor blades

    Energy Technology Data Exchange (ETDEWEB)

    Pollayi, Hemaraju; Harursampath, Dineshkumar [Nonlinear Multifunctional Composites - Analysis and Design Lab (NMCAD Lab) Department of Aerospace Engineering Indian Institute of Science Bangalore - 560012, Karnataka (India)

    2015-03-10

    This paper deals with modeling of the first damage mode, matrix micro-cracking, in helicopter rotor/wind turbine blades and how this effects the overall cross-sectional stiffness. The helicopter/wind turbine rotor system operates in a highly dynamic and unsteady environment leading to severe vibratory loads present in the system. Repeated exposure to this loading condition can induce damage in the composite rotor blades. These rotor/turbine blades are generally made of fiber-reinforced laminated composites and exhibit various competing modes of damage such as matrix micro-cracking, delamination, and fiber breakage. There is a need to study the behavior of the composite rotor system under various key damage modes in composite materials for developing Structural Health Monitoring (SHM) system. Each blade is modeled as a beam based on geometrically non-linear 3-D elasticity theory. Each blade thus splits into 2-D analyzes of cross-sections and non-linear 1-D analyzes along the beam reference curves. Two different tools are used here for complete 3-D analysis: VABS for 2-D cross-sectional analysis and GEBT for 1-D beam analysis. The physically-based failure models for matrix in compression and tension loading are used in the present work. Matrix cracking is detected using two failure criterion: Matrix Failure in Compression and Matrix Failure in Tension which are based on the recovered field. A strain variable is set which drives the damage variable for matrix cracking and this damage variable is used to estimate the reduced cross-sectional stiffness. The matrix micro-cracking is performed in two different approaches: (i) Element-wise, and (ii) Node-wise. The procedure presented in this paper is implemented in VABS as matrix micro-cracking modeling module. Three examples are presented to investigate the matrix failure model which illustrate the effect of matrix cracking on cross-sectional stiffness by varying the applied cyclic load.

  19. Unified continuum damage model for matrix cracking in composite rotor blades

    International Nuclear Information System (INIS)

    Pollayi, Hemaraju; Harursampath, Dineshkumar

    2015-01-01

    This paper deals with modeling of the first damage mode, matrix micro-cracking, in helicopter rotor/wind turbine blades and how this effects the overall cross-sectional stiffness. The helicopter/wind turbine rotor system operates in a highly dynamic and unsteady environment leading to severe vibratory loads present in the system. Repeated exposure to this loading condition can induce damage in the composite rotor blades. These rotor/turbine blades are generally made of fiber-reinforced laminated composites and exhibit various competing modes of damage such as matrix micro-cracking, delamination, and fiber breakage. There is a need to study the behavior of the composite rotor system under various key damage modes in composite materials for developing Structural Health Monitoring (SHM) system. Each blade is modeled as a beam based on geometrically non-linear 3-D elasticity theory. Each blade thus splits into 2-D analyzes of cross-sections and non-linear 1-D analyzes along the beam reference curves. Two different tools are used here for complete 3-D analysis: VABS for 2-D cross-sectional analysis and GEBT for 1-D beam analysis. The physically-based failure models for matrix in compression and tension loading are used in the present work. Matrix cracking is detected using two failure criterion: Matrix Failure in Compression and Matrix Failure in Tension which are based on the recovered field. A strain variable is set which drives the damage variable for matrix cracking and this damage variable is used to estimate the reduced cross-sectional stiffness. The matrix micro-cracking is performed in two different approaches: (i) Element-wise, and (ii) Node-wise. The procedure presented in this paper is implemented in VABS as matrix micro-cracking modeling module. Three examples are presented to investigate the matrix failure model which illustrate the effect of matrix cracking on cross-sectional stiffness by varying the applied cyclic load

  20. Composite Materials With Uncured Epoxy Matrix Exposed in Stratosphere During NASA Stratospheric Balloon Flight

    Science.gov (United States)

    Kondyurin, Alexey; Kondyurina, Irina; Bilek, Marcela; de Groh, Kim K.

    2013-01-01

    A cassette of uncured composite materials with epoxy resin matrixes was exposed in the stratosphere (40 km altitude) over three days. Temperature variations of -76 to 32.5C and pressure up to 2.1 torr were recorded during flight. An analysis of the chemical structure of the composites showed, that the polymer matrix exposed in the stratosphere becomes crosslinked, while the ground control materials react by way of polymerization reaction of epoxy groups. The space irradiations are considered to be responsible for crosslinking of the uncured polymers exposed in the stratosphere. The composites were cured on Earth after landing. Analysis of the cured composites showed that the polymer matrix remains active under stratospheric conditions. The results can be used for predicting curing processes of polymer composites in a free space environment during an orbital space flight.

  1. Effects of ductile matrix failure in three dimensional analysis of metal matrix composites

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    1998-01-01

    Full three dimensional numerical cell model analyses are carried out for a metal reinforced by short fibers, to study the development of ductile matrix failure. A porous ductile material model is used to describe the effect of the nucleation and growth of voids to coalescence. In each case studied...

  2. The Particle Shape of WC Governing the Fracture Mechanism of Particle Reinforced Iron Matrix Composites.

    Science.gov (United States)

    Li, Zulai; Wang, Pengfei; Shan, Quan; Jiang, Yehua; Wei, He; Tan, Jun

    2018-06-11

    In this work, tungsten carbide particles (WC p , spherical and irregular particles)-reinforced iron matrix composites were manufactured utilizing a liquid sintering technique. The mechanical properties and the fracture mechanism of WC p /iron matrix composites were investigated theoretically and experimentally. The crack schematic diagram and fracture simulation diagram of WC p /iron matrix composites were summarized, indicating that the micro-crack was initiated both from the interface for spherical and irregular WC p /iron matrix composites. However, irregular WC p had a tendency to form spherical WC p . The micro-cracks then expanded to a wide macro-crack at the interface, leading to a final failure of the composites. In comparison with the spherical WC p , the irregular WC p were prone to break due to the stress concentration resulting in being prone to generating brittle cracking. The study on the fracture mechanisms of WC p /iron matrix composites might provide a theoretical guidance for the design and engineering application of particle reinforced composites.

  3. Development and characterization of woven kevlar reinforced epoxy matrix composite materials

    International Nuclear Information System (INIS)

    Imran, A.; Alam, S.; Irfan, S.; Iftikhar, F.; Raza, M.A.

    2006-01-01

    Composite materials are actually well established materials that have demonstrated their promising advantages among the light weight structural materials used for aerospace and advanced applications. A great effort is now being made to develop and characterize the Kevlar Epoxy Composite Materials by changing the % age composition of curing agent in epoxy matrix. In order to study the phenomenon; how the change in composition of curing agent effect the composite material and which optimum composition can give the optimum properties of the material, when Kevlar reinforced to Epoxy Matrix by Hand Lay-up process. It was ensured that factors which can .affect the experiment remained the same for each experiment. The composite produced were subjected to mechanical tests to analyze the performance, to optimize the material. (author)

  4. Cu incorporated amorphous diamond like carbon (DLC) composites: An efficient electron field emitter over a wide range of temperature

    Science.gov (United States)

    Ahmed, Sk Faruque; Alam, Md Shahbaz; Mukherjee, Nillohit

    2018-03-01

    The effect of temperature on the electron field emission properties of copper incorporated amorphous diamond like carbon (a-Cu:DLC) thin films have been reported. The a-Cu:DLC thin films have been deposited on indium tin oxide (ITO) coated glass and silicon substrate by the radio frequency sputtering process. The chemical composition of the films was investigated using X-ray photoelectron spectroscopy and the micro structure was established using high resolution transmission electron microscopy. The sp2 and sp3 bonding ratio in the a-Cu:DLC have been analyzed by the Fourier transformed infrared spectroscopy studies. The material showed excellent electron field emission properties; which was optimized by varying the copper atomic percentage and temperature of the films. It was found that the threshold field and effective emission barrier were reduced significantly by copper incorporation as well as temperature and a detailed explanation towards emission mechanism has been provided.

  5. Nonlinear behavior of matrix-inclusion composites under high confining pressure: application to concrete and mortar

    Science.gov (United States)

    Le, Tuan Hung; Dormieux, Luc; Jeannin, Laurent; Burlion, Nicolas; Barthélémy, Jean-François

    2008-08-01

    This paper is devoted to a micromechanics-based simulation of the response of concrete to hydrostatic and oedometric compressions. Concrete is described as a composite made up of a cement matrix in which rigid inclusions are embedded. The focus is put on the role of the interface between matrix and inclusion which represent the interfacial transition zone (ITZ). A plastic behavior is considered for both the matrix and the interfaces. The effective response of the composite is derived from the modified secant method adapted to the situation of imperfect interfaces. To cite this article: T.H. Le et al., C. R. Mecanique 336 (2008).

  6. Correlation of magnetic and mechanical properties of hydrogenated, compositionally modulated, amorphous Fe80Zr20 films (abstract)

    International Nuclear Information System (INIS)

    Rengarajan, S.; Yun, E.J.; Lee, B.H.; Cho, B.I.; Walser, R.M.

    1996-01-01

    Recent research has demonstrated that large amounts of hydrogen can be electrolytically incorporated in amorphous, compositionally modulated (CM) FeZr films. The first irreversible changes in the magnetic state of an electrolytically hydrogenated iron-rich amorphous alloy were observed. The hydrogen-induced changes in the magnetization were interpreted in terms of specific structural rearrangements. In this work, simultaneous measurements of the variations in the magnetization and mechanical properties of these films were measured as a function of hydrogen charging to further clarify the hydrogen-induced structure changes. The Young close-quote s moduli E and internal friction d of as-deposited, and as-hydrogenated CM Fe 80 Zr 20 thin films were calculated from the displacements of a vibrating composite cantilever, measured using a laser heterodyne interferometer (LHI) having a displacement sensitivity of ∼0.01 A. E and d were measured using the resonant frequency method. CM films with thickness 1390 A and modulation wavelength ∼10 A were deposited on glass cantilevers (5 mm long, 2 mm wide, and 150 μm thick) by sequentially sputtering (rf diode) elemental Fe and Zr targets. The samples were electrolytically hydrogenated for various times in 2 N phosphoric acid with a current density of 26.3 mA/cm 2 . The maximum change in magnetization of the film (from 71.5 to 551 emu/cm 3 ) was observed after 5 min. During this time, E increased 18-fold from 535 GPa to 9.63 TPa. The unusually high Young close-quote s modulus of the as-deposited CM film is comparable to those previously observed in other CM films. The change is three times larger than the change in the E of carbon steel at the martensitic transformation, and nine times larger than the hydrogen induced increase in E of pure single crystals of iron. (Abstract Truncated)

  7. Effective longitudinal strength of high temperature metal-matrix composites

    International Nuclear Information System (INIS)

    Craddock, J.N.; Savvides, I.

    1991-01-01

    Several models for predicting the longitudinal strength of fiber composites are presented, ranging from a simple netting analysis to a model incorporating curvilinear strain hardening for all the components. Results from these models are presented for tungsten fiber reinforced superalloys, FeCrAlY and MARM200. It is shown that a simple elastic limit micromechanical model does not always adequately describe the useful strength of the composites. The methods proposed here are shown to be more appropriate for predicting the effective composite strength. 2 refs

  8. Pre-form ceramic matrix composite cavity and method of forming and method of forming a ceramic matrix composite component

    Science.gov (United States)

    Monaghan, Philip Harold; Delvaux, John McConnell; Taxacher, Glenn Curtis

    2015-06-09

    A pre-form CMC cavity and method of forming pre-form CMC cavity for a ceramic matrix component includes providing a mandrel, applying a base ply to the mandrel, laying-up at least one CMC ply on the base ply, removing the mandrel, and densifying the base ply and the at least one CMC ply. The remaining densified base ply and at least one CMC ply form a ceramic matrix component having a desired geometry and a cavity formed therein. Also provided is a method of forming a CMC component.

  9. Effect of particulate matrix inhibitors on microstructure and properties of 2-D carbon-carbon composites

    International Nuclear Information System (INIS)

    Tlomak, P.; Takano, Shigeru; Wright, M.A.; Ju, Chien-Ping.

    1991-01-01

    Extended-life applications of structural carbon-carbon (C-C) composites involve multiple periods of operation in high-temperature oxidizing environments and as such require a reliable oxidation protection system (OPS). Advanced OPS's generally consist of an external ceramic coating combined with an in-depth matrix inhibitor. This work investigated the effects produced by particulate inhibitors doped on the matrix on the microstructure of 2D, PAN fiber-pitch matrix C-C's. Boron and zirconium-based particulate inhibitors were added to the matrix material prior to heat treatment. A process was developed to assure a uniform distribution of the inhibitors. Oxidation behavior of such matrix-inhibited composites was evaluated using isothermal oxidation tests. 5 refs

  10. VARTM Processing of High Temperature Polymer Matrix Composites

    National Research Council Canada - National Science Library

    Criss, Jr, Jim M

    2008-01-01

    The overall technical objective of the Phase 1 effort was to extend and advance the state the-art in high temperature composite fabrication techniques by developing a High Tempera Vacuum Assisted Resin Transfer Molding (VARTM...

  11. Fabrication of fiber composites with a MAX phase matrix by reactive melt infiltration

    International Nuclear Information System (INIS)

    Lenz, F; Krenkel, W

    2011-01-01

    Due to the inherent brittleness of ceramics it is very desirable to increase the damage tolerance of ceramics. The ternary MAX phases are a promising group of materials with high fracture toughness. The topic of this study is the development of ceramic matrix composites (CMCs) with a matrix containing MAX phases, to achieve a damage tolerant structural composite material. For this purpose carbon fiber reinforced preforms with a carbon-titanium carbide matrix (C/C-TiC) were developed and infiltrated with silicon by a pressureless reactive melt infiltration. Finally liquid silicon caused the formation of SiC, TiSi 2 and Ti 3 SiC 2 in the matrix of the composite.

  12. Corrosion of Metal-Matrix Composites with Aluminium Alloy Substrate

    Directory of Open Access Journals (Sweden)

    B. Bobic

    2010-03-01

    Full Text Available The corrosion behaviour of MMCs with aluminium alloy matrix was presented. The corrosion characteristics of boron-, graphite-, silicon carbide-, alumina- and mica- reinforced aluminium MMCs were reviewed. The reinforcing phase influence on MMCs corrosion rate as well as on various corrosion forms (galvanic, pitting, stress corrosion cracking, corrosion fatique, tribocorrosion was discussed. Some corrosion protection methods of aluminium based MMCs were described

  13. Phase Stability and Thermal Conductivity of Composite Environmental Barrier Coatings on SiC/SiC Ceramic Matrix Composites

    Science.gov (United States)

    Benkel, Samantha; Zhu, Dongming

    2011-01-01

    Advanced environmental barrier coatings are being developed to protect SiC/SiC ceramic matrix composites in harsh combustion environments. The current coating development emphasis has been placed on the significantly improved cyclic durability and combustion environment stability in high-heat-flux and high velocity gas turbine engine environments. Environmental barrier coating systems based on hafnia (HfO2) and ytterbium silicate, HfO2-Si nano-composite bond coat systems have been processed and their stability and thermal conductivity behavior have been evaluated in simulated turbine environments. The incorporation of Silicon Carbide Nanotubes (SiCNT) into high stability (HfO2) and/or HfO2-silicon composite bond coats, along with ZrO2, HfO2 and rare earth silicate composite top coat systems, showed promise as excellent environmental barriers to protect the SiC/SiC ceramic matrix composites.

  14. Bone induction by composite of bioerodible polyorthoester and demineralized bone matrix in rats

    DEFF Research Database (Denmark)

    Pinholt, E M; Solheim, E; Bang, G

    1991-01-01

    A composite of a local, sustained, drug-release system, Alzamer bioerodible polyorthoester, and demineralized bone-matrix (DBM) particles implanted in the abdominal muscle of 89 Wistar rats induced cartilage and bone formation at the same rate as DBM when evaluated histologically and by 85Sr uptake....... The composite implant was technically easier to use than DBM alone....

  15. Bone induction by composite of bioerodible polyorthoester and deminiralized bone matrix in rats

    International Nuclear Information System (INIS)

    Pinholt, E.M.; Solheim, E.; Bang, G.; Sudmann, E.

    1991-01-01

    A composite of a local, sustained, drug-release system, Alzamer bioerodible polyorthoester, and demineralized bone-matrix (DBM) particles implanted in the abdominal muscle of 89 Wistar rats induced cartilage and bone formation at the same rate as DBM when evaluated histologically and by 85 Sr uptake. The composite implant was technically easier to use than DBM alone. (author)

  16. Effect of magnesium aluminum silicate glass on the thermal shock resistance of BN matrix composite ceramics

    NARCIS (Netherlands)

    Cai, Delong; Jia, Dechang; Yang, Zhihua; Zhu, Qishuai; Ocelik, Vaclav; Vainchtein, Ilia D.; De Hosson, Jeff Th M.; Zhou, Yu

    The effects of magnesium aluminum silicate (MAS) glass on the thermal shock resistance and the oxidation behavior of h-BN matrix composites were systematically investigated at temperature differences from 600 degrees C up to 1400 degrees C. The retained strength rate of the composites rose with the

  17. In vitro degradation and surface bioactivity of iron-matrix composites containing silicate-based bioceramic

    NARCIS (Netherlands)

    Wang, S; Xu, Y; Zhou, J.; Li, H; Chang, Jiang; Huan, Z

    2017-01-01

    Iron-matrix composites with calcium silicate (CS) bioceramic as the reinforcing phase were fabricated through powder metallurgy processes. The microstructures, mechanical properties, apatite deposition and biodegradation behavior of the Fe-CS composites, as well as cell attachment and proliferation

  18. Bibliography on Ceramic Matrix Composites and Reinforcing Whiskers, Platelets, and Fibers, 1970-1990

    Science.gov (United States)

    1993-08-01

    Triphasic Sol-Gel Route 2.2.3.8 Srikanth, V. Ravindranathan, P. Crystallization of Gel-Derived Mullite-Zirconia Rani, L. Roy, R. Composites Metal and...179 9.8.1 ArmorMaterials 9.8.1.5 Ceramic Matrix Composite Reactor /Radiator 9.8.1.1 Armor Structures Development and Current Status of Armor Pacquette, E

  19. Development and optimization of manufacture process for heat resistant fibre reinforced ceramic matrix composites

    Czech Academy of Sciences Publication Activity Database

    Glogar, Petr; Hron, P.; Burian, M.; Balík, Karel; Černý, Martin; Sucharda, Zbyněk; Vymazalová, Z.; Červencl, J.; Pivoňka, M.

    -, č. 14 (2005), 25-32 ISSN 1214-9691 R&D Projects: GA ČR(CZ) GA106/02/0177 Institutional research plan: CEZ:AV0Z30460519 Keywords : polysiloxane resin * pyrolysis * ceramic matrix composite Subject RIV: JI - Composite Materials

  20. Young`s modulus of ceramic matrix composites with polysiloxane based matrix at elevated temperatures

    Czech Academy of Sciences Publication Activity Database

    Černý, Martin; Glogar, Petr

    2004-01-01

    Roč. 39, č. 6 (2004), s. 2239-2242 ISSN 0022-2461 R&D Projects: GA ČR GA106/02/0177; GA ČR GP106/02/P025 Institutional research plan: CEZ:AV0Z3046908 Keywords : composite material * Young `s modulus * high temperature Subject RIV: JI - Composite Materials Impact factor: 0.864, year: 2004

  1. Update on the Chemical Composition Of Crystalline, Smectite, and Amorphous Components for Rocknest Soil and John Klein and Cumberland Mudstone Drill Fines at Gale Crater, Mars

    Science.gov (United States)

    Morris, R. V.; Ming, D. W.; Gellert, R.; Vaniman, D. T.; Bish, D. L.; Blake, D. F.; Chipera, S. J.; Morrison, S. M.; Downs, R. T.; Rampe, E. B.; hide

    2015-01-01

    We have previously calculated the chemical compositions of the X-ray-diffraction (XRD) amorphous component of three solid samples (Rocknest (RN) soil, John Klein (JK) drill fines, and Cumberland (CB) drill fines) using major-element chemistry (APXS), volatile-element chemistry (SAM), and crystalline- phase mineralogy (CheMin) obtained by the Curiosity rover as a part of the ongoing Mars Science Laboratory mission in Gale Crater. According to CheMin analysis, the RN and the JK and CB samples are mineralogically distinct in that RN has no detectable clay minerals and both JK and CB have significant concentrations of high-Fe saponite. The chemical composition of the XRD amorphous component is the composition remaining after mathematical removal of the compositions of crystalline components, including phyllosilicates if present. Subsequent to, we have improved the unit cell parameters for Fe-forsterite, augite, and pigeonite, resulting in revised chemical compositions for the XRD-derived crystalline component (excluding clay minerals). We update here the calculated compositions of amorphous components using these revised mineral compositions.

  2. Influence of reinforcement proportion and matrix composition on pitting corrosion behaviour of cast aluminium matrix composites (A3xx.x/SiCp)

    International Nuclear Information System (INIS)

    Pardo, A.; Merino, M.C.; Merino, S.; Viejo, F.; Carboneras, M.; Arrabal, R.

    2005-01-01

    The influence of silicon carbide (SiCp) proportion and matrix composition on four aluminium metal matrix composites (A360/SiC/10p, A360/SiC/20p, A380/SiC/10p, A380/SiC/20p) immersed in 1-3.5 wt% NaCl at 22 deg C was investigated by potentiodynamic polarization. The kinetics of the corrosion process was studied on the basis of gravimetric measurements. The nature of corrosion products was analysed by scanning electron microscopy (SEM) and low angle X-ray diffraction (XRD). The corrosion damage in Al/SiCp composites was caused by pitting attack and by nucleation and growth of Al 2 O 3 . 3H 2 O on the material surface. The main attack nucleation sites were the interface region between the matrix and the reinforcement particles. The corrosion process was influenced more by the concentration of alloy elements in the matrix than by the proportion of SiCp reinforcement and saline concentration

  3. Influence of reinforcement proportion and matrix composition on pitting corrosion behaviour of cast aluminium matrix composites (A3xx.x/SiCp)

    Energy Technology Data Exchange (ETDEWEB)

    Pardo, A. [Departamento de Ciencia de Materiales, Facultad de Quimica, Universidad Complutense, 28040 Madrid (Spain)]. E-mail: anpardo@quim.ucm.es; Merino, M.C. [Departamento de Ciencia de Materiales, Facultad de Quimica, Universidad Complutense, 28040 Madrid (Spain); Merino, S. [Departamento de Tecnologia Industrial, Universidad Alfonso X El Sabio, 28691, Villanueva de la Canada, Madrid (Spain); Viejo, F. [Departamento de Ciencia de Materiales, Facultad de Quimica, Universidad Complutense, 28040 Madrid (Spain); Carboneras, M. [Departamento de Ciencia de Materiales, Facultad de Quimica, Universidad Complutense, 28040 Madrid (Spain); Arrabal, R. [Departamento de Ciencia de Materiales, Facultad de Quimica, Universidad Complutense, 28040 Madrid (Spain)

    2005-07-01

    The influence of silicon carbide (SiCp) proportion and matrix composition on four aluminium metal matrix composites (A360/SiC/10p, A360/SiC/20p, A380/SiC/10p, A380/SiC/20p) immersed in 1-3.5 wt% NaCl at 22 deg C was investigated by potentiodynamic polarization. The kinetics of the corrosion process was studied on the basis of gravimetric measurements. The nature of corrosion products was analysed by scanning electron microscopy (SEM) and low angle X-ray diffraction (XRD). The corrosion damage in Al/SiCp composites was caused by pitting attack and by nucleation and growth of Al{sub 2}O{sub 3} . 3H{sub 2}O on the material surface. The main attack nucleation sites were the interface region between the matrix and the reinforcement particles. The corrosion process was influenced more by the concentration of alloy elements in the matrix than by the proportion of SiCp reinforcement and saline concentration.

  4. Damage analysis of fiber reinforced resin matrix composites irradiated by CW laser

    International Nuclear Information System (INIS)

    Wan Hong; Hu Kaiwei; Mu Jingyang; Bai Shuxin

    2008-01-01

    In this paper, the damage modes of the carbon fiber and the glass fiber reinforced epoxy or bakelite resin matrix composites irradiated by CW laser under different power densities were analyzed, and the changes of the microstructure and the tensile strength of the composites were also researched. When the resin matrix composites were radiated at a power density more than 0.1 kW/cm 2 , the matrix would be decomposed and the tensile properties of the radiated samples were lost over 30% while the carbon fiber hardly damaged and the glass fiber melted. When the power density of the laser was raised to 1 kW/cm 2 , the matrix burned violently and the carbon fiber cloth began to split with some carbon fiber being fractured, therefore, the fracture strength of the radiated sample lost over 80%. The higher the power density of radiation was, the more serious the damage of the sample was. It was also found that the difference of the matrixes had little effect on the damage extent of the composites. The influence of the radiation density on the temperature of the radiated surface of the carbon/resin composite was numerically calculated by ANSYS finite element software and the calculation results coincided with the damage mode of the radiated composites. (authors)

  5. Characterization of hybrid aluminum matrix composites for advanced applications – A review

    Directory of Open Access Journals (Sweden)

    Jaswinder Singh

    2016-04-01

    Full Text Available Hybrid aluminum matrix composites (HAMCs are the second generation of composites that have potential to substitute single reinforced composites due to improved properties. This paper investigates the feasibility and viability of developing low cost-high performance hybrid composites for automotive and aerospace applications. Further, the fabrication characteristics and mechanical behavior of HAMCs fabricated by stir casting route have also been reviewed. The optical micrographs of the HAMCs indicate that the reinforcing particles are fairly distributed in the matrix alloy and the porosity levels have been found to be acceptable for the casted composites. The density, hardness, tensile behavior and fracture toughness of these composites have been found to be either comparable or superior to the ceramic reinforced composites. It has been observed from the literature that the direct strengthening of composites occurs due to the presence of hard ceramic phase, while the indirect strengthening arises from the thermal mismatch between the matrix alloy and reinforcing phase during solidification. Based on the database for material properties, the application area of HAMCs has been proposed in the present review. It has been concluded that the hybrid composites offer more flexibility and reliability in the design of possible components depending upon the reinforcement's combination and composition.

  6. Microstructure Characteristics of Fe-Matrix Composites Reinforced by In-Situ Carbide Particulates

    Science.gov (United States)

    Huang, Xiaodong; Song, Yanpei

    2017-10-01

    Carbide particulates reinforced iron-matrix composites were prepared by in-situ synthesis reaction between Ti, V and C on liquid alloys surface. The microstructure of the composite was characterized by SEM, TEM and OM. The results showed that the main phases were α-Fe, carbide particulate; besides, there were small amounts of γ-Fe and graphite (G) in the composite. The carbides were TiVC2 and VC in the shape of short bar and graininess. The matrix consisted of martensite and small amounts of retained austenite.

  7. Residual strain evolution during the deformation of single fiber metal matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Hanan, J.C.; Uestuendag, E.; Clausen, B. [Dept. of Materials Science, California Inst. of Tech., Pasadena, CA (United States); Sivasambu, M.; Beyerlein, I.J. [Theoretical Div., Los Alamos National Lab., Los Alamos, NM (United States); Brown, D.W.; Bourke, M.A.M. [Materials Science and Technology Div., Los Alamos National Lab., Los Alamos, NM (United States)

    2002-07-01

    Successful application of metal matrix composites often requires strength and lifetime predictions that account for the deformation of each phase. Yet, the deformation of individual phases in composites usually differs significantly from their respective monolithic behaviors. An approach is presented that quantifies the deformation parameters of each phase using neutron diffraction measurements before, during, and after failure under tensile loading in model composites consisting of a single alumina fiber embedded in an aluminum matrix. The evolution of residual strains after loading was examined including the effects of fiber failure. (orig.)

  8. Fabrication and properties of ceramic composites with a boron nitride matrix

    International Nuclear Information System (INIS)

    Kim, D.P.; Cofer, C.G.; Economy, J.

    1995-01-01

    Boron nitride (BN) matrix composites reinforced by a number of different ceramic fibers have been prepared using a low-viscosity, borazine oligomer which converts in very high yield to a stable BN matrix when heated to 1,200 C. Fibers including Nicalon (SiC), FP (Al 2 O 3 ), Sumica and Nextel 440 (Al 2 O 3 -SiO 2 ) were evaluated. The Nicalon/BN and Sumica/BN composites displayed good flexural strengths of 380 and 420 MPa, respectively, and modulus values in both cases of 80 GPa. On the other hand, FP/BN and Nextel/BN composites exhibited very brittle behavior. Nicalon fiber with a carbon coating as a buffer barrier improved the strength by 30%, with a large amount of fiber pullout from the BN matrix. In all cases except for Nicalon, the composites showed low dielectric constant and loss

  9. CEMCAN Software Enhanced for Predicting the Properties of Woven Ceramic Matrix Composites

    Science.gov (United States)

    Murthy, Pappu L. N.; Mital, Subodh K.; DiCarlo, James A.

    2000-01-01

    Major advancements are needed in current high-temperature materials to meet the requirements of future space and aeropropulsion structural components. Ceramic matrix composites (CMC's) are one class of materials that are being evaluated as candidate materials for many high-temperature applications. Past efforts to improve the performance of CMC's focused primarily on improving the properties of the fiber, interfacial coatings, and matrix constituents as individual phases. Design and analysis tools must take into consideration the complex geometries, microstructures, and fabrication processes involved in these composites and must allow the composite properties to be tailored for optimum performance. Major accomplishments during the past year include the development and inclusion of woven CMC micromechanics methodology into the CEMCAN (Ceramic Matrix Composites Analyzer) computer code. The code enables one to calibrate a consistent set of constituent properties as a function of temperature with the aid of experimentally measured data.

  10. Stereological observations of platelet-reinforced mullite- and zirconia-matrix composites

    International Nuclear Information System (INIS)

    Cherian, I.K.; Kriven, W.M.; Lehigh, M.D.; Nettleship, I.

    1996-01-01

    Recently, the effect of solid inclusions on the sintering of ceramic powders has been explained in terms of a back-stress that opposes densification. Several analyses have been proposed to describe this problem. However, little quantitative information exists concerning the effect of reinforcement on microstructural evolution. This study compares the microstructural development of zirconia and mullite matrices in the presence of alumina platelets. The effect of platelet loading on density is similar for both composites. Quantitative stereological examinations reveal that the average grain size and pore size are finer for the zirconia-matrix composite. The platelet loading does not have any noticeable effect on the average grain size of the matrix in either composite. However, the average pore size increases as the volume fraction of platelets increases for both materials. Contiguity measurements have detected some aggregation of platelets in the zirconia-matrix composite

  11. Shrinking of silicon nanocrystals embedded in an amorphous silicon oxide matrix during rapid thermal annealing in a forming gas atmosphere

    Science.gov (United States)

    van Sebille, M.; Fusi, A.; Xie, L.; Ali, H.; van Swaaij, R. A. C. M. M.; Leifer, K.; Zeman, M.

    2016-09-01

    We report the effect of hydrogen on the crystallization process of silicon nanocrystals embedded in a silicon oxide matrix. We show that hydrogen gas during annealing leads to a lower sub-band gap absorption, indicating passivation of defects created during annealing. Samples annealed in pure nitrogen show expected trends according to crystallization theory. Samples annealed in forming gas, however, deviate from this trend. Their crystallinity decreases for increased annealing time. Furthermore, we observe a decrease in the mean nanocrystal size and the size distribution broadens, indicating that hydrogen causes a size reduction of the silicon nanocrystals.

  12. Ferromagnetic Levan Composite: An Affinity Matrix to Purify Lectin

    Directory of Open Access Journals (Sweden)

    Renata Angeli

    2009-01-01

    Full Text Available A simple and inexpensive procedure used magnetite and levan to synthesize a composite recovered by a magnetic field. Lectins from Canavalia ensiformis (Con A and Cratylia mollis (Cramoll 1 and Cramoll 1,4 did bind specifically to composite. The magnetic property of derivative favored washing out contaminating proteins and recovery of pure lectins with glucose elution. Cramoll 1 was purified by this affinity binding procedure in two steps instead of a previous three-step protocol with ammonium sulfate fractionation, affinity chromatography on Sephadex G-75, and ion exchange chromatography through a CM-cellulose column.

  13. Mechanics of Platelet-Matrix Composites across Scales: Theory, Multiscale Modeling, and 3D Fabrication

    Science.gov (United States)

    Sakhavand, Navid

    Many natural and biomimetic composites - such as nacre, silk and clay-polymer - exhibit a remarkable balance of strength, toughness, and/or stiffness, which call for a universal measure to quantify this outstanding feature given the platelet-matrix structure and material characteristics of the constituents. Analogously, there is an urgent need to quantify the mechanics of emerging electronic and photonic systems such as stacked heterostructures, which are composed of strong in-plane bonding networks but weak interplanar bonding matrices. In this regard, development of a universal composition-structure-property map for natural platelet-matrix composites, and stacked heterostructures opens up new doors for designing materials with superior mechanical performance. In this dissertation, a multiscale bottom-up approach is adopted to analyze and predict the mechanical properties of platelet-matrix composites. Design guidelines are provided by developing universally valid (across different length scales) diagrams for science-based engineering of numerous natural and synthetic platelet-matrix composites and stacked heterostructures while significantly broadening the spectrum of strategies for fabricating new composites with specific and optimized mechanical properties. First, molecular dynamics simulations are utilized to unravel the fundamental underlying physics and chemistry of the binding nature at the atomic-level interface of organic-inorganic composites. Polymer-cementitious composites are considered as case studies to understand bonding mechanism at the nanoscale and open up new venues for potential mechanical enhancement at the macro-scale. Next, sophisticated mathematical derivations based on elasticity and plasticity theories are presented to describe pre-crack (intrinsic) mechanical performance of platelet-matrix composites at the microscale. These derivations lead to developing a unified framework to construct series of universal composition

  14. A new method for soldering particle-reinforced aluminum metal matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jinbin; Mu, Yunchao [Zhongyuan University of Technology, Zhengzhou 450007 (China); Luo, Xiangwei [Zhengzhou University, Zhengzhou 450002 (China); Niu, Jitai, E-mail: niujitai@163.com [Zhongyuan University of Technology, Zhengzhou 450007 (China)

    2012-12-01

    Highlights: Black-Right-Pointing-Pointer Soldering of 55% SiCp/Al composite and Kovar is first achieved in the world. Black-Right-Pointing-Pointer The nickel plating is required on the surface of the composites before soldering. Black-Right-Pointing-Pointer Low welding temperature is set to avoid overheating of the matrix. Black-Right-Pointing-Pointer Chemical and metallurgical bonding of composites and Kovar is carried out. Black-Right-Pointing-Pointer High tension strength of 225 MPa in soldering seam has been obtained. - Abstract: Soldering of aluminum metal matrix composites (Al-SiC) to other structural materials, or even to themselves, has proved unsuccessful mainly due to the poor wetting of these composites by conventional soldering alloys. This paper reports a new approach, which improves the wetting properties of these composites by molting solder alloys to promote stronger bonds. The new approach relies on nickel-plating of the composite's faying surface prior to application of a solder alloy. Based on this approach, an aluminum metal matrix composite containing 55 vol.% SiC particles is successfully soldered to a Fe-Ni-Co alloy (commercially known as Kovar 4J29). The solder material is a zinc-based alloy (Zn-Cd-Ag-Cu) with a melting point of about 400 Degree-Sign C. Microscopic examinations of the aluminum metal matrix composites (Al-MMCs)-Kovar interfaces show that the nickel-plating, prior to soldering, could noticeably enhance the reaction between the molten solder and composites. The fractography of the shear-tested samples revealed that fracture occurs within the composite (i.e. cohesive failure), indicating a good adhesion between the solder alloy and the Al-SiC composite.

  15. A new method for soldering particle-reinforced aluminum metal matrix composites

    International Nuclear Information System (INIS)

    Lu, Jinbin; Mu, Yunchao; Luo, Xiangwei; Niu, Jitai

    2012-01-01

    Highlights: ► Soldering of 55% SiCp/Al composite and Kovar is first achieved in the world. ► The nickel plating is required on the surface of the composites before soldering. ► Low welding temperature is set to avoid overheating of the matrix. ► Chemical and metallurgical bonding of composites and Kovar is carried out. ► High tension strength of 225 MPa in soldering seam has been obtained. - Abstract: Soldering of aluminum metal matrix composites (Al–SiC) to other structural materials, or even to themselves, has proved unsuccessful mainly due to the poor wetting of these composites by conventional soldering alloys. This paper reports a new approach, which improves the wetting properties of these composites by molting solder alloys to promote stronger bonds. The new approach relies on nickel-plating of the composite's faying surface prior to application of a solder alloy. Based on this approach, an aluminum metal matrix composite containing 55 vol.% SiC particles is successfully soldered to a Fe–Ni–Co alloy (commercially known as Kovar 4J29). The solder material is a zinc-based alloy (Zn–Cd–Ag–Cu) with a melting point of about 400 °C. Microscopic examinations of the aluminum metal matrix composites (Al-MMCs)–Kovar interfaces show that the nickel-plating, prior to soldering, could noticeably enhance the reaction between the molten solder and composites. The fractography of the shear-tested samples revealed that fracture occurs within the composite (i.e. cohesive failure), indicating a good adhesion between the solder alloy and the Al–SiC composite.

  16. Optimization and characterization of woven kevlar reinforced epoxy matrix composite materials

    International Nuclear Information System (INIS)

    Imran, A.; Aslam, S.

    2007-01-01

    Composite materials are actually well established materials that have demonstrated their promising advantages among the light weight structural materials used for aerospace and advanced applications. An effort is now being made to develop and characterize the Kevlar Epoxy Composite Materials by changing the vol. fraction of Kevlar in epoxy matrix. The optimum characteristics were observed with 37% fiber with resin by applying hand-lay-up process. The composites produced were subjected to mechanical testing to evaluate the mechanical characteristics. (author)

  17. "A New Class of Creep Resistant Oxide/Oxide Ceramic Matrix Composites"

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Mohit Jain, Dr. Ganesh Skandan, Prof. Roger Cannon, Rutgers University

    2007-03-30

    Despite recent progress in the development of SiC-SiC ceramic matrix composites (CMCs), their application in industrial gas turbines for distributed energy (DE) systems has been limited. The poor oxidation resistance of the non-oxide ceramics warrants the use of envrionmental barrier coatings (EBCs), which in turn lead to issues pertaining to life expectancy of the coatings. On the other hand, oxide/oxide CMCs are potential replacements, but their use has been limited until now due to the poor creep resistance at high temperatures, particularly above 1200 oC: the lack of a creep resistant matrix has been a major limiting factor. Using yttrium aluminum garnet (YAG) as the matrix material system, we have advanced the state-of-the-art in oxide/oxide CMCs by introducing innovations in both the structure and composition of the matrix material, thereby leading to high temperature matrix creep properties not achieved until now. An array of YAG-based powders with a unique set of particle characteristics were produced in-house and sintered to full density and compressive creep data was obtained. Aided in part by the composition and the microstructure, the creep rates were found to be two orders of magnitude smaller than the most creep resistant oxide fiber available commercially. Even after accounting for porosity and a smaller matrix grain size in a practical CMC component, the YAG-based matrix material was found to creep slower than the most creep resistant oxide fiber available commercially.

  18. Niobium Carbide-Reinforced Al Matrix Composites Produced by High-Energy Ball Milling

    Science.gov (United States)

    Travessa, Dilermando Nagle; Silva, Marina Judice; Cardoso, Kátia Regina

    2017-06-01

    Aluminum and its alloys are key materials for the transportation industry as they contribute to the development of lightweight structures. The dispersion of hard ceramic particles in the Al soft matrix can lead to a substantial strengthening effect, resulting in composite materials exhibiting interesting mechanical properties and inspiring their technological use in sectors like the automotive and aerospace industries. Powder metallurgy techniques are attractive to design metal matrix composites, achieving a homogeneous distribution of the reinforcement into the metal matrix. In this work, pure aluminum has been reinforced with particles of niobium carbide (NbC), an extremely hard and stable refractory ceramic. Its use as a reinforcing phase in metal matrix composites has not been deeply explored. Composite powders produced after different milling times, with 10 and 20 vol pct of NbC were produced by high-energy ball milling and characterized by scanning electron microscopy and by X-ray diffraction to establish a relationship between the milling time and size, morphology, and distribution of the particles in the composite powder. Subsequently, an Al/10 pct NbC composite powder was hot extruded into cylindrical bars. The strength of the obtained composite bars is comparable to the commercial high-strength, aeronautical-grade aluminum alloys.

  19. Research on the preparation, biocompatibility and bioactivity of magnesium matrix hydroxyapatite composite material.

    Science.gov (United States)

    Linsheng, Li; Guoxiang, Lin; Lihui, Li

    2016-08-12

    In this paper, magnesium matrix hydroxyapatite composite material was prepared by electrophoretic deposition method. The optimal process parameters of electrophoretic deposition were HA suspension concentration of 0.02 kg/L, aging time of 10 days and voltage of 60 V. Animal experiment and SBF immersion experiment were used to test the biocompatibility and bioactivity of this material respectively. The SD rats were divided into control group and implant group. The implant surrounding tissue was taken to do tissue biopsy, HE dyed and organizational analysis after a certain amount of time in the SD rat body. The biological composite material was soaked in SBF solution under homeothermic condition. After 40 days, the bioactivity of the biological composite material was evaluated by testing the growth ability of apatite on composite material. The experiment results showed that magnesium matrix hydroxyapatite biological composite material was successfully prepared by electrophoretic deposition method. Tissue hyperplasia, connective tissue and new blood vessels appeared in the implant surrounding soft tissue. No infiltration of inflammatory cells of lymphocytes and megakaryocytes around the implant was found. After soaked in SBF solution, a layer bone-like apatite was found on the surface of magnesium matrix hydroxyapatite biological composite material. The magnesium matrix hydroxyapatite biological composite material could promot calcium deposition and induce bone-like apatite formation with no cytotoxicity and good biocompatibility and bioactivity.

  20. Alumina matrix ceramic-nickel composites formed by centrifugal slip casting

    Directory of Open Access Journals (Sweden)

    Justyna Zygmuntowicz

    2015-12-01

    Full Text Available The paper is focused on the possibility of fabricating the alumina matrix ceramic-nickel composites with gradient concentration of metal particles. Centrifugal slip casting method was chosen for the composite fabrication. This method allows fabrication of the graded distribution of nickel particles in the hollow cylinder composites. The horizontal rotation axis was applied. The samples were characterized by XRD, SEM and quantitative description of the microstructure. The macroscopic as well as SEM observations of the prepared composites confirmed the gradient concentration of Ni particles in the composite materials. The application of the centrifugal slip casting method allows for the graded distribution of metal particles in the samples.

  1. Effect of fiber content on the properties of glass fiber-phenolic matrix composite

    International Nuclear Information System (INIS)

    Zaki, M.Y.; Shahid, M.R.; Subhani, T.; Sharif, M.N.

    2003-01-01

    Glass fiber-Phenolic matrix composite is used for the manufacturing of parts /components related to electronic and aerospace industry due to its high strength, dimensional stability and excellent electrical insulation properties. The evaluation of this composite material is necessary prior to make parts/components of new designs. In the present research, thermosetting phenolic plastic was reinforced with E-glass fiber in different fiber-to-resin ratios to produce composites of different compositions. Mechanical and electrical properties of these composite materials were evaluated with reference to the effect of fiber content variation in phenolic resin. (author)

  2. Stimulated light emission in a dielectrically disordered composite porous matrix

    Science.gov (United States)

    Gross, E.; Künzner, N.; Diener, J.; Fujii, Minoru; Timoshenko, V. Yu.; Kovalev, D.

    2005-06-01

    We report on a medium exhibiting extremely efficient light scattering properties: a liquid network formed in a porous matrix. Liquid fragments confined in the solid matrix result in a random fluctuation of the dielectric function and act as scattering objects for photons. The optical scattering efficiency is defined by the filling factor of the liquid in the pores and its dielectric constant. The spectral dependence of the scattering length of photons indicates that the phenomenon is governed by a Mie-type scattering mechanism. The degree of the dielectric disorder of the medium, i.e. the level of opacity is tunable by the ambient vapor pressure of the dielectric substance. In the strongest scattering regime the scattering length of photons is found to be in the micrometer range. By incorporation of dye molecules in the voids of the porous layer a system exhibiting optical gain is realized. In the multiple scattering regime the optical path of diffusively propagating photons is enhanced and light amplification through stimulated emission occurs: a strong intensity enhancement of the dye emission accompanied by significant spectral narrowing is observed above the excitation threshold for a layer being in the opalescence state.

  3. Engineering Interfaces in Metal Matrix Composites (Volume 3)

    Science.gov (United States)

    1988-06-10

    or aluminum decreases as the modulus of the fibers increases (Amateau and Dull 1977; Baker and Bonfield 1978; Kohara and Muto 1986; Maruyama and...J.Wiley & Sons, N.Y., Chapter 15. Knox, C. E. (1982) Handbook of Composites, Edited by G.Lubin (Van Nostrand Reinhold) 136-195. Kohara , S. and Muto

  4. Laboratory for the Processing and Evaluation of Inorganic Matrix Composites

    Science.gov (United States)

    1989-06-01

    modulus of the fibers increases (Amateau and Dull 1977; Baker and Bonfield 1978; Kohara and Muto 1986; Maruyama and Rabenberg 1986; Chawla 1987...15. Knox, C. E. (1982) Handbook of Composites, Edited by G.Lubin (Van Nostrand Reinhold) 136-195. Kohara , S. and Muto, N., (1986) Degradation of PAN

  5. Mechanical properties of Nextel trademark 312 fiber-reinforced SiC matrix composites

    International Nuclear Information System (INIS)

    Vaidyanathan, K.R.; Sankar, J.; Kelkar, A.D.; Weaver, B.

    1995-01-01

    Vapor phase synthesis is emerging as a method for the preparation of near final-shape, ceramic matrix composites for advanced structural applications. Oxide fiber-reinforced silicon carbide matrix composites are currently being developed for these applications. The mechanical properties of Nextel trademark 312 fiber reinforced SiC matrix composites fabricated employing the forced-flow, thermal gradient chemical vapor infiltration process (FCVI) were evaluated at room temperature in pure tension. The composites were fabricated with a 0.15 μm pyrolytic carbon interface layer for improving the toughness of the composite system. Because of the available FCVI apparatus, only short length specimens (7--8 cm) could be fabricated. Room temperature tensile strengths were measured and compared to room temperature flexure strength results for the composite. Excellent toughness and composite behavior was obtained for the composite system. Fractography as well as possible factors responsible for the differences in tensile and flexural strengths for the composite system is presented in this paper

  6. High Dehumidification Performance of Amorphous Cellulose Composite Membranes prepared from Trimethylsilyl Cellulose

    KAUST Repository

    Puspasari, Tiara; Akhtar, Faheem Hassan; Ogieglo, Wojciech; Alharbi, Ohoud; Peinemann, Klaus-Viktor

    2018-01-01

    Cellulose is widely regarded as an environmentally friendly, natural and low cost material which can significantly contribute the sustainable economic growth. In this study, cellulose composite membranes were prepared via regeneration

  7. Non-self-similar cracking in unidirectional metal-matrix composites

    International Nuclear Information System (INIS)

    Rajesh, G.; Dharani, L.R.

    1993-01-01

    Experimental investigations on the fracture behavior of unidirectional Metal Matrix Composites (MMC) show the presence of extensive matrix damage and non-self-similar cracking of fibers near the notch tip. These failures are primarily observed in the interior layers of an MMC, presenting experimental difficulties in studying them. Hence an investigation of the matrix damage and fiber fracture near the notch tip is necessary to determine the stress concentration at the notch tip. The classical shear lag (CLSL) assumption has been used in the present study to investigate longitudinal matrix damage and nonself-similar cracking of fibers at the notch tip of an MMC. It is seen that non-self-similar cracking of fibers reduces the stress concentration at the notch tip considerably and the effect of matrix damage is negligible after a large number of fibers have broken beyond the notch tip in a non-self-similar manner. Finally, an effort has been made to include non-self-similar fiber fracture and matrix damage to model the fracture behavior of a unidirectional boron/aluminum composite for two different matrices viz. a 6061-0 fully annealed aluminum matrix and a heat treated 6061-T6 aluminum matrix. Results have been drawn for several characteristics pertaining to the shear stiffnesses and the shear yield stresses of the two matrices and compared with the available experimental results

  8. Wear study of Al-SiC metal matrix composites processed through microwave energy

    Science.gov (United States)

    Honnaiah, C.; Srinath, M. S.; Prasad, S. L. Ajit

    2018-04-01

    Particulate reinforced metal matrix composites are finding wider acceptance in many industrial applications due to their isotropic properties and ease of manufacture. Uniform distribution of reinforcement particulates and good bonding between matrix and reinforcement phases are essential features in order to obtain metal matrix composites with improved properties. Conventional powder metallurgy technique can successfully overcome the limitation of stir casting techniques, but it is time consuming and not cost effective. Use of microwave technology for processing particulate reinforced metal matrix composites through powder metallurgy technique is being increasingly explored in recent times because of its cost effectiveness and speed of processing. The present work is an attempt to process Al-SiC metal matrix composites using microwaves irradiated at 2.45 GHz frequency and 900 W power for 10 minutes. Further, dry sliding wear studies were conducted at different loads at constant velocity of 2 m/s for various sliding distances using pin-on-disc equipment. Analysis of the obtained results show that the microwave processed Al-SiC composite material shows around 34 % of resistance to wear than the aluminium alloy.

  9. The effect of alumina nanofillers size and shape on mechanical behavior of PMMA matrix composite

    Directory of Open Access Journals (Sweden)

    Ben Hasan Somaya Ahmed

    2014-01-01

    Full Text Available Composites with the addition of alumina nanofillers show improvement in mechanical properties. The PMMA polymer was used as a matrix and two different types of nanofillers, having extremely different shapes were added in the matrix to form the composite. Reinforcements were based on alumina nanoparticles having either spherical shape or whiskers having the length to diameter ratio of 100. The influence of alumina fillers size, shape and fillers loading on mechanical properties of prepared composite were studied using the nanoindentation measurements and dynamic mechanical analysis. It was observed that both alumina whiskers and alumina spherical nanoparticles added in the PMMA matrix improved the mechanical properties of the composite but the improvement was significantly higher with alumina whisker reinforcement. The concentration of the reinforcing alumina spherical nanoparticles and alumina whiskers in PMMA matrix varied up to 5 wt. %. The best performance was obtained by the addition of 3 wt. % of alumina whiskers in the PMMA matrix with regard to mechanical properties of the obtained composite.

  10. Zinc oxide-potassium ferricyanide composite thin film matrix for biosensing applications

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Shibu [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Arya, Sunil K. [Department of Science and Technology Centre on Biomolecular Electronics, National Physical Laboratory, New Delhi 110012 (India); Singh, S.P. [Department of Engineering Science and Materials, University of Puerto Rico, Mayaguez, PR 00680 (United States); Sreenivas, K. [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Malhotra, B.D. [Department of Science and Technology Centre on Biomolecular Electronics, National Physical Laboratory, New Delhi 110012 (India); Gupta, Vinay, E-mail: vgupta@physics.du.ac.in [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

    2009-10-27

    Thin film of zinc oxide-potassium ferricyanide (ZnO-KFCN) composite has been deposited on indium tin oxide (ITO) coated corning glass using pulsed laser deposition (PLD). The composite thin film electrode has been exploited for amperometric biosensing in a mediator-free electrolyte. The composite matrix has the advantages of high iso-electric point of ZnO along with enhanced electron communication due to the presence of a redox species in the matrix itself. Glucose oxidase (GOx) has been chosen as the model enzyme for studying the application of the developed matrix to biosensing. The sensing response of the bio-electrode, GOx/ZnO-KFCN/ITO/glass, towards glucose was studied using cylic voltammetry (CV) and photometric assay. The bio-electrode exhibits good linearity from 2.78 mM to 11.11 mM glucose concentration. The low value of Michaelis-Menten constant (1.69 mM) indicates an enhanced affinity of the immobilized enzyme towards its substrate. A quassireversible system is obtained with the composite matrix. The results confirm promising application of the ZnO-KFCN composite matrix for amperometric biosensing applications in a mediator-less electrolyte that could lead to the realization of an integrated lab-on-chip device.

  11. Zinc oxide-potassium ferricyanide composite thin film matrix for biosensing applications

    International Nuclear Information System (INIS)

    Saha, Shibu; Arya, Sunil K.; Singh, S.P.; Sreenivas, K.; Malhotra, B.D.; Gupta, Vinay

    2009-01-01

    Thin film of zinc oxide-potassium ferricyanide (ZnO-KFCN) composite has been deposited on indium tin oxide (ITO) coated corning glass using pulsed laser deposition (PLD). The composite thin film electrode has been exploited for amperometric biosensing in a mediator-free electrolyte. The composite matrix has the advantages of high iso-electric point of ZnO along with enhanced electron communication due to the presence of a redox species in the matrix itself. Glucose oxidase (GOx) has been chosen as the model enzyme for studying the application of the developed matrix to biosensing. The sensing response of the bio-electrode, GOx/ZnO-KFCN/ITO/glass, towards glucose was studied using cylic voltammetry (CV) and photometric assay. The bio-electrode exhibits good linearity from 2.78 mM to 11.11 mM glucose concentration. The low value of Michaelis-Menten constant (1.69 mM) indicates an enhanced affinity of the immobilized enzyme towards its substrate. A quassireversible system is obtained with the composite matrix. The results confirm promising application of the ZnO-KFCN composite matrix for amperometric biosensing applications in a mediator-less electrolyte that could lead to the realization of an integrated lab-on-chip device.

  12. Creep and threshold tension in aluminum-matrix composite with short fibers obtained by hot pressing

    International Nuclear Information System (INIS)

    Moreno, M.F; Gonzalez Oliver, C.R.J

    2004-01-01

    An aluminum matrix composite reinforced with 5% vol. of short fibers of silicon carbide and un-reinforced matrix, produced by pulvimetallurgy (PM) were studied using creep compression at different deformation speeds and in the range of 300 o C to 500 o C. The creep curve of both materials showed the typical behavior of a material with threshold tension τ 0 ; with an estimate value of 6.31MPa for the matrix at 400 o C and 6.43, 8.76 and 11MPa at 350, 400 and 450 o C respectively for the composite. The τ 0 was shown to obey a thermally activated mechanism whose energy is about 17 kJ/mol. Nanometric particles of aluminum oxide were scattered throughout the matrix and the composite, arising from the inevitable film of oxides and hydroxides formed in the metallic powder. The exponent of power-law creep occurs in the values of n = 4.3 to 4.85 by reducing the tension to an effective value τ-τ 0 , corresponding to a drilling fault in both materials. In the composite, the activation energy was estimated at 167 to 125 kJ/mol, close to the self- diffusion enthalpy of the pure aluminum at 143.4 kJ/mol so that the creep process in the composite is controlled exclusively by the deformation of the matrix (CW)

  13. Rapid synthesis of graphene/amorphous α-MnO{sub 2} composite with enhanced electrochemical performance for electrochemical capacitor

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Mingjun [Key Laboratory of Physics and Technology for Advanced Batteries, Ministry of Education, College of Physics, Jilin University, Jiefang Road 2519, Changchun 130012 (China); Long, Guohui [College of Life Sciences, Jilin Agricultural University, Changchun 130118 (China); Jiang, Shang [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012 (China); Ji, Yuan, E-mail: jiyuan@jlu.edu.cn [Key Laboratory of Physics and Technology for Advanced Batteries, Ministry of Education, College of Physics, Jilin University, Jiefang Road 2519, Changchun 130012 (China); Han, Wei [Key Laboratory of Physics and Technology for Advanced Batteries, Ministry of Education, College of Physics, Jilin University, Jiefang Road 2519, Changchun 130012 (China); Wang, Biao [Key Laboratory of Physics and Technology for Advanced Batteries, Ministry of Education, College of Physics, Jilin University, Jiefang Road 2519, Changchun 130012 (China); School of Science, University of Science and Technology Liaoning, Anshan 114051 (China); Liu, Xilong; Xi, Yunlong [Key Laboratory of Physics and Technology for Advanced Batteries, Ministry of Education, College of Physics, Jilin University, Jiefang Road 2519, Changchun 130012 (China)

    2015-04-15

    Highlights: • Graphene/MnO{sub 2} is successfully fabricated by a facile co-precipitation method. • The graphene/MnO{sub 2} electrode reaches 367 Fg{sup −1} in 1 M KOH electrolyte. • The electrode exhibits good cycling performance of 73.9% retention after 1000 cycles. - Abstract: Nanostructured graphene/amorphous α-MnO{sub 2} composites have been synthesized by a facile co-precipitation method under the alkaline condition, in which graphene nanosheets as a supporting substrate to grow MnO{sub 2}. Characterizations of prepared samples’ morphology and microstructures indicate MnO{sub 2} is successfully formed on the surface of graphene by electrostatic interaction. Moreover, the electrochemical properties of the synthesized electrode materials for supercapacitors are studied in a three-electrode experimental setup using a 1 M KOH aqueous solution as the electrolyte. As a result, the specific capacitance of graphene/MnO{sub 2} composite (weight ratio of graphene to MnO{sub 2} is 1:1) determined by a galvanostatic charge–discharge method at a current density of 1 Ag{sup −1} reaches 367 Fg{sup −1}, which is 1.8 and 4.6 fold higher than that of pure graphene and MnO{sub 2}. The capacity retention of the graphene/MnO{sub 2} composite is 73.9% of the original capacitance after 1000 cycles, indicating graphene/MnO{sub 2} composite is a promising electrode material for supercapacitors.

  14. On low cycle fatigue in metal matrix composites

    DEFF Research Database (Denmark)

    Pedersen, Thomas Ø; Tvergaard, Viggo

    2000-01-01

    A numerical cell model analysis is used to study the development of fatigue damage in aluminium reinforced by aligned, short SiC fibres. The material is subjected to cyclic loading with either stress control or strain control, and the matrix material is represented by a cyclic plasticity model......, in which continuum damage mechanics is incorporated to model fatigue damage evolution. This material model uses a superposition of kinematic and isotropic hardening, and is able to account for the Bauschinger effect as well as ratchetting, mean stress relaxation, and cyclic hardening or softening. The cell...... model represents a material with transversely staggered fibres. With focus on low cyclic fatigue, the effect of different fibre aspect ratios, different triaxial stress states, and balanced as well as unbalanced cyclic loading is studied....

  15. ac conductivity and dielectric properties of amorphous Se80Te20-xGex chalcogenide glass film compositions

    International Nuclear Information System (INIS)

    Hegab, N.A.; Afifi, M.A.; Atyia, H.E.; Farid, A.S.

    2009-01-01

    Thin films of the prepared Se 80 Te 20-x Ge x (x = 5, 7 and 10 at.%) were prepared by thermal evaporation technique. X-ray diffraction patterns showed that the films were in amorphous state. The ac conductivity and dielectric properties of the investigated film compositions were studied in the frequency range 0.1-100 kHz and in temperature range (303-373 K). The experimental results indicated that the ac conductivity and the dielectric properties depended on the temperature and frequency. The ac conductivity is found to obey the ω s law, in accordance with the hopping model, s is found to be temperature dependent (s 1 and dielectric loss ε 2 were found to decrease with frequency and increase with temperature. The maximum barrier height W m , calculated from dielectric measurements according to Guintini equation, agrees with that proposed by the theory of hopping over potential barrier as suggested by Elliott in case of chalcogenide glasses. The density of localized states was estimated for the studied film compositions. The variation of the studied properties with Ge content was also investigated.

  16. Charged Nanowire-Directed Growth of Amorphous Calcium Carbonate Nanosheets in a Mixed Solvent for Biomimetic Composite Films.

    Science.gov (United States)

    Liu, Yangyi; Liu, Lei; Chen, Si-Ming; Chang, Fu-Jia; Mao, Li-Bo; Gao, Huai-Ling; Ma, Tao; Yu, Shu-Hong

    2018-04-19

    Bio-inspired mineralization is an effective way for fabricating complicated inorganic materials, which inspires us to develop new methods to synthesize materials with fascinating properties. In this article, we report that the charged tellurium nanowires (TeNWs) can be used as bio-macromolecule analogues to direct the formation of amorphous calcium carbonate (ACC) nanosheets (ACCNs) in a mixed solvent. The effects of surface charges and the concentration of the TeNWs on the formation of ACCNs have been investigated. Particularly, the produced ACCNs can be functionalized by Fe3O4 nanoparticles to produce magnetic ACC/Fe3O4 hybrid nanosheets, which can be used to construct ACC/Fe3O4 composite films through a self-evaporation process. Moreover, sodium alginate-ACC nanocomposite films with remarkable toughness and good transmittance can also be fabricated by using such ACCNs as nanoscale building blocks. This mineralization approach in a mixed solvent using charged tellurium nanowires as bio-macromolecule analogues provides a new way for the synthesis of ACCNs, which can be used as nanoscale building blocks for fabrication of biomimetic composite films.

  17. Investigation of the low-speed impact behavior of dual particle size metal matrix composites

    International Nuclear Information System (INIS)

    Cerit, Afşın Alper

    2014-01-01

    Highlights: • AA2124 matrix composites reinforced with SiC particles were manufactured. • Low-speed impact behaviors of composites were investigated. • Composites were manufactured with single (SPS) and dual particle sizes (DPS). • Impact behaviors of DPS composites are more favorable than the SPS composites. • Approximately 50–60% of input energy was absorbed by the composite samples. - Abstract: SiC-reinforced aluminum matrix composites were manufactured by powder metallurgy using either single or dual particle sized SiC powders and samples sintered under argon atmosphere. Quasi-static loading, low-speed impact tests and hardness tests were used to investigate mechanical behavior and found that dual particle size composites had improved hardness and impact performance compared to single particle size composites. Sample microstructure, particle distributions, plastic deformations and post-testing damages were examined by scanning electron microscopy and identified microstructure agglomerations in SPS composites. Impact traces were characterized by broken and missing SiC particles and plastically deformed composite areas

  18. High Porosity Alumina as Matrix Material for Composites of Al-Mg Alloys

    International Nuclear Information System (INIS)

    Gömze, L A; Egész, Á; Gömze, L N; Ojima, F

    2013-01-01

    The sophisticated industry and technologies require higher and higher assumptions against mechanical strength and surface hardness of ceramic reinforced metal alloys and metal matrix composites. Applying the well-known alumina powders by dry pressing technology and some special pore-forming additives and sintering technology the authors have successfully developed a new, high porosity alumina matrix material for composites of advenced Al-Mg alloys. The developed new matrix material have higher than 30% porosity, with homogenous porous structure and pore sizes from few nano up to 2–3 mm depending on the alloys containments. Thanks to the used materials and the sintering conditions the authors could decrease the wetting angles less than 90° between the high porosity alumina matrix and the Al-Mg alloys. Applied analytical methods in this research were laser granulometry, scanning electron microscopy, and X-ray diffraction. Digital image analysis was applied to microscopy results, to enhance the results of transformation

  19. Chemical-vapor-infiltrated silicon nitride, boron nitride, and silicon carbide matrix composites

    International Nuclear Information System (INIS)

    Ventri, R.D.; Galasso, F.S.

    1990-01-01

    This paper reports composites of carbon/chemical-vapor-deposited (CVD) Si 3 N 4 , carbon/CVD BN, mullite/CVD SiC, and SiC yarn/CVD SiC prepared to determine if there were inherent toughness in these systems. The matrices were deposited at high enough temperatures to ensure that they were crystalline, which should make them more stable at high temperatures. The fiber-matrix bonding in the C/Si 3 N 4 composite appeared to be too strong; the layers of BN in the matrix of the C/BN were too weakly bonded; and the mullite/SiC composite was not as tough as the SiC/SiC composites. Only the SiC yarn/CVD SiC composite exhibited both strength and toughness

  20. The development and mechanical characterization of aluminium copper-carbon fiber metal matrix hybrid composite

    Science.gov (United States)

    Manzoor, M. U.; Feroze, M.; Ahmad, T.; Kamran, M.; Butt, M. T. Z.

    2018-04-01

    Metal matrix composites (MMCs) come under advanced materials that can be used for a wide range of industrial applications. MMCs contain a non-metallic reinforcement incorporated into a metallic matrix which can enhance properties over base metal alloys. Copper-Carbon fiber reinforced aluminium based hybrid composites were prepared by compo casting method. 4 weight % copper was used as alloying element with Al because of its precipitation hardened properties. Different weight compositions of composites were developed and characterized by mechanical testing. A significant improvement in tensile strength and micro hardness were found, before and after heat treatment of the composite. The SEM analysis of the fractured surfaces showed dispersed and embedded Carbon fibers within the network leading to the enhanced strength.

  1. Structure and properties of nanocrystalline soft magnetic composite materials with silicon polymer matrix

    International Nuclear Information System (INIS)

    Dobrzanski, L.A.; Nowosielski, R.; Konieczny, J.; PrzybyI, A.; WysIocki, J.

    2005-01-01

    The paper concerns investigation of nanocrystalline composites technology preparation. The composites in the form of rings with rectangular transverse section, and with polymer matrix and nanocrystalline metallic powders fulfillment were made, for obtaining good ferromagnetic properties. The nanocrystalline ferromagnetic powders were manufactured by high-energy ball milling of metallic glasses strips in an as-quenched state. Generally for investigation, Co matrix alloys with the silicon polymer were used. Magnetic properties in the form of hysteresis loop by rings method were measured. Generally composite cores showed lower soft ferromagnetic properties than winded cores of nanocrystalline strips, but composite cores showed interesting mechanical properties. Furthermore, the structure of strips and powders on properties of composites were investigated

  2. Consolidation effects on tensile properties of an elemental Al matrix composite

    Energy Technology Data Exchange (ETDEWEB)

    Tang, F. [Building 4515, MS 6064, Metals and Ceramics Division, Oak Ridge National Lab, Oak Ridge, TN 37831 (United States)]. E-mail: tangf@ornl.gov; Meeks, H. [Ceracon Inc., 5150 Fairoaks Blvd. 01-330, Carmichael, CA 95628 (United States); Spowart, J.E. [UES Incorporated, AFRL/MLLM Building 655, 2230 Tenth St. Suite 1, Wright-Patterson AFB, OH 45433 (United States); Gnaeupel-Herold, T. [NIST Center for Neutron Research, 100 Bureau Dr. Stop 8562, Gaithersburg, MD 20899-8562 (United States); Prask, H. [NIST Center for Neutron Research, 100 Bureau Dr. Stop 8562, Gaithersburg, MD 20899-8562 (United States); Anderson, I.E. [Materials and Engineering Physics Program, Ames Laboratory, Iowa State University, Ames, IA 50011 (United States)

    2004-11-25

    In a simplified composite design, an unalloyed Al matrix was reinforced by spherical Al-Cu-Fe alloy particles (30 vol.%), using either commercial purity (99.7%) or high purity (99.99%) fine powders (diameter < 10 {mu}m). This composite material was consolidated by either vacuum hot pressing (VHP) or quasi-isostatic forging. The spatial distribution of reinforcement particles in both VHP and forged samples was shown to be almost the same by quantitative characterization with a multi-scale area fraction analysis technique. The tensile properties of all composite samples were tested and the forged materials showed significantly higher strength, while the elastic modulus values of all composite materials were close to the upper bound of theoretical predictions. Neutron diffraction measurements showed that there were high compressive residual stresses in the Al matrix of the forged samples and relatively low Al matrix residual stresses (predominantly compressive) in the VHP samples. By tensile tests and neutron diffraction measurements of the forged samples after annealing, it was shown that the high compressive residual stresses in the Al matrix were relieved and that tensile strength was also reduced to almost the same level as that of the VHP samples. Therefore, it was deduced that increased compressive residual stresses and enhanced dislocation densities in the forged composites raised the tensile strength to higher values than those of the VHP composites.

  3. Microstructural characterisation of electrodeposited coatings of metal matrix composite with alumina nanoparticles

    International Nuclear Information System (INIS)

    Indyka, P; Beltowska-Lehman, E; Bigos, A

    2012-01-01

    In the present work a nanocrystalline Ni-W metallic matrix was used to fabricate Ni-W/Al 2 O 3 composite coatings. The MMC (metal matrix composite) coatings with inert α-Al 2 O 3 particles (30 - 90 nm) were electrodeposited from aqueous electrolytes under direct current (DC) and controlled hydrodynamic conditions in a system with a rotating disk electrode (RDE). The chemical composition and microstructure of electrodeposited composites mainly control their functional properties; however, the particles must be uniformly dispersed to exhibit the dispersion-hardening effect. In order to increase the alumina particles incorporation as well as to promote the uniform distribution of the ceramic phase in a matrix, outer ultrasonic field was applied during electrodeposition. The influence of embedded alumina nanoparticles on structural characteristics (morphology, phase composition, residual stresses) of the resulting Ni-W/Al 2 O 3 coatings was investigated in order to obtain a nanocomposite with high hardness and relatively low residual stresses. Surface and cross-section morphology and the chemical composition of deposits was examined in the scanning electron microscope, the EDS technique was used. Microstructure and phase composition were determined by transmission electron microscopy and X-ray diffraction. Based on microstructural and micromechanical properties of the coatings, the optimum conditions for obtaining crack-free homogeneous Ni-W/Al 2 O 3 composite coatings have been determined.

  4. Influence of reinforcement grade and matrix composition on corrosion resistance of cast aluminium matrix composites (A3xx.x/SiCp) in a humid environment

    Energy Technology Data Exchange (ETDEWEB)

    Pardo, A.; Viejo, F.; Carboneras, M. [Departamento de Ciencia de Materiales, Facultad de Quimica Universidad Complutense, 28040, Madrid (Spain); Merino, M.C. [Departamento de Ciencia de Materiales, Facultad de Quimica Universidad Complutense, 28040, Madrid (Spain); Departamento de Tecnologia Industrial, Universidad Alfonso X El Sabio, 28691, Villanueva de la Canada, Madrid (Spain); Lopez, M.D. [Escuela Superior de Ciencias Experimentales y Tecnologia, Universidad Rey Juan Carlos, 28931, Mostoles, Madrid (Spain); Merino, S. [Departamento de Tecnologia Industrial, Universidad Alfonso X El Sabio, 28691, Villanueva de la Canada, Madrid (Spain)

    2003-05-01

    A study of the influence of the silicon carbide (SiC{sub p}) proportion and the matrix concentration of four aluminium metal matrix composites (A360/SiC/10p, A360/SiC/20p, A380/SiC/10p, A380/SiC/20p) exposed to high relative humid environment was carried out under simulation in a climatic chamber. The matrix of A360/SiC/xxp composites was virtually free of copper while the A380/SiC/xxp matrix contained 3.13-3.45wt% Cu and 1.39-1.44wt% Ni. The kinetics of the corrosion process was studied on the basis of gravimetric tests. The nature of corrosion products was analysed by Scanning Electron Microscopy (SEM) and Low Angle X-Ray Diffraction (XRD) before and after accelerated testing to determine the influence of microstructural changes on corrosion behaviour during exposure to the corrosive environment. The corrosion damage to Al/SiCp composites was low at 80% Relative Humidity (RH) and increased with temperature, SiCp proportion, relative humidity and Cu matrix concentration. The main attack nucleation sites were the interface region between the matrix and the reinforcement particles. The corrosion process was influenced more by the concentration of alloy elements in the matrix than by the proportion of SiCp reinforcement. (Abstract Copyright [2003], Wiley Periodicals, Inc.) [German] Eine Studie zum Einfluss des Siliziumkarbidanteils (SiCp) und der Zusammensetzung des Grundwerkstoffs von vier Aluminiummatrixverbundwerkstoffen (A360/SiC/10p, A360/SiC/20p, A380/SiC/10p, A380/SiC/20p), die in Umgebungen mit relativ hoher Feuchtigkeit ausgelagert waren, wurde unter simulierten Bedingungen in einer Klimakammer durchgefuehrt. Die Matrix des A360/SiC/xxp-Verbundwerkstoffs war praktisch Kupfer-frei waehrend die A380/SiC/xxp Matrix 3,13-3,45 Gew.-% Cu und 1,39-1,44 Gew.-% Ni enthielt. Die Kinetik des Korrosionsprozesses wurde auf der Basis von gravimetrischen Messungen studiert. Die Beschaffenheit der Korrosionsprodukte wurde mittelt REM-Untersuchungen und

  5. Boron-bearing species in ceramic matrix composites for long-term aerospace applications

    International Nuclear Information System (INIS)

    Naslain, R.; Guette, A.; Rebillat, F.; Pailler, R.; Langlais, F.; Bourrat, X.

    2004-01-01

    Boron-bearing refractory species are introduced in non-oxide ceramic matrix fibrous composites (such as SiC/SiC composites) to improve their oxidation resistance under load at high temperatures with a view to applications in the aerospace field. B-doped pyrocarbon and hex-BN have been successfully used as interphase (instead of pure pyrocarbon) either as homogeneous or multilayered fiber coatings, to arrest and deflect matrix cracks formed under load (mechanical fuse function) and to give toughness to the materials. A self-healing multilayered matrix is designed and used in a model composite, which combines B-doped pyrocarbon mechanical fuse layers and B- and Si-bearing compound (namely B 4 C and SiC) layers forming B 2 O 3 -based fluid healing phases when exposed to an oxidizing atmosphere. All the materials are deposited by chemical vapor infiltration. Lifetimes under tensile loading of several hundreds hours at high temperatures are reported

  6. Synthesizing (ZrAl3 + AlN)/Mg-Al composites by a 'matrix exchange' method

    Science.gov (United States)

    Gao, Tong; Li, Zengqiang; Hu, Kaiqi; Han, Mengxia; Liu, Xiangfa

    2018-06-01

    A method named 'matrix exchange' to synthesize ZrAl3 and AlN reinforced Mg-Al composite was developed in this paper. By inserting Al-10ZrN master alloy into Mg matrix and reheating the cooled ingot to 550 °C, Al and Mg atoms diffuse to the opposite side. As a result, liquid melt occurs once the interface areas reach to proper compositions. Then dissolved Al atoms react with ZrN, leading to the in-situ formation of ZrAl3 and AlN particles, while the Al matrix is finally replaced by Mg. This study provides a new insight for preparing Mg composites.

  7. Niobium-Matrix-Composite High-Temperature Turbine Blades

    Science.gov (United States)

    Kaplan, Richard B.; Tuffias, Robert H.; La Ferla, Raffaele; Heng, Sangvavann; Harding, John T.

    1995-01-01

    High-temperture composite-material turbine blades comprising mainly niobium matrices reinforced with refractory-material fibers being developed. Of refractory fibrous materials investigated, FP-AL(2)0(3), tungsten, and polymer-based SiC fibers most promising. Blade of this type hollow and formed in nearly net shape by wrapping mesh of reinforcing refractory fibers around molybdenum mandrel, then using thermal-gradient chemical-vapor infiltration (CVI) to fill interstices with niobium. CVI process controllable and repeatable, and kinetics of both deposition and infiltration well understood.

  8. High-Temperature Ceramic Matrix Composite with High Corrosion Resistance

    Science.gov (United States)

    2010-06-02

    description of high temperature oxidation processes of composite ceramic materials of ZrB2 - SiC and ZrB2-SiC-Zr(Mo)Si2 systems up to high (~1300 °C...analysis was applied using MІN-7 mineralogical microscope and a set of standard immersion liquids with the known values of refraction coefficients...2.0 V) corresponds to the simultaneous formation of ZrO2 zirconium dioxide of monoclinic modification and Zr(OH)4 zirconium hydroxide which is

  9. Universal composition-structure-property maps for natural and biomimetic platelet-matrix composites and stacked heterostructures.

    Science.gov (United States)

    Sakhavand, Navid; Shahsavari, Rouzbeh

    2015-03-16

    Many natural and biomimetic platelet-matrix composites--such as nacre, silk, and clay-polymer-exhibit a remarkable balance of strength, toughness and/or stiffness, which call for a universal measure to quantify this outstanding feature given the structure and material characteristics of the constituents. Analogously, there is an urgent need to quantify the mechanics of emerging electronic and photonic systems such as stacked heterostructures. Here we report the development of a unified framework to construct universal composition-structure-property diagrams that decode the interplay between various geometries and inherent material features in both platelet-matrix composites and stacked heterostructures. We study the effects of elastic and elastic-perfectly plastic matrices, overlap offset ratio and the competing mechanisms of platelet versus matrix failures. Validated by several 3D-printed specimens and a wide range of natural and synthetic materials across scales, the proposed universally valid diagrams have important implications for science-based engineering of numerous platelet-matrix composites and stacked heterostructures.

  10. The effect of the matrix superplastic deformation on interface reaction in fiber-reinforced composites

    International Nuclear Information System (INIS)

    Astanin, V.V.; Imayeva, L.A.

    1995-01-01

    It is known that superplastic deformation affects the processes o solid phases bonding. In particular, the effect of a character of matrix flow upon nucleation and growth of the reaction products at the fiber/matrix interface should be expected during consolidation of the fiber-reinforced composites under superplastic conditions. The matrix material flow in thin clearance (about 20μm) between strengthening fibers is a special feature of composite consolidation. In previous papers, it was shown that the character of the flow in thin specimens, when the specimen thickness is equal to several grain sizes, is very different from that in thick specimens. In this manner the question of the effect of the deformation on the fiber/matrix interface formation is complicated and one should consider the peculiarities of matrix deformation during the composite fabrication and the effect of localization of the deformation on the fiber/matrix interface reaction. In this paper, the authors shall focus on these two problems

  11. Data on a Laves phase intermetallic matrix composite in situ toughened by ductile precipitates.

    Science.gov (United States)

    Knowles, Alexander J; Bhowmik, Ayan; Purkayastha, Surajit; Jones, Nicholas G; Giuliani, Finn; Clegg, William J; Dye, David; Stone, Howard J

    2017-10-01

    The data presented in this article are related to the research article entitled "Laves phase intermetallic matrix composite in situ toughened by ductile precipitates" (Knowles et al.) [1]. The composite comprised a Fe 2 (Mo, Ti) matrix with bcc (Mo, Ti) precipitated laths produced in situ by an aging heat treatment, which was shown to confer a toughening effect (Knowles et al.) [1]. Here, details are given on a focused ion beam (FIB) slice and view experiment performed on the composite so as to determine that the 3D morphology of the bcc (Mo, Ti) precipitates were laths rather than needles. Scanning transmission electron microscopy (S(TEM)) micrographs of the microstructure as well as energy dispersive X-ray spectroscopy (EDX) maps are presented that identify the elemental partitioning between the C14 Laves matrix and the bcc laths, with Mo rejected from the matrix into laths. A TEM selected area diffraction pattern (SADP) and key is provided that was used to validate the orientation relation between the matrix and laths identified in (Knowles et al.) [1] along with details of the transformation matrix determined.

  12. Data on a Laves phase intermetallic matrix composite in situ toughened by ductile precipitates

    Directory of Open Access Journals (Sweden)

    Alexander J. Knowles

    2017-10-01

    Full Text Available The data presented in this article are related to the research article entitled “Laves phase intermetallic matrix composite in situ toughened by ductile precipitates” (Knowles et al. [1]. The composite comprised a Fe2(Mo, Ti matrix with bcc (Mo, Ti precipitated laths produced in situ by an aging heat treatment, which was shown to confer a toughening effect (Knowles et al. [1]. Here, details are given on a focused ion beam (FIB slice and view experiment performed on the composite so as to determine that the 3D morphology of the bcc (Mo, Ti precipitates were laths rather than needles. Scanning transmission electron microscopy (S(TEM micrographs of the microstructure as well as energy dispersive X-ray spectroscopy (EDX maps are presented that identify the elemental partitioning between the C14 Laves matrix and the bcc laths, with Mo rejected from the matrix into laths. A TEM selected area diffraction pattern (SADP and key is provided that was used to validate the orientation relation between the matrix and laths identified in (Knowles et al. [1] along with details of the transformation matrix determined.

  13. Vertically aligned Si nanocrystals embedded in amorphous Si matrix prepared by inductively coupled plasma chemical vapor deposition (ICP-CVD)

    Energy Technology Data Exchange (ETDEWEB)

    Nogay, G. [Department of Physics, Middle East Technical University (METU), Ankara 06800 (Turkey); Center of Solar Energy Research and Application (GÜNAM), Middle East Technical University (METU), Ankara 06800 (Turkey); Saleh, Z.M., E-mail: zaki.saleh@aauj.edu [Center of Solar Energy Research and Application (GÜNAM), Middle East Technical University (METU), Ankara 06800 (Turkey); Department of Physics, Arab American University–Jenin (AAUJ), Jenin, Palestine (Country Unknown); Özkol, E. [Center of Solar Energy Research and Application (GÜNAM), Middle East Technical University (METU), Ankara 06800 (Turkey); Department of Chemical Engineering, Middle East Technical University (METU), Ankara 06800 (Turkey); Turan, R. [Department of Physics, Middle East Technical University (METU), Ankara 06800 (Turkey); Center of Solar Energy Research and Application (GÜNAM), Middle East Technical University (METU), Ankara 06800 (Turkey)

    2015-06-15

    Highlights: • Inductively-coupled plasma is used for nanostructured silicon at room temperature. • Low temperature deposition allows device processing on various substrates. • Deposition pressure is the most effective parameter in controlling nanostructure. • Films consist of quantum dots in a-Si matrix and exhibit columnar vertical growth. • Films are porous to oxygen infusion along columnar grain boundaries. - Abstract: Vertically-aligned nanostructured silicon films are deposited at room temperature on p-type silicon wafers and glass substrates by inductively-coupled, plasma-enhanced chemical vapor deposition (ICPCVD). The nanocrystalline phase is achieved by reducing pressure and increasing RF power. The crystalline volume fraction (X{sub c}) and the size of the nanocrystals increase with decreasing pressure at constant power. Columnar growth of nc-Si:H films is observed by high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). The films exhibit cauliflower-like structures with high porosity that leads to slow but uniform oxidation after exposure to air at room temperature. Films deposited at low pressures exhibit photoluminescence (PL) signals that may be deconvoluted into three distinct Gaussian components: 760–810, 920–935, and 990–1000 nm attributable to the quantum confinement and interface defect states. Hydrogen dilution is manifested in significant enhancement of the PL, but it has little effect on the nanocrystal size and X{sub c}.

  14. Tempering Behavior of TiC-Reinforced SKD11 Steel Matrix Composite

    Science.gov (United States)

    Hwang, Ji-In; Kim, Seong Hoon; Heo, Yoon-Uk; Kim, Dae Ha; Hwang, Keum-Cheol; Suh, Dong-Woo

    2018-03-01

    TiC-reinforced SKD11 steel matrix composite, fabricated by a pressure infiltration casting, undergoes monotonic decrease in hardness as tempering temperature increases. Element mappings by TEM-EDS and thermodynamic calculation indicate that remarkable redistribution of V between the reinforcement and the steel matrix occurs by partial dissolution and re-precipitation of MC carbides upon casting process. The absence of secondary hardening is led by the enrichment of V in the reinforcement that reduces the V content in the steel matrix; this reduction in V content makes the precipitation of fine VC sluggish during the tempering.

  15. A planar model study of creep in metal matrix composites with misaligned short fibres

    DEFF Research Database (Denmark)

    Sørensen, N.J.

    1993-01-01

    The effect of fibre misalignment on the creep behaviour of metal matrix composites is modelled, including hardening behaviour (stage 1), dynamic recovery and steady state creep (stage 2) of the matrix material, using an internal variable constitutive model for the creep behaviour of the metal...... matrix. Numerical plane strain results in terms of average properties and detailed local deformation behaviour up to large strains are needed to show effects of fibre misalignment on the development of inelastic strains and the resulting over-all creep resistance of the material. The creep resistance...

  16. Ultrasound as a tool for the development of aerospace structural titanium and ceramic matrix composites

    International Nuclear Information System (INIS)

    Karpur, P.

    1993-01-01

    This paper outlines new concepts for the utilization of various ultrasonic techniques for the evaluation of different aspects of development and use of metal matrix composites. The authors introduce a novel mechanical parameter called interfacial shear stiffness coefficient which can be measured using ultrasonic shear wave reflectivity technique to characterize and quantify the matrix-fiber interface. Such nondestructive methods of interface characterization are essential because the utilization of metal matrix composites for aerospace applications require good characterization and evaluation of nascent composite systems in research and developmental stages. During development, it would be critical to evaluate (a) the compatibility of different types of matrix materials with different types of fibers, (b) the effect of different types of fiber coating on the load transfer between the matrix and the fiber, (c) the effect of processing conditions such as temperature, pressure, duration of processing, etc., (d) the suitability of the overall mechanical properties for the intended application, and (e) the mechanical behavior of the composite for life prediction studies

  17. Thermomechanical and Environmental Durability of Environmental Barrier Coated Ceramic Matrix Composites Under Thermal Gradients

    Science.gov (United States)

    Zhu, Dongming; Bhatt, Ramakrishna T.; Harder, Bryan

    2016-01-01

    This paper presents the developments of thermo-mechanical testing approaches and durability performance of environmental barrier coatings (EBCs) and EBC coated SiCSiC ceramic matrix composites (CMCs). Critical testing aspects of the CMCs will be described, including state of the art instrumentations such as temperature, thermal gradient, and full field strain measurements; materials thermal conductivity evolutions and thermal stress resistance; NDE methods; thermo-mechanical stress and environment interactions associated damage accumulations. Examples are also given for testing ceramic matrix composite sub-elements and small airfoils to help better understand the critical and complex CMC and EBC properties in engine relevant testing environments.

  18. Requirements of frictional debonding at fiber/matrix interfaces for tough ceramic composites

    Science.gov (United States)

    Hsueh, Chun-Hway

    1992-11-01

    Optimum toughening of fiber-reinforced ceramic composites requires debonding at fiber/matrix interfaces and subsequent frictional sliding between the fibers and the matrix as the main crack extends through the composite. Criteria of both interfacial debonding vs fiber fracture, and frictional debonding vs frictionless debonding, are illustrated. To achieve interfacial debonding, the ratio of the fiber strength to the interfacial shear strength must exceed a critical value; to achieve a frictional interface after interfacial debonding, the ratio of the interfacial residual clamping stress to the interfacial shear strength must also exceed a critical value. While interfacial debonding is not sensitive to Poisson's effect, the frictional interface is sensitive to Poisson's effect.

  19. Combined-load buckling behavior of metal-matrix composite sandwich panels under different thermal environments

    Science.gov (United States)

    Ko, William L.; Jackson, Raymond H.

    1991-01-01

    Combined compressive and shear buckling analysis was conducted on flat rectangular sandwich panels with the consideration of transverse shear effects of the core. The sandwich panel is fabricated with titanium honeycomb core and laminated metal matrix composite face sheets. The results show that the square panel has the highest combined load buckling strength, and that the buckling strength decreases sharply with the increases of both temperature and panel aspect ratio. The effect of layup (fiber orientation) on the buckling strength of the panels was studied in detail. The metal matrix composite sandwich panel was much more efficient than the sandwich panel with nonreinforced face sheets and had the same specific weight.

  20. Sintering by infiltration of loose mixture of powders, a method for metal matrix composite elaboration

    International Nuclear Information System (INIS)

    Constantinescu, V.; Orban, R.; Colan, H.

    1993-01-01

    Starting from the observation that Sintering by Infiltration of Loose Mixture of Powders confers large possibilities for both complex shaped and of large dimensions Particulate Reinforced Metal Matrix Composite components elaboration, its mechanism comparative with those of the classical melt infiltration was investigated. Appropriate measures in order to prevent an excessive hydrostatic flow of the melt and, consequently, reinforcement particle dispersion, as well as to promote wetting in both infiltration and liquid phase sintering stages of the process were established as necessary. Some experimental results in the method application to the fusion tungsten carbide and diamond reinforced metal matrix composite elaboration are, also, presented. (orig.)

  1. Chemical stability of the fiber coating/matrix interface in silicon-based ceramic matrix composites

    International Nuclear Information System (INIS)

    Lee, K.N.; Jacobson, N.S.

    1995-01-01

    Carbon and boron nitride are used as fiber coatings in silicon-based composites. In order to assess the long-term stability of these materials, reactions of carbon/Si 3 N 4 and BN/SiC were studied at high temperatures with Knudsen effusion, coupon tests, and by microstructural examination. in the carbon/Si 3 N 4 system, carbon reacted with Si 3 N 4 to form gaseous N 2 and SiC. The formation of SiC limited further reaction by physically separating the carbon and Si 3 N 4 . Consequently, the development of high p(N 2 ) at the interface, predicted from thermochemical calculations, did not occur, thus limiting the potential deleterious effects of the reaction on the composite. Strong indications of a reaction between BN and SiC were shown by TEM and SIMS analysis of the BN/SiC interface. In long-term exposures, this reaction can lead to a depletion of a BN coating and/or an unfavorable change of the interfacial properties, limiting the beneficial effects of the coating

  2. Chemical Stability of the Fiber Coating/Matrix Interface in Silicon-Based Ceramic Matrix Composites

    Science.gov (United States)

    Lee, Kang N.; Jacobson, Nathan S.

    1995-01-01

    Carbon and boron nitride are used as fiber coatings in silicon-based composites. In order to assess the long-term stability of these materials, reactions of carbon/Si3N4 and BN/SiC were studied at high temperatures with Knudsen effusion, coupon tests, and microstructural examination. In the carbon/Si3N4 system, carbon reacted with Si3N4 to form gaseous N2 and SiC. The formation of SiC limited further reaction by physically separating the carbon and Si3N4. Consequently, the development of high p(N2) at the interface, predicted from thermochemical calculations, did not occur, thus limiting the potential deleterious effects of the reaction on the composite. Strong indications of a reaction between BN and SiC were shown by TEM and SIMS analysis of the BN/SiC interface. In long-term exposures, this reaction can lead to a depletion of a BN coating and/or an unfavorable change of the interfacial properties, limiting the beneficial effects of the coating.

  3. Optimal fabrication processes for unidirectional metal-matrix composites: A computational simulation

    Science.gov (United States)

    Saravanos, D. A.; Murthy, P. L. N.; Morel, M.

    1990-01-01

    A method is proposed for optimizing the fabrication process of unidirectional metal matrix composites. The temperature and pressure histories are optimized such that the residual microstresses of the composite at the end of the fabrication process are minimized and the material integrity throughout the process is ensured. The response of the composite during the fabrication is simulated based on a nonlinear micromechanics theory. The optimal fabrication problem is formulated and solved with non-linear programming. Application cases regarding the optimization of the fabrication cool-down phases of unidirectional ultra-high modulus graphite/copper and silicon carbide/titanium composites are presented.

  4. Optimal fabrication processes for unidirectional metal-matrix composites - A computational simulation

    Science.gov (United States)

    Saravanos, D. A.; Murthy, P. L. N.; Morel, M.

    1990-01-01

    A method is proposed for optimizing the fabrication process of unidirectional metal matrix composites. The temperature and pressure histories are optimized such that the residual microstresses of the composite at the end of the fabrication process are minimized and the material integrity throughout the process is ensured. The response of the composite during the fabrication is simulated based on a nonlinear micromechanics theory. The optimal fabrication problem is formulated and solved with nonlinear programming. Application cases regarding the optimization of the fabrication cool-down phases of unidirectional ultra-high modulus graphite/copper and silicon carbide/titanium composites are presented.

  5. Wear Resistance of TiC Reinforced Cast Steel Matrix Composite

    Directory of Open Access Journals (Sweden)

    Sobula S.

    2017-03-01

    Full Text Available Wear resistance of TiC-cast steel metal matrix composite has been investigated. Composites were obtained with SHSB method known as SHS synthesis during casting. It has been shown the differences in wear between composite and base cast steel. The Miller slurry machine test were used to determine wear loss of the specimens. The slurry was composed of SiC and water. The worn surface of specimens after test, were studied by SEM. Experimental observation has shown that surface of composite zone is not homogenous and consist the matrix lakes. Microscopic observations revealed the long grooves with SiC particles indented in the base alloy area, and spalling pits in the composite area. Due to the presence of TiC carbides on composite layer, specimens with TiC reinforced cast steel exhibited higher abrasion resistance. The wear of TiC reinforced cast steel mechanism was initially by wearing of soft matrix and in second stage by polishing and spalling of TiC. Summary weight loss after 16hr test was 0,14÷0,23 g for composite specimens and 0,90 g for base steel.

  6. Al-matrix composite materials reinforced by Al-Cu-Fe particles

    International Nuclear Information System (INIS)

    Bonneville, J; Laplanche, G; Joulain, A; Gauthier-Brunet, V; Dubois, S

    2010-01-01

    Al-matrix material composites were produced using hot isostatic pressing technique, starting with pure Al and icosahedral (i) Al-Cu-Fe powders. Depending on the processing temperature, the final reinforcement particles are either still of the initial i-phase or transformed into the tetragonal ω-Al0 0.70 Cu 0.20 Fe 0.10 crystalline phase. Compression tests performed in the temperature range 293K - 823K on the two types of composite, i.e. Al/i and Al/ω, indicate that the flow stress of both composites is strongly temperature dependent and exhibit distinct regimes with increasing temperature. Differences exist between the two composites, in particular in yield stress values. In the low temperature regime (T ≤ 570K), the yield stress of the Al/ω composite is nearly 75% higher than that of the Al/i composite, while for T > 570K both composites exhibit similar yield stress values. The results are interpreted in terms of load transfer contribution between the matrix and the reinforcement particles and elementary dislocation mechanisms in the Al matrix.

  7. Advanced ceramic matrix composites for high energy x-ray generation

    International Nuclear Information System (INIS)

    Khan, Amir Azam; Labbe, Jean Claude

    2011-01-01

    High energy x-ray targets are the anodes used in high performance tubes, designed to work for long operating times and at high power. Such tubes are used in computed tomography (CT) scan machines. Usually the tubes used in CT scanners have to continuously work at high temperatures and for longer scan durations in order to get maximum information during a single scan. These anodes are composed of a refractory substrate which supports a refractory metallic coating. The present work is a review of the development of a ceramic metal composite based on aluminium nitride (AlN) and molybdenum for potential application as the substrate. This composite is surface engineered by coating with tungsten, the most popular material for high energy x-ray targets. To spray metallic coatings on the surface of ceramic matrix composites dc blown arc plasma is employed. The objective is to increase the performance and the life of an x-ray tube. Aluminium nitride-molybdenum ceramic matrix composites were produced by uniaxial hotpressing mixtures of AlN and Mo powders. These composites were characterized for their mechanical, thermal, electrical and micro-structural properties. An optimized composition was selected which contained 25 vol.% of metallic phase dispersed in the AlN matrix. These composites were produced in the actual size of an anode and coated with tungsten through dc blown arc plasma spraying. The results have shown that sintering of large size anodes is possible through uniaxial pressing, using a modified sintering cycle

  8. Effect of aging hardening on in situ synthesis magnesium matrix composites

    International Nuclear Information System (INIS)

    Zhang Xiuqing; Liao Lihua; Ma Naiheng; Wang Haowei

    2006-01-01

    Magnesium matrix composites reinforced with TiC particulates was synthesized using in situ synthesis technique. The result of XRD revealed the presence of TiC in precursor blocks and TiC/AZ91 composites. Effect of aging hardening on the composites was described using Brinell hardness measurements and scanning electron microscopy (SEM). The results revealed that the aging hardening peak of TiC/AZ91 composite appeared earlier comparatively with that of AZ91 magnesium alloy. And the appearance of aging hardening peak was earlier under the higher aging temperature such as 200 deg. C. The precipitating behavior of Mg 17 Al 12 phase in AZ91 alloy and TiC/AZ91 composites was described. Little discontinuous was discovered in the composites, and the amount of continuous precipitate in the composite matrix is smaller comparatively to that of AZ91 alloy. These results were analyzed with the fine grain size, much more interface between TiC and magnesium and high-density dislocation in magnesium matrix, which was contributed to the addition of TiC particulates

  9. MC3T3-E1 cell response of amorphous phase/TiO{sub 2} nanocrystal composite coating prepared by microarc oxidation on titanium

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Rui [Department of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wei, Daqing, E-mail: daqingwei@hit.edu.cn [Department of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Yang, Haoyue; Feng, Wei [Department of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Cheng, Su [Department of Mechanical Engineering, School of Architecture and Civil Engineering, Harbin University of Science and Technology, Harbin 150001 (China); Li, Baoqiang; Wang, Yaming; Jia, Dechang; Zhou, Yu [Department of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2014-06-01

    Bioactive amorphous phase/TiO{sub 2} nanocrystal (APTN) composite coatings were fabricated by microarc oxidation (MAO) on Ti. The APTN coatings are composed of much amorphous phase with Si, Na, Ca, Ti and O elements and a few TiO{sub 2} nanocrystals. With increasing applied voltage, the micropore density of the APTN coating decreases and the micropore size of the APTN coating increases. The results indicate that less MC3T3-E1 cells attach on the APTN coatings as compared to Ti. However, the APTN coatings greatly enhance the cell proliferation ability and the activity of alkaline phosphatase. The amorphous phase and the concentrations of the released Ca and Si from the APTN coatings during cell culture have significant effects on the cell response. - Highlights: • Amorphous phase/TiO2 nanocrystal (APTN) composite coatings were fabricated. • The MC3T3-E1 cell response of the APTN coatings was evaluated. • The APTN coatings greatly enhanced the cell proliferation ability.

  10. Diode Laser Assisted Filament Winding of Thermoplastic Matrix Composites

    Science.gov (United States)

    Quadrini, Fabrizio; Squeo, Erica Anna; Prosperi, Claudia

    2010-01-01

    A new consolidation method for the laser-assisted filament winding of thermoplastic prepregs is discussed: for the first time a diode laser is used, as well as long glass fiber reinforced polypropylene prepregs. A consolidation apparatus was built by means of a CNC motion table, a stepper motor and a simple tensioner. Preliminary tests were performed in a hoop winding configuration: only the winding speed was changed, and all the other process parameters (laser power, distance from the laser focus, consolidation force) were kept constant. Small wound rings with an internal diameter of 25 mm were produced and compression tests were carried out to evaluate the composite agglomeration in dependence of the winding speed. At lower winding speeds, a strong interpenetration of adjacent layers was observed.

  11. Diode Laser Assisted Filament Winding of Thermoplastic Matrix Composites

    Directory of Open Access Journals (Sweden)

    Claudia Prosperi

    2010-01-01

    Full Text Available A new consolidation method for the laser-assisted filament winding of thermoplastic prepregs is discussed: for the first time a diode laser is used, as well as long glass fiber reinforced polypropylene prepregs. A consolidation apparatus was built by means of a CNC motion table, a stepper motor and a simple tensioner. Preliminary tests were performed in a hoop winding configuration: only the winding speed was changed, and all the other process parameters (laser power, distance from the laser focus, consolidation force were kept constant. Small wound rings with an internal diameter of 25 mm were produced and compression tests were carried out to evaluate the composite agglomeration in dependence of the winding speed. At lower winding speeds, a stronginterpenetration of adjacent layers was observed.

  12. Corn gluten meal as a biodegradable matrix material in wood fibre reinforced composites

    International Nuclear Information System (INIS)

    Beg, M.D.H.; Pickering, K.L.; Weal, S.J.

    2005-01-01

    This study was undertaken to investigate corn gluten meal (CGM) as a biodegradable matrix material for wood fibre reinforced composites. CGM was used alone, as well as hybridized with polypropylene, and reinforced with radiata pine (Pinus Radiata) fibre using a twin-screw extruder followed by injection moulding. Tensile testing, scanning electron microscopy and differential scanning calorimetry were carried out to assess the composites. For composites from CGM and wood fibres, extrusion was carried out with the aid of the following plasticizers: octanoic acid, glycerol, polyethylene glycol and water. Windows of processability for the different plasticizers were obtained for all plasticizers. These were found to lie between 20 and 50 wt.% of plasticizer with a maximum of approximately 20% wood fibre reinforcement. The best mechanical properties were obtained with a matrix containing 10 wt.% octanoic acid and 30 wt.% water, which gave a tensile strength and Young's modulus of 18.7 MPa and 4 GPa, respectively. Hybrid matrix composites were compounded with a maleated polypropylene coupling agent and benzoyl peroxide as a cross-linking agent. The highest tensile strength and Young's modulus obtained from hybrid matrix composites were 36.9 MPa and 5.8 GPa with 50 wt.% fibre

  13. Corn gluten meal as a biodegradable matrix material in wood fibre reinforced composites

    Energy Technology Data Exchange (ETDEWEB)

    Beg, M.D.H. [Department of Materials and Process Engineering, University of Waikato, Private Bag 3105, Hamilton (New Zealand); Pickering, K.L. [Department of Materials and Process Engineering, University of Waikato, Private Bag 3105, Hamilton (New Zealand)]. E-mail: klp@waikato.ac.nz; Weal, S.J. [Department of Materials and Process Engineering, University of Waikato, Private Bag 3105, Hamilton (New Zealand)

    2005-12-05

    This study was undertaken to investigate corn gluten meal (CGM) as a biodegradable matrix material for wood fibre reinforced composites. CGM was used alone, as well as hybridized with polypropylene, and reinforced with radiata pine (Pinus Radiata) fibre using a twin-screw extruder followed by injection moulding. Tensile testing, scanning electron microscopy and differential scanning calorimetry were carried out to assess the composites. For composites from CGM and wood fibres, extrusion was carried out with the aid of the following plasticizers: octanoic acid, glycerol, polyethylene glycol and water. Windows of processability for the different plasticizers were obtained for all plasticizers. These were found to lie between 20 and 50 wt.% of plasticizer with a maximum of approximately 20% wood fibre reinforcement. The best mechanical properties were obtained with a matrix containing 10 wt.% octanoic acid and 30 wt.% water, which gave a tensile strength and Young's modulus of 18.7 MPa and 4 GPa, respectively. Hybrid matrix composites were compounded with a maleated polypropylene coupling agent and benzoyl peroxide as a cross-linking agent. The highest tensile strength and Young's modulus obtained from hybrid matrix composites were 36.9 MPa and 5.8 GPa with 50 wt.% fibre.

  14. Processing, microstructure and mechanical properties of nickel particles embedded aluminium matrix composite

    International Nuclear Information System (INIS)

    Yadav, Devinder; Bauri, Ranjit

    2011-01-01

    Research highlights: → Al-Ni particle composite was successfully processed by FSP. → No harmful intermetallics formed. → The composite showed a 3 fold increase in yield strength with high ductility. → FSP also lead to a refined recrystallized grain structure. → A continuous type dynamic recrystallization process seems to be working during FSP. - Abstract: Nickel particles were embedded into an Al matrix by friction stir processing (FSP) to produce metal particle reinforced composite. FSP resulted in uniform dispersion of nickel particles with excellent interfacial bonding with the Al matrix and also lead to significant grain refinement of the matrix. The novelty of the process is that the composite was processed in one step without any pretreatment being given to the constituents and no harmful intermetallic formed. The novel feature of the composite is that it shows a three fold increase in the yield strength while appreciable amount of ductility is retained. The hardness also improved significantly. The fracture surface showed a ductile failure mode and also revealed the superior bonding between the particles and the matrix. Electron backscattered diffraction (EBSD) and transmission electron microscopy analysis revealed a dynamically recrystallized equiaxed microstructure. A gradual increase in misorientation from sub-grain to high-angle boundaries is observed from EBSD analysis pointing towards a continuous type dynamic recrystallization mechanism.

  15. Fiber coating/matrix reactions in silicon-base ceramic matrix composites

    International Nuclear Information System (INIS)

    Lee, K.N.; Jacobson, N.S.

    1992-01-01

    The Knudsen cell technique and coupons of carbon coated Si3N4 and BN coated SiC were employed to study the possible reactions at the SiC/C/Si3N4 and SiC/BN/SiC interface. Carbon reacts with Si3N4 to form gaseous N2 and solid SiC. Solid SiC acts as a physical barrier to the reaction, which prevents the generation of high N2 pressure predicted from thermochemical calculations. Thus, deleterious effects of the reaction to the composite are limited. Limited reactions between BN and C-rich SiC was observed. However, the vapor pressure was so low that it is not likely to cause any interfacial instability. The predicted formation of a BN-C solid solution was not observed. 10 refs

  16. Fiber coating/matrix reactions in silicon-base ceramic matrix composites

    Science.gov (United States)

    Lee, K. N.; Jacobson, N. S.

    1992-01-01

    The Knudsen cell technique and coupons of carbon coated Si3N4 and BN coated SiC were employed to study the possible reactions at the SiC/C/Si3N4 and SiC/BN/SiC interface. Carbon reacts with Si3N4 to form gaseous N2 and solid SiC. Solid SiC acts as a physical barrier to the reaction, which prevents the generation of high N2 pressure predicted from thermochemical calculations. Thus, deleterious effects of the reaction to the composite are limited. Limited reactions between BN and C-rich SiC was observed. However, the vapor pressure was so low that it is not likely to cause any interfacial instability. The predicted formation of a BN-C solid solution was not observed.

  17. Corrosion behaviour of 2124 aluminium alloy-silicon carbide metal matrix composites in sodium chloride environment

    International Nuclear Information System (INIS)

    Singh, Nirbhay; Vadera, K.K.; Ramesh Kumar, A.V.; Singh, R.S.; Monga, S.S.; Mathur, G.N.

    1999-01-01

    Aluminium alloy based particle reinforced metal matrix composites (MMCs) are being considered for a range of applications. Their mechanical properties have been investigated in detail, but more information about their corrosion resistance is needed. In this investigation, the corrosion behaviour of silicon carbide particulates (SiC p )-2124 aluminium metal matrix composites was studied in 3 wt% sodium chloride solution by means of electrochemical technique and optical microscope. The effects of weight percentages and particle size of silicon carbide particulates on corrosion behaviour of the composite were studied in NaCl and it was observed that corrosion rate increases linearly with the increasing weight percentage of SiC p . The corrosion rate of the MMC increases by increasing the size of SiC particles. Anodization improved corrosion resistance of the composites. (author)

  18. Fracture and fatigue considerations in the development of ductile-phase reinforced intermetallic-matrix composites

    International Nuclear Information System (INIS)

    Venkateswara Rao, K.T.; Ritchie, R.O.

    1994-01-01

    The salient microstructural factors influencing fracture and fatigue-crack growth resistance of ductile-particle reinforced intermetallic-matrix composites at ambient temperature are reviewed through examples from the Nb/MoSi 2 , TiNb/TiAl, Nb/TiAl and Nb/Nb 3 Al systems; specific emphasis is placed on properties and morphology of the reinforcement and its interfacial properties with the matrix. It is shown that composites must be fabricated with a high aspect ratio ductile-reinforcement morphology in order to promote crack-particle interception and resultant crack bridging for improved fracture and fatigue properties. Concurrently, however, the ductile phases have contrasting effects on crack growth under monotonic vs. cyclic loading suggesting that composite microstructures tailored for optimal toughness may not necessarily yield optimal fatigue resistance. Perspectives for the future development of damage-tolerant intermetallic-composite microstructures are discussed

  19. Support Services for Ceramic Fiber-Ceramic Matrix Composites

    Energy Technology Data Exchange (ETDEWEB)

    Hurley, J.P.

    2000-06-06

    Structural and functional materials used in solid- and liquid-fueled energy systems are subject to gas- and condensed-phase corrosion and erosion by entrained particles. For a given material, its temperature and the composition of the corrodents determine the corrosion rates, while gas flow conditions and particle aerodynamic diameters determine erosion rates. Because there are several mechanisms by which corrodents deposit on a surface, the corrodent composition depends not only on the composition of the fuel, but also on the temperature of the material and the size range of the particles being deposited. In general, it is difficult to simulate under controlled laboratory conditions all of the possible corrosion and erosion mechanisms to which a material may be exposed in an energy system. Therefore, with funding from the Advanced Research Materials Program, the University of North Dakota Energy & Environmental Research Center (EERC) is coordinating with NCC Engineering and the National Energy Technology Laboratory (NETL) to provide researchers with no-cost opportunities to expose materials in pilot-scale systems to conditions of corrosion and erosion similar to those occurring in commercial power systems. The EERC has two pilot-scale solid-fuel systems available for exposure of materials coupons. The slagging furnace system (SFS) was built under the DOE Combustion 2000 Program as a testing facility for advanced heat exchanger subsystems. It is a 2.5-MMBtu/hr (2.6 x 10{sup 6} kJ/hr) solid-fuel combustion system with exit temperatures of 2700 to 2900 F to ensure that the ash in the main combustor is molten and flowing. Sample coupons may be exposed in the system either within the slagging zone or near the convective air heater at 1800 F (980 C). In addition, a pilot-scale entrained-bed gasifier system known as the transport reactor development unit (TRDU) is available. Also operating at approximately 2.5 MMBtu/hr (2.6 x 10{sup 6} kJ/hr), it is a pressurized unit

  20. Effect of γ irradiation on the properties of basalt fiber reinforced epoxy resin matrix composite

    International Nuclear Information System (INIS)

    Li, Ran; Gu, Yizhuo; Yang, Zhongjia; Li, Min; Wang, Shaokai; Zhang, Zuoguang

    2015-01-01

    Gamma-ray (γ-ray) irradiation is a crucial reason for the aging in materials used for nuclear industry. Due to high specific strength and stiffness, light weight and good corrosion resistance, fiber reinforced composites are regarded as an alternative of traditional materials used on nuclear facilities. In this study, basalt fiber (BF)/AG80 epoxy composite laminates were fabricated by autoclave process and treated with "6"0Co gamma irradiation dose up to 2.0 MGy. Irradiation induced polymer chain scission and oxidation of AG80 resin were detected from physical and chemical analysis. The experimental results show that the tensile and flexural performances of irradiated BF/AG80 composite maintain stable and have a low amplitude attenuation respectively, and the interlaminar shear strength has increased from irradiation dose of 0–1.5 MGy. Furthermore, the comparison between the studied BF composite and reported polymer and composite materials was done for evaluating the γ resistance property of BF composite. - Highlights: • The properties of basalt fiber reinforced epoxy resin matrix composite under "6"0Co γ irradiation up to 2.0 MGy were studied. • Basalt fiber can weaken the aging effects of γ irradiation on the resin matrix. • Tensile property of basalt fiber composite remains stable and flexural property has a low degree of attenuation. • Basalt fiber composite is an ideal candidate of structural material for nuclear industry.

  1. Experimental and numerical analysis of short sisal fiber-cement composites produced with recycled matrix

    OpenAIRE

    Lima, Paulo Roberto Lopes; Barros, Joaquim A. O.; Santos, Daniele Justo; Fontes, Cintia Maria; Lima, José Mário F.; Toledo Filho, Romildo

    2016-01-01

    "Published online: 02 Jan 2017" The proper use of renewable or recycled source materials can contribute significantly to reducing the environmental impact of construction industry. In this work, cement based composites reinforced with natural fibers were developed and their mechanical behavior was characterized. To ensure the composite sustainability and durability, the ordinary Portland cement matrix was modified by adding metakaolin and the natural aggregate was substitute...

  2. Characterization of ceramic matrix composite degradation using Fourier transform infrared spectroscopy

    Science.gov (United States)

    Henry, Christine; Criner, Amanda Keck; Imel, Megan; King, Derek

    2018-04-01

    Data collected with a handheld Fourier Transform Infrared (FTIR) device is analyzed and considered as a useful method for detecting and quantifying oxidation on the surface of ceramic matrix composite (CMC) materials. Experiments examine silicon carbide (SiC) coupons, looking for changes in chemical composition before and after thermal exposure. Using mathematical, physical and statistical models for FTIR reflectance data, this research seeks to quantify any detected spectral changes as an indicator of surface oxidation on the CMC coupon.

  3. Mechanical behaviour of aluminium matrix composites with particles in high temperature

    International Nuclear Information System (INIS)

    Amigo, V.; Salvador, M. D.; Ferrer, C.; Costa d, C. E.; Busquets, D.

    2001-01-01

    The aluminium matrix composites materials reinforced by ceramic particles can be elaborated by powder metallurgy techniques, with extrusion processes. These can provide new materials, with a better mechanical behaviour and moreover when we need those properties at higher temperatures. Aluminium alloy reinforced composites with silicon nitride particles by powder extrusion process was done. Their mechanical properties were characterised at room and elevated temperatures. (Author) 28 refs

  4. Additional results on space environmental effects on polymer matrix composites: Experiment A0180

    International Nuclear Information System (INIS)

    Tennyson, R.C.

    1992-01-01

    Additional experimental results on the atomic oxygen erosion of boron, Kevlar, and graphite fiber reinforced epoxy matrix composites are presented. Damage of composite laminates due to micrometeoroid/debris impacts is also examined with particular emphasis on the relationship between damage area and actual hole size due to particle penetration. Special attention is given to one micrometeoroid impact on an aluminum base plate which resulted in ejecta visible on an adjoining vertical flange structure

  5. Nanofiber reinforcement of a geopolymer matrix for improved composite materials mechanical performance

    Science.gov (United States)

    Rahman, AKM Samsur

    Geopolymers have the potential to cross the process performance gap between polymer matrix and ceramic matrix composites (CMC), enabling high temperature capable composites that are manufactured at relatively low temperatures. Unfortunately, the inherently low toughness of these geopolymers limits the performance of the resulting fiber reinforced geopolymer matrix composites. Toughness improvements in composites can be addressed through the adjustments in the fiber/matrix interfacial strength and through the improvements in the inherent toughness of the constituent materials. This study investigates the potential to improve the inherent toughness of the geopolymer matrix material through the addition of nanofillers, by considering physical dimensions, mechanical properties, reinforcing capability and interfacial bond strength effects. A process optimization study was first undertaken to develop the ability to produce consistent, neat geopolymer samples, a critical precursor to producing nano-filled geopolymer for toughness evaluation. After that, single edge notched bend beam fracture toughness and un-notched beam flexural strength were evaluated for silicon carbide, alumina and carbon nanofillers reinforced geopolymer samples treated at various temperatures in reactive and inert environments. Toughness results of silicon carbide and carbon nanofillers reinforced geopolymers suggested that with the improved baseline properties, high aspect ratio nanofillers with high interfacial bond strength are the most capable in further improving the toughness of geopolymers. Among the high aspect ratio nanofillers i.e. nanofibers, 2vol% silicon carbide whicker (SCW) showed the highest improvement in fracture toughness and flexural strength of ~164% & ~185%, respectively. After heat treatment at 650 °C, SCW reinforcement was found to be effective, with little reduction in the performance, while the performance of alumina nanofiber (ANF) reinforced geopolymer significantly

  6. Effect of atmosphere on the fabrication of Si2N2O matrix composites

    Directory of Open Access Journals (Sweden)

    Wei Li

    2018-03-01

    Full Text Available Si2N2O matrix composites were fabricated by solid/gas reaction in air or N2 atmosphere. The effects of atmosphere on the phase and microstructure of the composites were investigated. The reaction mechanism of Si2N2O system was discussed by analysing the variation of the Gibbs free energy with temperature. The effect of N2 and air on sintering of Si2N2O matrix composites was discussed in relation to observed kinetics and thermodynamic calculations. The results showed that gradient structure of Si2N2O matrix composites were obtained in N2 atmosphere. While high N2 concentration was useful for the formation of the pure β-Si3N4 ceramics, low N2 concentration was proposed to form the pure Si2N2O ceramics. However, in the air atmosphere, structure of the Si3N4/SiO2 composites is homogeneous without the gradient structure appearing. Its composition is a little different as the O2 concentration changes.

  7. Standard test method for translaminar fracture toughness of laminated and pultruded polymer matrix composite materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 This test method covers the determination of translaminar fracture toughness, KTL, for laminated and pultruded polymer matrix composite materials of various ply orientations using test results from monotonically loaded notched specimens. 1.2 This test method is applicable to room temperature laboratory air environments. 1.3 Composite materials that can be tested by this test method are not limited by thickness or by type of polymer matrix or fiber, provided that the specimen sizes and the test results meet the requirements of this test method. This test method was developed primarily from test results of various carbon fiber – epoxy matrix laminates and from additional results of glass fiber – epoxy matrix, glass fiber-polyester matrix pultrusions and carbon fiber – bismaleimide matrix laminates (1-4, 6, 7). 1.4 A range of eccentrically loaded, single-edge-notch tension, ESE(T), specimen sizes with proportional planar dimensions is provided, but planar size may be variable and adjusted, with asso...

  8. Friction Stir Processing of Copper-Coated SiC Particulate-Reinforced Aluminum Matrix Composite

    Directory of Open Access Journals (Sweden)

    Chih-Wei Huang

    2018-04-01

    Full Text Available In the present work, we proposed a novel friction stir processing (FSP to produce a locally reinforced aluminum matrix composite (AMC by stirring copper-coated SiC particulate reinforcement into Al6061 alloy matrix. Electroless-plating process was applied to deposit the copper surface coating on the SiC particulate reinforcement for the purpose of improving the interfacial adhesion between SiC particles and Al matrix. The core-shell SiC structure provides a layer for the atomic diffusion between aluminum and copper to enhance the cohesion between reinforcing particles and matrix on one hand, the dispersion of fine copper in the Al matrix during FSP provides further dispersive strengthening and solid solution strengthening, on the other hand. Hardness distribution and tensile results across the stir zone validated the novel concept in improving the mechanical properties of AMC that was realized via FSP. Optical microscope (OM and Transmission Electron Microscopy (TEM investigations were conducted to investigate the microstructure. Energy dispersive spectrometer (EDS, electron probe micro-analyzer (EPMA, and X-ray diffraction (XRD were explored to analyze the atomic inter-diffusion and the formation of intermetallic at interface. The possible strengthening mechanisms of the AMC containing Cu-coated SiC particulate reinforcement were interpreted. The concept of strengthening developed in this work may open a new way of fabricating of particulate reinforced metal matrix composites.

  9. Microstructure and Strengthening Mechanisms of Carbon Nanotube Reinforced Magnesium Matrix Composites Fabricated by Accumulative Roll Bonding

    International Nuclear Information System (INIS)

    Yoo, Seong Jin; Kim, Woo Jin

    2014-01-01

    A combination of accumulative roll bonding (ARB) and high-energy ball milling was used to fabricate carbon nano tube (CNT)-reinforced Mg composites in sheet form. CNT-Al composite powders synthesized using the high-energy ball-milling process, were coated on the surface of Mg sheets using either spraying or dipping methods. The coated sheets were stacked and then subjected to ARB. Formation of CNT-intermetallic compounds through inter-diffusion between Al and Mg, fragmentation of the CNTintermetallic compounds, and their dispersion into the matrix by plastic flow; as well as dissolution of the intermetallic compound particles into the matrix while leaving CNTs in the matrix, occurred in sequence during the ARB process. This eventually resulted in the uniform distribution of nano-sized CNT particles in the Mg matrix. As the thickness of the Mg sheet and of the coating layer of Al-CNT powder on the surface of the Mg sheet were similar, the dispersion of CNTs into the Mg matrix occurred more uniformly and the strengthening effect of adding CNTs was greater. The strengthening gained by adding CNTs was attributed to Orowan strengthening and dislocation-density increase due to a thermal mismatch between the matrix and the CNTs.

  10. Excellent plasticity of a new Ti-based metallic glass matrix composite upon dynamic loading

    Energy Technology Data Exchange (ETDEWEB)

    Wu, R.F. [Laboratory of Applied Physics and Mechanics of Advanced Materials, College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081 (China); Jiao, Z.M. [Institute of Applied Mechanics and Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Wang, Y.S.; Wang, Z. [Laboratory of Applied Physics and Mechanics of Advanced Materials, College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Wang, Z.H.; Ma, S.G. [Institute of Applied Mechanics and Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Qiao, J.W., E-mail: qiaojunwei@gmail.com [Laboratory of Applied Physics and Mechanics of Advanced Materials, College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081 (China)

    2016-11-20

    Quasi-static and dynamic compressive properties of in-situ Ti{sub 60}Zr{sub 14}V{sub 12}Cu{sub 4}Be{sub 10} bulk metallic glass matrix composites containing ductile dendrites were investigated. Upon quasi-static compressive loading, the composite exhibits a high fracture strength of ~2,600 MPa, combined with a considerable plasticity of ~40% at room temperature. However, upon dynamic loading, an excellent plasticity of ~16% can be obtained due to the abundant dislocations and severe lattice distortions within dendrites and multiplication of shear bands within the glass matrix analyzed by transmission-electron microscopy. A constitutive relationship is obtained by Johnson-Cook plasticity model, which is employed to model the dynamic flow stress behavior. In addition, under dynamic compression, the adiabatic temperature rise increases with increasing strain rates, resulting in that the softening effect within the glass matrix is obviously enhanced during deformation.

  11. Analysis of metal-matrix composite structures. I - Micromechanics constitutive theory. II - Laminate analyses

    Science.gov (United States)

    Arenburg, R. T.; Reddy, J. N.

    1991-01-01

    The micromechanical constitutive theory is used to examine the nonlinear behavior of continuous-fiber-reinforced metal-matrix composite structures. Effective lamina constitutive relations based on the Abouli micromechanics theory are presented. The inelastic matrix behavior is modeled by the unified viscoplasticity theory of Bodner and Partom. The laminate constitutive relations are incorporated into a first-order deformation plate theory. The resulting boundary value problem is solved by utilizing the finite element method. Attention is also given to computational aspects of the numerical solution, including the temporal integration of the inelastic strains and the spatial integration of bending moments. Numerical results the nonlinear response of metal matrix composites subjected to extensional and bending loads are presented.

  12. Mechanical Properties of TC4 Matrix Composites Prepared by Laser Cladding

    Directory of Open Access Journals (Sweden)

    WANG Lin

    2017-06-01

    Full Text Available In order to improve the penetration performance of TC4, the direct laser deposition technology was used to prepare TC4 composite material. TA15+30% TiC powder, TA15+20%Cr3C2 powder and TA15+15%B4C powder were used as deposited materials for TC4 matrix. The micromorphology, change of hardness of the deposited coating and mechanical properties of the three composites were studied. The experimental results demonstrate that the TC4 matrix with the three kinds of materials can form a complete metallurgical bonding, and the strength of TC4-(TA15+TiC, TC4-(TA15+Cr3C2 and TC4-(TA15+B4C are higher than that of TC4 matrix materials, while the plasticity is slightly worse.

  13. The converse magnetoelectric coupling in asymmetric granule/matrix composite film with Ni/PZT component

    Science.gov (United States)

    Chen, Bo; Su, Ning-Ning; Cui, Wen-Li; Yan, Shi-Nong

    2018-04-01

    In this work, a type of asymmetric granule/matrix composite film is designed, where the Ni granule is dispersed in PZT matrix, meanwhile the top and bottom electrode is constituted by Au and SRO respectively. Predicted through the electrostatic screening model and mean field approximation, considerable electrostatic charge is induced on Ni granule surface by ferroelectric PZT polarization. Predicted through the spin splitting model and spherical shell approximation, both the magnetization and magnetic anisotropy of Ni granule are modulated by ferroelectric PZT polarization. As the volume fraction of Ni granule is increased, the electric modulation of magnetization and magnetic anisotropy is reduced and enhanced respectively. As the dimension of granule/matrix composite is varied, such modulation is retained. Due to the large area-volume ratio of nano-granule, this work benefits to realize the converse magnetoelectric coupling in nanoscale.

  14. A Study on AE Signal Analysis of Composite Materials Using Matrix Piezo Electric Sensor

    International Nuclear Information System (INIS)

    Yu, Yeun Ho; Choi, Jin Ho; Kweon, Jin Hwe

    2007-01-01

    As fiber reinforced composite materials are widely used in aircraft, space structures and robot arms, the study on non-destructive testing methods has become an important research area for improving their reliability and safety. AE (acoustic emission) can evaluate the defects by detecting the emitting strain energy when elastic waves are generated by the initiation and growth of crack, plastic deformation, fiber breakage, matrix cleavage, or delamination. In the paper, AE signals generated under uniaxial tension were measured and analyzed using the 8x8 matrix piezo electric sensor. The electronic circuit to control the transmitting distance of AE signals was designed and constructed. The optical data storage system was also designed to store the AE signal of 64 channels using LED (light emitting diode) elements. From the tests, it was shown that the source location and propagation path of AE signals in composite materials could be detected effectively by the 8x8 matrix piezo electric sensor

  15. Nondestructive evaluation of ceramic and metal matrix composites for NASA's HITEMP and enabling propulsion materials programs

    Science.gov (United States)

    Generazio, Edward R.

    1992-01-01

    In a preliminary study, ultrasonic, x-ray opaque, and fluorescent dye penetrants techniques were used to evaluate and characterize ceramic and metal matrix composites. Techniques are highlighted for identifying porosity, fiber alignment, fiber uniformity, matrix cracks, fiber fractures, unbonds or disbonds between laminae, and fiber-to-matrix bond variations. The nondestructive evaluations (NDE) were performed during processing and after thermomechanical testing. Specific examples are given for Si3N4/SiC (SCS-6 fiber), FeCrAlY/Al2O3 fibers, Ti-15-3/SiC (SCS-6 fiber) materials, and Si3N4/SiC (SCS-6 fiber) actively cooled panel components. Results of this study indicate that the choice of the NDE tools to be used can be optimized to yield a faithful and accurate evaluation of advanced composites.

  16. Effect of sintering temperatures on titanium matrix composites reinforced by ceramic particles

    Energy Technology Data Exchange (ETDEWEB)

    Romero, F.; Amigo, V.; Busquets, D.; Klyatskina, E. [Mechanical and Materials Engineering Department. Polytechnical University of Valencia, Valencia (Spain)

    2005-07-01

    Titanium and titanium composites have a potential use in aerospace and biotechnology industries, and nowadays in others like sports and fashion ones. In this work composite materials, based on titanium matrix reinforced with ceramic particles, have been developed. PM route is used to obtain compact and sintered samples. TiN and TiAl powders, are milled with Ti powder in different volumetric percentages in a ball mill. These mixtures are pressed in a uniaxial press and sintered in a vacuum furnace at different temperatures between 1180 to 1220 deg. C. Porosity of samples is analysed, before and after the sintering process, by Archimedes technique and by image analysis. Mechanical properties and the reinforcement particles influence in the titanium matrix are studied by flexion test in green and sintered states, and by hardness and microhardness tests. Complimentarily, a microstructural analysis is carried out by optical and electron microscopy, and the reactivity between the reinforce particles and titanium matrix are studied. (authors)

  17. Sliding wear resistance of metal matrix composite layers prepared by high power laser

    NARCIS (Netherlands)

    Ocelik, Vaclav; Matthews, D; de Hosson, Jeff

    2005-01-01

    Two laser surface engineering techniques, Laser Cladding and Laser Melt Injection (LMI), were used to prepare three different metal matrix composite layers with a thickness of about 1 mm and approximately 25-30% volume fraction of ceramic particles. SiC/Al-8Si, WC/Ti-6Al-4V and TiB2/Ti-6Al-4V layers

  18. Effect of static pre-loading on fracture toughness of Nicalon fibre glass matrix composite

    Czech Academy of Sciences Publication Activity Database

    Dlouhý, Ivo; Chlup, Zdeněk; Chawla, K. K.; Kulkarmi, R.; Koopman, M.; Boccaccini, A. R.

    č. 367 (2004), s. 17-23 ISSN 0921-5093 R&D Projects: GA AV ČR IAA2041003; GA MŠk ME 491 Institutional research plan: CEZ:AV0Z2041904 Keywords : Nicalon fibre * glass matrix composite * fracture toughness Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 1.445, year: 2004

  19. Significance of Shrinkage Induced Clamping Pressure in Fiber-Matrix Bonding in Cementitious Composite Materials

    DEFF Research Database (Denmark)

    Stang, Henrik

    1996-01-01

    used in high performance cementitious composite materials.Assuming a Coulomb type of friction on the fiber/matrix interface andusing typical values for the frictional coefficient it is shownthat the shrinkage induced clamping pressure could be one of the mostimportant factors determining the frictional...

  20. Effects of thermal residual stresses and fiber packing on deformation of metal-matrix composites

    International Nuclear Information System (INIS)

    Nakamura, T.; Suresh, S.

    1993-01-01

    The combined effects of thermal residual stresses and fiber spatial distribution on the deformation of a 6061 aluminum alloy containing a fixed concentration unidirectional boron fibers have been analyzed using detailed finite element models. The geometrical structure includes perfectly periodic, uniformly space fiber arrangements in square and hexagonal cells, as well as different cells in which either 30 or 60 fibers are randomly placed in the ductile matrix. The model involves an elastic-plastic matrix, elastic fibers, and mechanically bonded interfaces. The results indicate that both fiber packing and thermal residual stresses can have a significant effect on the stress-strain characteristics of the composite. The thermal residual stresses cause pronounced matrix yielding which also influences the apparent overall stiffness of the composite during the initial stages of subsequent far-field loading along the axial and transverse direction. Furthermore, the thermal residual stresses apparently elevate the flow stress of the composite during transverse tension. Such effects can be traced back to the level of constraint imposed on the matrix by local fiber spacing. The implications of the present results to the processing of the composites are also briefly addressed

  1. Metal particles constraint in glass matrix composites and its impact on fracture toughness enhancement

    Czech Academy of Sciences Publication Activity Database

    Kotoul, M.; Dlouhý, Ivo

    387-389 (2004), s. 404-408 ISSN 0921-5093 R&D Projects: GA ČR GA101/02/0683 Institutional research plan: CEZ:AV0Z2041904 Keywords : brittle matrix composites * crack bridging * crack trapping Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 1.445, year: 2004

  2. Thermomechanically induced residual strains in Al/SiCp metal-matrix composites

    DEFF Research Database (Denmark)

    Lorentzen, T.; Clarke, A.P.

    1998-01-01

    Residual lattice strains in the aluminium and SiC phases of F3S.20S extruded A359 20% SiC metal-matrix composite were measured by using neutron diffi action at room and elevated temperatures to monitor the effects of in situ uniaxial plastic deformations. The results are interpreted with referenc...

  3. Production of NbC reinforced aluminum matrix composites by mechanical alloying

    International Nuclear Information System (INIS)

    Silva, Marina Judice; Cardoso, Katia Regina; Travessa, Dilermando Nagle

    2014-01-01

    Aluminum and their alloys are key materials for the automotive and aerospace industries. The dispersion of hard ceramic particles in the Al soft matrix produces lightweight composites with interesting properties, as environmental resistance, high specific strength and stiffness, high thermal and electrical conductivity, and good wear resistance, encouraging their technological use. Powder metallurgy techniques like mechanical alloying (MA) are very attractive to design metal matrix composites, as they are able to achieve a homogeneous distribution of well dispersed particles inside the metal matrix. In this work, pure aluminum has been reinforced with particles of Niobium carbide (NbC), an extremely hard and stable refractory ceramic. NbC is frequently used as a grain growth inhibitor in micro-alloyed steel due to their low solubility in austenite. In the present work, NbC is expected to act as a reinforcing phase by its fine dispersion into the aluminum matrix, produced by MA. Composite powders produced after different milling times (up to 50h), with 10 and 20% (volume) of NbC were characterized by diffraction laser particle size analysis, scanning electron microscopy (SEM) and by X-ray diffraction (DRX), in order to establish a relationship between the milling time and the characteristics of the powder produced, as size and morphology, crystallite size and reinforcement distribution. This characterization is important in defining the MA process for production of composites for further consolidation by hot extrusion process. (author)

  4. Advanced bredigite-containing magnesium-matrix composites for biodegradable bone implant applications

    NARCIS (Netherlands)

    Naddaf Dezfuli, S.; Huan, Z.; Mol, J.M.C.; Leeflang, M.A.; Chang, Jiang; Zhou, J.

    2017-01-01

    The present research was aimed at developing magnesium-matrix composites that could allow effective control over their physiochemical and mechanical responses when in contact with physiological solutions. A biodegradable, bioactive ceramic - bredigite was chosen as the reinforcing phase in the

  5. Hardfacing of aluminium alloys by means of metal matrix composites produced by laser surface alloying

    CSIR Research Space (South Africa)

    Pityana, SL

    2009-06-01

    Full Text Available . In these experiments the laser power was varied from 3 to 4.0 kW, the laser scan speed was varied from 0.8 to 2.0 m/min. The powder feed rate was varied from 2 to 5 g/min. The structural characterisation of the metal matrix composite included X-ray diffraction (XRD...

  6. Microstructure and wear behaviour of Al/TiB2 metal matrix composite

    CSIR Research Space (South Africa)

    Popoola, AP

    2010-10-01

    Full Text Available Al/TiB2 metal matrix composite (MMCs) was fabricated on aluminium AA1200 with the aim of improving the wear resistance property of the substrate. The characterization of the MMCs was carried out by Optical Microscopy (OM), Scanning Electron...

  7. Composite biomaterials with chemical bonding between hydroxyapatite filler particles and PEG/PBT copolymer matrix

    NARCIS (Netherlands)

    Liu, Qing; de Wijn, J.R.; van Blitterswijk, Clemens

    1998-01-01

    In an effort to make composites from hydroxyapatite and a PEG/PBT copolymer (PolyactiveTM 70/30), chemical linkages were introduced between the filler particles and polymer matrix using hexamethylene diisocyanate as a coupling agent. Infrared spectra (IR) and thermal gravimetric analysis (TGA)

  8. Fabrication of WCp/NiBSi metal matrix composite by electron beam melting

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Hui, E-mail: penghui@buaa.edu.cn [School of Materials Science and Engineering, Beihang University (BUAA), No. 37 Xueyuan Road, Beijing 100191 (China); Beijing Key Laboratory for Advanced Functional Material and Thin Film Technology, Beihang University, No. 37 Xueyuan Road, Beijing 100191 (China); Key Laboratory of Aerospace Materials & Performance (Ministry of Education), Beihang University, No. 37 Xueyuan Road, Beijing 100191 (China); Liu, Chang [School of Materials Science and Engineering, Beihang University (BUAA), No. 37 Xueyuan Road, Beijing 100191 (China); Guo, Hongbo, E-mail: guo.hongbo@buaa.edu.cn [School of Materials Science and Engineering, Beihang University (BUAA), No. 37 Xueyuan Road, Beijing 100191 (China); Beijing Key Laboratory for Advanced Functional Material and Thin Film Technology, Beihang University, No. 37 Xueyuan Road, Beijing 100191 (China); Key Laboratory of Aerospace Materials & Performance (Ministry of Education), Beihang University, No. 37 Xueyuan Road, Beijing 100191 (China); Yuan, Yuan [Zhuzhou Seed Cemented Carbide Technology Co. Ltd, No. 1099 Xiangda Road, Zhuzhou, Hunan 412000 (China); Gong, Shengkai; Xu, Huibin [School of Materials Science and Engineering, Beihang University (BUAA), No. 37 Xueyuan Road, Beijing 100191 (China); Beijing Key Laboratory for Advanced Functional Material and Thin Film Technology, Beihang University, No. 37 Xueyuan Road, Beijing 100191 (China); Key Laboratory of Aerospace Materials & Performance (Ministry of Education), Beihang University, No. 37 Xueyuan Road, Beijing 100191 (China)

    2016-06-01

    A blend of NiBSi and WC powders was used as raw material for fabricating a metal matrix composite (MMC) by electron beam melting (EBM). Dense and crack-free microstructure was produced with evenly distributed WC reinforcements. Mechanical properties, including macro- and micro-hardness, flexural strength, impact toughness and compressive strength, were investigated.

  9. Weld microstructure in cast AlSi9/SiC(p metal matrix composites

    Directory of Open Access Journals (Sweden)

    J. Wysocki

    2009-04-01

    Full Text Available Welded joint in cast AlSi9/SiC/20(p metal matrix composite by manual TIG arc welding using AlMg5 filler metal has been described inhis paper. Cooling curves have been stated, and the influence in distribution of reinforced particles on crystallization and weldmicrostructure. Welded joint mechanical properties have been determined: hardness and tensile.

  10. Microstructure characterization of laser-deposited titanium carbide and zirconium-based titanium metal matrix composites

    CSIR Research Space (South Africa)

    Ochonogor, OF

    2012-09-01

    Full Text Available . In this work, the technique is used to fabricate metal matrix composites (MMCs) by using an elementally blended feedstock combining metal and ceramic powders in the melt pool, which melt and solidify to create the required morphology. Ti6Al4V + TiC MMCs were...

  11. METAL MATRIX COMPOSITE BRAKE ROTORS: HISTORICAL DEVELOPMENT AND PRODUCT LIFE CYCLE ANALYSIS

    Directory of Open Access Journals (Sweden)

    M.M. Rahman

    2011-12-01

    Full Text Available Metal matrix composites (MMCs have become attractive for engineering structural applications due to their excellent specific strength and are increasingly seen as an alternative to conventional materials, particularly in the automotive industry. In this study, a historical background on the development and application of metal matrix composites for automotive brake rotors is presented. The discussion also includes an analysis of the product life cycle with stir casting as a case study. The historical review analysis revealed that gradual development of material and processing techniques have led to lighter weight, lower cost and higher performance brake rotors as a result of a better understanding of the mechanics of metal matrix composites. It emerged from the study that the stir casting technique provides ease of operation, sustainability and, most significantly, very competitive costs without sacrificing quality relative to other techniques; as such, it is the most attractive manufacturing process in the industry. These findings can be used for future design and manufacture of an efficient and effective aluminium matrix composite brake rotor for automotive and other applications.

  12. On the homogenization of metal matrix composites using strain gradient plasticity

    DEFF Research Database (Denmark)

    Azizi, Reza; Niordson, Christian Frithiof; Legarth, Brian Nyvang

    2014-01-01

    The homogenized response of metal matrix composites (MMC) is studied using strain gradient plasticity. The material model employed is a rate independent formulation of energetic strain gradient plasticity at the micro scale and conventional rate independent plasticity at the macro scale. Free...

  13. Properties of porous FeAlOy/FeAlx ceramic matrix composite ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 36; Issue 7. Properties of porous FeAlO/FeAl ceramic matrix composite influenced by mechanical activation of FeAl powder. V Usoltsev S Tikhov A Salanov V Sadykov G Golubkova O Lomovskii. Volume 36 Issue 7 December 2013 pp 1195-1200 ...

  14. Production of NbC reinforced aluminum matrix composites by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Marina Judice; Cardoso, Katia Regina; Travessa, Dilermando Nagle, E-mail: dilermando.travessa@unifesp.br [Universidade Federal de Sao Paulo (UNIFESP), Sao Jose dos Campos, SP (Brazil). Instituto de Ciencia e Tecnologia

    2014-07-01

    Aluminum and their alloys are key materials for the automotive and aerospace industries. The dispersion of hard ceramic particles in the Al soft matrix produces lightweight composites with interesting properties, as environmental resistance, high specific strength and stiffness, high thermal and electrical conductivity, and good wear resistance, encouraging their technological use. Powder metallurgy techniques like mechanical alloying (MA) are very attractive to design metal matrix composites, as they are able to achieve a homogeneous distribution of well dispersed particles inside the metal matrix. In this work, pure aluminum has been reinforced with particles of Niobium carbide (NbC), an extremely hard and stable refractory ceramic. NbC is frequently used as a grain growth inhibitor in micro-alloyed steel due to their low solubility in austenite. In the present work, NbC is expected to act as a reinforcing phase by its fine dispersion into the aluminum matrix, produced by MA. Composite powders produced after different milling times (up to 50h), with 10 and 20% (volume) of NbC were characterized by diffraction laser particle size analysis, scanning electron microscopy (SEM) and by X-ray diffraction (DRX), in order to establish a relationship between the milling time and the characteristics of the powder produced, as size and morphology, crystallite size and reinforcement distribution. This characterization is important in defining the MA process for production of composites for further consolidation by hot extrusion process. (author)

  15. Fabrication of WCp/NiBSi metal matrix composite by electron beam melting

    International Nuclear Information System (INIS)

    Peng, Hui; Liu, Chang; Guo, Hongbo; Yuan, Yuan; Gong, Shengkai; Xu, Huibin

    2016-01-01

    A blend of NiBSi and WC powders was used as raw material for fabricating a metal matrix composite (MMC) by electron beam melting (EBM). Dense and crack-free microstructure was produced with evenly distributed WC reinforcements. Mechanical properties, including macro- and micro-hardness, flexural strength, impact toughness and compressive strength, were investigated.

  16. Microstructure evolution and mechanical properties of a particulate reinforced magnesium matrix composites forged at elevated temperatures

    International Nuclear Information System (INIS)

    Deng, K.K.; Wu, K.; Wang, X.J.; Wu, Y.W.; Hu, X.S.; Zheng, M.Y.; Gan, W.M.; Brokmeier, H.G.

    2010-01-01

    SiCp/AZ91 magnesium matrix composite was fabricated by stir casting. The as-cast ingots were cut into cylindrical billets, and then forged at different temperatures (320, 370, 420, 470 and 520 deg. C) at a constant RAM speed of 15 mm/s with 50% reduction. The microstructure evolution of the composites during forging was investigated by optical microscope, scanning electron microscope, and transmission electron microscope. The texture of the forged composites was measured by neutron diffraction. Mechanical properties of the composite at different forging temperatures were tested by tensile tests at room temperature. It was found that a strong basal plane texture formed during forging, and the intensity of basal plane texture weakened as forging temperatures increased. The particle distribution in the composite was significantly improved by hot forging. Typical microstructures were obtained after forging at different temperatures and the composite with different microstructures offered different mechanical properties during tensile test.

  17. Design feasibility study of a divertor component reinforced with fibrous metal matrix composite laminate

    International Nuclear Information System (INIS)

    You, J.-H.

    2005-01-01

    Fibrous metal matrix composites possess advanced mechanical properties compared to conventional alloys. It is expected that the application of these composites to a divertor component will enhance the structural reliability. A possible design concept would be a system consisting of tungsten armour, copper composite interlayer and copper heat sink where the composite interlayer is locally inserted into the highly stressed domain near the bond interface. For assessment of the design feasibility of the composite divertor concept, a non-linear multi-scale finite element analysis was performed. To this end, a micro-mechanics algorithm was implemented into a finite element code. A reactor-relevant heat flux load was assumed. Focus was placed on the evolution of stress state, plastic deformation and ductile damage on both macro- and microscopic scales. The structural response of the component and the micro-scale stress evolution of the composite laminate were investigated

  18. Design feasibility study of a divertor component reinforced with fibrous metal matrix composite laminate

    Energy Technology Data Exchange (ETDEWEB)

    You, J.-H. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany)]. E-mail: j.h.you@ipp.mpg.de

    2005-01-01

    Fibrous metal matrix composites possess advanced mechanical properties compared to conventional alloys. It is expected that the application of these composites to a divertor component will enhance the structural reliability. A possible design concept would be a system consisting of tungsten armour, copper composite interlayer and copper heat sink where the composite interlayer is locally inserted into the highly stressed domain near the bond interface. For assessment of the design feasibility of the composite divertor concept, a non-linear multi-scale finite element analysis was performed. To this end, a micro-mechanics algorithm was implemented into a finite element code. A reactor-relevant heat flux load was assumed. Focus was placed on the evolution of stress state, plastic deformation and ductile damage on both macro- and microscopic scales. The structural response of the component and the micro-scale stress evolution of the composite laminate were investigated.

  19. Effect of matrix constitution on interface of aluminium/δ-Al2O3 and strength of metal matrix composites

    International Nuclear Information System (INIS)

    Johansson, P.; Hutchinson, B.; Savage, S.J.

    1992-06-01

    Aluminium based fiber composites have been made by squeeze casting. The 'saffil' pre-forms used in the work employed aluminium oxide binder or silica binder. Two families of alloys have been used based either on high purity aluminium or 3% copper containing alloys. These were both alloyed with a range of magnesium contents from 0.1% to 5% with the aim of varying the degree of reaction and bonding between the matrix and the reinforcing fibres. Studies of macro- and micro structures have been performed as well as non-destructive testing by X-ray radiography. Tensile testing, three point bend tests on notched bars and wetting studies in a wetting balance are also included in the investigation. The structure of the squeeze cast products shows different zones. The extension and appearance of the zones are dependent on the alloy constitution. In general the surface of the casting have small equiaxed grains. This surface zone is replaced by a columnar grain zone which, in the center, transforms to an equiaxed crystal zone. Defects such as pores, fibre-free zones, and 'pockets' in the interface matrix/fiber have been found. Of these defects, only pores can be detected by X-ray radiography. Evaluation of tensile testing shows a relatively large scatter of results. The results reveal a dominant role of matrix composition on strength level. For the 20 vol% reinforced metals, with performs with silica binder, the maximum measured elongation was 3.5%. With alumina binder approximately half of the above mentioned ductility is obtained. The use of grain-refiner, Al-5Ti-B, decreases the ductility of the composite below 2%, independent of the type of binder. From 3-point bend tests fracture energies are estimated to vary between 0.3 and 0.6 Joule. The toughness is low. Studies of the wetting between pieces of ceramic pre-forms and molten Al-2Mg show that generally the wetting is poor. At the same time, the wettability of d-alumina with silicon oxide as binding medium was slightly

  20. Influence of Heat Treatment on Abrasive Wear Resistance of Silumin Matrix Composite Castings

    Directory of Open Access Journals (Sweden)

    Gawdzińska K.

    2016-03-01

    Full Text Available The authors attempted at examining the effect of heat treatment on abrasive wear resistance of metal composite castings. Metal matrix composites were made by infiltrating preforms created from unordered short fibers (graphite or silumin with liquid aluminium alloy AlSi12(b. Thus prepared composites were subject to solution heat treatment at a temperature of 520°C for four hours, then aging at a temperature of 220°C for four hours. Abrasion resistance of the material was tested before and after thermal treatment.

  1. Features of film growth during plasma anodizing of Al 2024/SiC metal matrix composite

    Energy Technology Data Exchange (ETDEWEB)

    Xue Wenbin [Key Laboratory for Radiation Beam Technology and Materials Modification, Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China)]. E-mail: xuewb@bnu.edu.cn

    2006-07-15

    Plasma anodizing is a novel promising process to fabricate corrosion-resistant protective films on metal matrix composites. The corrosion-resistant films were prepared by plasma anodizing on SiC reinforced aluminum matrix composite. The morphology and microstructure of films were analyzed by scanning electron microscopy. Specifically, the morphology of residual SiC reinforcement particles in the film was observed. It is found that the most SiC reinforcement particles have been molten to become silicon oxide, but a few tiny SiC particles still remain in the film close to the composite/film interface. This interface is irregular due to the hindering effect of SiC particles on the film growth. Morphology and distribution of residual SiC particles in film provide direct evidence to identify the local melt occurs in the interior of plasma anodizing film even near the composite/film interface. A model of film growth by plasma anodizing on metal matrix composites was proposed.

  2. Features of film growth during plasma anodizing of Al 2024/SiC metal matrix composite

    International Nuclear Information System (INIS)

    Xue Wenbin

    2006-01-01

    Plasma anodizing is a novel promising process to fabricate corrosion-resistant protective films on metal matrix composites. The corrosion-resistant films were prepared by plasma anodizing on SiC reinforced aluminum matrix composite. The morphology and microstructure of films were analyzed by scanning electron microscopy. Specifically, the morphology of residual SiC reinforcement particles in the film was observed. It is found that the most SiC reinforcement particles have been molten to become silicon oxide, but a few tiny SiC particles still remain in the film close to the composite/film interface. This interface is irregular due to the hindering effect of SiC particles on the film growth. Morphology and distribution of residual SiC particles in film provide direct evidence to identify the local melt occurs in the interior of plasma anodizing film even near the composite/film interface. A model of film growth by plasma anodizing on metal matrix composites was proposed

  3. Fabrication of conducting composite sheets using cost-effective graphite flakes and amorphous styrene acrylonitrile for enhanced thermistor, dielectric, and electromagnetic interference shielding properties

    Energy Technology Data Exchange (ETDEWEB)

    Panwar, Varij, E-mail: varijpanwarcertain@gmail.com [Electronics and Communication Engineering, Graphic Era University, Dehradun, Uttarakhand (India); Gill, Fateh Singh; Rathi, Vikas; Tewari, V.K. [Electronics and Communication Engineering, Graphic Era University, Dehradun, Uttarakhand (India); Mehra, R.M. [Sharda University, Greater Noida (India); Park, Jong-Oh, E-mail: jop@jnu.ac.kr [School of Mechanical Engineering, Chonnam National University, Gwangju (Korea, Republic of); Park, Sukho, E-mail: shpark12@dgist.ac.kr [Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology, Daegu (Korea, Republic of)

    2017-06-01

    The fabrication of strong conducting composite sheets (CCSs) using a simple technique with cost-effective materials is desirable for capacitor, decoupling capacitor, and electromagnetic interference (EMI) shielding applications. Here, we used cost-effective graphite flakes (GFs) as a conducting filler and amorphous poly (styrene-co-acrylonitrile) (PSAN) as an insulating polymer to fabricate a CCS via a simple mechanical mixing and hot compression molding process in 2.5 h, with the aim to save time and avoid the use of toxic reagents, which are generally used in chemical methods. In the present method, the GFs are connected in diffusively adhere polymer matrix, controlled by temperature and pressure that generate the conduction in the CCSs. The resulting PSAN/GF CCSs were characterized by using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and hardness tests. The GFs penetrated the interfacial region of PSAN, thus improving the thermistor and dielectric properties (dielectric constant, AC conductivity, and dissipation factor) of the PSAN/GF CCSs. Furthermore, the PSAN/GF CCSs showed enhanced hardness and EMI shielding effectiveness (SE) properties in the X-band frequency range (8.5–12.5 GHz). The percolation theory was implemented to DC and AC conductivity. To detect the transition of the dielectric properties, the dielectric constant of the CCSs was analyzed with increasing volume fraction of GFs in the radio frequency region. The improved dielectric constant, AC conductivity, and dissipation factor of the PSAN/GF CCS, indicated a significant improvement in their EMI shielding properties in the X-band frequency range, which were measured using the waveguide method. The ac conductivity of PSAN/GF CCS shows stable behavior in the higher frequency ranges. The EMISE of PSAN/GF CCS were found to increase with increasing GF content due to the absorbance mechanism. - Highlights: • Enhanced hardness and

  4. Vacuum brazing of high volume fraction SiC particles reinforced aluminum matrix composites

    Science.gov (United States)

    Cheng, Dongfeng; Niu, Jitai; Gao, Zeng; Wang, Peng

    2015-03-01

    This experiment chooses A356 aluminum matrix composites containing 55% SiC particle reinforcing phase as the parent metal and Al-Si-Cu-Zn-Ni alloy metal as the filler metal. The brazing process is carried out in vacuum brazing furnace at the temperature of 550°C and 560°C for 3 min, respectively. The interfacial microstructures and fracture surfaces are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy spectrum analysis (EDS). The result shows that adequacy of element diffusion are superior when brazing at 560°C, because of higher activity and liquidity. Dislocations and twins are observed at the interface between filler and composite due to the different expansion coefficient of the aluminum alloy matrix and SiC particles. The fracture analysis shows that the brittle fracture mainly located at interface of filler and composites.

  5. Oxidation behaviour of cast aluminium matrix composites with Ce surface coatings

    International Nuclear Information System (INIS)

    Pardo, A.; Merino, M.C.; Arrabal, R.; Feliu, S.; Viejo, F.

    2007-01-01

    The oxidation behaviour of SiC-reinforced aluminium matrix composites (A3xx.x/SiCp) has been studied after Ce-based treatments. Kinetics data of oxidation process were obtained from gravimetric tests performed at different temperatures (350, 425 and 500 o C). The nature of the oxidation layer was analyzed by scanning electron and atomic force microscopy, energy dispersive X-ray analysis, X-ray photoelectron spectroscopy and X-ray diffraction. The extent of oxidation degradation in untreated composites was preferentially localized in matrix/SiCp interfaces favouring the MgO formation. Ce coatings favoured a uniform oxidation of the composite surface with MgAl 2 O 4 spinel formation. This oxide increased the surface hardness of the materials

  6. Dry Sliding Friction and Wear Studies of Fly Ash Reinforced AA-6351 Metal Matrix Composites

    Directory of Open Access Journals (Sweden)

    M. Uthayakumar

    2013-01-01

    Full Text Available Fly ash particles are potentially used in metal matrix composites due to their low cost, low density, and availability in large quantities as waste by-products in thermal power plants. This study describes multifactor-based experiments that were applied to research and investigation on dry sliding wear system of stir-cast aluminum alloy 6351 with 5, 10, and 15 wt.% fly ash reinforced metal matrix composites (MMCs. The effects of parameters such as load, sliding speed, and percentage of fly ash on the sliding wear, specific wear rate, and friction coefficient were analyzed using Grey relational analysis on a pin-on-disc machine. Analysis of variance (ANOVA was also employed to investigate which design parameters significantly affect the wear behavior of the composite. The results showed that the applied load exerted the greatest effect on the dry sliding wear followed by the sliding velocity.

  7. Characterization on C/SiC Ceramic Matrix Composites with Novel Fiber Coatings

    Science.gov (United States)

    Petko, Jeanne; Kiser, J. Douglas; McCue, Terry; Verrilli, Michael

    2002-01-01

    Ceramic Matrix Composites (CMCs) are attractive candidate materials in the aerospace industry due to their high specific strength, low density and higher temperature capabilities. The National Aeronautics and Space Administration (NASA) is pursuing the use of CMC components in advanced Reusable Launch Vehicle (RLV) propulsion applications. Carbon fiber-reinforced silicon carbide (C/SiC) is the primary material of interest for a variety of RLV propulsion applications. These composites offer high- strength carbon fibers and a high modulus, oxidation-resistant matrix. For comparison, two types of carbon fibers were processed with novel types of interface coatings (multilayer and pseudoporous). For RLV propulsion applications, environmental durability will be critical. The coatings show promise of protecting the carbon fibers from the oxidizing environment. The strengths and microstructures of these composite materials are presented.

  8. Fabrication of BN/Al(-Mg) metal matrix composite (MMC) by pressureless infiltration technique

    Energy Technology Data Exchange (ETDEWEB)

    Jung, W.G.; Kwon, H. [School of Advanced Materials Eng., Kookmin Univ., Seoul (Korea)

    2004-07-01

    BN/Al(-Mg) metal matrix composite (MMC) was fabricated by the pressureless infiltration technique. The phase characterizations of the composites were analyzed using the SEM, TEM, EDS and EPMA on reaction products after the electrochemical dissolution of the matrix. It is confirmed that aluminum nitride (AlN) was formed by the reaction of Mg{sub 3}N{sub 2} and Al alloy melt. Plate type AlN and polyhedral type Mg(-Al) boride were formed by the reaction between Mg{sub 3}N{sub 2}, BN and molten Al in the composite. The reaction mechanism in the fabrication of BN/Al(-Mg) MMC was derived from the phase analysis results and the thermodynamic investigation. (orig.)

  9. Composite Coatings with Ceramic Matrix Including Nanomaterials as Solid Lubricants for Oil-Less Automotive Applications

    Directory of Open Access Journals (Sweden)

    Posmyk A.

    2016-06-01

    Full Text Available The paper presents the theoretical basis of manufacturing and chosen applications of composite coatings with ceramic matrix containing nanomaterials as a solid lubricant (AHC+NL. From a theoretical point of view, in order to reduce the friction coefficient of sliding contacts, two materials are required, i.e. one with a high hardness and the other with low shear strength. In case of composite coatings AHC+NL the matrix is a very hard and wear resistant anodic oxide coating (AHC whereas the solid lubricant used is the nanomaterial (NL featuring a low shear strength such as glassy carbon nanotubes (GC. Friction coefficient of cast iron GJL-350 sliding against the coating itself is much higher (0.18-0.22 than when it slides against a composite coating (0.08-0.14. It is possible to reduce the friction due to the presence of carbon nanotubes, or metal nanowires.

  10. Insights on synergy of materials and structures in biomimetic platelet-matrix composites

    Science.gov (United States)

    Sakhavand, Navid; Shahsavari, Rouzbeh

    2018-01-01

    Hybrid materials such as biomimetic platelet-matrix composites are in high demand to confer low weight and multifunctional mechanical properties. This letter reports interfacial-bond regulated assembly of polymers on cement-an archetype model with significant infrastructure applications. We demonstrate a series of 20+ molecular dynamics studies on decoding and optimizing the complex interfacial interactions including the role and types of various heterogeneous, competing interfacial bonds that are key to adhesion and interfacial strength. Our results show an existence of an optimum overlap length scale (˜15 nm) between polymers and cement crystals, exhibiting the best balance of strength, toughness, stiffness, and ductility for the composite. This finding, combined with the fundamental insights into the nature of interfacial bonds, provides key hypotheses for selection and processing of constituents to deliberate the best synergy in the structure and materials of platelet-matrix composites.

  11. Preparation of Ti-aluminide reinforced in situ aluminium matrix composites by reactive hot pressing

    International Nuclear Information System (INIS)

    Roy, D.; Ghosh, S.; Basumallick, A.; Basu, B.

    2007-01-01

    Aluminium based metal matrix composites reinforced with in situ Ti-aluminide and alumina particles were prepared by reactive hot pressing a powder mix of aluminium and nanosized TiO 2 powders. The reinforcements were formed in situ by exothermal reaction between the TiO 2 nano crystalline powder and aluminium. The thermal characteristics of the in situ reaction were studied with the aid of Differential scanning calorimetry (DSC). X-ray diffraction (XRD), Energy dispersive spectroscopy (EDS) and Scanning electron microscopy (SEM) techniques were employed to study the microstructural architecture of the composites as a function of hot pressing temperature and volume percent reinforcement. Microhardness measurements on the as prepared in situ aluminium matrix composites exhibit significant increase in hardness with increase in hot pressing temperature and volume fraction of reinforcement

  12. Evaluation of mechanical properties of aluminium alloy–alumina–boron carbide metal matrix composites

    International Nuclear Information System (INIS)

    Vijaya Ramnath, B.; Elanchezhian, C.; Jaivignesh, M.; Rajesh, S.; Parswajinan, C.; Siddique Ahmed Ghias, A.

    2014-01-01

    Highlights: • Fabrication of MMC with aluminium alloy–alumina–boron carbide is done. • Different proportions of reinforcements are added. • The effects of varying proportions are studied. • Investigation on mechanical properties above composites is performed. • Failure morphology analysis is done using SEM. - Abstract: This paper deals with the fabrication and mechanical investigation of aluminium alloy, alumina (Al 2 O 3 ) and boron carbide metal matrix composites. Aluminium is the matrix metal having properties like light weight, high strength and ease of machinability. Alumina which has better wear resistance, high strength, hardness and boron carbide which has excellent hardness and fracture toughness are added as reinforcements. Here, the fabrication is done by stir casting which involves mixing the required quantities of additives into stirred molten aluminium. After solidification, the samples are prepared and tested to find the various mechanical properties like tensile, flexural, impact and hardness. The internal structure of the composite is observed using Scanning Electron Microscope (SEM)

  13. Overall mechanical properties of fiber-reinforced metal matrix composites for fusion applications

    International Nuclear Information System (INIS)

    You, J.H.; Bolt, H.

    2002-01-01

    The high-temperature strength and creep properties are among the crucial criteria for the structural materials of plasma facing components (PFC) of fusion reactors, as they will be subjected to severe thermal stresses. The fiber-reinforced metal matrix composites are a potential heat sink material for the PFC application, since the combination of different material properties can lead to versatile performances. In this article, the overall mechanical properties of two model composites based on theoretical predictions are presented. The matrix materials considered were a precipitation hardened CuCrZr alloy and reduced activation martensitic steel 'Eurofer'. Continuous SiC fibers were used for the reinforcement. The results demonstrate that yield stress, ultimate tensile strength, work hardening rate and creep resistance could be extensively improved by the fiber reinforcement up to fiber content of 40 vol.%. The influence of the residual stresses on the plastic behavior of the composites is also discussed

  14. EVALUATION OF EFFECTIVE PROPERTIES OF BASALT TEXTILE REINFORCED CERAMIC MATRIX COMPOSITES

    Directory of Open Access Journals (Sweden)

    Soňa Valentová

    2017-11-01

    Full Text Available The present paper is concerned with the analysis of a ceramic matrix composite, more specifically the plain weave textile fabric composite made of basalt fibers embedded into the pyrolyzed polysiloxane matrix. Attention is paid to the determination of effective elastic properties of the yarn via homogenization based on the Mori-Tanaka averaging scheme and the 1st order numerical homogenization method adopting a suitable representative computational model. The latter approach is then employed to simulate the response of the yarn when loaded beyond the elastic limits. The required mechanical properties of individual material phases are directly measured using nanoindentation with in-build scanning probe microscopy. Applicability of the proposed computational methodology is supported by the analysis of a unidirectional fibrous composite, representing the yarn, subjected to a macroscopically uniform strain.

  15. Enhancement of interfacial properties of basalt fiber reinforced nylon 6 matrix composites with silane coupling agents

    Directory of Open Access Journals (Sweden)

    2010-10-01

    Full Text Available In this work solution surface treatment was applied for producing basalt fiber reinforced PA6 matrix composites. Beyond scanning electron microscopy, static and dynamic mechanical tests, dynamic mechanical analysis of composites was used for qualifying the interfacial adhesion in a wide temperature range. The loss factor peak height of loss factor is particularly important, because it is in close relationship with the mobility of polymer molecular chain segments and side groups, hence it correlates with the number and strength of primary or secondary bondings established between the matrix and the basalt fibers. It was proven, that the interfacial adhesion between basalt fibers and polyamide can be largely improved by the application of silane coupling agents in the entire usage temperature range of composites. The presence of coupling agents on the surface of basalt fibers was proven by Fourier transform infrared spectroscopy. The best results were obtained by 3-glycidoxypropyltrimethoxysilane coupling agent.

  16. Microstructure and hardness of WC-Co particle reinforced iron matrix surface composite

    Directory of Open Access Journals (Sweden)

    Zhang Peng

    2013-11-01

    Full Text Available In this study, a high Cr cast iron surface composite material reinforced with WC-Co particles 2-6 mm in size was prepared using a pressureless sand mold infiltration casting technique. The composition, microstructure and hardness were determined by means of energy dispersive spectrometry (EDS, electron probe microanalysis (EPMA, scanning electron microscope (SEM and Rockwell hardness measurements. It is determined that the obtained composite layer is about 15 mm thick with a WC-Co particle volumetric fraction of ~38%. During solidification, interface reaction takes place between WC-Co particles and high chromium cast iron. Melting and dissolving of prefabricated particles are also found, suggesting that local Co melting and diffusion play an important role in promoting interface metallurgical bonding. The composite layer is composed of ferrite and a series of carbides, such as (Cr, W, Fe23C6, WC, W2C, M6C and M12C. The inhomogeneous hardness in the obtained composite material shows a gradient decrease from the particle reinforced metal matrix composite layer to the matrix layer. The maximum hardness of 86.3 HRA (69.5 HRC is obtained on the particle reinforced surface, strongly indicating that the composite can be used as wear resistant material.

  17. Composites Based on Polytetrafluoroethylene and Detonation Nanodiamonds: Filler-Matrix Chemical Interaction and Its Effect on a Composite's Properties

    Science.gov (United States)

    Koshcheev, A. P.; Perov, A. A.; Gorokhov, P. V.; Zaripov, N. V.; Tereshenkov, A. V.; Khatipov, S. A.

    2018-06-01

    Specific properties of PTFE composites filled with ultradisperse detonation diamonds (UDDs) with different surface chemistries are studied. It is found for the first time that filler in the form of UDDs affects not only the rate of PTFE thermal decomposition in vacuum pyrolysis, but also the chemical composition of the products of degradation. The wear resistance of UDD/PTFE composites is shown to depend strongly on the UDD surface chemistry. The presence of UDDs in a PTFE composite is found to result in perfluorocarbon telomeres, released as a readily condensable fraction upon composite pyrolysis. The chemical interaction between PTFE and UDDs, characterized by an increase in the rate of gas evolution and a change in the desorbed gas's composition, is found to occur at temperature as low as 380°C. It is shown that the intensity of this interaction depends on the concentration of oxygen-containing surface groups, the efficiency of UDDs in terms of the composite's wear resistance being reduced due to the presence of these groups. Based on the experimental data, a conclusion is reached about the chemical interaction between UDDs and a PTFE matrix, its dependence on the nanodiamond surface chemistry, and its effect on a composite's tribology.

  18. A study of microstructure and wear behaviour of TiB2/Al metal matrix composites

    Directory of Open Access Journals (Sweden)

    A. Sreenivasan

    Full Text Available The present paper deals with the study of microstructure and wear characteristics of TiB2 reinforced aluminium metal matrix composites (MMCs. Matrix alloys with 5, 10 and 15% of TiB2 were made using stir casting technique. Effect of sliding velocity on the wear behaviour and tribo-chemistry of the worn surfaces of both matrix and composites sliding against a EN24 steel disc has been investigated under dry conditions. A pin-on-disc wear testing machine was used to find the wear rate, in which EN24 steel disc was used as the counter face, loads of 10-60N in steps of 10N and speeds of 100, 200, 300, 400 and 500 rpm were employed. The results showed that the wear rate was increased with an increase in load and sliding speed for both the materials. However, a lower wear rate was obtained for MMCs when compared to the matrix alloys. The wear transition from slight to severe was presented at the critical applied loads. The transition loads for the MMCs were much higher than that of the matrix alloy. The transition loads were increased with increase in TiB2 and the same was decreased with the increase of sliding speeds. The SEM and EDS analyses were undertaken to demonstrate the effect of TiB2 particles on the wear mechanism for each conditions.

  19. Flight-vehicle materials, structures, and dynamics - Assessment and future directions. Vol. 3 - Ceramics and ceramic-matrix composites

    Science.gov (United States)

    Levine, Stanley R. (Editor)

    1992-01-01

    The present volume discusses ceramics and ceramic-matrix composites in prospective aerospace systems, monolithic ceramics, transformation-toughened and whisker-reinforced ceramic composites, glass-ceramic matrix composites, reaction-bonded Si3N4 and SiC composites, and chemical vapor-infiltrated composites. Also discussed are the sol-gel-processing of ceramic composites, the fabrication and properties of fiber-reinforced ceramic composites with directed metal oxidation, the fracture behavior of ceramic-matrix composites (CMCs), the fatigue of fiber-reinforced CMCs, creep and rupture of CMCs, structural design methodologies for ceramic-based materials systems, the joining of ceramics and CMCs, and carbon-carbon composites.

  20. Improvement of thermal conductivity of ceramic matrix composites for 4. generation nuclear reactors

    International Nuclear Information System (INIS)

    Cabrero, J.

    2009-11-01

    This study deals with thermal conductivity improvement of SiCf/SiC ceramic matrix composites materials to be used as cladding material in 4. generation nuclear reactor. The purpose of the study is to develop a composite for which both the temperature and irradiation effect is less pronounced on thermal conductivity of material than for SiC. This material will be used as matrix in CMC with SiC fibers. Some TiC-SiC composites with different SiC volume contents were prepared by spark plasma sintering (SPS). The sintering process enables to fabricate specimens very fast, with a very fine microstructure and without any sintering aids. Neutron irradiation has been simulated using heavy ions, at room temperature and at 500 C. Evolution of the thermal properties of irradiated materials is measured using modulated photothermal IR radiometry experiment and was related to structural evolution as function of dose and temperature. It appears that such approach is reliable to evaluate TiC potentiality as matrix in CMC. Finally, CMC with TiC matrix and SiC fibers were fabricated and both mechanical and thermal properties were measured and compare to SiCf/SiC CMC. (author)

  1. Mapping the coupled role of structure and materials in mechanics of platelet-matrix composites

    Science.gov (United States)

    Farzanian, Shafee; Shahsavari, Rouzbeh

    2018-03-01

    Despite significant progresses on understanding and mimicking the delicate nano/microstructure of biomaterials such as nacre, decoding the indistinguishable merger of materials and structures in controlling the tradeoff in mechanical properties has been long an engineering pursuit. Herein, we focus on an archetype platelet-matrix composite and perform ∼400 nonlinear finite element simulations to decode the complex interplay between various structural features and material characteristics in conferring the balance of mechanical properties. We study various combinatorial models expressed by four key dimensionless parameters, i.e. characteristic platelet length, matrix plasticity, platelet dissimilarity, and overlap offset, whose effects are all condensed in a new unifying parameter, defined as the multiplication of strength, toughness, and stiffness over composite volume. This parameter, which maximizes at a critical characteristic length, controls the transition from intrinsic toughening (matrix plasticity driven without crack growths) to extrinsic toughening phenomena involving progressive crack propagations. This finding, combined with various abstract volumetric and radar plots, will not only shed light on decoupling the complex role of structure and materials on mechanical performance and their trends, but provides important guidelines for designing lightweight staggered platelet-matrix composites while ensuring the best (balance) of their mechanical properties.

  2. Matrix intensification alters avian functional group composition in adjacent rainforest fragments.

    Directory of Open Access Journals (Sweden)

    Justus P Deikumah

    Full Text Available Conversion of farmland land-use matrices to surface mining is an increasing threat to the habitat quality of forest remnants and their constituent biota, with consequences for ecosystem functionality. We evaluated the effects of matrix type on bird community composition and the abundance and evenness within avian functional groups in south-west Ghana. We hypothesized that surface mining near remnants may result in a shift in functional composition of avifaunal communities, potentially disrupting ecological processes within tropical forest ecosystems. Matrix intensification and proximity to the remnant edge strongly influenced the abundance of members of several functional guilds. Obligate frugivores, strict terrestrial insectivores, lower and upper strata birds, and insect gleaners were most negatively affected by adjacent mining matrices, suggesting certain ecosystem processes such as seed dispersal may be disrupted by landscape change in this region. Evenness of these functional guilds was also lower in remnants adjacent to surface mining, regardless of the distance from remnant edge, with the exception of strict terrestrial insectivores. These shifts suggest matrix intensification can influence avian functional group composition and related ecosystem-level processes in adjacent forest remnants. The management of matrix habitat quality near and within mine concessions is important for improving efforts to preserveavian biodiversity in landscapes undergoing intensification such as through increased surface mining.

  3. Feasibility study on development of metal matrix composite by microwave stir casting

    Science.gov (United States)

    Lingappa, S. M.; Srinath, M. S.; Amarendra, H. J.

    2018-04-01

    Need for better service oriented materials has boosted the demand for metal matrix composite materials, which can be developed to have necessary properties. One of the most widely utilized metal matrix composite is Al-SiC, which is having a matrix made of aluminium metal and SiC as reinforcement. Lightweight and conductivity of aluminium, when combined with hardness and wear resistance of SiC provides an excellent platform for various applications in the field of electronics, automotives, and aerospace and so on. However, uniform distribution of reinforcement particles is an issue and has to be addressed. The present study is an attempt made to develop Al-SiC metal matrix composite by melting base metal using microwave hybrid heating technique, followed by addition of reinforcement and stirring the mixture for obtaining homogenous mixture. X-Ray Diffraction analysis shows the presence of aluminium and SiC in the cast material. Further, microstructural study shows the distribution of SiC particles in the grain boundaries.

  4. An investigation of flow properties of metal matrix composites suspensions for injection molding

    International Nuclear Information System (INIS)

    Ahmad, F.; Bevis, M.J.

    1997-01-01

    Flow properties of metal matrix composites suspensions have significant effects on the fibre orientation during mould filling. The results presented in this paper relate to the flow properties of aluminium powder and glass fibres compounded into a sacrificial thermoplastics binder. For this purpose, a range of aluminium compounds and aluminium composite suspensions were investigated over a wide shear rate range expected to occur during injection mould process. Aluminium composites wee prepared by substituting glass fibres for aluminium in aluminium compound. Aluminium composite containing a maximum critical volume fraction of fibres which did not exhibit an increase n viscosity was determined. The effect of temperature on the flow behaviour of aluminium composite was also investigated. (author)

  5. MOFwich: Sandwiched Metal-Organic Framework-Containing Mixed Matrix Composites for Chemical Warfare Agent Removal.

    Science.gov (United States)

    Peterson, Gregory W; Lu, Annie X; Hall, Morgan G; Browe, Matthew A; Tovar, Trenton; Epps, Thomas H

    2018-02-28

    This work describes a new strategy for fabricating mixed matrix composites containing layered metal-organic framework (MOF)/polymer films as functional barriers for chemical warfare agent protection. Through the use of mechanically robust polymers as the top and bottom encasing layers, a high-MOF-loading, high-performance-core layer can be sandwiched within. We term this multifunctional composite "MOFwich". We found that the use of elastomeric encasing layers enabled core layer reformation after breakage, an important feature for composites and membranes alike. The incorporation of MOFs into the core layer led to enhanced removal of chemical warfare agents while simultaneously promoting moisture vapor transport through the composite, showcasing the promise of these composites for protection applications.

  6. Physical and Microstructure Properties of MgAl2C2 Matrix Composite Coating on Titanium

    Science.gov (United States)

    Li, Peng

    2014-12-01

    This work is based on the dry sliding wear of the MgAl2C2-TiB2-FeSi composite coating deposited on a pure Ti using a laser cladding technique. Scanning electron microscope images indicate that the nanocrystals and amorphous phases are produced in such coating. X-ray diffraction result indicated that such coating mainly consists of MgAl2C2, Ti-B, Ti-Si, Fe-Al, Ti3SiC2, TiC and amorphous phases. The high resolution transmission electron microscope image indicated that the TiB nanorods were produced in the coating, which were surrounded by other fine precipitates, favoring the formation of a fine microstructure. With increase of the laser power from 0.85 kW to 1.00 kW, the micro-hardness decreased from 1350 1450 HV0.2 to 1200 1300 HV0.2. The wear volume loss of the laser clad coating was 1/7 of pure Ti.

  7. Optical properties of silver doped amorphous films of composition Ge28S72 and Ge22Ga6S72

    Czech Academy of Sciences Publication Activity Database

    Bartoš, M.; Wágner, T.; Válková, S.; Pavlišta, M.; Vlček, Milan; Beneš, L.; Frumar, M.

    2011-01-01

    Roč. 13, 11-12 (2011), 1442-1446 ISSN 1454-4164. [Fifth International Conference on Amorphous and Nanostructured Chalcogenides. Magurele - Bucharest, 26.06.2011-01.07.2011] Institutional research plan: CEZ:AV0Z40500505 Keywords : amorphous films * chalcogenides * optical properties Subject RIV: CA - Inorganic Chemistry Impact factor: 0.457, year: 2011 http://joam.inoe.ro/index.php?option=magazine&op=view&idu=2941&catid=68

  8. A study of the diffusional behavior of a two-phase metal matrix composite exposed to a high temperature environment

    Science.gov (United States)

    Tenney, D. R.

    1974-01-01

    The progress of diffusion-controlled filament-matrix interaction in a metal matrix composite where the filaments and matrix comprise a two-phase binary alloy system was studied by mathematically modeling compositional changes resulting from prolonged elevated temperature exposure. The analysis treats a finite, diffusion-controlled, two-phase moving-interface problem by means of a variable-grid finite-difference technique. The Ni-W system was selected as an example system. Modeling was carried out for the 1000 to 1200 C temperature range for unidirectional composites containing from 6 to 40 volume percent tungsten filaments in a Ni matrix. The results are displayed to show both the change in filament diameter and matrix composition as a function of exposure time. Compositional profiles produced between first and second nearest neighbor filaments were calculated by superposition of finite-difference solutions of the diffusion equations.

  9. Growing GaN LEDs on amorphous SiC buffer with variable C/Si compositions

    Science.gov (United States)

    Cheng, Chih-Hsien; Tzou, An-Jye; Chang, Jung-Hung; Chi, Yu-Chieh; Lin, Yung-Hsiang; Shih, Min-Hsiung; Lee, Chao-Kuei; Wu, Chih-I; Kuo, Hao-Chung; Chang, Chun-Yen; Lin, Gong-Ru

    2016-01-01

    The epitaxy of high-power gallium nitride (GaN) light-emitting diode (LED) on amorphous silicon carbide (a-SixC1−x) buffer is demonstrated. The a-SixC1−x buffers with different nonstoichiometric C/Si composition ratios are synthesized on SiO2/Si substrate by using a low-temperature plasma enhanced chemical vapor deposition. The GaN LEDs on different SixC1−x buffers exhibit different EL and C-V characteristics because of the extended strain induced interfacial defects. The EL power decays when increasing the Si content of SixC1−x buffer. The C-rich SixC1−x favors the GaN epitaxy and enables the strain relaxation to suppress the probability of Auger recombination. When the SixC1−x buffer changes from Si-rich to C-rich condition, the EL peak wavelengh shifts from 446 nm to 450 nm. Moreover, the uniform distribution contour of EL intensity spreads between the anode and the cathode because the traping density of the interfacial defect gradually reduces. In comparison with the GaN LED grown on Si-rich SixC1−x buffer, the device deposited on C-rich SixC1−x buffer shows a lower turn-on voltage, a higher output power, an external quantum efficiency, and an efficiency droop of 2.48 V, 106 mW, 42.3%, and 7%, respectively. PMID:26794268

  10. Hydrophobic matrix-free graphene-oxide composites with isotropic and nematic states

    Science.gov (United States)

    Wåhlander, Martin; Nilsson, Fritjof; Carlmark, Anna; Gedde, Ulf W.; Edmondson, Steve; Malmström, Eva

    2016-08-01

    We demonstrate a novel route to synthesise hydrophobic matrix-free composites of polymer-grafted graphene oxide (GO) showing isotropic or nematic alignment and shape-memory effects. For the first time, a cationic macroinitiator (MI) has been immobilised on anionic GO and subsequently grafted with hydrophobic polymer grafts. Dense grafts of PBA, PBMA and PMMA with a wide range of average graft lengths (MW: 1-440 kDa) were polymerised by surface-initiated controlled radical precipitation polymerisation from the statistical MI. The surface modification is designed similarly to bimodal graft systems, where the cationic MI generates nanoparticle repulsion, similar to dense short grafts, while the long grafts offer miscibility in non-polar environments and cohesion. The state-of-the-art dispersions of grafted GO were in the isotropic state. Transparent and translucent matrix-free GO-composites could be melt-processed directly using only grafted GO. After processing, birefringence due to nematic alignment of grafted GO was observed as a single giant Maltese cross, 3.4 cm across. Permeability models for composites containing aligned 2D-fillers were developed, which were compared with the experimental oxygen permeability data and found to be consistent with isotropic or nematic states. The storage modulus of the matrix-free GO-composites increased with GO content (50% increase at 0.67 wt%), while the significant increases in the thermal stability (up to 130 °C) and the glass transition temperature (up to 17 °C) were dependent on graft length. The tuneable matrix-free GO-composites with rapid thermo-responsive shape-memory effects are promising candidates for a vast range of applications, especially selective membranes and sensors.We demonstrate a novel route to synthesise hydrophobic matrix-free composites of polymer-grafted graphene oxide (GO) showing isotropic or nematic alignment and shape-memory effects. For the first time, a cationic macroinitiator (MI) has been

  11. An Assessment of Mechanical and Tribological Property of Hybrid Aluminium Metal Matrix Composite

    Directory of Open Access Journals (Sweden)

    R. Santosh Kumar

    2017-04-01

    Full Text Available Composite materials has huge requirement in the area of automobile, aerospace, and wear resistant applications. This study presents the synthesis of composite reinforced with SiC and Al2O3 using gravity stir casting. Stir casting is the manufacturing process that is incorporated to produce the composite material because of its extreme bonding capacity with base material. The composition of reinforcement with 6061 aluminium matrix is SiC-7.5% and Al2O3 -2.5% respectively. The average size of reinforcement particle is 30-40 microns. The synthesised composite casting is machined using EDM to prepare specimens for various tests. Microstructure study was carried and the microstructure images prove the existence and dispersion of reinforcement particles in the metal matrix. There is no visible porosity is observed. The hardness of the specimen is tested using Vickers hardness tester and found considerable increase when compare with parent alloy Al 6061. Also mechanical and tribological properties of hybrid Aluminium metal matrix composite were employed. The fortifying material, Silicon Carbide is composed of tetrahedral of carbon and silicon atoms with strong bonds in crystal lattice along with its excellent wear resistance property and alumina have high strength and wear resistance. To avoid enormous material wastage and to achieve absolute accuracy, wire-cut EDM process is capitalised to engrave the specimen as per required dimensions. Three Tensile test specimens were prepared, in order to achieve reliability in results as per ASTM- E8 standard, and the values were tabulated. Impact test was carried out and the readings were tabulated. Wear test was carried out using pin on disc wear test apparatus and the results show considerable increase in wear resistant property when compare with parent alloy Al6061.The above work proves the successful fabrication of composite and evaluation of properties.

  12. Additive Manufacturing of Silicon Carbide-Based Ceramic Matrix Composites: Technical Challenges and Opportunities

    Science.gov (United States)

    Singh, Mrityunjay; Halbig, Michael C.; Grady, Joseph E.

    2016-01-01

    Advanced SiC-based ceramic matrix composites offer significant contributions toward reducing fuel burn and emissions by enabling high overall pressure ratio (OPR) of gas turbine engines and reducing or eliminating cooling air in the hot-section components, such as shrouds, combustor liners, vanes, and blades. Additive manufacturing (AM), which allows high value, custom designed parts layer by layer, has been demonstrated for metals and polymer matrix composites. However, there has been limited activity on additive manufacturing of ceramic matrix composites (CMCs). In this presentation, laminated object manufacturing (LOM), binder jet process, and 3-D printing approaches for developing ceramic composite materials are presented. For the laminated object manufacturing (LOM), fiber prepreg laminates were cut into shape with a laser and stacked to form the desired part followed by high temperature heat treatments. For the binder jet, processing optimization was pursued through silicon carbide powder blending, infiltration with and without SiC nano powder loading, and integration of fibers into the powder bed. Scanning electron microscopy was conducted along with XRD, TGA, and mechanical testing. Various technical challenges and opportunities for additive manufacturing of ceramics and CMCs will be presented.

  13. Studies on the optimization of deformation processed metal metal matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, Tim W. [Iowa State Univ., Ames, IA (United States)

    1994-01-04

    A methodology for the production of deformation processed metal metal matrix composites from hyper-eutectic copper-chromium alloys was developed. This methodology was derived from a basic study of the precipitation phenomena in these alloys encompassing evaluation of microstructural, electrical, and mechanical properties. The methodology developed produces material with a superior combination of electrical and mechanical properties compared to those presently available in commercial alloys. New and novel alloying procedures were investigated to extend the range of production methods available for these material. These studies focused on the use of High Pressure Gas Atomization and the development of new containment technologies for the liquid alloy. This allowed the production of alloys with a much more refined starting microstructure and lower contamination than available by other methods. The knowledge gained in the previous studies was used to develop two completely new families of deformation processed metal metal matrix composites. These composites are based on immissible alloys with yttrium and magnesium matrices and refractory metal reinforcement. This work extends the physical property range available in deformation processed metal metal matrix composites. Additionally, it also represents new ways to apply these metals in engineering applications.

  14. Polyurethane elastomer as a matrix material for short carbon fiber reinforced thermoplastic composites

    Directory of Open Access Journals (Sweden)

    Ümit Tayfun

    2017-09-01

    Full Text Available Short carbon fibers (CF with different surface sized (epoxy (EP and polyurethane (PU were used as reinforcing agent in thermoplastic polyurethane (TPU based composites. Composites containing 5, 10, 15, and 20 weight % sized and desized CFs were prepared by using melt-mixing method. The surface characteristics of CFs were examined by energy dispersive X-ray spectroscopy (EDX and Fourier transform infrared spectroscopy (FTIR. Tensile testing, shore hardness test, dynamic mechanical analysis (DMA and melt flow index (MFI test were performed for determining final composite properties. The dispersion of CFs in TPU matrix was examined by scanning electron microscopy (SEM. Tensile strength, Youngs’ modulus and Shore hardness of TPU were enhanced by the addition of sized CFs. About two-fold improvement for tensile strength and ten-fold improvement for Youngs’ modulus were observed with the incorporation of 20 wt% EP-CF and PU-CF in TPU. The storage modulus of PU-CF containing composites was higher than those of TPU and other composites. No remarkable change was observed in MFI value of TPU after CF loadings. Processing conditions in this work was suitable for composite production. Sized CFs exhibited better dispersion with regard to desized CF due to the stronger adhesion of TPU matrix to fiber surface.

  15. Nanoparticle and gelation stabilized functional composites of an ionic salt in a hydrophobic polymer matrix.

    Directory of Open Access Journals (Sweden)

    Selin Kanyas

    Full Text Available Polymer composites consisted of small hydrophilic pockets homogeneously dispersed in a hydrophobic polymer matrix are important in many applications where controlled release of the functional agent from the hydrophilic phase is needed. As an example, a release of biomolecules or drugs from therapeutic formulations or release of salt in anti-icing application can be mentioned. Here, we report a method for preparation of such a composite material consisted of small KCOOH salt pockets distributed in the styrene-butadiene-styrene (SBS polymer matrix and demonstrate its effectiveness in anti-icing coatings. The mixtures of the aqueous KCOOH and SBS-cyclohexane solutions were firstly stabilized by adding silica nanoparticles to the emulsions and, even more, by gelation of the aqueous phase by agarose. The emulsions were observed in optical microscope to check its stability in time and characterized by rheological measurements. The dry composite materials were obtained via casting the emulsions onto the glass substrates and evaporations of the organic solvent. Composite polymer films were characterized by water contact angle (WCA measurements. The release of KCOOH salt into water and the freezing delay experiments of water droplets on dry composite films demonstrated their anti-icing properties. It has been concluded that hydrophobic and thermoplastic SBS polymer allows incorporation of the hydrophilic pockets/phases through our technique that opens the possibility for controlled delivering of anti-icing agents from the composite.

  16. Preliminary Investigation to Determine the Suitable Mixture Composition for Corn Starch Matrix

    Science.gov (United States)

    Huzaimi Zakaria, Nazri; Ngali, Zamani; Zulkefli Selamat, Mohd

    2017-01-01

    The use of natural fiber as reinforcement in polymeric composites has been seen a dramatically increase over the last decades. The surge in the interest of natural fiber composite or biodegradable composite is mainly due to the attractive cost of production, improved of hardness, better fatigue endurance and good thermal and mechanical resistivity. In this work, corn starch in the form of powder is utilized as the matrix of the composite. However, starch is brittle and has low strength make it inappropriate candidate for matrix binder. The main objective of this study is to modify the mechanical properties of pure corn starch by mixing it with water, glycerol and vinegar. The composition ratio of water is 60~80%, corn starch 10~35%, glycerol is 5~15% and vinegar is 0~5%, ten samples (A-J) have been manufactured and the best mixture composition is selected based on few selection criteria. The selection criteria are visual impaction, hardness and density. From the results, the samples without vinegar are not suitable to be used because of the fungus availability on the surface. Meanwhile the results from the samples with 5 ml vinegar have no fungus on their surface even has been exposed to the ambient air. While the sample C has shown the best sample based on the visual, hardness and density test.

  17. Amorphous structure evolution of high power diode laser cladded Fe–Co–B–Si–Nb coatings

    International Nuclear Information System (INIS)

    Zhu Yanyan; Li Zhuguo; Huang Jian; Li Min; Li Ruifeng; Wu Yixiong

    2012-01-01

    Highlights: ► Fabricated amorphous composited coating by high power diode laser cladding with single track. ► Lower dilution and higher scanning speed are desired to obtain higher amorphous phase fraction. ► White spots phase with high content of Nb embedded in the amorphous matrix. - Abstract: Fe–Co–B–Si–Nb coatings were fabricated on the surface of low carbon steel using high power diode laser cladding of [(Fe 0.5 Co 0.5 ) 0.75 B 0.2 Si 0.05 ] 95.7 Nb 4.3 amorphous powders at three different scanning speeds of 6, 17 and 50 m/s. At each scanning speed, laser power was optimized to obtain low dilution ratio. Scanning electron microscopy, X-ray diffraction, transmission electron microscopy with energy dispersive spectrometer and electron probe micro analysis were carried out to characterize the microstructure and chemical composition of the cladded coatings. Differential scanning calorimetry was also carried out to investigate the fraction of the amorphous phase. The results showed that dilution ratio and scanning speed were the two main factors for fabricating Fe–Co–B–Si–Nb amorphous coating by high power diode laser cladding. Low dilution ratio was crucial for the formation of amorphous phase. When the dilution ratio was low, the fraction of amorphous phase in the cladded coatings increased upon increasing the scanning speed.

  18. Advanced bredigite-containing magnesium-matrix composites for biodegradable bone implant applications.

    Science.gov (United States)

    Dezfuli, Sina Naddaf; Huan, Zhiguang; Mol, Arjan; Leeflang, Sander; Chang, Jiang; Zhou, Jie

    2017-10-01

    The present research was aimed at developing magnesium-matrix composites that could allow effective control over their physiochemical and mechanical responses when in contact with physiological solutions. A biodegradable, bioactive ceramic - bredigite was chosen as the reinforcing phase in the composites, based on the hypothesis that the silicon- and magnesium-containing ceramic could protect magnesium from fast corrosion and at the same time stimulate cell proliferation. Methods to prepare composites with integrated microstructures - a prerequisite to achieve controlled biodegradation were developed. A systematic experimental approach was taken in order to elucidate the in vitro biodegradation mechanisms and kinetics of the composites. It was found that the composites with 20-40% homogenously dispersed bredigite particles, prepared from powders, could indeed significantly decrease the degradation rate of magnesium by up to 24 times. Slow degradation of the composites resulted in the retention of the mechanical integrity of the composites within the strength range of cortical bone after 12days of immersion in a cell culture medium. Cell attachment, cytotoxicity and bioactivity tests confirmed the stimulatory effects of bredigite embedded in the composites on the attachment, viability and differentiation of bone marrow stromal cells. Thus, the multiple benefits of adding bredigite to magnesium in enhancing degradation behavior, mechanical properties, biocompatibility and bioactivity were obtained. The results from this research showed the excellent potential of the bredigite-containing composites for bone implant applications, thus warranting further in vitro and in vivo research. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Fabrication of Nano-CeO2 and Application of Nano-CeO2 in Fe Matrix Composites

    International Nuclear Information System (INIS)

    Tiebao, W.; Chunxiang, C.; Xiaodong, W.; Guobin, L.

    2010-01-01

    It is expatiated that nano-CeO2 is fabricated by the direct sedimentation method. The components and particles diameter of nano-CeO2 powders are analyzed by XRD and SEM . The thermodynamic analysis and acting mechanism of nano-CeO2 with Al in Fe matrix composites are researched, which shows that the reaction is generated between CeO2 and Al in the composite, that is, 3CeO2+4Al - 2Al2O3+3[Ce], which obtains Al2O3 and active [Ce] during the sintering process. The active [Ce] can improve the performance of CeO2/Fe matrix composites. The suitable amount of CeO2 is about 0.05% in CeO2/Fe matrix composites. SEM fracture analysis shows that the toughness sockets in nano-CeO2/Fe matrix composites are more than those in no-added nano-CeO2 composites, which can explain that adding nano-CeO2 into Fe matrix composite, the toughness of the composite is improved significantly. Applied nano-CeO2 to Fe matrix diamond saw blades shows that Fe matrix diamond saw blade is sharper and of longer cutting life than that with no-added nano-CeO2.

  20. Graphene-Reinforced Aluminum Matrix Composites: A Review of Synthesis Methods and Properties

    Science.gov (United States)

    Chen, Fei; Gupta, Nikhil; Behera, Rakesh K.; Rohatgi, Pradeep K.

    2018-06-01

    Graphene-reinforced aluminum (Gr-Al) matrix nanocomposites (NCs) have attracted strong interest from both research and industry in high-performance weight-sensitive applications. Due to the vastly different bonding characteristics of the Al matrix (metallic) and graphene (in-plane covalent + inter-plane van der Waals), the graphene phase has a general tendency to agglomerate and phase separate in the metal matrix, which is detrimental for the mechanical and chemical properties of the composite. Thus, synthesis of Gr-Al NCs is extremely challenging. This review summarizes the different methods available to synthesize Gr-Al NCs and the resulting properties achieved in these NCs. Understanding the effect of processing parameters on the realized properties opens up the possibility of tailoring the synthesis methods to achieve the desired properties for a given application.

  1. Graphene-Reinforced Aluminum Matrix Composites: A Review of Synthesis Methods and Properties

    Science.gov (United States)

    Chen, Fei; Gupta, Nikhil; Behera, Rakesh K.; Rohatgi, Pradeep K.

    2018-03-01

    Graphene-reinforced aluminum (Gr-Al) matrix nanocomposites (NCs) have attracted strong interest from both research and industry in high-performance weight-sensitive applications. Due to the vastly different bonding characteristics of the Al matrix (metallic) and graphene (in-plane covalent + inter-plane van der Waals), the graphene phase has a general tendency to agglomerate and phase separate in the metal matrix, which is detrimental for the mechanical and chemical properties of the composite. Thus, synthesis of Gr-Al NCs is extremely challenging. This review summarizes the different methods available to synthesize Gr-Al NCs and the resulting properties achieved in these NCs. Understanding the effect of processing parameters on the realized properties opens up the possibility of tailoring the synthesis methods to achieve the desired properties for a given application.

  2. Influence of cold rolling and fatigue on the residual stress state of a metal matrix composite

    International Nuclear Information System (INIS)

    Hanus, E.; Ericsson, T.; Lu, J.; Decomps, F.

    1993-01-01

    The large difference in the coefficient of thermal expansion between the matrix alloy and the particle in a metal matrix composite gives rise to residual stresses in the material. In the present work the effect of cold rolling and four-point bending fatigue on the residual stress state of a silicon carbide particle reinforced aluminium alloy (AA 2014) has been investigated. The three dimensional stress state measured in both phases: matrix and reinforcement, has been determined by using an X-ray diffraction technique. It was found that cold rolling induces surface compressive macrostresses of about -250 MPa, with a penetration depth around 2 mm. The absolute values of the pseudomacrostresses in both phases are significantly reduced due to the single track rolling. Stress relaxation occurs during four-point bending fatigue. (orig.)

  3. Interfacial reaction in cast WC particulate reinforced titanium metal matrix composites coating produced by laser processing

    Science.gov (United States)

    Liu, Dejian; Hu, Peipei; Min, Guoqing

    2015-06-01

    Laser injection of ceramic particle was conducted to produce particulate reinforced metal matrix composites (MMCs) coating on Ti-6Al-4V alloy. Cast WC particle (WCp) was used as injection reinforcement to avoid excessive release of carbon atoms into the melt pool. The interfaces and boundaries between WC and Ti matrix were investigated by electron microscopy study. Compared with single crystal WCp, cast WCp was an appropriate solution to control the reaction products (TiC) in the matrix and the total amount of reaction products was significantly reduced. Irregular-shape reaction layers were formed around cast WCp. The reaction layers consist of a W2C layer and a mixed layer of W and TiC. Such reaction layers are effective in load transfer under an external load.

  4. Anabolic action of parathyroid hormone (PTH) does not compromise bone matrix mineral composition or maturation.

    Science.gov (United States)

    Vrahnas, Christina; Pearson, Thomas A; Brunt, Athena R; Forwood, Mark R; Bambery, Keith R; Tobin, Mark J; Martin, T John; Sims, Natalie A

    2016-12-01

    Intermittent administration of parathyroid hormone (PTH) is used to stimulate bone formation in patients with osteoporosis. A reduction in the degree of matrix mineralisation has been reported during treatment, which may reflect either production of undermineralised matrix or a greater proportion of new matrix within the bone samples assessed. To explore these alternatives, high resolution synchrotron-based Fourier Transform Infrared Microspectroscopy (sFTIRM) coupled with calcein labelling was used in a region of non-remodelling cortical bone to determine bone composition during anabolic PTH treatment compared with region-matched samples from controls. 8week old male C57BL/6 mice were treated with vehicle or 50μg/kg PTH, 5 times/week for 4weeks (n=7-9/group). Histomorphometry confirmed greater trabecular and periosteal bone formation and 3-point bending tests confirmed greater femoral strength in PTH-treated mice. Dual calcein labels were used to match bone regions by time-since-mineralisation (bone age) and composition was measured by sFTIRM in six 15μm 2 regions at increasing depth perpendicular to the most immature bone on the medial periosteal edge; this allowed in situ measurement of progressive changes in bone matrix during its maturation. The sFTIRM method was validated in vehicle-treated bones where the expected progressive increases in mineral:matrix ratio and collagen crosslink type ratio were detected with increasing bone maturity. We also observed a gradual increase in carbonate content that strongly correlated with an increase in longitudinal stretch of the collagen triple helix (amide I:amide II ratio). PTH treatment did not alter the progressive changes in any of these parameters from the periosteal edge through to the more mature bone. These data provide new information about how the bone matrix matures in situ and confirm that bone deposited during PTH treatment undergoes normal collagen maturation and normal mineral accrual. Copyright © 2016

  5. Heterogeneous nucleation of amorphous alloys on catalytic nanoparticles to produce 2D patterned nanocrystal arrays

    Energy Technology Data Exchange (ETDEWEB)

    Gangopadhyay, A K [Department of Physics, Washington University in St Louis, MO 63130 (United States); Krishna, H [Department of Physics, Washington University in St Louis, MO 63130 (United States); Favazza, C [Department of Physics, Washington University in St Louis, MO 63130 (United States); Miller, C [Center for Materials Innovation, Washington University in St Louis, MO 63130 (United States); Kalyanaraman, R [Department of Physics, Washington University in St Louis, MO 63130 (United States)

    2007-12-05

    Templates are widely used to produce artificial nanostructures. Here, laser-assisted self-organization has been used to form one- and two-dimensional (D) nanoarrays of Cu nanocrystals. Using these nanoarrays as a template, a 2D patterned ferromagnetic nanostructure of FeCrSi nanocrystals has been produced by heterogeneous nucleation and growth of nanocrystals by partial devitrification from an amorphous Fe{sub 64.5}Cr{sub 10}Si{sub 13.5}B{sub 9}Nb{sub 3} alloy with the Cu nanoparticles acting as catalytic nucleation sites. The interaction among the ferromagnetic nanocrystals via the residual amorphous matrix can be controlled by suitable choice of the amorphous alloy composition. Although demonstrated for a ferromagnetic system, the processing method may have much wider applicability for producing artificial nanostructures of a wide variety of materials when materials-specific catalysts and amorphous alloy compositions are judiciously chosen.

  6. Heterogeneous nucleation of amorphous alloys on catalytic nanoparticles to produce 2D patterned nanocrystal arrays

    International Nuclear Information System (INIS)

    Gangopadhyay, A K; Krishna, H; Favazza, C; Miller, C; Kalyanaraman, R

    2007-01-01

    Templates are widely used to produce artificial nanostructures. Here, laser-assisted self-organization has been used to form one- and two-dimensional (D) nanoarrays of Cu nanocrystals. Using these nanoarrays as a template, a 2D patterned ferromagnetic nanostructure of FeCrSi nanocrystals has been produced by heterogeneous nucleation and growth of nanocrystals by partial devitrification from an amorphous Fe 64.5 Cr 10 Si 13.5 B 9 Nb 3 alloy with the Cu nanoparticles acting as catalytic nucleation sites. The interaction among the ferromagnetic nanocrystals via the residual amorphous matrix can be controlled by suitable choice of the amorphous alloy composition. Although demonstrated for a ferromagnetic system, the processing method may have much wider applicability for producing artificial nanostructures of a wide variety of materials when materials-specific catalysts and amorphous alloy compositions are judiciously chosen

  7. Fabrication of in-situ grown graphene reinforced Cu matrix composites

    Science.gov (United States)

    Chen, Yakun; Zhang, Xiang; Liu, Enzuo; He, Chunnian; Shi, Chunsheng; Li, Jiajun; Nash, Philip; Zhao, Naiqin

    2016-01-01

    Graphene/Cu composites were fabricated through a graphene in-situ grown approach, which involved ball-milling of Cu powders with PMMA as solid carbon source, in-situ growth of graphene on flaky Cu powders and vacuum hot-press sintering. SEM and TEM characterization results indicated that graphene in-situ grown on Cu powders guaranteed a homogeneous dispersion and a good combination between graphene and Cu matrix, as well as the intact structure of graphene, which was beneficial to its strengthening effect. The yield strength of 244 MPa and tensile strength of 274 MPa were achieved in the composite with 0.95 wt.% graphene, which were separately 177% and 27.4% enhancement over pure Cu. Strengthening effect of in-situ grown graphene in the matrix was contributed to load transfer and dislocation strengthening. PMID:26763313

  8. AlN nanoparticle-reinforced nanocrystalline Al matrix composites: Fabrication and mechanical properties

    International Nuclear Information System (INIS)

    Liu, Y.Q.; Cong, H.T.; Wang, W.; Sun, C.H.; Cheng, H.M.

    2009-01-01

    To improve the specific strength and stiffness of Al-based composites, AlN/Al nanoparticles were in-situ synthesized by arc plasma evaporation of Al in nitrogen atmosphere and consolidated by hot-pressing to fabricate AlN nanoparticle-reinforced nanocrystalline Al composites (0-39 vol.% AlN). Microstructure characterization shows that AlN nanoparticles homogeneously distribute in the matrix of Al nanocrystalline, which forms atomically bonded interfaces of AlN/Al. The hardness and the elastic modulus of the nanocomposite have been improved dramatically, up to 3.48 GPa and 142 GPa, respectively. Such improvement is believed to result from the grain refinement strengthening and the interface strengthening (load transfer) between the Al matrix and AlN nanoparticles

  9. High power X-ray welding of metal-matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, Richard A.; Goeppner, George A.; Noonan, John R.; Farrell, William J.; Ma, Qing

    1997-12-01

    A method for joining metal-matrix composites (MMCs) by using high power x-rays as a volumetric heat source is provided. The method involves directing an x-ray to the weld line between two adjacent MMCs materials to create an irradiated region or melt zone. The x-rays have a power density greater than about 10{sup 4} watts/cm{sup 2} and provide the volumetric heat required to join the MMC materials. Importantly, the reinforcing material of the metal-matrix composites remains uniformly distributed in the melt zone, and the strength of the MMCs are not diminished. In an alternate embodiment, high power x-rays are used to provide the volumetric heat required to weld metal elements, including metal elements comprised of metal alloys. In an alternate embodiment, high power x-rays are used to provide the volumetric heat required to weld metal elements, including metal elements comprised of metal alloys.

  10. Performance of Plain Woven Jute Fabric-Reinforced Polyester Matrix Composite in Multilayered Ballistic System

    Directory of Open Access Journals (Sweden)

    Sergio Neves Monteiro

    2018-02-01

    Full Text Available The ballistic performance of plain woven jute fabric-reinforced polyester matrix composites was investigated as the second layer in a multilayered armor system (MAS. Volume fractions of jute fabric, up to 30 vol %, were mixed with orthophthalic polyester to fabricate laminate composites. Ballistic tests were conducted using high velocity 7.62 mm ammunition. The depth of penetration caused by the bullet in a block of clay witness, simulating a human body, was used to evaluate the MAS ballistic performance according to the international standard. The fractured materials after tests were analyzed by scanning electron microscopy (SEM. The results indicated that jute fabric composites present a performance similar to that of the much stronger Kevlar™, which is an aramid fabric laminate, as MAS second layer with the same thickness. The mechanism of this similar ballistic behavior as well as the comparative advantages of the jute fabric composites over the Kevlar™ are discussed.

  11. Effects of mold geometry on fiber orientation of powder injection molded metal matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Faiz, E-mail: faizahmad@petronas.com.my; Aslam, Muhammad, E-mail: klaira73@gmail.com; Altaf, Khurram, E-mail: khurram.altaf@petronas.com.my; Shirazi, Irfan, E-mail: irfanshirazi@hotmail.com [Mechanical Engineering Universiti Teknologi PETRONAS Malaysia (Malaysia)

    2015-07-22

    Fiber orientations in metal matrix composites have significant effect on improving tensile properties. Control of fiber orientations in metal injection molded metal composites is a difficult task. In this study, two mold cavities of dimensions 6x6x90 mm and 10x20x180 mm were used for comparison of fiber orientation in injection molded metal composites test parts. In both mold cavities, convergent and divergent flows were developed by modifying the sprue dimensions. Scanning electron microscope (SEM) was used to examine the fiber orientations within the test samples. The results showed highly aligned fiber in injection molded test bars developed from the convergent melt flow. Random orientation of fibers was noted in the composites test bars produced from divergent melt flow.

  12. Friction and wear behavior of TiC particle reinforced ZA43 matrix composites

    Institute of Scientific and Technical Information of China (English)

    谢贤清; 张荻; 刘金水; 吴人洁

    2001-01-01

    TiC/ZA43 composites were fabricated by XDTM and stirring-casting techniques. The tribology properties of the unreinforced ZA43 alloy and the composites were studied by using a block-on-ring apparatus. Experimental results show that the incorporation of TiC particles improves the microstructure of ZA43 matrix alloy. The coefficient of friction μ and the width of worn groove decrease with the increase of TiC volume fraction φ(TiC). The width of worn groove and μ of the composite during wear testing increase with increasing the applied load. Metallographic examinations reveal that unreinforced ZA43 alloy has deep ploughing grooves with obvious adhesion phenomenon, whereas TiC/ZA43 composites have smooth worn surface. Delamination formation is related to the fatigue cracks and the shear cracks on the surface.

  13. Graphene-reinforced aluminum matrix composites prepared by spark plasma sintering

    Institute of Scientific and Technical Information of China (English)

    Wen-ming Tian; Song-mei Li; Bo Wang; Xin Chen; Jian-hua Liu; Mei Yu

    2016-01-01

    Graphene-reinforced 7055 aluminum alloy composites with different contents of graphene were prepared by spark plasma sinter-ing (SPS). The structure and mechanical properties of the composites were investigated. Testing results show that the hardness, compressive strength, and yield strength of the composites are improved with the addition of 1wt% graphene. A clean, strong interface is formed between the metal matrix and graphene via metallurgical bonding on atomic scale. Harmful aluminum carbide (Al4C3) is not formed during SPS processing. Further addition of graphene (above 1wt%) results in the deterioration in mechanical properties of the composites. The agglomeration of graphene plates is exacerbated with increasing graphene content, which is the main reason for this deterioration.

  14. Tensile strength of ramie yarn (spinning by machine)/HDPE thermoplastic matrix composites

    International Nuclear Information System (INIS)

    Banowati, Lies; Hadi, Bambang K.; Suratman, Rochim; Faza, Aulia

    2016-01-01

    Technological developments should be trooped to prevent a gap between technology and environmental sustainability, then it needs to be developed “Green technology”. In this research is making of green composites which use natural fiber ramie as reinforcement. Whereas the matrix used was HDPE (High Density Polyethylene) thermoplastic polymer which could be recycled and had a good formability and flexibility. The ramie yarns and fibers for unidirectional (0°) direction respectively were mixed with HDPE powder and processed using hot compression molding. The surface morphology was observed by SEM (Scanning Electrone Microscopy). Results showed that both tensile strength of the ramie fiber/HDPE composites increased in comparison with the ramie yarn (spinning by machine)/HDPE composites. However, the ramie yarn (spinning by machine)/HDPE composites have a good producibility for wider application. Analysis of the test results using the Weibull distribution as approaches to modeling the reliability of the specimens.

  15. Tensile strength of ramie yarn (spinning by machine)/HDPE thermoplastic matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Banowati, Lies, E-mail: liesbano@gmail.com; Hadi, Bambang K., E-mail: bkhadi@ae.itb.ac.id; Suratman, Rochim, E-mail: rochim@material.itb.ac.id; Faza, Aulia [Faculty of Mechanical and Aerospace Engineering, Bandung Institute of Technology, Indonesia Jl. Ganesha 10, Bandung (Indonesia)

    2016-03-29

    Technological developments should be trooped to prevent a gap between technology and environmental sustainability, then it needs to be developed “Green technology”. In this research is making of green composites which use natural fiber ramie as reinforcement. Whereas the matrix used was HDPE (High Density Polyethylene) thermoplastic polymer which could be recycled and had a good formability and flexibility. The ramie yarns and fibers for unidirectional (0°) direction respectively were mixed with HDPE powder and processed using hot compression molding. The surface morphology was observed by SEM (Scanning Electrone Microscopy). Results showed that both tensile strength of the ramie fiber/HDPE composites increased in comparison with the ramie yarn (spinning by machine)/HDPE composites. However, the ramie yarn (spinning by machine)/HDPE composites have a good producibility for wider application. Analysis of the test results using the Weibull distribution as approaches to modeling the reliability of the specimens.

  16. Determination of Dispersion Curves for Composite Materials with the Use of Stiffness Matrix Method

    Directory of Open Access Journals (Sweden)

    Barski Marek

    2017-06-01

    Full Text Available Elastic waves used in Structural Health Monitoring systems have strongly dispersive character. Therefore it is necessary to determine the appropriate dispersion curves in order to proper interpretation of a received dynamic response of an analyzed structure. The shape of dispersion curves as well as number of wave modes depends on mechanical properties of layers and frequency of an excited signal. In the current work, the relatively new approach is utilized, namely stiffness matrix method. In contrast to transfer matrix method or global matrix method, this algorithm is considered as numerically unconditionally stable and as effective as transfer matrix approach. However, it will be demonstrated that in the case of hybrid composites, where mechanical properties of particular layers differ significantly, obtaining results could be difficult. The theoretical relationships are presented for the composite plate of arbitrary stacking sequence and arbitrary direction of elastic waves propagation. As a numerical example, the dispersion curves are estimated for the lamina, which is made of carbon fibers and epoxy resin. It is assumed that elastic waves travel in the parallel, perpendicular and arbitrary direction to the fibers in lamina. Next, the dispersion curves are determined for the following laminate [0°, 90°, 0°, 90°, 0°, 90°, 0°, 90°] and hybrid [Al, 90°, 0°, 90°, 0°, 90°, 0°], where Al is the aluminum alloy PA38 and the rest of layers are made of carbon fibers and epoxy resin.

  17. Kevlar/PMR-15 polyimide matrix composite for a complex shaped DC-9 drag reduction fairing

    Science.gov (United States)

    Kawai, R. T.; Mccarthy, R. F.; Willer, M. S.; Hrach, F. J.

    1982-01-01

    The Aircraft Energy Efficiency (ACEE) Program was established by NASA to improve the fuel efficiency of commercial transport aircraft and thereby to reduce the amount of fuel consumed by the air transportation industry. One of the final items developed by the program is an improved fairing which is the aft closure for the thrust reverser actuators on the JT8D nacelles on DC-9 aircraft. The reduced-drag fairing uses, in the interest of weight savings, an advanced composite construction. The composite material contains Kevlar 49 fibers in a PMR-15 matrix. Attention is given to the aerodynamic configuration, the material system, and aspects of fabrication development.

  18. Mechanical properties of unidirectional and randomly oriented kenaf bast fibre composites using polypropylene resin matrix

    International Nuclear Information System (INIS)

    Sharifah Hanisah Syed Abd Aziz; Khairul Zaman Mohd Dahlan

    2004-01-01

    Fibres are known to confer strength and rigidity to the weak and brittle matrix and currently, research in composite materials is being directed at using natural fibers instead of synthetic fibres. In this work long and random kenaf fibers were used in the as-received condition and alkalized with a 0.06M NaOH solution. They were combined with polypropylene thin sheets and hot-pressed to form natural fibre composites. The mechanical properties of the composites were investigated to observe the effect of fibre alignment, fibre treatment, and the method of moulding technique used. A general trend was observed whereby alkalized and long fibre composites give higher flexural modulus and flexural strength compared with random mat and untreated fibres. The long fibre composites also gave a higher work of fracture. However, the correlation between fibre surface treatment and the work of fracture was less clear. The method of moulding used also need to be improved to optimize the performance of the composites manufactured as the overall mechanical test result showed some irregularities. Pre-irradiation on the polypropylene pellets before the composite is manufactured will be considered as one of the mechanism in enhancing the mechanical performance of the composites in future work. (Author)

  19. Matrix composition effects on the tensile properties of tungsten-molybdenum heavy alloys

    International Nuclear Information System (INIS)

    Bose, A.; German, R.N.

    1990-01-01

    Tungsten-base heavy alloys are liquid-phase sintered from mixed tungsten, nickel, and iron powders. The sintered product is a composite consisting of interlaced tungsten and solidified matrix (W-Ni-Fe) phases. These alloys are most useful in applications requiring high density, strength, and toughness. The design of improved tungsten heavy alloys has been the subject of several research investigations. Much success has taken place through improved processing, but parallel compositional studies have resulted in new microstructure-property combinations. As part of these investigations, the Ni/Fe ratio has been varied, with the general conclusion that optimal strength and ductility occur with a ratio between 2 and 4. Brittle intermetallic phases can form outside of this composition range. Historically, a 7/3 Ni/Fe ratio has been selected for processing studies. Recently, others reported higher ductilities and impact energies for 90 and 93 pct W heavy alloys with the 8/2 Ni/Fe ratio. Alternatively, these alloys can be strengthened by both solid solution and grain size refinement through incorporation of molybdenum, tantalum, or rhenium. These additions are soluble in both the tungsten and matrix phases and retard solution-reprecipitation during liquid phase sintering. In this study, the alloy composition was varied in the nickel/iron ratio and molybdenum was partially substituted for tungsten. The sintered tensile properties are assessed vs these compositional variations

  20. Die-cast heterophase composites with AlSi13Mg1CuNi matrix

    Directory of Open Access Journals (Sweden)

    M. Dyzia

    2010-01-01

    Full Text Available On the basis of the performed tests, an advantageous interaction of glassy carbon particles in a couple consisting of a heterophase composite and a spheroidal cast iron has been corroborated. It was found that, the presence of glassy carbon in the heterophase composite (SiC+C affects the stabilization of the friction coefficient value as a function of the friction distance and reduces the intensity of the wearing-in stage of the interacting surfaces. Both a decrease of the friction coefficient and the wear of the heterophase composites may be connected with the carbon particles' chipping effect and the deposition of its fragments on the surface of the interacting components of the friction couple, which forms a kind of a solid lubricating agent in the system. This should allow applying of this material to the composite piston - cylinder sleeve system in piston air-compressors. Further works will concern the selection of the matrix alloy composition with the purpose of reducing the phenomenon of particles chipping during machining. It seems that one of the possibilities is the application of a more plastic matrix and optimizing the fraction of reinforcing phases and their gradient distribution in the casting.

  1. The Effect of Stochastically Varying Creep Parameters on Residual Stresses in Ceramic Matrix Composites

    Science.gov (United States)

    Pineda, Evan J.; Mital, Subodh K.; Bednarcyk, Brett A.; Arnold, Steven M.

    2015-01-01

    Constituent properties, along with volume fraction, have a first order effect on the microscale fields within a composite material and influence the macroscopic response. Therefore, there is a need to assess the significance of stochastic variation in the constituent properties of composites at the higher scales. The effect of variability in the parameters controlling the time-dependent behavior, in a unidirectional SCS-6 SiC fiber-reinforced RBSN matrix composite lamina, on the residual stresses induced during processing is investigated numerically. The generalized method of cells micromechanics theory is utilized to model the ceramic matrix composite lamina using a repeating unit cell. The primary creep phases of the constituents are approximated using a Norton-Bailey, steady state, power law creep model. The effect of residual stresses on the proportional limit stress and strain to failure of the composite is demonstrated. Monte Carlo simulations were conducted using a normal distribution for the power law parameters and the resulting residual stress distributions were predicted.

  2. Processing and Material Characterization of Continuous Basalt Fiber Reinforced Ceramic Matrix Composites Using Polymer Derived Ceramics.

    Science.gov (United States)

    Cox, Sarah B.

    2014-01-01

    The need for high performance vehicles in the aerospace industry requires materials which can withstand high loads and high temperatures. New developments in launch pads and infrastructure must also be made to handle this intense environment with lightweight, reusable, structural materials. By using more functional materials, better performance can be seen in the launch environment, and launch vehicle designs which have not been previously used can be considered. The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Polymer matrix composites can be used for temperatures up to 260C. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in the composites. In this study, continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. The oxyacetylene torch testing and three point bend testing have been performed on test panels and the test results are presented.

  3. Modelling of high temperature interfacial reactions in continuously reinforced Ti/SiC metal matrix composites (MMCs)

    International Nuclear Information System (INIS)

    Fox, K.M.

    1993-01-01

    Previous experimental work by Gundel and Wawner showed that the matrix alloy has a strong effect on reaction layer growth in Ti alloy/SCS-6 composite systems. A finite difference technique was used to model the reaction layer growth, which predicts the same trends as those exhibited by the experimental data. Matrix alloying elements such as Mo and Cr in metastable β alloys will affect the equilibrium compositions and diffusivities in the matrix, but matrix diffusion is not found to be rate controlling. Regular solution thermodynamic models indicate that the main affect of matrix composition is in controlling carbon-flux through the reaction layer by altering equilibrium C-TiC-Ti interfacial compositions. (orig.)

  4. Effect of platelet orientation on the properties of alumina platelet zirconia matrix composites

    DEFF Research Database (Denmark)

    Toft Sørensen, O.; Li, W.-Y.

    1996-01-01

    Platelet alignment in Al2O3pl - TZ3YS composites formed by injection moulding, slip casting, and tape casting, has been examined. Mechanical properties have been determined in terms of flexural strength and fracture toughness, with respect to materials formed by different techniques, and to the p...... 220 and 300 degrees C, which is approximately in the same range as for the matrix....

  5. Research Progress in Plasma arc welding of Magnesium Alloys and Magnesium Matrix Composites

    Science.gov (United States)

    Hui, Li; Yang, Zou; Yongbo, Li; Lei, Jiao; Ruijun, Hou

    2017-11-01

    Magnesium alloys and magnesium matrix composites by means of its excellent performance have wide application prospect in electronics, automotive, biotechnology, aerospace field, and welding technology has become a key of restricting its application. This paper describes the welding characteristics of magnesium, the obvious advantages in the application and the domestic and foreign research advance technology of plasma arc welding of magnesium, and summarizes the existing problems and development trends of plasma arc welding technology of magnesium.

  6. Evaluation of a Melt Infiltrated SiC/SiC Ceramic Matrix Composite

    Science.gov (United States)

    2017-12-20

    temperature performance of a state- of-the-art CMC provides evidence that this new class of materials can, or perhaps cannot, meet the harsh...and elevated temperature . This report describes tensile, creep, and fatigue testing procedures and presents the results. 15. SUBJECT TERMS ceramic...matrix composites, creep, dwell fatigue, fatigue, high temperature , melt infiltrated, SiC/SiC 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF

  7. Aging linear viscoelasticity of matrix-inclusion composite materials featuring ellipsoidal inclusions

    OpenAIRE

    LAVERGNE, Francis; SAB, Karam; SANAHUJA, Julien; BORNERT, Michel; TOULEMONDE, Charles

    2016-01-01

    A multi-scale homogenization scheme is proposed to estimate the time-dependent strains of fiber-reinforced concrete. This material is modeled as an aging linear viscoelastic composite material featuring ellipsoidal inclusions embedded in a viscoelastic cementitious matrix characterized by a time-dependent Poisson's ratio. To this end, the homogenization scheme proposed in Lavergne et al. [1] is adapted to the case of a time-dependent Poisson's ratio and it is successfully validated on a non-a...

  8. Analytical Modeling of the High Strain Rate Deformation of Polymer Matrix Composites

    Science.gov (United States)

    Goldberg, Robert K.; Roberts, Gary D.; Gilat, Amos

    2003-01-01

    The results presented here are part of an ongoing research program to develop strain rate dependent deformation and failure models for the analysis of polymer matrix composites subject to high strain rate impact loads. State variable constitutive equations originally developed for metals have been modified in order to model the nonlinear, strain rate dependent deformation of polymeric matrix materials. To account for the effects of hydrostatic stresses, which are significant in polymers, the classical 5 plasticity theory definitions of effective stress and effective plastic strain are modified by applying variations of the Drucker-Prager yield criterion. To verify the revised formulation, the shear and tensile deformation of a representative toughened epoxy is analyzed across a wide range of strain rates (from quasi-static to high strain rates) and the results are compared to experimentally obtained values. For the analyzed polymers, both the tensile and shear stress-strain curves computed using the analytical model correlate well with values obtained through experimental tests. The polymer constitutive equations are implemented within a strength of materials based micromechanics method to predict the nonlinear, strain rate dependent deformation of polymer matrix composites. In the micromechanics, the unit cell is divided up into a number of independently analyzed slices, and laminate theory is then applied to obtain the effective deformation of the unit cell. The composite mechanics are verified by analyzing the deformation of a representative polymer matrix composite (composed using the representative polymer analyzed for the correlation of the polymer constitutive equations) for several fiber orientation angles across a variety of strain rates. The computed values compare favorably to experimentally obtained results.

  9. Electrodeposition of Metal Matrix Composites and Materials Characterization for Thin-Film Solar Cells

    Science.gov (United States)

    2017-12-04

    Air Mass CNT Carbon Nanotubes DIV Dark Current -Voltage DMA Dynamic Mechanical Analysis EL Electroluminescence FEM Finite Element Method IMM...AFRL-RV-PS- AFRL-RV-PS- TR-2017-0174 TR-2017-0174 ELECTRODEPOSITION OF METAL MATRIX COMPOSITES AND MATERIALS CHARACTERIZATION FOR THIN-FILM SOLAR...research which is exempt from public affairs security and policy review in accordance with AFI 61-201, paragraph 2.3.5.1. This report is available to

  10. Effect of oxidation at elevated temperature on elastic and interface properties of ceramic matrix composites

    Czech Academy of Sciences Publication Activity Database

    Brandstetter, J.; Glogar, Petr; Loidl, D.; Kromp, K.

    2005-01-01

    Roč. 290, - (2005), s. 340-343 ISSN 1013-9826. [International conference on fractography of advanced ceramics /2./. Stará Lesná, 03.10.2005-06.10.2005] R&D Projects: GA AV ČR(CZ) KSK2067107 Institutional research plan: CEZ:AV0Z30460519 Keywords : polysiloxane * ceramic matrix composite * shear modulus Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 0.224, year: 2005

  11. The extracellular matrix: Structure, composition, age-related differences, tools for analysis and applications for tissue engineering.

    Science.gov (United States)

    Kular, Jaspreet K; Basu, Shouvik; Sharma, Ram I

    2014-01-01

    The extracellular matrix is a structural support network made up of diverse proteins, sugars and other components. It influences a wide number of cellular processes including migration, wound healing and differentiation, all of which is of particular interest to researchers in the field of tissue engineering. Understanding the composition and structure of the extracellular matrix will aid in exploring the ways the extracellular matrix can be utilised in tissue engineering applications especially as a scaffold. This review summarises the current knowledge of the composition, structure and functions of the extracellular matrix and introduces the effect of ageing on extracellular matrix remodelling and its contribution to cellular functions. Additionally, the current analytical technologies to study the extracellular matrix and extracellular matrix-related cellular processes are also reviewed.

  12. Fatigue of a 3D Orthogonal Non-crimp Woven Polymer Matrix Composite at Elevated Temperature

    Science.gov (United States)

    Wilkinson, M. P.; Ruggles-Wrenn, M. B.

    2017-12-01

    Tension-tension fatigue behavior of two polymer matrix composites (PMCs) was studied at elevated temperature. The two PMCs consist of the NRPE polyimide matrix reinforced with carbon fibers, but have different fiber architectures: the 3D PMC is a singly-ply non-crimp 3D orthogonal weave composite and the 2D PMC, a laminated composite reinforced with 15 plies of an eight harness satin weave (8HSW) fabric. In order to assess the performance and suitability of the two composites for use in aerospace components designed to contain high-temperature environments, mechanical tests were performed under temperature conditions simulating the actual operating conditions. In all elevated temperature tests performed in this work, one side of the test specimen was at 329 °C while the other side was open to ambient laboratory air. The tensile stress-strain behavior of the two composites was investigated and the tensile properties measured for both on-axis (0/90) and off-axis (±45) fiber orientations. Elevated temperature had little effect on the on-axis tensile properties of the two composites. The off-axis tensile strength of both PMCs decreased slightly at elevated temperature. Tension-tension fatigue tests were conducted at elevated temperature at a frequency of 1.0 Hz with a ratio of minimum stress to maximum stress of R = 0.05. Fatigue run-out was defined as 2 × 105 cycles. Both strain accumulation and modulus evolution during cycling were analyzed for each fatigue test. The laminated 2D PMC exhibited better fatigue resistance than the 3D composite. Specimens that achieved fatigue run-out were subjected to tensile tests to failure to characterize the retained tensile properties. Post-test examination under optical microscope revealed severe delamination in the laminated 2D PMC. The non-crimp 3D orthogonal weave composite offered improved delamination resistance.

  13. Direct observation of toughening mechanisms in carbon nanotube ceramic matrix composites

    International Nuclear Information System (INIS)

    Xia, Z.; Riester, L.; Curtin, W.A.; Li, H.; Sheldon, B.W.; Liang, J.; Chang, B.; Xu, J.M.

    2004-01-01

    The excellent mechanical properties of carbon nanotubes (CNTS) are driving research into the creation of new strong, tough nanocomposite systems. Here, the first evidence of toughening mechanisms operating in carbon-nanotube-reinforced ceramic composites is presented. A highly ordered array of parallel multiwall CNTs in an alumina matrix was fabricated. Nanoindentation introduced controlled cracks and the damage was examined by scanning electron microscopy. These nanocomposites exhibit the three hallmarks of toughening found in micron-scale fiber composites: crack deflection at the CNT/matrix interface; crack bridging by CNTs; and CNT pullout on the fracture surfaces. Interface debonding and sliding can thus occur in materials with microstructures approaching the atomic scale. Furthermore, for certain geometries a new mechanism of nanotube collapse in 'shear bands' occurs, rather than crack formation, suggesting that these materials can have multiaxial damage tolerance. The quantitative indentation data and computational models are used to determine the multiwall CNT axial Young's modulus as 200-570 GPa, depending on the nanotube geometry and quality. Three-dimensional FEM analysis indicates that matrix residual stresses on the order of 300 MPa are sustained in these materials without spontaneous cracking, suggesting that residual stress can be used to engineer enhanced performance. These nanoscale ceramic composites thus have potential for toughening and damage tolerance at submicron scales, and so are excellent candidates for wear-resistant coatings

  14. Copper matrix composites as heat sink materials for water-cooled divertor target

    Directory of Open Access Journals (Sweden)

    Jeong-Ha You

    2015-12-01

    Full Text Available According to the recent high heat flux (HHF qualification tests of ITER divertor target mock-ups and the preliminary design studies of DEMO divertor target, the performance of CuCrZr alloy, the baseline heat sink material for DEMO divertor, seems to only marginally cover the envisaged operation regime. The structural integrity of the CuCrZr heat sink was shown to be affected by plastic fatigue at 20 MW/m². The relatively high neutron irradiation dose expected for the DEMO divertor target is another serious concern, as it would cause significant embrittlement below 250 °C or irradiation creep above 350 °C. Hence, an advanced design concept of the divertor target needs to be devised for DEMO in order to enhance the HHF performance so that the structural design criteria are fulfilled for full operation scenarios including slow transients. The biggest potential lies in copper-matrix composite materials for the heat sink. In this article, three promising Cu-matrix composite materials are reviewed in terms of thermal, mechanical and HHF performance as structural heat sink materials. The considered candidates are W particle-reinforced, W wire-reinforced and SiC fiber-reinforced Cu matrix composites. The comprehensive results of recent studies on fabrication technology, design concepts, materials properties and the HHF performance of mock-ups are presented. Limitations and challenges are discussed.

  15. Aroma release in the oral cavity after wine intake is influenced by wine matrix composition.

    Science.gov (United States)

    Esteban-Fernández, Adelaida; Muñoz-González, Carolina; Jiménez-Girón, Ana; Pérez-Jiménez, María; Pozo-Bayón, María Ángeles

    2018-03-15

    The aim of this study has been to investigate if wine matrix composition might influence the interaction between odorants and oral mucosa in the oral cavity during a "wine intake-like" situation. Aroma released after exposing the oral cavity of three individuals to different wines (n=12) previously spiked with six target aromas was followed by an -in vivo intra-oral SPME approach. Results showed a significant effect of wine matrix composition on the intra-oral aroma release of certain odorants. Among the wine matrix parameters, phenolic compounds showed the largest impact. This effect was dependent on their chemical structure. Some phenolic acids (e.g. hippuric, caffeic) were associated to an increase in the intra-oral release of certain odorants (e.g. linalool, β-ionone), while flavonoids showed the opposite effect, decreasing the intra-oral release of aliphatic esters (ethyl hexanoate). This work shows for the first time, the impact of wine composition on oral-mucosa interactions under physiological conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. X-ray tomography investigation of intensive sheared Al–SiC metal matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    De Giovanni, Mario; Warnett, Jason M.; Williams, Mark A. [WMG, University of Warwick, Coventry CV4 7AL (United Kingdom); Haribabu, Nadendla [BCAST, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Srirangam, Prakash, E-mail: p.srirangam@warwick.ac.uk [WMG, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2015-12-15

    X-ray computed tomography (XCT) was used to characterise three dimensional internal structure of Al–SiC metal matrix composites. The alloy composite was prepared by casting method with the application of intensive shearing to uniformly disperse SiC particles in the matrix. Visualisation of SiC clusters as well as porosity distribution were evaluated and compared with non-shearing samples. Results showed that the average particle size as well as agglomerate size is smaller in sheared sample compared to conventional cast samples. Further, it was observed that the volume fraction of porosity was reduced by 50% compared to conventional casting, confirming that the intensive shearing helps in deagglomeration of particle clusters and decrease in porosity of Al–SiC metal matrix composites. - Highlights: • XCT was used to visualise 3D internal structure of Al-SiC MMC. • Al-SiC MMC was prepared by casting with the application of intensive shearing. • SiC particles and porosity distribution were evaluated. • Results show shearing deagglomerates particle clusters and reduces porosity in MMC.

  17. ECAP – New consolidation method for production of aluminium matrix composites with ceramic reinforcement

    Directory of Open Access Journals (Sweden)

    Mateja Šnajdar Musa

    2013-06-01

    Full Text Available Aluminium based metal matrix composites are rapidly developing group of materials due to their unique combination of properties that include low weight, elevated strength, improved wear and corrosion resistance and relatively good ductility. This combination of properties is a result of mixing two groups of materials with rather different properties with aluminium as ductile matrix and different oxides and carbides added as reinforcement. Al2O3, SiC and ZrO2 are the most popular choices of reinforcement material. One of the most common methods for producing this type of metal matrix composites is powder metallurgy since it has many variations and also is relatively low-cost method. Many different techniques of compacting aluminium and ceramic powders have been previously investigated. Among those techniques equal channel angular pressing (ECAP stands out due to its beneficial influence on the main problem that arises during powder compaction and that is a non-uniform distribution of reinforcement particles. This paper gives an overview on ECAP method principles, advantages and produced powder composite properties.

  18. Damping mathematical modelling and dynamic responses for FRP laminated composite plates with polymer matrix

    Directory of Open Access Journals (Sweden)

    Liu Qimao

    2018-02-01

    Full Text Available This paper proposes an assumption that the fibre is elastic material and polymer matrix is viscoelastic material so that the energy dissipation depends only on the polymer matrix in dynamic response process. The damping force vectors in frequency and time domains, of FRP (Fibre-Reinforced Polymer matrix laminated composite plates, are derived based on this assumption. The governing equations of FRP laminated composite plates are formulated in both frequency and time domains. The direct inversion method and direct time integration method for nonviscously damped systems are employed to solve the governing equations and achieve the dynamic responses in frequency and time domains, respectively. The computational procedure is given in detail. Finally, dynamic responses (frequency responses with nonzero and zero initial conditions, free vibration, forced vibrations with nonzero and zero initial conditions of a FRP laminated composite plate are computed using the proposed methodology. The proposed methodology in this paper is easy to be inserted into the commercial finite element analysis software. The proposed assumption, based on the theory of material mechanics, needs to be further proved by experiment technique in the future.

  19. Damping mathematical modelling and dynamic responses for FRP laminated composite plates with polymer matrix

    Science.gov (United States)

    Liu, Qimao

    2018-02-01

    This paper proposes an assumption that the fibre is elastic material and polymer matrix is viscoelastic material so that the energy dissipation depends only on the polymer matrix in dynamic response process. The damping force vectors in frequency and time domains, of FRP (Fibre-Reinforced Polymer matrix) laminated composite plates, are derived based on this assumption. The governing equations of FRP laminated composite plates are formulated in both frequency and time domains. The direct inversion method and direct time integration method for nonviscously damped systems are employed to solve the governing equations and achieve the dynamic responses in frequency and time domains, respectively. The computational procedure is given in detail. Finally, dynamic responses (frequency responses with nonzero and zero initial conditions, free vibration, forced vibrations with nonzero and zero initial conditions) of a FRP laminated composite plate are computed using the proposed methodology. The proposed methodology in this paper is easy to be inserted into the commercial finite element analysis software. The proposed assumption, based on the theory of material mechanics, needs to be further proved by experiment technique in the future.

  20. Role of manufacturing process parameters on the characteristics of aluminum matrix composites

    International Nuclear Information System (INIS)

    Zaid, A.I.O.

    2003-01-01

    Metal matrix composites, (MMC), are engineered combinations of two or more materials (one of which is a metal) in which tailored properties are achieved by systematic combinations consisting of continuous or discontinuous fibers, whiskers, or particles in a metal result in combinations of very high specific strength. Furthermore, systematic design and procedures can be developed to achieve unique combinations of engineering properties such as high elevated-temperature strengths, damping or electrical properties. In this paper, the theory and practice of MMC are reviewed and discussed. The different techniques used in the manufacturing of MMC in general and aluminum matrix composites in particular e.g. unidirectional solidification, squeeze casting, vortex method and compocasting are presented and discussed. The parameters involved in these techniques and their effects on the characteristics of MMC product are also given and discussed. These include: crucible size and shape, melt temperature, size and shape of the impeller, stirring speed, rate of addition of the particles, the degree of agitation and cooling rate. Furthermore, the effect of these parameters on the mechanical strength and machinability are also presented and discussed. Finally, recent research results in aluminum matrix composites and their future developments are outlined and discussed. (author)