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Sample records for aluminium matrix composites

  1. Aluminium matrix composites fabricated by infiltration method

    OpenAIRE

    L.A. Dobrzański; M. Kremzer; A. J. Nowak; Nagel, A.

    2009-01-01

    Purpose: The aim of this work is to examine the structure and properties of metal matrix composites obtained by infiltration method of porous ceramic preforms by liquid aluminium alloy.Design/methodology/approach: Ceramic preforms were manufactured by the sintering method of ceramic powder. The preform material consists of powder Condea Al2O3 CL 2500, however, as the pore forming the carbon fibers Sigrafil C10 M250 UNS were used. Then ceramic preforms were infiltrated with liquid eutectic EN ...

  2. Aluminium matrix composites: Challenges and opportunities

    Indian Academy of Sciences (India)

    M K Surappa

    2003-02-01

    Aluminium matrix composites (AMCs) refer to the class of light weight high performance aluminium centric material systems. The reinforcement in AMCs could be in the form of continuous/discontinuous fibres, whisker or particulates, in volume fractions ranging from a few percent to 70%. Properties of AMCs can be tailored to the demands of different industrial applications by suitable combinations of matrix, reinforcement and processing route. Presently several grades of AMCs are manufactured by different routes. Three decades of intensive research have provided a wealth of new scientific knowledge on the intrinsic and extrinsic effects of ceramic reinforcement vis-a-vis physical, mechanical, thermo-mechanical and tribological properties of AMCs. In the last few years, AMCs have been utilised in high-tech structural and functional applications including aerospace, defence, automotive, and thermal management areas, as well as in sports and recreation. It is interesting to note that research on particle-reinforced cast AMCs took root in India during the 70’s, attained industrial maturity in the developed world and is currently in the process of joining the mainstream of materials. This paper presents an overview of AMC material systems on aspects relating to processing, microstructure, properties and applications.

  3. Low cost aluminium metal matrix composite

    Energy Technology Data Exchange (ETDEWEB)

    Withers, G.

    2007-03-15

    Low cost, light weight Ultalite{reg_sign} is an Aluminium Metal Matrix Composite (AL-MMC) which utilises wear resistant ceramic particles derived from flyash. Ultalite AL-MMC typically contains between 10 and 30 per cent ceramic particles, and is formulated for the manufacture of wear resistant automotive components. Due to its low density and ease of processing into net shape die casting, Ultalite AL-MMC provides weight savings of up to 60 per cent over components fabricated from cast iron, thereby providing improved fuel efficiency with reduced greenhouse emissions. The original flyash material was sourced from a black coal power station in Queensland, where it contained a wide range of particles sizes. To narrow the size range and to remove impurities, a proprietary pretreatment developed by Dr Thomas Robl and co-researchers at the University of Kentucky was employed. The University of Kentucky developed the technology for the classification and benefaction of flyash to produce high-grade Pozzolan, which is used in Portland Cement product. This technology is now being applied to the production of Ultalite AL-MMC. Testing performed by Dr Robl has shown that the proprietary technology can eliminate the hollow particles, extract detrimental carbon-based impurities and remove the extremely fine and coarse particles. All that remains are dense ceramic particles with an average particle size of approximately 30 {mu}m. 9 refs., 3 figs.

  4. METAL MATRIX COMPOSITES BASED ON ALUMINIUM LITHIUM AND SILICON CARBIDE

    OpenAIRE

    White, J.; Hughes, I; Willis, T.; Jordan, R.

    1987-01-01

    The present study tests the feasibility of producing metal matrix composites based on aluminium-lithium alloys. The first step in this process has been to produce an MMC based on 8090 with SiC. This has been successfully produced by Alcan International using the "Osprey" spray deposition process. The raw billets have been processed initially by extrusion. The tensile properties of this material have been determined and the strength compares favourably with DC cast alloys. Modulus is improved ...

  5. Interface reaction in aluminium matrix composite at laser welding

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Interface reaction of SiCw/6061Al aluminium matrix composite subjected to laser welding was studied. It is pointed out that the main reason for bad weldability of the material is concerned with the interface reaction during the welding. Effects of welding parameters on interface reaction were also investigated. The results show that the interface bonding state can be improved by laser beam, and the main welding parameter affecting the strength of weld is laser output power. The smaller the output power, the lower the extent of interface reaction and the better the mechanical properties.

  6. 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

  7. 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.

  8. Pemanfaatan Limbah Abu Terbang Sebagai Penguat Aluminium Matrix Composite

    Directory of Open Access Journals (Sweden)

    Subarmono Subarmono

    2008-01-01

    Full Text Available This research aims to utilize fly ash which is obtained from waste of combustion of coal in steam power plant as a reinforcement of aluminum matrix composite (AMC. The amounts of fly ash of 2.5%, 5%, 7.5% and 10% wt were added to fine aluminum powder (dimension of particles are smaller than 40 µm. Each composition was mixed using a rotary mixer for 3 hr. The mixture was uniaxially pressed and it was followed by isostatic compaction with a pressure of 100 MPa to produce green bodies. They was pressureless sintered in argon atmosphere at various temperatures of 500°C, 525°C, 550°C, 575°C and 600ºC. Bending strength, Vickers hardness, wear resistance, density of the AMC were tested, and the microstructures were observed using SEM. The results show that the mechanical properties increase with increasing the fly ash content up to 5% wt. The bending strength, hardness, porosity and wear rate are 74 MPa, 66 VHN, 4.5% and 0.04 mg/(MPa.m, respectively. Abstract in Bahasa Indonesia: Penelitian ini bertujuan untuk memanfaatkan abu terbang sebagai penguat komposit bermatrik aluminium (AMC. Abu terbang merupakan limbah pembakaran batu bara pada pembangkit listrik tenaga uap. Abu terbang sejumlah 2,5%; 5%; 7,5% dan 10% berat dicampur dengan serbuk aluminium (ukuran serbuk lebih kesil dari 40 µm. Setiap campuran diaduk menggunakan rotay mixer selama 3 jam. Campuran aluminum dan abu terbang dikompaksi secara uniaksial dilanjutkan kompaksi secara isostatik dengan tekanan 100 MPa dan diikuti sintering tanpa tekanan dengan lingkungan gas argon dan variasi temperatur 500°C, 525°C, 550°C, 575°C dan 600°C. Kekuatan bending, kekerasan Vickers, ketahanan aus dan densitas komposit diuji serta struktur mikro diamati menggunakan SEM. Hasil pengujian menunjukkan bahwa sifat mekanis meningkat seiring dengan peningkatan fraksi berat abu terbang sampai 5% berat, selebihnya terjadi penurunan. Kekuatam bending, kekerasan Vickers, porositas dan laju keausan berturut

  9. Aluminium Matrix Composites Reinforced with Co-continuous Interlaced Phases Aluminium-alumina Needles

    Directory of Open Access Journals (Sweden)

    Elvio de Napole Gregolin

    2002-09-01

    Full Text Available An Al-5SiO2 (5 wt% of SiO2 aluminium matrix fiber composite was produced where the reinforcement consists of fossil silica fibers needles. After being heat-treated at 600 °C, the original fiber morphology was retained but its microstructure changed from solid silica to an interconnected (Al-Si/Al2O3 interlaced structure named co-continuous composite. A technique of powder metallurgy, using commercial aluminium powder and the silica fibers as starting materials, followed by hot extrusion, was used to produce the composite. The co-continuous microstructure was obtained partially or totally on the fibers as a result of the reaction, which occurs during the heat treatment, first by solid diffusion and finally by the liquid Al-Si in local equilibrium, formed with the silicon released by reaction. The internal structure of the fibers was characterized using field emission electron microscope (FEG-SEM and optical microscopy on polished and fractured samples.

  10. Evaluation of mechanical properties of aluminium alloy–alumina–boron carbide metal matrix composites

    International Nuclear Information System (INIS)

    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 (Al2O3) 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)

  11. Preparation of Hybrid Aluminium Metal Matrix Composites by Using Stir Process

    OpenAIRE

    V.Chandramohan*,; R.Arjunraj

    2014-01-01

    Generally aluminiums are used for various applications in industrial sectors and home based products. Metal matrix composites (MMCs) possess significantly improved properties including high specific strength, specific modulus, damping capacity and good wear resistance compared to unreinforced alloys. The objective of the project is to fabricate Al356/Fly ash, Graphite& Boron Carbide metal matrix composite by using stir process and study the properties of the fabricated composite. ...

  12. Influence of Surface Modification of Alumina on Improvement of Wetability in Aluminium Matrix Composite

    Directory of Open Access Journals (Sweden)

    Alireza Samiee

    2014-01-01

    Full Text Available In this research, aluminium powder (50 wt% and alumina (50 wt% were first milled at a specific ball-to-powder ratio in a high-energy planetary mill at different times to manufacture Al-Al2O3 composite. Then, the capsules of powdery composites (Al-Al2O3CP produced at the milling stage were added to aluminium melt and cast through ex situ. Scanning electron microscope SEM was used to study the morphology of the capsules and the microstructure of the produced composite. The percentage of powdery composite capsules and reinforcing particles present in the microstructure of Al-Al2O3 composite was measured by Image Tool software. The results of the tests showed that, by optimizing the milling time to 5 hours, the alumina particles are sufficiently placed in the matrix of the capsules; on the other hand, alumina particles are also properly coated with aluminium powder. When these capsules are added to aluminium melt, the rate of the wetting of alumina particles greatly increases and accordingly the percentage of the reinforcing particles in the cast composite matrix increases dramatically. By surface modification and accordingly increasing percentage of Al2O3, the tensile strength increases and the tensile strength of the composites is higher than that of the matrix alloy.

  13. Powder metallurgy route in production of aluminium alloy matrix particulate composites

    OpenAIRE

    Al-Rashed, A.; Holecek, S.; PrazÁk, M.; Procio, M.

    1993-01-01

    Meta1 matrix composites based on an aluminium alloys were produced by powder metallurgy route, involved unidirectionally hot pressing under 500 MPa for 15 minutes at temperature about 0.95 Ts [Solidus Temperature]. Metal matrix contains different weight percents of SiC, αAl2O3, WC and Si3N4 with different particle size. Wear and mechanical tests have been carried out on composites, and it was found that about 90% of wear reduction occured in composite with 30% SiC compared with pressed matrix.

  14. Application of pressure infiltration to the manufacturing of aluminium matrix composite materials with different reinforcement shape

    OpenAIRE

    L.A. Dobrzański; M. Kremzer; Nagel, A.

    2007-01-01

    Purpose: The purpose of this work is to investigate the influence of reinforcing phase’s shape on structure and properties of composite materials with aluminium alloy matrix.Design/methodology/approach: The material for studies was produced by a method of pressure infiltration of the porous ceramic framework. In order to investigate the influence of reinforcing phase’s shape the comparison was made between the properties of the composite material based on preforms obtained by Al2O3 Alcoa CL...

  15. Manufacturing of aluminium matrix composite materials reinforced by Al2O3 particles

    OpenAIRE

    A. Włodarczyk-Fligier; L.A. Dobrzański; M. Kremzer; M. Adamiak

    2008-01-01

    Purpose: The purpose of the paper is to show and compare of modern method composite materials with aluminium alloy matrix reinforced by Al2O3 particles manufacturing.Design/methodology/approach: Material for investigation was manufactured by two methods: powder metallurgy (consolidation, pressing, hot extrusion of powder mixtures of aluminium EN AW-AlCu4Mg1(A) and ceramic particles Al2O3) and pressure infiltration of porous performs by liquid alloy EN AC AlSi12 (performs were prepared by sint...

  16. Process optimisation and numerical modelling of powder metallurgical aluminium matrix composites

    OpenAIRE

    O'Donnell, Gareth

    1999-01-01

    The present research focuses on optimisation of a novel application of the cold uniaxial pressing and liquid phase sintering powder metallurgical method to the processing of ceramic particulate reinforced aluminium matrix composites and the numerical modelling of these advanced materials. The investigated process areas include material selection, powder mixing and powder heat treatment, lubrication type, quantity and method, compaction and ejection, green sample conditioning, sintering time, ...

  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. Dry Sliding Wear behaviour of Aluminium-Red mud- Tungsten Carbide Hybrid metal matrix composites

    Science.gov (United States)

    Devi Chinta, Neelima; Selvaraj, N.; Mahesh, V.

    2016-09-01

    Red mud is an industrial waste obtained during the processing of alumina by Bayer's process. An attempt has been made to utilize the solid waste by using it as the reinforcement material in metal matrix composites. Red mud received from NALCO has been subjected for sieve analysis and milled to 42 nanometers using high energy ball mill. Red mud is used as a reinforcement material in Pure Aluminium matrix composite at 2%, 4%, and 6% weight at 100 microns level as well as 42 nano meters along with 4%Tungsten carbide by weight. Micro and Nano structured red mud powders, Tungsten carbide powder and Aluminium is mixed in a V-Blender, compacted at a pressure of 40 bar and samples are prepared by conventional sintering with vacuum as medium. In this current work, dry sliding wear characteristics at normal and heat treatment conditions are investigated with optimal combination of Aluminium, Tungsten carbide and different weight fractions of micro and nano structured red mud powder.

  19. Development of a new aluminium matrix composite reinforced with iron oxide (Fe3O4

    Directory of Open Access Journals (Sweden)

    E. Bayraktar

    2010-01-01

    Full Text Available Purpose: of this paper is to develop new aluminium matrix (intermetallic composites reinforced with iron oxide (Fe3O4 that will be used in aeronautical engineering or in electronic industry. Different parameters such as sintering time and temperature, reinforcement, compact pressure were evaluated. The final purpose of this project is going on to improve conductivity and magnetic permeability of this new composite.Design/methodology/approach: In this paper, a new alternative materials “aluminium–iron oxide (Fe3O4, naturally as the mineral magnetite powder composite” has been developed by using a microwave (in the laboratory scale sintering programme with various aspect ratios, that iron oxide (Fe3O4 particle sizes and aluminium powders together were prepared. This paper contains partially preliminary results of our going-on research project.Findings: Green density increased regularly depending on the compact pressure and percentage of the iron oxide (Fe3O4. Micro and macro porosity was not found due to very clean microwave sintering. Density after microwave sintering was higher than that of traditional sintering in an electrical oven.Research limitations/implications: This project is going on and magnetic permeability and conductivity of this composite will be improved.Practical implications: This composite is new and clean and thanks to the new microwave sintering basically will be used in aeronautical engineering. Microwave heating results in lower energy costs and decreased processing times for many industrial processes.Originality/value: Originality of this paper is to use a new reinforcement in the aluminium matrix composite; Fe3O4-iron oxide. A new method - microwave sintering- has been carried out on this composite.

  20. Mechanical alloying for fabrication of aluminium matrix composite powders with Ti-Al intermetallics reinforcement

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    M. Adamiak

    2008-12-01

    Full Text Available Purpose: The aim of this work is to report the effect of the high energy milling processes, on fabrication ofaluminium matrix composite powders, reinforced with a homogeneous dispersion of the intermetallic Ti3Alreinforcing particles.Design/methodology/approach: MA process are considered as a method for producing composite metalpowders with a controlled fine microstructure. It occurs by the repeated fracturing and re-welding of powdersparticles mixture in a highly energetic ball mill.Findings: Mechanical alloying, applied for composite powder fabrication, improves the distribution of theTi3Al intermetallic reinforcing particles throughout the aluminium matrix, simultaneously reducing their size.Observed microstructural changes influence on the mechanical properties of powder particles.Research limitations/implications: Contributes to the knowledge on composite powders production via MA.Practical implications: Gives the answer to evolution of the powder production stages, during mechanicalalloying and theirs final properties.Originality/value: Broadening of the production routes for homogeneous particles reinforced aluminium matrixcomposites.

  1. Aluminium EN AW-2124 alloy matrix composites reinforced with Ti(C,N), BN and Al2O3 particles

    International Nuclear Information System (INIS)

    Investigation results of the aluminium alloy EN AW-2124 matrix composite materials with particles of the powders Ti(C,N), BN and Al2O3 (15 wt.%) are presented in the paper. In order to obtain uniform distribution of reinforcement particles in aluminium alloy matrix powders of composite components have been milled in the rotary ball-bearing pulverizer. The composites have been pressed in laboratory vertical press at room temperature under the pressure of 500 kN. Obtained die samplings have been heated to the temperature 520-550 oC and extruded. Bars of diameter 8 mm have been received as a final product. Metallographic examination of the composites materials' structure shows non-uniform distribution of reinforced powders in the aluminium alloy matrix banding of reinforcements particles corresponds to the extrusion direction. Particles of reinforcement distribution in aluminium alloy matrix is irregular, some agglomerations of powder of aluminium oxide and porosity of different size have been noticed. Investigations of hardness and ultimate compressive strength show that the particles of reinforcement improve mechanical properties of composite materials. Investigations of compressive strength, carried out at room temperature, enable to compare mechanical properties of matrix and composite. (author)

  2. Processing and mechanical properties of aluminium-silicon carbide metal matrix composites

    Science.gov (United States)

    Nuruzzaman, D. M.; Kamaruzaman, F. F. B.

    2016-02-01

    In this study, aluminium-silicon carbide (Al-SiC) metal matrix composites (MMCs) of different compositions were prepared under different compaction loads. Three different types Al-SiC composite specimens having 10%, 20% and 30% volume fractions of silicon carbide were fabricated using conventional powder metallurgy (PM) route. The specimens of different compositions were prepared under different compaction loads 10 ton and 15 ton. The effect of volume fraction of SiC particulates and compaction load on the properties of Al/SiC composites were investigated. The obtained results show that density and hardness of the composites are greatly influenced by volume fraction of silicon carbide particulates. Results also show that density, hardness and microstructure of Al-SiC composites are significantly influenced depending on the compaction load. The increase in the volume fraction of SiC enhances the density and hardness of the Al/SiC composites. For 15 ton compaction load, the composites show increased density and hardness as well as improved microstructure than the composites prepared under 10 ton compaction load. Furthermore, optical micrographs reveal that SiC particulates are uniformly distributed in the Al matrix.

  3. Fatigue behaviour analysis of a range of aluminium matrix composites; Analyse du comportement a la fatigue d'une gamme de composites a matrice aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Couturier, L.; Lieurade, H.P.; FLavenot, J.F. [Centre Technique des Industries Mecaniques (CETIM), Dept. Materiaux, 60 - Senlis (France); Massinon, D. [Montupet SA, Dept. Materiaux, 60 - Nogent sur Oise (France); Lu, J. [Universite de Technologie de Troyes, LASMIS, 10 - Troyes (France)

    2000-07-01

    This paper provides an analysis of aluminium matrix composites (AMC) fatigue behaviour. The fatigue test results obtained in four points bending (R = 0,1) are compared in the medium and high cycles regimes (S-N curves) for five AMC and a non reinforced aluminium alloy. The discussion on the results is mainly based on the fatigue strength levels, the scatter on the results, the endurance ratio, in connection with the rate of defects which initiate crack. This discussion points out that the main sites of crack initiation are defects of elaboration (pores). In fact, manufacturing processes induce defects more or less important, leading to a large variation in the fatigue strength. An analysis of stress intensity factors estimated from the surface flaws leads to a classification of the composite materials in terms of damage tolerance approach. (authors)

  4. Application of pressure infiltration to the manufacturing of aluminium matrix composite materials with different reinforcement shape

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2007-10-01

    Full Text Available Purpose: The purpose of this work is to investigate the influence of reinforcing phase’s shape on structure and properties of composite materials with aluminium alloy matrix.Design/methodology/approach: The material for studies was produced by a method of pressure infiltration of the porous ceramic framework. In order to investigate the influence of reinforcing phase’s shape the comparison was made between the properties of the composite material based on preforms obtained by Al2O3 Alcoa CL 2500 powder sintered with addition of pore forming agent in form of carbon fibres Sigrafil C 10 M250 UNS from Carbon Group company and composite materials based on much more expensive commercial fibrous preforms. The matrix consisted of cast aluminium alloy EN AC – AlSi12. The observations of the structure were made on the light microscope and in the scanning electron microscope. The strength properties were established on the basis of static tensile tests.Findings: The composite materials, obtained on the basis of ceramic preforms consisted of Al2O3 particles, are showing better strength properties in comparison to materials obtained by the fibrous preform infiltration.Practical implications: The composite materials made by the developed method can find application as the elements of devices where beside the benefits from utilizable properties the small weight is required (mainly in aircraft and motorization industries.Originality/value: The obtained results show the possibility of manufacturing the composite materials by the method of porous sintered framework pressure infiltration based on the ceramic particles, characterized with the better properties than similar composites reinforced with fibres.

  5. Aluminium EN AC-AlSi12 alloy matrix composite materials reinforced by Al2O3 porous preforms

    OpenAIRE

    Nagel, A.; M. Kremzer; L.A. Dobrzański,

    2007-01-01

    Purpose: The purpose of this work is to elaborate the method of manufacturing of composite materials based on porous ceramic preforms infiltrated by eutectic aluminium alloy.Design/methodology/approach: The material for investigations was fabricated by pressure infiltration method of ceramic porous preforms. The eutectic aluminium alloy EN AC – AlSi12 was use as a matrix while as reinforcement were used ceramic preforms fabricated by sintering of Al2O3 Alcoa CL 2500 powder with addition of po...

  6. Wear Behavior of Aluminium Metal Matrix Composite Prepared from Industrial Waste

    Directory of Open Access Journals (Sweden)

    L. Francis Xavier

    2016-01-01

    Full Text Available With an increase in the population and industrialization, a lot of valuable natural resources are depleted to prepare and manufacture products. However industrialization on the other hand has waste disposal issues, causing dust and environmental pollution. In this work, Aluminium Metal Matrix Composite is prepared by reinforcing 10 wt% and 20 wt% of wet grinder stone dust particles an industrial waste obtained during processing of quarry rocks which are available in nature. In the composite materials design wear is a very important criterion requiring consideration which ensures the materials reliability in applications where they come in contact with the environment and other surfaces. Dry sliding wear test was carried out using pin-on-disc apparatus on the prepared composites. The results reveal that increasing the reinforcement content from 10 wt% to 20 wt% increases the resistance to wear rate.

  7. Characterization of aluminium matrix composites reinforced by Al–Cu–Fe quasicrystalline particles

    Energy Technology Data Exchange (ETDEWEB)

    Lityńska-Dobrzyńska, L.; Dutkiewicz, J.; Stan-Głowińska, K.; Wajda, W. [Institute of Metallurgy and Materials Science Polish Academy of Sciences, 30-059 Kraków, 25 Reymonta St. (Poland); Dembinski, L.; Langlade, C.; Coddet, C. [Universite de Technologie de Belfort-Montbeliard, Site de Sevenans 90010, Belfort (France)

    2015-09-15

    Highlights: • Al powder and atomised Al{sub 65}Cu{sub 20}Fe{sub 15} powder were consolidated by vacuum hot pressing. • No changes in microstructure of Al{sub 65}Cu{sub 20}Fe{sub 15} powder in 20% and 40% composites. • Al{sub 2}Cu precipitates at the interfaces and inside the matrix in the 60% composite. • Increase of microhardness and compressive strength with content of reinforcement. • The friction coefficient were in the range 0.5–0.7. - Abstract: Aluminium matrix composites were consolidated from elemental Al powder and atomised Al{sub 65}Cu{sub 20}Fe{sub 15} particles by vacuum hot pressing technique. The spherical Al{sub 65}Cu{sub 20}Fe{sub 15} particles consisted of icosahedral quasicrystalline dendrites or cells and cubic τ-AlCu(Fe) phase located in interdendritic areas. The composites with different content of the reinforcement particles (20, 40 and 60 wt%) were prepared. All composites showed density about 99% and a good bonding between the Al{sub 65}Cu{sub 20}Fe{sub 15} particles and the matrix. It was shown that the phase composition of the atomised particles did not change after consolidation for the composite containing 20% and 40% added particles while Al{sub 2}Cu precipitates formed at the Al/Al{sub 65}Cu{sub 20}Fe{sub 15} interfaces and inside the matrix in the composite with 60% of Al{sub 65}Cu{sub 20}Fe{sub 15} particles. With the increase of the volume fraction of the reinforcement in the composite the hardness as well as compressive strength increased reaching the value of 173 HV{sub 0.5} and 370 MPa, respectively for 60% of Al{sub 65}Cu{sub 20}Fe{sub 15} particles. The friction coefficient slightly varied in the range 0.5–0.7 depending on the composition.

  8. Micro/Nanostructure and Tribological Characteristics of Pressureless Sintered Carbon Nanotubes Reinforced Aluminium Matrix Composites

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    P. Manikandan

    2016-01-01

    Full Text Available This study reports the manufacture, microstructure, and tribological behaviour of carbon nanotube reinforced aluminium composites against pure aluminium. The specimens were fabricated using powder metallurgy method. The nanotubes in weight percentages of 0.5, 1.0, 1.5, and 2.0 were homogeneously dispersed and mechanically alloyed using a high energy ball milling. The milled powders were cold compacted and then isothermally sintered in air. The density of all samples was measured using Archimedes method and all had a relative density between 92.22% and 97.74%. Vickers hardness increased with increasing CNT fraction up to 1.5 wt% and then reduced. The microstructures and surfaces were investigated using high resolution scanning electron microscope (SEM. The tribological tests showed that the CNT reinforced composites displayed lower wear rate and friction coefficient compared to the pure aluminium under mild wear conditions. However, for severe wear conditions, the CNT reinforced composites exhibited higher friction coefficient and wear rate compared to the pure aluminium. It was also found that the friction and wear behaviour of CNT reinforced composites is significantly dependent on the applied load and there is a critical load beyond which CNTs could have adverse impact on the wear resistance of aluminium.

  9. Investigations into Deformation Characteristics during Open-Die Forging of SiCp Reinforced Aluminium Metal Matrix Composites

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    Deep Verma

    2013-01-01

    Full Text Available The deformation characteristics during open-die forging of silicon carbide particulate reinforced aluminium metal matrix composites (SiCp AMC at cold conditions are investigated. The material was fabricated by liquid stir casting method in which preheated SiC particles were mixed with molten LM6 aluminium casting alloy and casted in the silicon mould. Finally, preforms obtained were machined in required dimensions. Two separate cases of deformation, that is, open-die forging of solid disc and solid rectangular preforms, were considered. Both upper bound theoretical analysis and experimental investigations were performed followed by finite element simulation using DEFORM, considering composite interfacial friction law, barreling of preform vertical sides, and inertia effects, that is, effect of die velocity on various deformation characteristics like effective stress, strain, strain rate, forging load, energy dissipations, and height reduction. Results have been presented graphically and critically investigated to evaluate the concurrence among theoretical, experimental, and finite element based computational findings.

  10. EVALUATION & COMPARISION OF MECHANICAL PROPERTIES OF ALUMINIUM ALLOY 5052 REINFORCED WITH SILICONCARBIDE, GRAPHITE AND FLY ASH HYBRID METAL MATRIX COMPOSITES

    Directory of Open Access Journals (Sweden)

    ANKUSH SACHDEVA

    2013-10-01

    Full Text Available The engineering fraternity has always been looking forward to develop an outstanding and wonder-materials which would fit the ever-changing demands of the world. In order to fullfill the demands various newdiscoveries have been made by scientists, engineers and resrearchers. In todays competitive world many, materials have been tried for various unexplored conditions , but the never ending demand of the world encourages the researchers to develop the new material. Now the researchers are preparing the material by the combination of different materials called hybrid composite material.. Metal Matrix Composites (MMCs have emerged as a class of materials suitable for structural, aerospace, automotive, electronic, thermal and wearapplications owing to their advantages over the conventional materials. The present study was taken up to explore the possibility of using different reinforcements (silicon carbide, fly ash and graphite to enhance the properties of aluminium alloy (Al5052 composites. Different samples were prepared from the aluminium withvarying reinforcement composition. The mechanical properties studied after the experiment were strength, hardness and elongation.Further, these composites were characterized with the help of, mechanical testing and scanning electron microscopy.

  11. The effect of reinforcement on superplastic flow in powder-metallurgy processed aluminium matrix composites

    International Nuclear Information System (INIS)

    ''Particle weakening'' phenomenon was observed in 2124 Al composites as well as in 6061 Al composites. At high temperatures where superplastic flow controls the plastic flow, composite is weaker than unreinforced matrix alloy even after compensating for grain size and threshold stress. Furthermore, such strength differential between the two materials is temperature dependent, which increases with increasing temperature. This may resulted from the presence of liquid phase at the reinforcement/Al matrix whose amount is expected to increase with increase in temperature. (orig.)

  12. Features of microstructure and fracture in the transient liquid phase bonded aluminium-based metal matrix composite joints

    Institute of Scientific and Technical Information of China (English)

    孙大谦; 刘卫红; 吴建红; 贾树盛; 邱小明

    2002-01-01

    Transient liquid phase (TLP) bonded aluminium-based metal matrix composite (MMC) joints can be classified into three distinct regions, i.e. the particulate segregation region, the denuded particulate region and the base material region. The microstructure of the particulate segregation region consists of alumina particulate and Al alloy matrix with the Al2Cu and MgAl2O4. It contains more and smaller alumina particulates compared with the base material region. The TLP bonded joints have the tensile strength of 150MPa~200MPa and the shear strength of 70MPa~100MPa. With increasing tensile stress, cracks initiate in the particulate segregation region, especially in the particulate/particulate interface and the particulate/matrix interface, and propagate along particulate/matrix interface, througth thin matrix metal and by linking up the close cracks. The particulate segregation region is the weakest during tensile testing and shear testing due to obviously increased proportion of weak bonds (particulate-particulate bond and particulate-matrix bond).

  13. Processing, microstructure and mechanical properties of nickel particles embedded aluminium matrix composite

    International Nuclear Information System (INIS)

    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.

  14. Effect of stress ratio and frequency on fatigue crack growth rate of 2618 aluminium alloy silicon carbide metal matrix composite

    Indian Academy of Sciences (India)

    Nirbhay Singh; Ram Khelawan; G N Mathur

    2001-04-01

    Effect of stress ratio and frequency on the fatigue crack propagation of 2618 aluminium alloy–silicon carbide composite were investigated at ambient temperature. With the first set of specimens, the fatigue crack growth rates were studied at three frequencies of 1 Hz, 5 Hz and 10 Hz at a stress ratio of 0.1 whereas the effects of stress ratios of 0.1, 0.25 and 0.50 were studied with the second set of specimens. The study showed that the fatigue crack propagation behaviour of this metal matrix composite was influenced to an appreciable extent by the stress ratio, but not by the fatigue frequencies used in this investigation.

  15. Influence of particle size on Cutting Forces and Surface Roughness in Machining of B4Cp - 6061 Aluminium Matrix Composites

    Science.gov (United States)

    Hiremath, Vijaykumar; Badiger, Pradeep; Auradi, V.; Dundur, S. T.; Kori, S. A.

    2016-02-01

    Amongst advanced materials, metal matrix composites (MMC) are gaining importance as materials for structural applications in particular, particulate reinforced aluminium MMCs have received considerable attention due to their superior properties such as high strength to weight ratio, excellent low-temperature performance, high wear resistance, high thermal conductivity. The present study aims at studying and comparing the machinability aspects of B4Cp reinforced 6061Al alloy metal matrix composites reinforced with 37μm and 88μm particulates produced by stir casting method. The micro structural characterization of the prepared composites is done using Scanning Electron Microscopy equipped with EDX analysis (Hitachi Su-1500 model) to identify morphology and distribution of B4C particles in the 6061Al matrix. The specimens are turned on a conventional lathe machine using a Polly crystalline Diamond (PCD) tool to study the effect of particle size on the cutting forces and the surface roughness under varying machinability parameters viz., Cutting speed (29-45 m/min.), Feed rate (0.11-0.33 mm/rev.) and depth of cut (0.5-1mm). Results of micro structural characterization revealed fairly uniform distribution of B4C particles (in both cases i.e., 37μm and 88μm) in 6061Al matrix. The surface roughness of the composite is influenced by cutting speed. The feed rate and depth of cut have a negative influence on surface roughness. The cutting forces decreased with increase in cutting speed whereas cutting forces increased with increase in feed and depth of cut. Higher cutting forces are noticed while machining Al6061 base alloy compared to reinforced composites. Surface finish is high during turning of the 6061Al base alloy and surface roughness is high with 88μm size particle reinforced composites. As the particle size increases Surface roughness also increases.

  16. On the Strength of Silicon Carbide Particulate Reinforced Aluminium Alloy Matrix Composites

    Institute of Scientific and Technical Information of China (English)

    Mingjiu ZHAO; Yue LIU; Liqing CHEN; Jing BI

    2004-01-01

    In the present study, the modified continuum model, quench strengthening and dislocation pile-up model was respectively used to estimate the yield strength of SiCp/Al composites. The experimental results showed that the modified shear lag model or quench strengthening model would underestimate the yield strength of SiCp/Al composites. However, the modified Hall-Petch correlation on the basis of the dislocation pile-up model, expressed as σcy = 244 + 371λ-1/2, fitted very well with the experimental data, which indicated that the strength increase of SiCp/Al composites might be due to the direct blocking of dislocation motion by the particulate-matrix interface.Namely, the dislocation pile-up is the most possible strengthening mechanism for SiCp/Al composites.

  17. Weibull Probability Model for Fracture Strength of Aluminium (1101)-Alumina Particle Reinforced Metal Matrix Composite

    Institute of Scientific and Technical Information of China (English)

    A.Suresh Babu; V.Jayabalan

    2009-01-01

    In recent times, conventional materials are replaced by metal matrix composites (MMCs) due to their high specific strength and modulus.Strength reliability, one of the key factors restricting wider use of composite materials in various applications, is commonly characterized by Weibull strength distribution function.In the present work, statistical analysis of the strength data of 15% volume alumina particle (mean size 15 μm)reinforced in aluminum alloy (1101 grade alloy) fabricated by stir casting method was carried out using Weibull probability model.Twelve tension tests were performed according to ASTM B577 standards and the test data, the corresponding Weibull distribution was obtained.Finally the reliability of the composite behavior in terms of its fracture strength was presented to ensure the reliability of composites for suitable applications.An important implication of the present study is that the Weibull distribution describes the experimentally measured strength data more appropriately.

  18. The influence of reinforcement shape on wear behaviour of aluminium matrix composite materials

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2010-09-01

    Full Text Available urpose: The purpose of this paper is to present the research results of modern metal matrix composite materials. The matrix material was EN AC - AlSi12 alloy while the reinforcement ceramic performs. In order to investigate the influence of reinforcing phase’s shape on tribological properties the comparison was made between the composite material based on preforms obtained by Al2O3 Alcoa CL 2500 powder sintered with addition of pore forming agent in form of carbon fibres Sigrafil C 10 M250 UNS from Carbon Group company and composite materials based on much more expensive commercial fibrous preforms.Design/methodology/approach: The composite was produced by the use of porous material pressure infiltration method. Obtained composite materials were examined with light and scanning electron microscopy. Hardness test was carried out with Rockwell method in A scale. Additionally, the wear resistance was measured by the use of device designed in the Institute of Engineering Materials and Biomaterials. The device realize dry friction wear mechanism of reciprocating movement conditions.Findings: The obtained results show the possibility of manufacturing the new composite materials by the method of porous sintered framework pressure infiltration based on the ceramic particles, with desired microstructure and properties, being a cheaper alternative for materials with base of ceramic fibers.Practical implications: Tested composite materials can be apply among the others in automotive and aircraft industries.Originality/value: Worked out technology of composite materials manufacturing can be used in the production of near net shape and locally reinforced elements

  19. Formation process,microstructure and mechanical property of transient liquid phase bonded aluminium-based metal matrix composite joint

    Institute of Scientific and Technical Information of China (English)

    孙大谦; 刘卫红; 贾树盛; 邱小明

    2004-01-01

    The formation process, microstructure and mechanical properties of transient liquid phase (TLP) bonded aluminium-based metal matrix composite (MMC) joint with copper interlayer were investigated. The formation process of the TLP joint comprises a number of stages: plastic deformation and solid diffusion (stage 1), dissolution of interlayer and base metal (stage 2), isothermal solidification (stage 3) and homogenization (stage 4). The microstructure of the joint depends on the joint formation process (distinct stages). The plastic deformation and solid diffusion in stage 1 favoure the intimate contact at interfaces and liquid layer formation. The microstructure of joint consists of aluminium solid solution, alumina particle, Al2Cu and MgAl2O4 compounds in stage 2. The most pronounced feature of joint microstructure in stage 3 is the alumina particle segregation in the center of the joint. The increase of joint shear strength with increasing bonding temperature is mainly attributed to improving the fluidity and wettability of liquid phase and decreasing the amount of Al2Cu brittle phase in the joint. The principal reason of higher bonding temperature (>600 ℃) resulting in lowering obviously the joint shear strength is the widening of alumina particle segregation region that acts as a preferential site for failure. The increase of joint shear strength with increasing holding time is mainly associated with decreasing the amount of Al2 Cu brittle phase and promoting homogenization of joint.

  20. Experimental Investigation and Prediction of Mechanical Properties of Friction Stir Welded Aluminium Metal Matrix Composite Plates

    Directory of Open Access Journals (Sweden)

    Yahya BOZKURT

    2012-12-01

    Full Text Available Friction stir welding (FSW is a relatively contemporary solid state welding process and has been employed in aerospace, railway, automotive and marine industries for joining of aluminum, magnesium, zinc, titanium, copper alloys, dissimilar metals and thermoplastics. The FSW process parameters such as tool rotation speed, tool traverse speed and tilt angle play an important role in deciding the joining quality. The present study defines the effect of FSW process on the tensile properties of the AA2124/SiC/25p metal matrix composite (MMC plates. Obtained results showed that the joint efficiency decreases by increasing the tool traverse speed while tool rotation speed was kept constant. Second contribution of this study is the application of decision tree technique to predict the tensile properties of friction stir welded MMC plates. It is seen that methodology can be applied with great accuracy.DOI: http://dx.doi.org/10.5755/j01.ms.18.4.3092

  1. Metal matrix Composites

    OpenAIRE

    Pradeep K. Rohatgi

    1993-01-01

    This paper reviews the world wide upsurge in metal matrix composite research and development activities with particular emphasis on cast metal-matrix particulate composites. Extensive applications of cast aluminium alloy MMCs in day-to-day use in transportation as well as durable good industries are expected to advance rapidly in the next decade. The potential for extensive application of cast composites is very large in India, especially in the areas of transportation, energy and elec...

  2. Precipitation phenomena in aluminium-based metal matrix composites: Effects of reinforcement on kinetics and misfit accomodation. Doctoral thesis

    Energy Technology Data Exchange (ETDEWEB)

    Starink, M.J.

    1992-06-15

    In the thesis several articles are brought together which focus on the influence of dispersed particles on the precipitation in aluminium alloys. As dispersed particles, silicon and aluminiumoxide particles were studied. The matrix of the alloys studied consisted of Al-Cu, Al-Cu-Si, and Al-Cu-Mg-Si. The articles concerning the first two alloys make up Part 1 of the thesis. The work on Al-Cu-Mg-Si alloys is compiled in Part 2. Precipitation was studied by differential scanning calorimetry (DSC), X-ray diffraction and hardness measurements.

  3. Aluminium composite casting dispersion reinforced with iron-aluminium and silicon carbide phases

    OpenAIRE

    B. Formanek; J. Piątkowski; J. Szymszal

    2010-01-01

    Aluminium matrix composite with dispersion-reinforced, made by similar to stircasting process was characterised. The mixture of powders was produced by the process of mechanical agglomeration of powdered FexAly and SiC with aluminium. The chemical composition ofagglomerates was selected in a way such as to obtain 25 wt.% reinforcement of the AlSi9Cu4 silumin matrix. Applying thermal analysis ATD, the alloy solidification process was determined, reading out the typical solidification parameter...

  4. The effect of palm kernel shell ash on the mechanical properties of as-cast aluminium alloy matrix composites

    Directory of Open Access Journals (Sweden)

    Isiaka Oluwole OLADELE

    2016-06-01

    Full Text Available The present work describes the effect of palm kernel shell ash (PKSA as reinforcement on the mechanical properties of As-cast aluminium alloy. Recycled aluminium alloy from cylinder of an automotive engine block was degreased by using premium motor spirit (PMS also known as petrol, washed thoroughly with soap and water and sun dried for 5 days. The palm kernel shell was screened of dirt and other unwanted foreign materials before being roasted in furnace. The ash was further pulverized by laboratory ball mill machine followed by sieving to obtain particle sizes of 106 µm and divided into two parts. One portion was treated with NaOH solution while the other part was left as untreated before they are used to reinforced molten aluminium alloy in predetermined proportions. The newly developed composites were characterized with respect to their mechanical properties in response to the tests that were carried out on them. The results indicate that palm kernel shell ash can be used as potential reinforcing material for automobile applications.

  5. Softening Resistance, Dimensional Stability and Corrosion Behaviour of Alumina and Rice Husk Ash Reinforced Aluminium Matrix Composites Subjected to Thermal Cycling

    Directory of Open Access Journals (Sweden)

    K.K. Alaneme

    2015-06-01

    Full Text Available The softening resistance, dimensional stability and corrosion behaviour of stir cast alumina and rice husk ash reinforced aluminium matrix composites subjected to thermal cycling has been investigated. Aluminium hybrid composites having 10 wt% reinforcement consisting of alumina (Al2O3 and rice husk ash (RHA in weight ratios of 1:0, 3:1, 1:1, 1:3, and 0:1 respectively were produced. The composites were subjected to varying thermal cycles of 3, 6, 9 and 12 from room temperature to 200 oC repeatedly. Hardness, linear change in dimensions, microstructural examination and corrosion test were used to characterize the composites produced. From the results, no obvious change in the microstructure could be discerned with thermal cycling. There were only marginal changes in hardness with increase in thermal cycling also less than 2 % change in linear dimensions was observed with thermal cycling. The composites were also observed to be very resistant to corrosion in 3.5 % NaCl solution with no appreciable change in corrosion resistance noted with increase in thermal cycling. However, in 0.3M H2SO4 solution, the corrosion resistance increased with increase in RHA content and samples subjected to 9 and 12 thermal cycles exhibited a relatively higher susceptibility to corrosion.

  6. Aluminium composite casting dispersion reinforced with iron-aluminium and silicon carbide phases

    Directory of Open Access Journals (Sweden)

    B. Formanek

    2010-10-01

    Full Text Available Aluminium matrix composite with dispersion-reinforced, made by similar to stircasting process was characterised. The mixture of powders was produced by the process of mechanical agglomeration of powdered FexAly and SiC with aluminium. The chemical composition ofagglomerates was selected in a way such as to obtain 25 wt.% reinforcement of the AlSi9Cu4 silumin matrix. Applying thermal analysis ATD, the alloy solidification process was determined, reading out the typical solidification parameters. The methods of light and scanning microscopy were used to reveal the structure of composite casting. Changes in chemical composition and phase composition of particles of the FeAl intermetallic phase in aluminium matrix were confirmed. The structure of silumin casting with matrix containing microregions of ceramic and intermetallic phases, typical of hybrid reinforcements, was obtained.

  7. Aluminium AA6061 Matrix Composite Reinforced with Spherical Alumina Particles Produced by Infiltration: Perspective on Aerospace Applications

    Directory of Open Access Journals (Sweden)

    Claudio Bacciarini

    2014-01-01

    Full Text Available Metal matrix composites, based on AA6061 reinforced with 60 vol% Al2O3 spherical particles, were produced by gas pressure infiltration and characterized for hardness, impulse excitation modulus, tensile properties (at room temperature and at 250°C, and machining. It was experimentally demonstrated that the novel alumina powder used in the present work does not react with the liquid Mg-containing matrix during the infiltration process. The AA6061 matrix therefore retains its ability to be strengthened by precipitation heat treatment. The latter behaviour combined with the spherical particle shape confers the studied material higher strength and better machinability in comparison with similar composites produced using standard angular alumina particles. The overall features are promising for applications in the aerospace industry, where light and strong materials are required.

  8. A Simple Model to Estimate the Yield Strength of Silicon Carbide Particulate Reinforced Aluminium Alloy Matrix Composites

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In the present study, a modified Hall-Petch correlation on the basis of dislocation pile-up model was used to estimate the yield strength of SiCp/Al composites. The experimental results show that the modified Hall-Petch correlation expressed as σcy=244+371λ-1/2 fits very well with the experimental data, which indicated that the strength increase of SiCp/Al composites might be due to the direct blocking of dislocation motion by the particulate-matrix interface,namely, the dislocation pile-up is the most possible strengthening mechanism for SiCp/Al composites.

  9. Selected properties of the aluminium alloy base composites reinforced with intermetallic particles

    OpenAIRE

    M. Adamiak

    2005-01-01

    Purpose: The main aim of this work is to investigate two types of intermetallics TiAl and Ti3Al as reinforcement and their influence on selected properties and microstructure of aluminium matrix composites.Design/methodology/approach: Aluminium matrix composites were produced employing the atomised aluminium alloy AA6061 as metal matrix, when as reinforcement TiAl and Ti3Al intermetallics particles were used. The powders were cold pressed and then hot extruded. To evaluate the effect of mecha...

  10. Metal matrix Composites

    Directory of Open Access Journals (Sweden)

    Pradeep K. Rohatgi

    1993-10-01

    Full Text Available This paper reviews the world wide upsurge in metal matrix composite research and development activities with particular emphasis on cast metal-matrix particulate composites. Extensive applications of cast aluminium alloy MMCs in day-to-day use in transportation as well as durable good industries are expected to advance rapidly in the next decade. The potential for extensive application of cast composites is very large in India, especially in the areas of transportation, energy and electromechanical machinery; the extensive use of composites can lead to large savings in materials and energy, and in several instances, reduce environmental pollution. It is important that engineering education and short-term courses be organized to bring MMCs to the attention of students and engineering industry leaders. India already has excellent infrastructure for development of composites, and has a long track record of world class research in cast metal matrix particulate composites. It is now necessary to catalyze prototype and regular production of selected composite components, and get them used in different sectors, especially railways, cars, trucks, buses, scooters and other electromechanical machinery. This will require suitable policies backed up by funding to bring together the first rate talent in cast composites which already exists in India, to form viable development groups followed by setting up of production plants involving the process engineering capability already available within the country. On the longer term, cast composites should be developed for use in energy generation equipment, electronic packaging aerospace systems, and smart structures.

  11. A Computational Study on the Use of an Aluminium Metal Matrix Composite and Aramid as Alternative Brake Disc and Brake Pad Material

    Directory of Open Access Journals (Sweden)

    Nosa Idusuyi

    2014-01-01

    Full Text Available A computational model for the heat generation and dissipation in a disk brake during braking and the following release period has been formulated. The model simulates the braking action by investigating the thermal behaviour occurring on the disc and pad surfaces during this period. A comparative study was made between grey cast iron (GCI, asbestos, Aluminium metal matrix composite (AMC, and aramid as brake pad and disc materials. The braking process and following release period were simulated for four material combinations, GCI disc and Asbestos pad, GCI disc and Aramid pad, AMC disc and Asbestos pad, AMC disc and Aramid pad using COMSOL Multiphysics software. The results show similarity in thermal behaviour at the contact surface for the asbestos and aramid brake pad materials with a temperature difference of 1.8 K after 10 seconds. For the brake disc materials, the thermal behaviour was close, with the highest temperature difference being 9.6 K. The GCI had a peak temperature of 489 K at 1.2 seconds and AMC was 465.5 K but cooling to 406.4 K at 10 seconds, while the GCI was 394.7 K.

  12. Production and some properties of Si3N4 reinforced aluminium alloy composites

    Directory of Open Access Journals (Sweden)

    Pardeep Sharma

    2015-09-01

    Full Text Available The present research work focuses on the production of aluminium (AA6082-T6 matrix composites reinforced with various weight percentage of silicon nitride particles by conventional stir casting route. The percentage of reinforcement is varied from 0 wt.% to 12 wt.% in a stage of 3%. The microstructures and mechanical properties of the fabricated aluminium matrix composites are investigated. The scanning electron microstructure images reveal the presence of Si3N4 particles in the aluminium matrix. The distribution of Si3N4 particles has also been recognized with X-ray diffraction technique. The mechanical properties such as ultimate tensile strength and hardness have improved at the cost of reduction in ductility with increase in weight percentage of silicon nitride particulates in the aluminium metal matrix. The density and porosity of the composites also show an increasing trend with increase in volume fraction of Si3N4 particles in the aluminium matrix.

  13. 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...

  14. Torni materiali za zavorne diske iz aluminijevega kompozitnega materiala (Al-MMCs): Friction materials for aluminium metal matrix composite rotors:

    OpenAIRE

    Stadler, Zmago

    1999-01-01

    Lately the Al-SiC MMCs materials became chipper and more attainable for use in automotive industry. Because of its excellent mechanical and thermal properties in composition with grey cast iron, Al-SiC MMCs became more interesting as brake rotors material. In this paper the development results of brake pad material for Al-SiC MMCs is presented. Completely new development approach was required, because friction materials for grey cast iron rotors are unsuitable for Al-SiC MMCs rotors. Friction...

  15. Interface and microstructure characteristics of SiCp/2024 aluminium alloy composite

    Institute of Scientific and Technical Information of China (English)

    罗守靖; 姜巨福; 王迎; 藤东东; 祖丽君

    2003-01-01

    Electron microscope examination of the microstructure, interface and fracture surface of SiC particulatereinforced 2024 aluminium alloy composites produced by powder mixing and semi-solid extrusion process was pres-ented. The microstructure of SiCp/2024 composites fabricated by the present method is characterized by uniformlydistributed SiC particulates in well-densified matrix. Conventional transmission electron microscopy(TEM) revealsthe interface between the SiC particulates and the aluminium matrix. It is shown that this interface provides verystrong bonding which is further evidenced by the fractographic results, and that there is no apparent chemical reac-tion. Examination of the fracture surface indicates that the bonding strength between the SiC particulates and the a-luminium alloy matrix is stronger than that of the matrix. The dimples and tearing edges on the fracture surface ofcomposites are obviously observed.

  16. Analysis of Orthogonal Cutting of Aluminium-based Composites

    Directory of Open Access Journals (Sweden)

    P. Ravinder Reddy

    2002-10-01

    Full Text Available A turning test on aluminium-based metal-matrix composites (MMCs (aluminium-30% silicon carbide was performed with K-20 carbide tool material and wear patterns and the wear land growth rates were analysed to evaluate the wear characteristics and to classify the relationship between the physical (mechanical properties and the flank wear of cutting tools. The study was also extended to the machining aspects and the width of cuts on MMCs and the influence of various cutting parameters. The experiments were conducted to measure the temperature along the cutting tool edge using thermocouple at various cutting speeds, and depth of cuts, keeping the feed rate constant while turning with K-20 carbide cutting tool. The finite-element method was used to simulate the orthogonal cutting of aluminium-based MMCs. The heat generation at the chip-tool interface, frictional heat generation at the tool flank, and the heat generation at the work tool interface were calculated analytically and imposed as boundary conditions. The analysis of the steady-state heat transfer was carried out and the temperature distribution at cutting edge, shear zone, and interface regions have been reported.

  17. Friction and Wear Behaviours of Aluminium Matrix Composites Reinforced with Particulates of TiB2%TiB2颗粒增强铝基复合材料摩擦磨损性能的研究

    Institute of Scientific and Technical Information of China (English)

    杨云龙; 于海侠; 曾建民

    2012-01-01

    Aluminium matrix composites reinforced with particulates of TiB2 were in-situ synthesized. Using MMW-1 friction test instrument, the friction and wear behaviour of the composites in room temperature was investigated under various loads and rotary speeds. Scanning electron microscopy is used for supporting analysis. The results show that the properties of friction and wear of the composites are improved compared with aluminum alloy. The wear mechanism is abrasive wear because a large of furrows appear in the surface of friction and wear.%采用原位反应合成法制备出TiB2颗粒增强铝基复合材料.利用MMW-1型摩擦实验机,在不同载荷和转速下,测试不同成分原位生成的TiB2增强铝基复合材料在室温下的摩擦磨损性能变化情况;并用扫描电镜分析技术进行辅助研究.结果表明,TiB2颗粒增强铝基复合材料的摩擦磨损性能在很大程度上得到改善;实验过程在摩擦磨损表面出现大规模的“犁沟”,属于磨粒磨损.

  18. A Study on Effect of Graphite Particles on Tensile, Hardness and Machinability of Aluminium 8011 Matrix Material

    Science.gov (United States)

    Latha Shankar, B.; Anil, K. C.; Karabasappagol, Prasann J.

    2016-09-01

    Industrial application point of view, metal matrix composites in general and Aluminium alloy matrix composites in particular are ideal candidates because of their favourable engineering properties. Being lightweight Aluminium matrix composites are widely used in aircraft, defence and automotive industries. In this work Aluminium 8011 metal matrix was reinforced with fine Graphite particles of 50 μm. developed by two-step Stir casting method. Graphite weight %was varied in the range 2, 4, 6 and 8%. Uniform dispersion of graphite particle is examined under optical microscope. Tensile test coupons were prepared as per standard to determine % of elongation and tensile strength for various % of graphite particle. Hardness of developed composite for various % of graphite particle and Machinability parameters were also studied for effect on surface finish. It was observed that with increase of weight percentage of Graphite particles up to 8% in Aluminium 8011 alloy matrix there was increase in tensile strength, decrease in % of elongation with increase in hardness. Machinability study revealed that, there was decrease in surface roughness with increase in Graphite content.

  19. Aluminium composites casting in rotating magnetic field

    Directory of Open Access Journals (Sweden)

    M. Cholewa

    2008-04-01

    Full Text Available In this paper technological and material conception of composite manufacturing with intensify of ex-situ powders and some results was shown. Technology of powders stirring with liquid metal in the crucible was shown. For composites required dispersion of reinforcement and matrix crystallization was assisted with rotating electromagnetic field. Improvement of reinforcing particles distribution can be observed. Composite structure was studied with use of light microscopy. Electromagnetic field processing positive influence on reinforcing phase distribution and matrix crystallization process was proved.

  20. Fabrication experience of aluminium clad aluminium matrix dispersion fuels at BARC

    International Nuclear Information System (INIS)

    Aluminium clad, aluminium matrix plate type dispersion fuels have been fabricated in BARC in recent years as part of fuel development programme for small non-power research reactors. The present paper describes the flowsheet developed for fabrication of Al-UAlx, Al-U3Si2 and Al-U3O8 fuels at BARC. The Al-20% U alloy fuel for KAMINI neutron radiography reactor was prepared by 'melting and casting' route, followed by picture framing and roll-bonding. For higher 'U' density fuels namely, Al-UAlx, Al-U3O8 and Al-U3Si2 the 'powder metallurgy' route was followed for preparation of fuel meat. The novel features in fabrication route were: addition of Zr for stabilizing UAl3 phase in Al-20% U alloy; x-ray radiography and microdensitometric scanning of radiographs for location of fuel outline inside fuel element and for confirming homogeneous distribution of fissile atoms; immersion ultrasonic testing for confirming good bonding between mating Al surface of the fuel plate. (author)

  1. 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.

  2. Selected properties of the aluminium alloy base composites reinforced with intermetallic particles

    Directory of Open Access Journals (Sweden)

    M. Adamiak

    2005-12-01

    Full Text Available Purpose: The main aim of this work is to investigate two types of intermetallics TiAl and Ti3Al as reinforcement and their influence on selected properties and microstructure of aluminium matrix composites.Design/methodology/approach: Aluminium matrix composites were produced employing the atomised aluminium alloy AA6061 as metal matrix, when as reinforcement TiAl and Ti3Al intermetallics particles were used. The powders were cold pressed and then hot extruded. To evaluate the effect of mechanical milling two types of ball mills were used: a low energy (horizontal ball mill and a high energy one (eccentric ball mill. Reinforcement contents for both processes 5, 10, 15 % by weight. To determine hardness Vickers tests were performed. Microstructure observations were made by optical microscopy and scanning electron microscopy SEM.Findings: Based on the examinations carried out one can state that the mechanical milling can produce composites powders with homogenous distribution of reinforcement particles. The mechanically milled and extruded composites show finer and better distribution of reinforcement particles what leads to better mechanical properties of obtained products.Research limitations/implications: In order to evaluate with more detail the possibility of applying these composite materials at practical application, further investigations should be concentrated on the interface reaction of the matrix and reinforcing particles during elevated temperature exposition and their influence on mechanical properties.Practical implications: The composites materials produced by this way have shown significant improvement of the mechanical properties in comparision with matrix materials. Good properties of the composites make them suitable for various technical and industrial applications.Originality/value: It should be stressed that the materials as intermetallic compounds with outstanding mechanical properties and good thermal stability were

  3. 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)

  4. Influence of filler size and morphology in controlling the thermal emissivity of aluminium/polymer composites for space applications

    Energy Technology Data Exchange (ETDEWEB)

    Babrekar, Harshada A., E-mail: harshada98@gmail.co [Department of Physics, University of Pune, Ganeshkhind Road, Pune 411 007 (India); Kulkarni, Naveen V. [Department of Physics, University of Pune, Ganeshkhind Road, Pune 411 007 (India); Jog, Jyoti P. [National Chemical Laboratory, Pashan Road, Pune 411 008 (India); Mathe, Vikas L.; Bhoraskar, Sudha V. [Department of Physics, University of Pune, Ganeshkhind Road, Pune 411 007 (India)

    2010-04-15

    The paper has addressed the problem of controlling the thermal emissivities from metal/polymer composites prepared by solution method. Aluminium is used as a filler and polystyrene as a polymer-matrix. Aluminium particles, with micrometer and nanometer dimensions having different morphologies, were employed. The values of emissivities were reduced when the coarse grains and flakes of aluminium were used as fillers, whereas, no significant change was observed when nano-aluminium was used in the composite. Dielectric dispersion for the composites was measured and the results are analysed in view of Fresnel relation. The differences in the values of dielectric constants, between the experimentally measured and those which can be predicted theoretically, are thought to arise from the interfacial polarization.

  5. Usinage des composites a matrice d'alliage d'aluminium GrA-Ni(Reg)

    Science.gov (United States)

    Songmene, Victor

    2001-07-01

    Aluminium Metal Matrix Composites (MMC) reinforced with ceramic particles have been increasingly developed during the last decade. Ceramic particles used as reinforcement that improve the wear resistance of composites also cause high abrasive wear on cutting tools. This thesis investigates the machinability of graphitic MMC consisting of an aluminium alloy matrix reinforced with both soft nickel-coated graphite particles and hard (SiC or Al2O 3) particles. These composites were developed seven years ago, but the lack of optimised machining data to machine GrA-NIRTM composites cost effectively have been slowing down their use in engineering applications. Turning, milling and drilling tests were performed to evaluate the machinability of different GrA-NIRTM and to establish cutting conditions. It was found that: (1) The machinability of GrA-NiRTM composites depends on the nature and the percentage of the reinforcing particles. GrA-NiRTM containing alumina and graphite are easier to machine than those reinforced with silicon carbide and graphite. (2) Polycrystalline (PCD) and diamond-coated carbide (DCC) are the tool material of choice for machining GrA-NiRTM. DCC tools are most cost effective while PCD tools produce better part finishes. (3) The cutting force required to machine the GrA-NIRTM composites is similar to that used for aluminium alloys such as Al 380.

  6. A Numerical Analysis of the Resistance and Stiffness of the Aluminium and Concrete Composite Beam

    OpenAIRE

    Polus Łukasz; Szumigała Maciej

    2015-01-01

    In this paper a numerical analysis of the resistance and stiffness of the aluminium and concrete composite beam is presented. Composite aluminium and concrete structures are quite new and they have not been thoroughly tested. Composite structures have a lot of advantages. The composite aluminium and concrete beam is more corrosion-resistant, fire-resistant and stiff than the aluminium beam. The contemporary idea of sustainable buildings relies on new solutions which are more environmentally f...

  7. Abrasive wear response of aluminium alloy-sillimanite particle reinforced composite under low stress condition

    Energy Technology Data Exchange (ETDEWEB)

    Singh, M. [Regional Research Laboratory (CSIR), Hoshangabad Road, Near Habibganj Naka, Bhopal 462 026 (India)]. E-mail: mulayam_singh@hotmail.com; Mondal, D.P. [Regional Research Laboratory (CSIR), Hoshangabad Road, Near Habibganj Naka, Bhopal 462 026 (India); Das, S. [Regional Research Laboratory (CSIR), Hoshangabad Road, Near Habibganj Naka, Bhopal 462 026 (India)

    2006-03-15

    The abrasive wear behaviour of aluminium alloy-sillimanite particle reinforced composite under low stress condition has been reported and the results have been compared with the corresponding matrix alloy which was produced and cast under similar conditions. The study showed that wear resistance (inverse of wear rate) of the composite was higher than the matrix alloy. The wear rate decreased with sliding distance and increased with applied load irrespective of materials. The worn surfaces and subsurfaces of the tested samples were examined in the scanning electron microscope in order to understand the material removal mechanism during low stress abrasive wear process.

  8. Development of textile-reinforced carbon fibre aluminium composites manufactured with gas pressure infiltration methods

    Directory of Open Access Journals (Sweden)

    W. Hufenbach

    2009-08-01

    Full Text Available Purpose: The aim of his paper is to show potential of textile-reinforced carbon fibre aluminium composite with advantage of the lightweight construction of structural components subjected to thermo-mechanical stress.Design/methodology/approach: The manufacture of specimens of the carbon fibre-reinforced aluminium was realised with the aid of an advanced differential gas pressure infiltration technique, which was developed at ILK, TU Dresden.Findings: The gas pressure infiltration technology enables to fabricate complex carbon aluminium composites with fibre or textile reinforcement using moulds of graphite, but in future development the optimization of infiltration process is required. The load-adapted combination of 3D reinforced semi-finished fibre products (textile preforms made from carbon fibres (CF with aluminium light metal alloys (Al offers a considerable lightweight construction potential, which up to now has not been exploited.Research limitations/implications: Gas pressure infiltration technology enables to fabricate complex carbon aluminium composites with fibre or textile reinforcement using precision moulds of graphite, but in future development the optimization of infiltration process is required.Practical implications: Load-adapted CF/Al-MMC, due to the relatively high stiffness and strength of the metal matrix, allow the introduction of extremely high forces, thereby enabling a much better exploitation of the existing lightweight construction potential of this material in comparison to other composite materials.Originality/value: Constantly rising demands on extremely stressed lightweight structures, particularly in traffic engineering as well as in machine building and plant engineering, increasingly require the use of endless fibre-reinforced composite materials which, due to their selectively adaptable characteristics profiles, are clearly superior to conventional monolithic materials.

  9. A Numerical Analysis of the Resistance and Stiffness of the Aluminium and Concrete Composite Beam

    Science.gov (United States)

    Polus, Łukasz; Szumigała, Maciej

    2015-03-01

    In this paper a numerical analysis of the resistance and stiffness of the aluminium and concrete composite beam is presented. Composite aluminium and concrete structures are quite new and they have not been thoroughly tested. Composite structures have a lot of advantages. The composite aluminium and concrete beam is more corrosion-resistant, fire-resistant and stiff than the aluminium beam. The contemporary idea of sustainable buildings relies on new solutions which are more environmentally friendly. Aluminium is lighter and more resistant to corrosion than steel, which is often used in composite structures.

  10. A Numerical Analysis of the Resistance and Stiffness of the Aluminium and Concrete Composite Beam

    Directory of Open Access Journals (Sweden)

    Polus Łukasz

    2015-03-01

    Full Text Available In this paper a numerical analysis of the resistance and stiffness of the aluminium and concrete composite beam is presented. Composite aluminium and concrete structures are quite new and they have not been thoroughly tested. Composite structures have a lot of advantages. The composite aluminium and concrete beam is more corrosion-resistant, fire-resistant and stiff than the aluminium beam. The contemporary idea of sustainable buildings relies on new solutions which are more environmentally friendly. Aluminium is lighter and more resistant to corrosion than steel, which is often used in composite structures.

  11. Role of work hardening characteristics of matrix alloys in the strengthening of metal matrix composites

    Indian Academy of Sciences (India)

    K T Kashyap; C Ramachandra; C Dutta; B Chatterji

    2000-02-01

    The strengthening of particulate reinforced metal–matrix composites is associated with a high dislocation density in the matrix due to the difference in coefficient of thermal expansion between the reinforcement and the matrix. While this is valid, the role of work hardening characteristics of the matrix alloys in strengthening of these composites is addressed in the present paper. It is found that commercial purity aluminium which has the lowest work hardening rate exhibits the highest strength increment. This effect is due to increased prismatic punching of dislocations. This relationship of decreasing work hardening rate associated with increasing prismatic punching of dislocations in the order 7075, 2014, 7010, 2024, 6061 and commercial purity aluminium leading to increased strength increments is noted.

  12. Use of Propranolol-Magnesium Aluminium Silicate Intercalated Complexes as Drug Reservoirs in Polymeric Matrix Tablets

    OpenAIRE

    T. Pongjanyakul; S Rojtanatanya

    2012-01-01

    The objective of the present study was to investigate the use of propranolol-magnesium aluminium silicate intercalated complexes as drug reservoirs in hydroxypropylmethylcellulose tablets. The matrix tablets containing the complexes were prepared and characterised with respect to propranolol release and were subsequently compared with those loading propranolol or a propranolol-magnesium aluminium silicate physical mixture. Additionally, the effects of varying viscosity grades of hydroxypropyl...

  13. The Effects of Cocos Nucifera (Coconut Shell on the Mechanical and Tribological Properties of Recycled Waste Aluminium Can Composites

    Directory of Open Access Journals (Sweden)

    J.O. Agunsoye

    2014-06-01

    Full Text Available The dry sliding wear behaviour and mechanical properties of recycled aluminium metal matrix composite reinforced with 5 and 10 % coconut shell particles (CSp has been investigated. The particle size of Cocosnucifera (coconut shell that were used ranges from 50-300µm. The wear behaviors of developed samples were investigated under varied loads and speed using pin on disc equipment. The samples were also subjected to tensile, impact and hardness test. The result shows that the additions of coconut shell particles improved the wear resistance of the recycled aluminium can/CSp composites at low Speed (2.36 m/s. However, with increase in Speed (4.72 m/s, an increase in the specific wear rates were observed. Increasing the coconut shell particles additions to the recycled waste aluminium cans (RWAlC reduced the impact resistance, hence the toughness of the RWAlC/CSp composite samples. However, the impact resistance of the composites increased as the Cocosnucifera particle size increased. The result of the filler size variation shows that decrease in filler particles size improved the tensile strength and yield strength of the developed aluminium metal matrix /CSp composite. The hardness of the composite increased with increased additions of the filler within the matrix.

  14. Composite Ni-Co-fly ash coatings on 5083 aluminium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Panagopoulos, C.N., E-mail: chpanag@metal.ntua.gr [Laboratory of Physical Metallurgy, National Technical University of Athens, Zografos, 15780 Athens (Greece); Georgiou, E.P.; Tsopani, A.; Piperi, L. [Laboratory of Physical Metallurgy, National Technical University of Athens, Zografos, 15780 Athens (Greece)

    2011-03-15

    Ni-Co-fly ash coatings were deposited on zincate treated 5083 wrought aluminium alloy substrates with the aid of the electrodeposition technique. Structural and chemical characterization of the produced composite coatings was performed with the aid of X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron dispersive X-ray analysis (EDS) techniques. The Ni-Co-fly ash coatings were found to consist of a crystalline Ni-Co solid solution with dispersed fly ash particles. In addition, chemical analysis of the Ni-Co matrix showed that it consisted of 80 wt.% Ni and 20 wt.% Co. The co-deposition of fly ash particles leads to a significant increase of the microhardness of the coating. The corrosion behaviour of the Ni-Co-fly ash/zincate coated aluminium alloy, in a 0.3 M NaCl solution (pH = 3.5), was studied by means of potentiodynamic corrosion experiments.

  15. Evaluation of the mechanical properties and corrosion behaviour of coconut shell ash reinforced aluminium (6063 alloy composites

    Directory of Open Access Journals (Sweden)

    Oluyemi O. DARAMOLA

    2015-12-01

    Full Text Available Aluminium 6063/Coconut shell ash (CSAp composites having 3-12 weight percent (wt% coconut shell ash were fabricated by double stir-casting method. The microstructure, ultimate tensile strength, hardness values, density and corrosion behaviour in 0.3M H2SO4 and 3.5wt% NaCl solution of the composites were evaluated. The density of the composites exhibit a linear and proportional decreased as the percentage of coconut shell ash increases in the aluminium alloy. It implies that composites with lower weight component can be produced by adding CSAp. The microstructural analysis showed uniform distribution of coconut shell ash particles in the aluminium alloy matrix. Significant improvement in hardness and ultimate tensile strength values was noticeable as the wt% of the coconut shell ash increased in the alloy, although this occur at the expense of ductility of the composites as the modulus of elasticity of the composites decreases as the percentage of CSAp increases. Hence, this work has established that incorporation of coconut shell particles in aluminum matrix can lead to the production of low cost aluminum composites with improved hardness and tensile strength values.

  16. Survey of aluminum matrix composites

    International Nuclear Information System (INIS)

    This is a review of the current stage of development of fiber reinforced Al matrix composites: primary and secondary fabrication, physical and mechanical properties, environmental effects, applications, current and projected costs of raw material and composites, and future developments. Boron and beryllium are among the filament materials. (101 references, 32 fig.) (U.S.)

  17. 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.

  18. MECHANICAL PROPERTY EVALUATION OF A356/SiCp/Gr METAL MATRIX COMPOSITES

    OpenAIRE

    B. M. VISWANATHA; M. PRASANNA KUMAR; S. Basavarajappa; T. S. KIRAN

    2013-01-01

    In the present investigation, studies on microstructure and mechanical properties of Aluminium Matrix Composites (AMCs) reinforced with silicon carbide (SiCp) and graphite (Gr) particles. A356 alloy is used as the matrix material with varying the reinforcement of SiCp from 0 to 9 wt% in steps of 3 wt% and fixed quantity of 3 wt% of graphite. The composites were fabricated by liquid metallurgy method. The prepared composites were examined for microstructure to know the particle distribution in...

  19. Aspects regarding wearing behaviour in case of aluminium composite materials reinforced with carbon fibers

    Science.gov (United States)

    Caliman, R.

    2016-08-01

    This paper presents a study regarding wear comportment of sintered composite materials obtained by mixture of aluminium with short carbon fibers. The necessity to satisfying more and more the specific functions during design of high performance structures leads to perform multi-materials such as reinforced composite parts. The wear tests were made on three different orientations of fibers on a standard machine of tribology, pin disk type. Counter-disk was made of cast iron with a superficial hardness of 92 HB. The wear rate and friction coefficient decreased exponentially with time of friction and reached a stationary value. This behaviour was attributed to the development of a lubricating film on the friction surface. To conduct this work was performed measurements on samples from the Al matrix composites and carbon fiber 43%, wear mechanism was investigated by scanning electron microscopy. In addition to fiber orientation, the tribological behaviour of metal matrix composites reinforced with fiber is influenced by the interfacial reaction of fiber-matrix. The characteristics and the dimensions of the interface depend on the cycle of temperature and time at which the material has been subjected during the manufacturing process and thereafter.

  20. Interface in silicon carbide whisker reinforced aluminium composites

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Li; Geng, Lin; Yao, Zhongkai; Lei, Tingquan (Harbin Institute of Technology (China))

    1989-09-01

    The interface in SiCw/Al composites was examined. The Auger electron spectroscope analysis of the fracture surface after sputter etching shows that the bonding between SiC whisker and Al matrix is quite good. TEM and X-ray diffraction analysis show that there is no reaction layer at the SiC-Al interface. Si and C cannot diffuse into the matrix, and Al cannot diffuse into the whisker. The experimental results also show that there may be certain orientation relationships between the SiC whisker and the nearby matrix. 7 refs.

  1. Influence of cold rolling and fatigue on the residual stress state of a metal matrix composite

    OpenAIRE

    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...

  2. Electrochemical characteristics of a carbon fibre composite and the associated galvanic effects with aluminium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Z., E-mail: zuojia.liu@gmail.com; Curioni, M.; Jamshidi, P.; Walker, A.; Prengnell, P.; Thompson, G.E.; Skeldon, P.

    2014-09-30

    Highlights: • Exposed carbon fibres on two defined regions (“front” and “side”) are a focus of the investigation in NaCl electrolyte. • The exposed carbon fibres on the side and front regions are responsible for a high cathodic current density. • The NaCl + CuSO{sub 4} electrolyte was used to investigate the cathodic polarization behaviour of the exposed carbon fibres. • Galvanic coupling behaviour between the composite and aluminium alloys (AA7075-T6 and AA1050) was measured in NaCl electrolyte. • The higher galvanic current density measured on AA1050 alloy introduced a higher dissolution rate than the AA7075-T6 alloy. - Abstract: The electrochemical behaviour of a carbon fibre reinforced epoxy matrix composite in 3.5% NaCl and 3.5% NaCl + 0.5 M CuSO{sub 4} electrolytes was examined by potentiodynamic polarisation, potentiostatic polarisation and scanning electron microscopy. Exposed carbon fibres on two defined regions (“front” and “side”) are a focus of the investigation. The large size of the exposed carbon fibres on the side region is responsible for a higher cathodic current density than the front region in the NaCl electrolyte. The deposition of copper on the front surface of composite confirmed that the significantly higher cathodic current resulted from the exposure of the fibres to the NaCl electrolyte. Galvanic coupling between the composite and individual aluminium alloys (AA7075-T6 and AA1050) was used to measure galvanic potentials and galvanic current densities. The highly alloyed AA7075-T6 alloy and its high population density of cathodic sites compared to the AA1050 acted to reduce the galvanic effect when coupled to the composite front or side regions.

  3. Titanium Matrix Composite Pressure Vessel Project

    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...

  4. 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...

  5. Optimization of machining parameters in drilling hybrid aluminium metal matrix composites%混合铝基复合材料钻削工艺参数的优化

    Institute of Scientific and Technical Information of China (English)

    T.RAJMOHAN; K.PALANIKUMAR; M.KATHIRVEL

    2012-01-01

    Taguchi method with grey relational analysis was used to optimize the machining parameters with multiple performance characteristics in drilling hybrid metal matrix A1356/SiC-mica composites.Experiments were conducted on a computer numerical control vertical machining centre and L18 orthogonal array was chosen for the experiments.The drilling parameters namely spindle speed,feed rate,drill type and mass fraction of mica were optimized based on the multiple performance characteristics including thrust force,surface roughness,tool wear and burr height (exit).The results show that the feed rate and the type of drill are the most significant factors which affect the drilling process and the performance in the drilling process can be effectively improved by using this approach.%采用Taguchi方法和灰色关联分析对A1356/SiC-云母混合金属基复合材料的钻削工艺参数进行优化.实验采用L18正交阵列,在计算机的控制立式机床上进行.考察的钻削性能指标包括轴向力、表面粗糙度、刀具磨损和毛刺高度,对影响这些性能的钻削工艺参数进行了优化,包括轴转数、给进速度、钻头类型和云母质量分数.结果表明:给进速度和钻头类型是影响钻削过程的重要因素,通过这种方法可以有效地改进钻削工艺的性能.

  6. Water defluoridation by aluminium oxide-manganese oxide composite material.

    Science.gov (United States)

    Alemu, Sheta; Mulugeta, Eyobel; Zewge, Feleke; Chandravanshi, Bhagwan Singh

    2014-08-01

    In this study, aluminium oxide-manganese oxide (AOMO) composite material was synthesized, characterized, and tested for fluoride removal in batch experiments. AOMO was prepared from manganese(II) chloride and aluminium hydroxide. The surface area of AOMO was found to be 30.7m2/g and its specific density was determined as 2.78 g/cm3. Detailed investigation of the adsorbent by inductively coupled plasma-optical emission spectrometry, inductively coupled plasma-mass spectrometry, and ion chromatography (for sulphate only) showed that it is composed of Al, Mn, SO4, and Na as major components and Fe, Si, Ca, and Mg as minor components. Thermogravimetric analysis was used to study the thermal behaviour of AOMO. X-ray diffraction analysis showed that the adsorbent is poorly crystalline. The point of zero charge was determined as 9.54. Batch experiments (by varying the proportion of MnO, adsorbent dose, contact time, initial F concentration, and raw water pH) showed that fluoride removal efficiency ofAOMO varied significantly with percentage of MnO with an optimum value of about I11% of manganese oxide in the adsorbent. The optimum dose of the adsorbent was 4 g/L which corresponds to the equilibrium adsorption capacity of 4.8 mg F-/g. Both the removal efficiency and adsorption capacity showed an increasing trend with an increase in initial fluoride concentration of the water. The pH for optimum fluoride removal was found to be in the range between 5 and 7. The adsorption data were analysed using the Freundlich, Langmuir, and Dubinirn-Radushkevich models. The minimum adsorption capacity obtained from the non-linear Freundlich isotherm model was 4.94 mg F-/g and the maximum capacity from the Langmuir isotherm method was 19.2mg F-/g. The experimental data of fluoride adsorption on AOMO fitted well to the Freundlich isotherm model. Kinetic studies showed that the adsorption is well described by a non-linear pseudo-second-order reaction model with an average rate constant of 3

  7. Mechanical properties of silver matrix composites reinfroced with ceramic particles

    Directory of Open Access Journals (Sweden)

    J. Śleziona

    2006-04-01

    Full Text Available Purpose: Silver, silver alloys, as well as silver matrix based composites have been well known and applied in the electrotechnical and electronics industry for several decades. For many applications in electrotechnology, including electric contacts and brushes, unreinforced sliver alloys do not meet the requirements concerning mainly durability and wear resistance, first of all to tribological and electroerosive wear. These wear processes may be prevented by introducing to silver reinforcement particles and alloys. The target of the research included basic mechanical properties determination of the silver matrix composites reinforced with ceramic particles, manufactured with the use of suspension methods.Design/methodology/approach: In the presented paper the authors demonstrate possibilities of manufacturing of silver matrix composites on the way of casting technology utilization.Findings: The results of the research prove that applied suspension technology, based on introducing of agglomerated foundry alloy which is the carrier for reinforcement particles (SiC lub Al2O3 allows to produce in an effective and, what is important, in an economically attractive way, sliver alloys based composites.Research limitations/implications: The researches on the structure of manufactured composites and their mechanical properties that are presented in the paper prove the possibilities of mechanical mixing technology application for producing mechanical and stable connection between silver matrix and ceramic particles of aluminium oxide and silicon carbide.Originality/value: The manufacturing of this type of composites is based most of all on the utilization of powder metallurgy techniques. However the obtained results of the research prove that there is a possibility of silver matrix composites forming in the casting and plastic working processes. Extrusion process carried out in the hydraulic press KOBO has its favourably influence on ceramic reinforcement

  8. Development of textile-reinforced carbon fibre aluminium composites manufactured with gas pressure infiltration methods

    OpenAIRE

    W. Hufenbach; Gude, M.; A. Czulak; J. Śleziona; A. Dolata-Grosz; M. Dyzia

    2009-01-01

    Purpose: The aim of his paper is to show potential of textile-reinforced carbon fibre aluminium composite with advantage of the lightweight construction of structural components subjected to thermo-mechanical stress.Design/methodology/approach: The manufacture of specimens of the carbon fibre-reinforced aluminium was realised with the aid of an advanced differential gas pressure infiltration technique, which was developed at ILK, TU Dresden.Findings: The gas pressure infiltration technology e...

  9. Phase composition, microstructure and microhardness of electroless nickel composite coating co-deposited with SiC on cast aluminium LM24 alloy substrate

    OpenAIRE

    Franco, M.; Sha, W.; Malinov, S.; Rajendran, R

    2013-01-01

    Electroless Ni–P (EN) and composite Ni–P–SiC (ENC) coatings were developed on cast aluminium alloy substrate, LM24. The coating phase composition, microstructure and microhardness were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and microhardness tester, respectively, on as-plated and heat-treated specimens. The original microstructure of the Ni–P matrix is not affected by the inclusion of the hard particles SiC. No formation of Ni–Si phase was observed up t...

  10. Characterisation of phase composition, microstructure and microhardness of electroless nickel composite coating co-deposited with SiC on casting aluminium LM24 alloy substrate

    OpenAIRE

    Franco, M.; Sha, Wei; Malinov, Savko

    2013-01-01

    Electroless Ni-P (EN) and composite Ni-P-SiC (ENC) coatings were developed on cast aluminium alloy, LM24. The coating phase composition, microstructure and microhardness were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and microhardness tester, respectively, on as-plated and heat-treated specimens. The original microstructure of the Ni-P matrix is not affected by the inclusion of the hard particles SiC. No formation of Ni-Si phase was observed upto 500°C of ...

  11. Surface mechanical behaviour of composite Ni-P-fly ash/zincate coated aluminium alloy

    International Nuclear Information System (INIS)

    Ni-P-fly ash coatings were produced on zincate coated 5083 wrought aluminium alloy substrates with the aid of an electroless deposition technique. Structural and chemical characterization of the produced coatings was performed with the aid of X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron dispersive X-ray analysis (EDS) techniques. The Ni-P-fly ash coating was found to consist of an amorphous Ni-P matrix with dispersed fly ash particles. The wear resistance of the Ni-P-fly ash coating on zincate treated aluminium alloy was observed to be higher than that of the bare aluminium alloy, when sliding against a stainless steel counterface. In addition, the adhesion between the Ni-P-fly ash/zincate coating and the aluminium alloy substrate was also studied with a scratch testing apparatus. The adhesion strength of Ni-P-fly ash/zincate coating on the aluminium alloy substrate was observed to be higher in comparison to the Ni-P/zincate coating on the same aluminium alloy.

  12. Synthesis and forming behavior of aluminium-based hybrid powder metallurgic composites

    Institute of Scientific and Technical Information of China (English)

    M.Ravichandran; A. Naveen Sait; V.Anandakrishnan

    2014-01-01

    Aluminium-based metal matrix composites were synthesized from Al-TiO2-Gr powder mixtures using the powder metallurgy technique and their forming characteristics were studied during cold upsetting. Green cylindrical compacts of pure Al, Al-5wt%TiO2, Al-5wt%TiO2-2wt%Gr, and Al-5wt%TiO2-4wt%Gr were made using a 400-kN hydraulic press equipped with suitable punch and die and by sintering at (590 ± 10)°C for 3 h. Cold upset forging tests were carried out, the true axial stress (σz), the true hoop stress (σө), and the true hy-drostatic stress (σm) were evaluated and, their behavior against the true axial strain (εz) was also analyzed. It is observed that the addition of 5wt%TiO2 into the Al matrix increasesσz,σө, andσm. The addition of both TiO2 and Gr reinforcements reduces the densification and defor-mation characteristics of the sintered preforms during cold upsetting. Microstructure analyses of the as-sintered and cold upset forged speci-mens also were carried out to substantiate the experimental results.

  13. Manufacturing of EN AW6061 matrix composites reinforced by halloysite nanotubes

    OpenAIRE

    L.A. Dobrzański; Tomiczek, B.; M. Adamiak

    2011-01-01

    Purpose: The core of the work consists in the elaboration of composite materials of aluminium alloy matrix, manufactured with the use of powder metallurgy technologies, including mechanical milling and hot extrusion and in determining the influence of the share of halloysite nanotubes – as the reinforcing phase on the structure and mechanical properties of fabricated composites.Design/methodology/approach: Mechanical milling and hot extrusion are considering as a method for fabricating compos...

  14. A low cost, light weight cenosphere–aluminium composite for brake disc application

    Indian Academy of Sciences (India)

    V Saravanan; P R Thyla; S R Balakrishnan

    2016-02-01

    The commonly used composite material for brake rotor consists of silicon carbide (SiC) or aluminium oxide (Al$_2$O$_3$) particles which are more expensive. The weight of conventionally used composite is more compared to base alloy. The aim of this paper is to develop a light weight material for brake disc applications thereby substituting base alloy and conventional composite. This analysis led to 10 vol% cenosphere reinforced aluminium alloy (AA) 6063 composite as the most appropriate material for brake disc. To ensure the manufacturability of composite, composite brake rotor was casted using the sand casting technique and was machined to achieve the final component. Thermal capability of brake disc was ensured by studying temperature variation through vehicle testing procedure of disc brake. Cost reduction is one of the important benefit acquired using cenosphere reinforced composite. This was ensured by cost estimation and analysis. The cost estimated to manufacture the AA6063 brake disc was compared with composite cost.

  15. Hard magnetic composite materials with polymer matrix reinforced Nd-Fe-B hard magnetic particles

    International Nuclear Information System (INIS)

    Investigation results of the polymer matrix hard magnetic composite materials with particles of the powered rapid quenched Nd-Fe-B strip quenched Nd-Fe-B strip are presented at this paper. The Nd-Fe-B powder was doped (10 wt.%) with powder of iron, aluminium, CuSn10 casting copper alloy with tin, high alloy steel X2CrNiNo17-12-2 and aluminium oxide. Epoxy resin has been used as a matrix (2.5 wt.%). The pressure of 800-900 MPa and cured afterwards for 2 hours at 180 oC. The influence of dopes' materials kind on magnetic and mechanical composites were unilaterally and uniaxially pressed at room temperature under properties of composite materials was estimated. Metallographic examination of the composite materials' structure and XRD analysis has been made. Investigations of magnetic properties of composite materials show the influence of the addition material. It was estimated that dopes of soft magnetic material decrease coercive force HcB and slightly reduce remanence Br of composite. The addition of non-magnetic material decreases coercive force HcB and reduces remanence Br. Metallographic examination of the structure shows uniform distribution of Nd-Fe-B powder in the polymer matrix, grains are irregular elongated in the direction. Dopes distribution in a polymer matrix is irregular, agglomerations of powders of aluminium, iron and copper casting alloy with tin have noticed. Ultimate compressive strength of composite materials is improved for all the addition material, except powder of aluminium oxide. XRD analysis has identified the hard magnetic phase Nd2Fe14B. (author)

  16. Ultrasonic vibration assisted scratch surface morphology of silicon carbide particle reinforced aluminium matrix composites%铝基碳化硅复合材料超声振动辅助划痕表面形貌研究

    Institute of Scientific and Technical Information of China (English)

    周晓勤; 梁桂强; 郭婷婷

    2014-01-01

    为了揭示 SiCp/Al 复合材料超声振动加工的去除机理,开展针对 SiCp/Al 复合材料的超声振动辅助划痕(UVAS)和普通划痕对比实验,从划痕形貌方面进行UVAS和普通划痕对比分析。结果表明,普通划痕凹槽处出现大颗粒的破碎,而 UVAS 凹槽表面则呈现较多的细小碎屑;超声划痕的材料去除率比普通划痕的大。超声振动的引入对改善加工表面形貌有明显作用,是SiCp/Al精密加工的有效方法。%It was proposed in this paper to conduct ultrasonic vibration-assisted scratch(UVAS)test with single particle diamond indenter on SiCp/Al composite to study the removal mechanism.Tests were done to compare the material removal of SiCp/Al under UVAS and traditional scratches in terms of scratch morphology in order to find the material removal mechanism of the composites.It was shown that large particles were obserseved in grooves caused by traditional scratches,but small chipping were found in the grooves of ultrasonic scrathes, which indicated material removal ratio of ultrasonic scrathes was higher than that of traditional ones.To sum up,it was an effective way to study the matrial removal mechanism of SiCp/Al composite with UVAS.

  17. Effect of aluminium in propellant composition on acoustic emission parameters (Short Communication

    Directory of Open Access Journals (Sweden)

    Rm. Muthiah

    2001-04-01

    Full Text Available The study reports the variation in acoustic emission signals acquired during combustion of typical propellants with varying aluminium and ammonium perchlorate content. It was observed that when propellant strands having the same composition undergo combustion under similar conditions, they produce consistent acoustic emission signals. To study the effect of variation of aluminium content in the propellant composition on the acoustic emission produced during combustion, the aluminium content was varied from 6 per cent to 18 per cent in a HTPB-based composite propellant with 86 per cent solid loading. Experiments were carried out with propellant strands under the same conditions for a comparative study. Acoustic emission parameters, such as peak amplitude, ring-down counts, average frequency, hits and energy were studied as functions of time. Among these parameters, only energy ring-down counts and frequency varied significantly with aluminium content. The effect of cumulative values of energy, frequency and ring-down counts, the effect of burn rate and theoretical specific impulse against the aluminium percentage variation, and the variation of specific impulse against acoustic energy can all be correlated. The clear trend is indicative of possible prediction of propellant performance parameter like specific impulse from acoustic emission parameters.

  18. Steel sheet composite materials with foamed aluminium; Stahlblechverbundwerkstoffe mit geschaeumtem Aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Baumeister, J.; Weber, M. [Institut fuer Angewandte Materialforschung, Bremen (Germany); Bleck, W.; Hagen, H. von [Technische Hochschule Aachen (Germany). Lehrstuhl und Inst. fuer Eisenhuettenkunde

    1999-07-01

    Sandwich structured steel sheets with a core of foamed aluminium can be produced by roll-bonding and glueing. Results of corrosion tests and laser welding tests so far were positive. Several applications have been proposed but none of them has been implemented as yet. The material is recommended for applications with a profile of requirements comprising structurally and functionally relevant characteristics. Recycling is unproblematic. [German] Zur Herstellung von Stahlblechsandwichverbunden mit einem Aluminiumschaumkern lassen sich die Verfahren Walzplattieren und Kleben einsetzen. Es sind Sandwichverbunde mit Gesamtdichten von 0,7 bis 2,0 g/cm{sup 3} und Gesamtdicken zwischen 10 und 32 mm darstellbar. Die Tafelgroessen fuer die vielversprechendsten Verfahren liegen derzeit bei ueber DIN A3 (konventionell geschaeumt) oder 160 mm x mehrere m (kontinuierlich im Banddurchlaufofen geschaeumt) und 2 m x 600 mm (geklebt). Es lassen sich gute mechanische Eigenschaften des Sandwichverbundes (Biegesteifigkeit) und hohe Versagensreserven bei Druck- und Biegebeanspruchungen sowie interessante funktionelle Eigenschaften (z.B. hohe Energieaufnahme) erzielen. Aus Tastversuchen zu Korrosionseigenschaften und Fuegeverfahren (Laserschweissen) konnten positive Resultate gewonnen werden. Vorschlaege zu Anwendungen bestehen, aber ein direkter Einsatz ist noch nicht realisiert worden. Ein Einsatz des Werkstoffverbundes ist sinnvoll in Gebieten, in denen ein Anforderungsprofil von strukturell und funktionell relevanten Eigenschaften vorherrscht. Das Recycling der rein metallischen Verbunde ist problemlos. (orig.)

  19. Alkali-Activated Aluminium-Silicate Composites as Insulation Materials for Industrial Application

    Science.gov (United States)

    Dembovska, L.; Bajare, D.; Pundiene, I.; Bumanis, G.

    2015-11-01

    The article reports on the study of thermal stability of alkali-activated aluminium- silicate composites (ASC) at temperature 800-1100°C. ASC were prepared by using calcined kaolinite clay, aluminium scrap recycling waste, lead-silicate glass waste and quartz sand. As alkali activator, commercial sodium silicate solution modified with an addition of sodium hydroxide was used. The obtained alkali activation solution had silica modulus Ms=1.67. Components of aluminium scrap recycling waste (aluminium nitride (AlN) and iron sulphite (FeSO3)) react in the alkali media and create gases - ammonia and sulphur dioxide, which provide the porous structure of the material [1]. Changes in the chemical composition of ASC during heating were identified and quantitatively analysed by using DTA/TG, dimension changes during the heating process were determined by using HTOM, pore microstructure was examined by SEM, and mineralogical composition of ASC was determined by XRD. The density of ASC was measured in accordance with EN 1097-7. ASC with density around 560 kg/m3 and heat resistance up to 1100°C with shrinkage less than 5% were obtained. The intended use of this material is the application as an insulation material for industrial purposes at elevated temperatures.

  20. Microwave Processed Multifunctional Polymer Matrix Composites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA has identified polymer matrix composites (PMCs) as a critical need for launch and in-space vehicles, but the significant costs of such materials limits their...

  1. Spark plasma sintering of aluminum matrix composites

    Science.gov (United States)

    Yadav, Vineet

    2011-12-01

    Aluminum matrix composites make a distinct category of advanced engineering materials having superior properties over conventional aluminum alloys. Aluminum matrix composites exhibit high hardness, yield strength, and excellent wear and corrosion resistance. Due to these attractive properties, aluminum matrix composites materials have many structural applications in the automotive and the aerospace industries. In this thesis, efforts are made to process high strength aluminum matrix composites which can be useful in the applications of light weight and strong materials. Spark Plasma Sintering (SPS) is a relatively novel process where powder mixture is consolidated under the simultaneous influence of uniaxial pressure and pulsed direct current. In this work, SPS was used to process aluminum matrix composites having three different reinforcements: multi-wall carbon nanotubes (MWCNTs), silicon carbide (SiC), and iron-based metallic glass (MG). In Al-CNT composites, significant improvement in micro-hardness, nano-hardness, and compressive yield strength was observed. The Al-CNT composites further exhibited improved wear resistance and lower friction coefficient due to strengthening and self-lubricating effects of CNTs. In Al-SiC and Al-MG composites, microstructure, densification, and tribological behaviors were also studied. Reinforcing MG and SiC also resulted in increase in micro-hardness and wear resistance.

  2. Resolidification of metal matrix composites in microgravity

    Energy Technology Data Exchange (ETDEWEB)

    Vugt, L. van; Froyen, L. [Leuven Univ., Heverlee (BE). Dept. of Metallurgy and Materials Engineering (MTM)

    2000-07-01

    During EuroMIR 94 (Altibor) and EuroMIR 95 (Alinsitu) space experiments, the influence of gravity on segregation and clustering of ceramic particles in an aluminium matrix is investigated, in combination with the effect of the thermal gradient and cooling rate. The reinforcements were respectively TiB{sub 2} and SiC. On comparison with the ground processed reference samples it appears that the distribution of the particles in the resolidified material is much more homogeneous, due to sedimentation of the reinforcements. On microscopic scale, differences in particle distribution can be found at a slow and fast cooling. The agglomeration of particles increases with a decreasing of the thermal gradient. In all used systems the particles arranged as a three dimensional skeleton during the liquid state, which interact with the solid-liquid interface during solidification. (orig.)

  3. Polypropylene matrix composites reinforced with coconut fibers

    OpenAIRE

    Maria Virginia Gelfuso; Pedro Vieira Gurgel da Silva; Daniel Thomazini

    2011-01-01

    Polypropylene matrix composites reinforced with treated coconut fibers were produced. Fibers chemically treated (alkalization-CCUV samples) or mechanically treated (ultrasonic shockwave-CMUV samples) were dried using UV radiation. The goal was to combine low cost and eco-friendly treatments to improve fiber-matrix adhesion. Composite samples containing up to 20 vol. (%) of untreated and treated coconut fibers were taken from boxes fabricated by injection molding. Water absorption and mechanic...

  4. Manufacturing Titanium Metal Matrix Composites by Consolidating Matrix Coated Fibres

    Institute of Scientific and Technical Information of China (English)

    Hua-Xin PENG

    2005-01-01

    Titanium metal matrix composites (TiMMCs) reinforced by continuous silicon carbide fibres are being developed for aerospace applications. TiMMCs manufactured by the consolidation of matrix-coated fibre (MCF) method offer optimum properties because of the resulting uniform fibre distribution, minimum fibre damage and fibre volume fraction control. In this paper, the consolidation of Ti-6Al-4V matrix-coated SiC fibres during vacuum hot pressing has been investigated. Experiments were carried out on multi-ply MCFs under vacuum hot pressing (VHP). In contrast to most of existing studies, the fibre arrangement has been carefully controlled either in square or hexagonal arraysthroughout the consolidated sample. This has enabled the dynamic consolidation behaviour of MCFs to be demonstrated by eliminating the fibre re-arrangement during the VHP process. The microstructural evolution of the matrix coating was reported and the deformation mechanisms involved were discussed.

  5. Manufacturing of aluminium nano hybrid composites: a state of review

    Science.gov (United States)

    Madhukar, P.; Selvaraj, N.; Rao, CSP

    2016-09-01

    This paper gives the details of hybrid composites, their fabrication methods and evaluation of mechanical, tribological behaviour and machining characteristics. Investigations on the various aspects of Hybrid composites furnish several conclusions regarding the influence of various parameters on the performance of the composites. Mostly micro structures of the hybrid composites fabricated through casting routes have been found to be stable with the distribution of uniformed reinforce particles. therefore, the hybrid composites can be constructed with various combinations of reinforcements to carry out desirable mechanical properties. The density of Hybrid composites increases with increasing reinforcements such as SiC, TiC, B4C....etc, while incorporation of partial reinforcements like fly ash, mica, rice husk, etc. reduces the density of composites. The study also reports that the hybrid composites can be treated as a replacement for regular composite materials in different advanced applications.

  6. Early age corrosion of aluminium in calcium sulfo-aluminate cement based composites

    International Nuclear Information System (INIS)

    At present, encapsulation of low level and intermediate level nuclear wastes using Portland Cement (PC) based matrices is a preferred approach. However, it is now widely accepted that the high pH of the pore solution of these PC-based matrices (usually above pH 12.5) can cause concerns over the stability of certain wastes containing reactive metals, such as aluminium and uranium. One potential low pH system for reducing the corrosion of aluminium is calcium sulfo-aluminate cement (CSA). However, significant heat could be generated from the hydration of CSA, causing another concern to the nuclear industry. In the current study, various additives, namely pulverized fuel ash (PFA), ground granulated blast furnace slag (GGBS) and limestone powder (LSP) were used to replace part of the CSA in order to reduce the heat output. The results indicated that the replacement of CSA with GGBS, PFA and LSP can reduce the heat output of 100% CSA, although it is still higher than the control GGBS/PC 9:1 system. The corrosion rate of aluminium in each of the CSA composites was slightly higher than 100% CSA, however, all the CSA systems had corrosion rates lower than GGBS/PC 9:1 after 15 hours. Therefore, the composite CSA systems investigated in this study provide a good compromise between the heat output and the resistance to the corrosion of aluminium. Hence, offers a good potential for dealing with some historical nuclear wastes where the corrosion of aluminium is a concern. (authors)

  7. 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.

  8. Intermetallic bonded ceramic matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Plucknett, K.P.; Tiegs, T.N.; Alexander, K.B.; Becher, P.F.; Schneibel, J.H.; Waters, S.B.; Menchhofer, P.A. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

    1995-07-01

    A range of carbide and oxide-based cermets have been developed utilizing ductile nickel aluminide (Ni{sub 3}Al) alloy binder phases. Some of these, notably materials based upon tungsten and titanium carbides (WC and TiC respectively), offer potential as alternatives to the cermets which use cobalt binders (i.e. WC/Co). Samples have been prepared by blending commercially available Ni{sub 3}Al alloy powders with the desired ceramic phases, followed by hot-pressing. Alumina (Al{sub 2}O{sub 3}) matrix materials have also been prepared by pressurized molten alloy infiltration. The microstructure, flexure strength and fracture toughness of selected materials are discussed.

  9. MECHANICAL PROPERTY EVALUATION OF A356/SiCp/Gr METAL MATRIX COMPOSITES

    Directory of Open Access Journals (Sweden)

    B. M. VISWANATHA

    2013-12-01

    Full Text Available In the present investigation, studies on microstructure and mechanical properties of Aluminium Matrix Composites (AMCs reinforced with silicon carbide (SiCp and graphite (Gr particles. A356 alloy is used as the matrix material with varying the reinforcement of SiCp from 0 to 9 wt% in steps of 3 wt% and fixed quantity of 3 wt% of graphite. The composites were fabricated by liquid metallurgy method. The prepared composites were examined for microstructure to know the particle distribution in the matrix material. Hardness and tensile properties were studied and compared with the alloy. There was a significant improvement in hardness and tensile properties by increasing the weight percentage of SiC particles.

  10. Study on sintering technique of NiFe2O4/SiCp used as matrix of inert anodes in aluminium electrolysis

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Shu-ting; YAO; Guang-chun; LIU; Yi-han

    2005-01-01

    In order to improve deficiencies of NiFe2O4 spinel used as matrix of inert anode in aluminium electrolysis, NiFe2O4/SiCp were prepared by the solid state reaction for the first time. Microstructural changes were observed by scanning electronic microscope and phase was determined with X-ray detector. Effect of sintering temperature and times on density, porosity and microstructure were researched, and the reasons that caused the difference were discussed deeply. At the same time the thermodynamical compatibility of NiFe2O4 and SiC was proved under 1200℃ by DTA.The results showed that the microstructure was more homogeneous when the sintering temperature reached 1 180℃and the density attained their maximum about 6 h sintering. The appropriate sintering technique of NiFe2 O4/SiCw composite materials was 1180℃× 6 h.

  11. Drilling of polymer-matrix composites

    CERN Document Server

    Krishnaraj, Vijayan; Davim, J Paulo

    2013-01-01

    Polymeric composites are recognised as good candidates for structural components due to their inherent properties. However, they present several kinds of damages while creating holes for assembly. Delamination is considered the most serious damage since it reduces service life of the component. Thrust and delamination can be controlled by proper drill point geometry. Drilling at high speed is also a current requirement of the aerospace industry. This book focus on drilling of polymer matrix composites for aerospace and defence applications. The book presents introduction to machining of polymer composites and discusses drilling as a processing of composites.

  12. Wear performance of garnet aluminium composites at high contact pressure

    Science.gov (United States)

    Sharma, Anju; Arora, Rama; Kumar, Suresh; Singh, Gurmel; Pandey, O. P.

    2016-05-01

    To satisfy the needs of the engineering sector, researchers and material scientists in this area adopted the development of composites with tailor made properties to enhance efficiency and cost savings in the manufacturing sector. The technology of the mineral industry is shaping the supply and demand of minerals derived materials. The composites are best classified as high performance materials have high strength-to-weight ratios, and require controlled manufacturing environments for optimum performance. Natural mineral garnet was used as the reinforcement of composite because of satisfactory mechanical properties as well as an attractive ecological alternative to others ceramics. For this purpose, samples have been prepared with different sizesof the garnet reinforcement using the mechanical stirring method to achieve the homogeneously dispersed strengthening phase. A systematic study of the effect of high contact pressure on the sliding wear behaviour of garnet reinforced LM13 alloy composites is presented in this paper. The SEM analysis of the worn samples and debris reveals the clues about the wear mechanism. The drastic improvement in the wear resistance of the composites at high contact pressure shows the high potential of the material to be used in engineering applications.

  13. Effect of type and percentage of reinforcement for optimization of the cutting force in turning of Aluminium matrix nanocomposites using response surface methodologies

    Energy Technology Data Exchange (ETDEWEB)

    Priyadarshi, Devinder [DAV Institute of Engineering and Technology, Jalandhar (India); Sharma, Rajesh Kumar [Institute of Technology, Hamirpur (India)

    2016-03-15

    Aluminium matrix composites (AMCs) now hold a significant share of raw materials in many applications. It is of prime importance to study the machinability of such composites so as to enhance their applicability. Sufficient work has been done for studying the machining of AMCs with particle reinforcements of micron range. This paper presents the study of AMCs with particle reinforcement of under micron range i.e. nanoparticles. This paper brings out the results of an experimental investigation of type and weight percent of nanoparticles on the tangential cutting force during turning operation. SiC, Gr and SiC-Gr (in equal proportions) were used with Al-6061 alloy as the matrix phase. The results indicate that composites with SiC require greater cutting force followed by hybrid and then Gr. Increase in the weight percent also significantly affected the magnitude of cutting force. RSM was used first to design and analyze the experiments and then to optimize the turning process and obtain optimal conditions of weight and type of reinforcements for turning operation.

  14. Development of Matrix Microstructures in UHTC Composites

    Science.gov (United States)

    Johnson, Sylvia; Stackpoole, Margaret; Gusman, Michael

    2012-01-01

    One of the major issues hindering the use of ultra high temperature ceramics for aerospace applications is low fracture toughness. There is considerable interest in developing fiber-reinforced composites to improve fracture toughness. Considerable knowledge has been gained in controlling and improving the microstructure of monolithic UHTCs, and this paper addresses the question of transferring that knowledge to composites. Some model composites have been made and the microstructures of the matrix developed has been explored and compared to the microstructure of monolithic materials in the hafnium diboride/silicon carbide family. Both 2D and 3D weaves have been impregnated and processed.

  15. Diamond/aluminium nitride composites for efficient thermal management applications

    Science.gov (United States)

    Cervenka, J.; Dontschuk, N.; Ladouceur, F.; Duvall, S. G.; Prawer, S.

    2012-07-01

    Synthetic diamond/AlN composite materials have been fabricated by a combination of microwave plasma-assisted chemical vapor deposition and molecular beam epitaxy. These wide band gap semiconductor heterojunctions show promises for many applications, including thermal management, deep ultraviolet light emitting devices, and high power and high temperature electronics. Here, we report results of an interface study of polycrystalline diamond layers grown on single crystal AlN(0001). High resolution transmission microscopy revealed atomically sharp interfaces between diamond and AlN. Temperature dependent Raman spectroscopy measurements showed reduced thermal resistance on diamond-coated AlN substrates compared to uncoated AlN at temperatures above 330 K.

  16. Emerging Trends in Polymer Matrix Composites .

    Directory of Open Access Journals (Sweden)

    Vikas M. Nadkarni

    1993-10-01

    Full Text Available The performance characteristics of PMC products are determined by the microstructure developed during the processing of composite materials. The structure development in processing is the result of integration of process parameters and inherent material characteristics. The properties of PMCs can thus be manipulated through both changes in the materials composition and process conditions. The present article illustrates the scientific approach followed in engineering of matrix materials and optimization of the processing conditions with specific reference to case studies on toughening of thermosetting resins and structure development in injection molding of thermoplastic composites. A novel approach is demonstrated for toughening of unsaturated polyester resins that involves the use of reactive liquid polymers chemically bonded to the matrix. The use of processing science is demonstrated by the significant effect of the mold temperature on the crystallinity and properties of molded poly (phenylene sulfide, a high performance engineering thermoplastic. An interactive approach is proposed for specific product and applications development.

  17. Machinability of Al-SiC metal matrix composites using WC, PCD and MCD inserts

    Energy Technology Data Exchange (ETDEWEB)

    Beristain, J.; Gonzalo, O.; Sanda, A.

    2014-04-01

    The aim of this work is the study of the machinability of aluminium-silicon carbide Metal Matrix Composites (MMC) in turning operations. The cutting tools used were hard metal (WC) with and without coating, different grades and geometries of Poly-Crystalline Diamond (PCD) and Mono-Crystalline Diamond (MCD). The work piece material was AMC225xe, composed of aluminium-copper alloy AA 2124 and 25% wt of SiC, being the size of the SiC particles around 3 {mu}m. Experiments were conducted at various cutting speeds and cutting parameters in facing finishing operations, measuring the surface roughness, cutting forces and tool wear. The worn surface of the cutting tool was examined by Scanning Electron Microscope (SEM). It was observed that the Built Up Edge (BUE) and stuck material is higher in the MCD tools than in the PCD tools. The BUE acts as a protective layer against abrasive wear of the tool. (Author)

  18. High Strain-Rate Mechanical Behaviour of a Copper Matrix Composite for Nuclear Applications

    CERN Document Server

    Peroni, L

    2012-01-01

    Aim of this work is the investigation of mechanical behaviour of an alumina dispersion strengthened copper, known by the trade name GLIDCOP®, subjected to dynamic loads: it is a composite material with a copper matrix strengthened with aluminium oxide ceramic particles. Since the particle content is quite small the material keeps the OFE copper physical properties, such as thermal and electrical conductivity, but with a higher yield strength, like a mild-carbon steel. Besides, with the addition of aluminium oxide, the good mechanical properties are retained also at high temperatures and the resistance to thermal softening is increased: the second phase blocks the dislocation movement preventing the grain growth. Thanks to these properties GLIDCOP® finds several applications in particle accelerator technologies, where problems of thermal management, combined with structural requirements, play a key role. Currently, it is used for the construction of structural and functional parts of the particle beam collim...

  19. Experimental Study on Fatigue Characteristics for Aluminium and Al-SiC Composite Material Edge Crack Specimens under Flexural Loading Conditions

    Directory of Open Access Journals (Sweden)

    Shanmugavel P.

    2014-03-01

    Full Text Available Crack propagation studies on an Aluminium plate and Aluminium-Silicon Carbide composite plate under three point bend test conditions were done experimentally and the results so obtained been compared between Isotropic Aluminium and Aluminium-Silicon Carbide composite materials. The specimens with different crack length (a to the depth (d ratios (a/d Ratios were prepared and the fracture characteristics of the specimens with different a/d ratios have been obtained experimentally and analyzed. The analysis has been done for both the Isotropic Aluminium and Aluminium-Silicon Carbide composite material specimens with different a/d ratios. A comparative analysis between the fracture characteristics of the Aluminium and Aluminium-Silicon Carbide composite material specimens for the same a/d ratio has been done and the results been plotted. Also the fractography at the cracked surface of the Aluminium and Aluminium-Silicon Carbide composite material specimens were undertaken along with the microstructures of these specimens. An attempt has been made to relate the fracture location and propagation to the microstructure of the material specimens.

  20. Characterization and Empirical Modelling of Sliding Wear on Sintered Aluminium-Graphite Composites

    Directory of Open Access Journals (Sweden)

    Amrishraj Doraisamy

    2014-01-01

    Full Text Available Aluminium-graphite composites were synthesized using powder metallurgy route. Graphite was added as reinforcement in the range of 0, 3, and 6 weight % and composites were prepared by P/M. Microstructural analysis of the newly synthesized composites was carried out using SEM. The hardness of the composites was studied using Vickers microhardness tester, by applying a load of 1 kg for 5 sec. Also the amount of porosity was determined. Further the wear test was conducted on the sintered specimens using pin-on-disc wear apparatus according to ASTM-G99 standards. A regression model was developed to predict the wear rate of the specimen. Then the worn images were studied using SEM based on response surface methodology in order to understand the various wear mechanisms involved. The study revealed that mild wear, oxidational wear, plowing, cutting, and plastic deformation are the main mechanisms responsible for causing the wear.

  1. Evaluation of the mechanical properties and corrosion behaviour of coconut shell ash reinforced aluminium (6063) alloy composites

    OpenAIRE

    Oluyemi O. DARAMOLA; Adeolu A.ADEDIRAN; Ayodele T. FADUMIYE

    2015-01-01

    Aluminium 6063/Coconut shell ash (CSAp) composites having 3-12 weight percent (wt%) coconut shell ash were fabricated by double stir-casting method. The microstructure, ultimate tensile strength, hardness values, density and corrosion behaviour in 0.3M H2SO4 and 3.5wt% NaCl solution of the composites were evaluated. The density of the composites exhibit a linear and proportional decreased as the percentage of coconut shell ash increases in the aluminium alloy. It implies tha...

  2. Polypropylene matrix composites reinforced with coconut fibers

    Directory of Open Access Journals (Sweden)

    Maria Virginia Gelfuso

    2011-09-01

    Full Text Available Polypropylene matrix composites reinforced with treated coconut fibers were produced. Fibers chemically treated (alkalization-CCUV samples or mechanically treated (ultrasonic shockwave-CMUV samples were dried using UV radiation. The goal was to combine low cost and eco-friendly treatments to improve fiber-matrix adhesion. Composite samples containing up to 20 vol. (% of untreated and treated coconut fibers were taken from boxes fabricated by injection molding. Water absorption and mechanical properties were investigated according to ASTM D570-98 and ASTM D638-03, respectively. Electrical characterizations were carried out to identify applications of these composites in the electrical sector. NBR 10296-Electrical Tracking Standard (specific to industry applications and conductivity measurements were obtained applying 5 kV DC to the samples. CMUV samples containing 5 vol. (% fiber presented superior tensile strength values (σ~28 MPa compared to the untreated fibers composite (σ~22 MPa or alkali treatment (σ~24 MPa. However, CMUV composites containing 10 vol. (% fiber presented best results for the electrical tracking test and electrical resistivity (3 × 10(7 Ω.m. The results suggest that composites reinforced with mechanically treated coconut fibers are suitable for electrical applications.

  3. Process optimization in Nd:YAG laser microdrilling of alumina–aluminium interpenetrating phase composite

    Directory of Open Access Journals (Sweden)

    Ranjib Biswas

    2015-07-01

    Full Text Available In laser beam micromachining process, the quality of the drilled hole is of great importance. The quality of the microdrilled hole mainly depends on appropriate selection of process parameters. Predefined diameter of hole with minimum taper is of today's demand. The composite used for microdrilling operation is alumina–aluminium (Al2O3–Al interpenetrating phase composite (IPC, which is widely used in aircraft and space stations. Until date, no experimental study has been done to obtain microdrilled hole of desired diameter. In the present paper three hole qualities such as hole diameter at entry, at exit and hole taper have been optimized individually as well as simultaneously using a central composite design (CCD based on response surface methodology (RSM during pulsed Nd:YAG laser microdrilling operation on alumina–aluminium IPC sheet of 1.14 mm thickness. The analysis of variance (ANOVA test has also been done to identify the process parameters that contributed the most to get desired hole quality.

  4. Curing of epoxy matrix composite in stratosphere

    Science.gov (United States)

    Kondyurin, Alexey; Kondyurina, Irina; Bilek, Marcela

    Large structures for habitats, greenhouses, space bases, space factories are needed for next stage of space exploitation. A new approach enabling large-size constructions in space relies on the use of the polymerization technology of fiber-filled composites with a curable polymer matrix applied in the free space environment. The polymerisation process is proposed for the material exposed to high vacuum, dramatic temperature changes, space plasma, sun irradiation and atomic oxygen (in low Earth orbit), micrometeorite fluence, electric charging and microgravitation. The stratospheric flight experiments are directed to an investigation of the curing polymer matrix under the stratospheric conditions on. The unique combination of low atmospheric pressure, high intensity UV radiation including short wavelength UV and diurnal temperature variations associated with solar irradiation strongly influences the chemical processes in polymeric materials. The first flight experiment with uncured composites was a part of the NASA scientific balloon flight program realised at the NASA stratospheric balloon station in Alice Springs, Australia. A flight cassette installed on payload was lifted with a “zero-pressure” stratospheric balloon filled with Helium. Columbia Scientific Balloon Facility (CSBF) provided the launch, flight telemetry and landing of the balloon and payload. A cassette of uncured composite materials with an epoxy resin matrix was exposed 3 days in the stratosphere (40 km altitude). The second flight experiment was realised in South Australia in 2012, when the cassette was exposed in 27 km altitude. An analysis of the chemical structure of the composites showed, that the space irradiations are responsible for crosslinking of the uncured polymers exposed in the stratosphere. The first prepreg in the world was cured successfully in stratosphere. The investigations were supported by Alexander von Humboldt Foundation, NASA and RFBR (12-08-00970) grants.

  5. Influence of cold rolling and fatigue on the residual stress state of a metal matrix composite

    International Nuclear Information System (INIS)

    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.)

  6. Nanotube reinforced thermoplastic polymer matrix composites

    Science.gov (United States)

    Shofner, Meisha Lei

    The inherent high strength, thermal conductivity, and electrical conductivity make nanotubes attractive reinforcements for polymer matrix composites. However, the structure that makes them desirable also causes highly anisotropic properties and limited reactivity with other materials. This thesis isolates these problems in two separate studies aimed at improving mechanical properties with single wall nanotube (SWNT) reinforced thermoplastic polymer composites. The two studies demonstrate the effect of solid freeform fabrication (SFF) and chemical functionalization on anisotropy and limited reactivity, respectively. Both studies showed mechanical property improvements. The alignment study demonstrates a maximum increase of 93% in tensile modulus with single wall nanotubes (SWNTs). The chemical functionalization study shows a larger increase in storage modulus for functionalized SWNTs as compared to purified SVWNTs with respective increases of 9% and 44% in storage modulus. Improved interfacial properties are also observed as a decrease in mechanical damping. Maximum property increases in composites are obtained when nanotubes are aligned, requiring additional processing consideration to the anisotropic structure. Melt spinning and extrusion processing effectively align nanotubes, but the end product of these techniques, composite fibers, requires further processing to be incorporated into finished parts. Extrusion-based SFF is a novel technique for processing nanotube reinforced composites because it allows for the direct fabrication of finished parts containing aligned nanotubes. SFF processing produces parts containing preferentially oriented nanotubes with improved mechanical properties when compared to isotropic composites. Functionalization of the nanotube surface disrupts the rope structure to obtain smaller ropes and promote further interfacial bonding. The chemically inert nature of nanotubes resulting from a structure containing few defects and the

  7. Production and characterization of Al-Mg matrix composite by mechanical alloying

    International Nuclear Information System (INIS)

    Mechanical alloying technique has been used to produce aluminium-based metal matrix composite powders. Powders of AI, Mg (5 wt %) and SiC (10-40 vol %) were used for the composite development. These powders were mechanically mixed in planetary ball mill (Retsch PM 200). The parameters used were 10:1 ball to powder weight ratio, 800 rpm speed of vial rotation and WC as grinding media. These milled powders were characterized by XRD. Mechanical alloying for the production of composite was achieved in only one step. There was decrease in density with the increase of contents of SiC. Compacted samples were sintered at 580 Co for 80 minutes. Maximum density achieved was 98.7% for composite containing 40 % SiC. Vickers hardness of consolidated samples was found to increase with the increase of SiC contents. (author)

  8. Shock wave profiles in polymer matrix composite

    Science.gov (United States)

    Boteler, J. Michael; Rajendran, A. M.; Grove, David

    2000-04-01

    The promise of lightweight armor which is also structurally robust is of particular importance to the Army for future combat vehicles. Fiber reinforced organic matrix composites such as Polymer Matrix Composite (PMC) are being considered for this purpose due to their lower density and promising dynamic response. The work discussed here extends the prior work of Boteler who studied the delamination strength of PMC and Dandekar and Beaulieu who investigated the compressive and tensile strengths of PMC. In a series of shock wave experiments, the wave profile was examined as a function of propagation distance in PMC. Uniaxial strain was achieved by symmetric plate impact in the ARL 102 mm bore single-stage light gas gun. Embedded polyvinylidene flouride (PVDF) stress-rate gauges provided a stress history at three unique locations in the PMC and particle velocity history was recorded with VISAR. All stress data was compared to a Lagrangian hydrocode (EPIC) employing a model to describe the viscoelastic response of the composite material in one-dimension. The experimental stress histories displayed attenuation and loading properties in good agreement with model predictions. However, the unloading was observed to be markedly different than the hydrocode simulations. These results are discussed.

  9. Metal-Matrix/Hollow-Ceramic-Sphere Composites

    Science.gov (United States)

    Baker, Dean M.

    2011-01-01

    A family of metal/ceramic composite materials has been developed that are relatively inexpensive, lightweight alternatives to structural materials that are typified by beryllium, aluminum, and graphite/epoxy composites. These metal/ceramic composites were originally intended to replace beryllium (which is toxic and expensive) as a structural material for lightweight mirrors for aerospace applications. These materials also have potential utility in automotive and many other terrestrial applications in which there are requirements for lightweight materials that have high strengths and other tailorable properties as described below. The ceramic component of a material in this family consists of hollow ceramic spheres that have been formulated to be lightweight (0.5 g/cm3) and have high crush strength [40.80 ksi (.276.552 MPa)]. The hollow spheres are coated with a metal to enhance a specific performance . such as shielding against radiation (cosmic rays or x rays) or against electromagnetic interference at radio and lower frequencies, or a material to reduce the coefficient of thermal expansion (CTE) of the final composite material, and/or materials to mitigate any mismatch between the spheres and the matrix metal. Because of the high crush strength of the spheres, the initial composite workpiece can be forged or extruded into a high-strength part. The total time taken in processing from the raw ingredients to a finished part is typically 10 to 14 days depending on machining required.

  10. Optimisation of the rivet joints of the CFRP composite material and aluminium alloy

    Directory of Open Access Journals (Sweden)

    A. Czulak

    2007-01-01

    Full Text Available Purpose: The project included analysis of strain, cracking, and failure of riveted joints of plate elements madefrom the carbon-fibre-reinforced plastics (CFRP and from the 6061 aluminium alloy.Design/methodology/approach: The modelled static tensile strength test carried out for the plates from CFRPand from the 6061 aluminium alloy joined with the steel rivet. Computer simulation was carried out with IDEASsoftware package employing the FEM.Findings: Simulations using the mesh with a bigger number of FEM elements do not yield better accuracy ofcalculations and do not improve convergence with the results of laboratory experiments. Only the calculationtime gets longer. Computer simulation has also show that the type of contacts employed between elementsaffects the results significantly.Research limitations/implications: For the composite materials, joints between materials and computersimulation examinations are planed.Practical implications: Results obtained for the mesh with 4 and 5 FEM elements are the closest to the resultsof laboratory experiments, which is confirmed by the strain plot. Simulations using the mesh with a biggernumber of FEM elements do not yield better accuracy of calculations and do not improve convergence with theresults of laboratory experiments. Only the calculation time gets longer. Computer simulation has show that thetype of contacts employed between elements affects the results significantly.Originality/value: The paper presents influence of fibre mesh closeness on convergence of the results with laboratorytests. Simulation results were collected and compared with the laboratory static tensile strength tests results.

  11. Investigation and in situ removal of spatter generated during laser ablation of aluminium composites

    Science.gov (United States)

    Popescu, A. C.; Delval, C.; Shadman, S.; Leparoux, M.

    2016-08-01

    Spatter generated during laser irradiation of an aluminium alloy nanocomposite (AlMg5 reinforced with Al2O3 nanoparticles) was monitored by high speed imaging. Droplets trajectory and speed were assessed by computerized image analysis. The effects of laser peak power and laser focusing on the plume expansion and expulsed droplet speeds were studied in air or under argon flow. It was found that the velocity of visible droplets expulsed laterally or at the end of the plume emission from the metal surface was not dependent on the plasma plume speed. The neighbouring area of irradiation sites was studied by optical and scanning electron microscopy. Droplets deposited on the surface were classified according to their size and counted using a digital image processing software. It was observed that the number of droplets on surface was 1.5-3 times higher when the laser beam was focused in depth as compared to focused beams, even though the populations average diameter were comparable. Three methods were selected for removing droplets in situ, during plume expansion: an argon gas jet crossing the plasma plume, a fused silica plate collector transparent to the laser wavelength placed parallel to the irradiated surface and a mask placed onto the aluminium composite surface. The argon gas jet was efficient only for low power irradiation conditions, the fused silica plate failed in all tested conditions and the mask was successful for all irradiation regimes.

  12. Graphite fiber reinforced glass matrix composites for aerospace applications

    Science.gov (United States)

    Prewo, K. M.; Bacon, J. F.; Dicus, D. L.

    1979-01-01

    The graphite fiber reinforced glass matrix composite system is described. Although this composite is not yet a mature material, it possesses low density, attractive mechanical properties at elevated temperatures, and good environmental stability. Properties are reported for a borosilicate glass matrix unidirectionally reinforced with 60 volume percent HMS graphite fiber. The flexural strength and fatigue characteristics at room and elevated temperature, resistance to thermal cycling and continuous high temperature oxidation, and thermal expansion characteristics of the composite are reported. The properties of this new composite are compared to those of advanced resin and metal matrix composites showing that graphite fiber reinforced glass matrix composites are attractive for aerospace applications.

  13. 多层喷射沉积颗粒增强铝基复合材料的研究现状与发展趋势%Current State and Developing Trends of Multiinlayer Spray Deposited Aluminium Matrix Composites Reinforced with Particles

    Institute of Scientific and Technical Information of China (English)

    贺毅强; 陈志钢

    2012-01-01

    Multi-layer spray deposition technology employed to make particle reinforced aluminum matrix composites can promote the effect of fast cooling, refine and homogenize microstructure, narrow the particle size distribution and optimize the particles and matrix bonding. In this paper, the current situations of R~D of spray deposited aluminum matrix composites, the principles and processing parameters of multi-layer spray deposition are reviewed. The developments of spray deposited A1-Zn-Mg, A1-Fe and A1-Si matrix composites are summarized. Densification methods for spray deposited aluminum matrix composites, especially novel methods including wedge pressing, cage rolling, ceramics rolling, and hot pressing for bulk preform compacted on a light tonnage equipment are emphasized. Developing trends of multi-layer spray deposited aluminum matrix composites are also presented. It is Considered that the bonding of the interface between the reinforcement particles and the aluminum matrix needs to be optimized. Multi-layer spray deposition has been invented to preparing bulk parts with uniform and high density in a programmable control. Densifieation methods are also developed towards light tonnage compact bulk preform. And the forming ability of the bulk deposits can be enhanced effectively by hot and wedge pressing, and then benefitting the deformation in next step.%通过多层喷射沉积技术制备颗粒增强铝基复合材料,强化了冷却效果,能获得细小均匀的显微组织,优化复合材料中增强相的分布及其与基体的结合状态。本文综述了喷射沉积颗粒增强铝基复合材料的发展现状;介绍了多层喷射沉积技术的原理与工艺参数;概述了喷射沉积颗粒增强Al-Zn—Mg系、Al—Fe系与Al-Si系复合材料;并介绍喷射沉积颗粒增强铝基复合材料的致密化技术,着重介绍在小吨位设备上致密大块多孔材料的楔形压制工艺、外框限制轧制、陶粒包覆轧制工

  14. Characterization of Hybrid CNT Polymer Matrix Composites

    Science.gov (United States)

    Grimsley, Brian W.; Cano, Roberto J.; Kinney, Megan C.; Pressley, James; Sauti, Godfrey; Czabaj, Michael W.; Kim, Jae-Woo; Siochi, Emilie J.

    2015-01-01

    Carbon nanotubes (CNTs) have been studied extensively since their discovery and demonstrated at the nanoscale superior mechanical, electrical and thermal properties in comparison to micro and macro scale properties of conventional engineering materials. This combination of properties suggests their potential to enhance multi-functionality of composites in regions of primary structures on aerospace vehicles where lightweight materials with improved thermal and electrical conductivity are desirable. In this study, hybrid multifunctional polymer matrix composites were fabricated by interleaving layers of CNT sheets into Hexcel® IM7/8552 prepreg, a well-characterized toughened epoxy carbon fiber reinforced polymer (CFRP) composite. The resin content of these interleaved CNT sheets, as well as ply stacking location were varied to determine the effects on the electrical, thermal, and mechanical performance of the composites. The direct-current electrical conductivity of the hybrid CNT composites was characterized by in-line and Montgomery four-probe methods. For [0](sub 20) laminates containing a single layer of CNT sheet between each ply of IM7/8552, in-plane electrical conductivity of the hybrid laminate increased significantly, while in-plane thermal conductivity increased only slightly in comparison to the control IM7/8552 laminates. Photo-microscopy and short beam shear (SBS) strength tests were used to characterize the consolidation quality of the fabricated laminates. Hybrid panels fabricated without any pretreatment of the CNT sheets resulted in a SBS strength reduction of 70 percent. Aligning the tubes and pre-infusing the CNT sheets with resin significantly improved the SBS strength of the hybrid composite To determine the cause of this performance reduction, Mode I and Mode II fracture toughness of the CNT sheet to CFRP interface was characterized by double cantilever beam (DCB) and end notch flexure (ENF) testing, respectively. Results are compared to the

  15. Analysis of Aluminium Nano Composites using Anova in CNC Machining Process

    Directory of Open Access Journals (Sweden)

    Maria Joe Christopher Poonthota Irudaya Raj

    2013-08-01

    Full Text Available The Objective of this work is to reinforce the Aluminum alloy with CNT by Stir Casting Method in different weight percentage of CNT was added to Aluminium separately to make composites and it physical and thermal properties have been investigated using test like tensile, hardness, Micro Structure and XRD. The improvement of mechanical, Physical and thermal properties for both the cases has been compared with pure aluminum. The TAGUCHI – ORTHOGONAL ARRAY experimental technique is used to optimize the machining parameters. The predicted surface roughness was estimated using S/N ratio and compared with actual values. ANOVA analysis is used to find the significant factors affecting the machining process in order to improve the surface characteristics of Al Material.

  16. Appearance of anodised aluminium: Effect of alloy composition and prior surface finish

    DEFF Research Database (Denmark)

    Aggerbeck, Martin; Canulescu, Stela; Dirscherl, Kai;

    2014-01-01

    that the roughness of the as-etched surface increases with the degree of alloying due to second phase particles making the reflection more diffused, and that the as-etched surface morphology is similar to the oxide–substrate interface after anodising. Proper polishing is achieved on hard alloys and the glossy......Effect of alloy composition and prior surface finish on the optical appearance of the anodised layer on aluminium alloys was investigated. Four commercial alloys namely AA1050, Peraluman 706, AA5754, and AA6082 were used for the investigation. Microstructure and surface morphology of the substrate...... prior to anodising were analysed using scanning electron microscopy and atomic force microscopy. The optical appearance of the anodised surface with and without sealing was investigated using a photography setup, photospectrometry and bidirectional reflectance distribution function. It was found...

  17. Chemical composition and morphology of oxidic ceramics at filtration of steel deoxidised by aluminium

    Directory of Open Access Journals (Sweden)

    J. Bažan

    2009-10-01

    Full Text Available Composition and morphology of filter ceramics were investigated during filtration of steel deoxidised by aluminium. Filtration was realized with use of filters based on oxidic ceramics Cr2O3, TiO2, SiO2, ZrO2, Al2O3, 3Al2O3•2SiO2 and MgO•Al2O3. It was established that change of interphase (coating occurs during filtration of steel on the surface of capillaries of ceramics, where content of basic oxidic component decreases. Loss of oxidic component in the coating is replaced by increase of oxides of manganese and iron and it is great extent inversely proportional to the value of Gibbs’ energy of oxide, which forms this initial basis of ceramics.

  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. Formation of aluminium, aluminium nitride and nitrogen clusters via laser ablation of nano aluminium nitride. Laser Desorption Ionisation and Matrix-Assisted Laser Desorption Ionisation Time-of-Flight Mass Spectrometry.

    Science.gov (United States)

    Panyala, Nagender Reddy; Prysiazhnyi, Vadym; Slavíček, Pavel; Černák, Mirko; Havel, Josef

    2011-06-30

    Laser Desorption Ionisation (LDI) and Matrix-Assisted Laser Desorption Ionisation (MALDI) Time-of-Flight Mass Spectrometry (TOFMS) were used to study the pulsed laser ablation of aluminium nitride (AlN) nano powder. The formation of Al(m)(+) (m=1-3), N(n)(+) (n=4, 5), AlN(n)(+) (n=1-5, 19, 21), Al(m)N(+) (m=2-3), Al(3)N(2)(+), Al(9)N(n)(+) (n=5, 7, 9, 11 and 15), Al(11)N(n)(+) (n=4, 6, 10, 12, 19, 21, 23, and 25), and Al(13)N(n)(+) (n=25, 31, 32, 33, 34, 35, and 36) clusters was detected in positive ion mode. Similarly, Al(m)(-) (m=1-3), AlN(n)(-) (n=1-3, 5), Al(m)N(-) (n=2, 3), Al(2)N(n)(-) (n=2-4, 28, 30), N(n)(-) (n=2, 3), Al(4)N(7)(-) Al(8)N(n)(-) (n=1-6), and Al(13)N(n)(-) (n=9, 18, 20, 22, 24, 26, 28, 33, 35, 37, 39, 41 and 43) clusters were observed in negative ion mode. The formation of the stoichiometric Al(10) N(10) cluster was shown to be of low abundance. On the contrary, the laser ablation of nano-AlN led mainly to the formation of nitrogen-rich Al(m)N(n) clusters in both negative and positive ion mode. The stoichiometry of the Al(m)N(n) clusters was determined via isotopic envelope analysis and computer modelling.

  20. Formation of aluminium, aluminium nitride and nitrogen clusters via laser ablation of nano aluminium nitride. Laser Desorption Ionisation and Matrix-Assisted Laser Desorption Ionisation Time-of-Flight Mass Spectrometry.

    Science.gov (United States)

    Panyala, Nagender Reddy; Prysiazhnyi, Vadym; Slavíček, Pavel; Černák, Mirko; Havel, Josef

    2011-06-30

    Laser Desorption Ionisation (LDI) and Matrix-Assisted Laser Desorption Ionisation (MALDI) Time-of-Flight Mass Spectrometry (TOFMS) were used to study the pulsed laser ablation of aluminium nitride (AlN) nano powder. The formation of Al(m)(+) (m=1-3), N(n)(+) (n=4, 5), AlN(n)(+) (n=1-5, 19, 21), Al(m)N(+) (m=2-3), Al(3)N(2)(+), Al(9)N(n)(+) (n=5, 7, 9, 11 and 15), Al(11)N(n)(+) (n=4, 6, 10, 12, 19, 21, 23, and 25), and Al(13)N(n)(+) (n=25, 31, 32, 33, 34, 35, and 36) clusters was detected in positive ion mode. Similarly, Al(m)(-) (m=1-3), AlN(n)(-) (n=1-3, 5), Al(m)N(-) (n=2, 3), Al(2)N(n)(-) (n=2-4, 28, 30), N(n)(-) (n=2, 3), Al(4)N(7)(-) Al(8)N(n)(-) (n=1-6), and Al(13)N(n)(-) (n=9, 18, 20, 22, 24, 26, 28, 33, 35, 37, 39, 41 and 43) clusters were observed in negative ion mode. The formation of the stoichiometric Al(10) N(10) cluster was shown to be of low abundance. On the contrary, the laser ablation of nano-AlN led mainly to the formation of nitrogen-rich Al(m)N(n) clusters in both negative and positive ion mode. The stoichiometry of the Al(m)N(n) clusters was determined via isotopic envelope analysis and computer modelling. PMID:21598328

  1. Influence of in situ formed ZrB2 particles on microstructure and mechanical properties of AA6061 metal matrix composites

    International Nuclear Information System (INIS)

    Highlights: → In situ fabrication of aluminium metal matrix composite reinforced ZrB2 particles. → Colour metallography of composites. → Improvement of matrix properties by ZrB2 particles. → Sliding wear behaviour of in situ composites. - Abstract: Particulate reinforced metal matrix composites (PMMCs) have gained considerable amount of research emphasis and attention in the present era. Research is being carried out across the globe to produce new combination of PMMCs. PMMCs are prepared by adding a variety of ceramic particles with monolithic alloys using several techniques. An attempt has been made to produce aluminium metal matrix composites reinforced with zirconium boride (ZrB2) particles by the in situ reaction of K2ZrF6 and KBF4 salts with molten aluminium. The influence of in situ formed ZrB2 particles on the microstructure and mechanical properties of AA6061 alloy was studied in this work. The in situ formed ZrB2 particles significantly refined the microstructure and enhanced the mechanical properties of AA6061 alloy. The weight percentage of ZrB2 was varied from 0 to 10 in steps of 2.5. Improvement of hardness, ultimate tensile strength and wear resistance of AA6061 alloy was observed with the increase in ZrB2 content.

  2. Effects of the action of hydrogen peroxide on the electrical properties of polyaniline-aluminium composites

    Energy Technology Data Exchange (ETDEWEB)

    Gmati, Fethi; Manaii, Aymen; Mohamed, Abdellatif Belhadj [Laboratory of Photovoltaic (LPV), Centre of Research and Technology of Energy (CRTEn), Technopole of Borj Cedria, Hammam Lif 2050 (Tunisia); Fattoum, Arbi, E-mail: gmati_fethi@yahoo.fr [Unit of Research: Materials Environment and Energy (06/UR/12-01), Faculty of Sciences Gafsa (Tunisia)

    2011-08-10

    The effects of the action of hydrogen peroxide (H{sub 2}O{sub 2}) as an oxidizing agent on the electrical properties of polyaniline-aluminium (PANI-Al) composites are studied. Direct current (dc) electrical conductivity is investigated in the temperature range 303-453 K. A decrease in the conductivity with attack time is observed. The results are compatible with UV-visible and infrared absorption measurements and scanning electron microscopy analysis. The experimental data show a transition from a negative temperature coefficient of resistivity (TCR) to a positive TCR. This transition becomes more pronounced when the attack time increases. Depending on the H{sub 2}O{sub 2} attack time, we found that the dc conductivity of the composites is described by two distinct models: the first is a series combination between the fluctuation-induced tunnelling (FIT) model with a metallic transport model, the second is a combination between Mott's three-dimensional variable range hopping with an intrinsic metallic model. The different FIT and Mott parameters are evaluated. The change in the conduction mechanism is attributed to the disorder and the localization effect caused by the action of H{sub 2}O{sub 2} on the PANI-Al composite.

  3. Multifunctional Metal Matrix Composite Filament Wound Tank Liners Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Metal Matrix Composite (MMC) materials offer tremendous potential for lightweight propellant and pressurant tankage for space applications. Thin MMC liners for...

  4. Cavitation-erosion mechanism of laser cladded SiC particle reinforced metal matrix composite

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chun-hua; ZHANG Song; YANG Hong-gang; ZHU Sheng-long; MAN Hau-chung; CAI Qing-kui

    2005-01-01

    With 2 kW continuous wave Nd-YAG laser,SiC ceramic powder was laser-cladded on the AA6061 aluminium alloy surface.Within the range of process parameters investigated,the parameters were optimized to produce the SiCp reinforced metal matrix composites(MMC) modified layer on AA6061 alloy surface.After being treated,the modified layer is crack-free,porosity free,and has good metallurgical bond with the substrate.The microstructure and chemical composition of the modified layer were analyzed by such detection devices as scanning electronic microscope(SEM-EDX) and X-ray diffractometer(XRD).The performance of electrochemical corrosion and cavitation erosion and their mechanism were estimated by the microhardness tester,potentiostat and ultrasonicinduced cavitation device.

  5. Effect of friction time on the properties of friction welded YSZ‐alumina composite and 6061 aluminium alloy

    Directory of Open Access Journals (Sweden)

    Uday M. Basheer

    2012-03-01

    Full Text Available The aim of this work was to study the effect of friction time on the microstructure and mechanical properties of alumina 0, 25, 50 wt% yttria stabilized zirconia (YSZ composite and 6061 aluminium alloy joints formed by friction welding. The alumina-YSZ composites were prepared through slip casting in plaster of Paris molds (POP and subsequently sintered at 1600°C, while the aluminium rods were machined down using a lathe machine to the dimension required. The welding process was carried out under different rotational speeds and friction times, while friction force (0.5 ton-force was kept constant. Scanning electron microscopy was used to characterize the interface of the joints structure. The experimental results showed that the friction time has a significant effect on joint structure and mechanical properties.

  6. Investigations on thermal properties, stress and deformation of Al/SiC metal matrix composite based on finite element method

    Directory of Open Access Journals (Sweden)

    K. A. Ramesh Kumar

    2014-09-01

    Full Text Available AlSiC is a metal matrix composite which comprises of aluminium matrix with silicon carbide particles. It is characterized by high thermal conductivity (180-200 W/m K, and its thermal expansion are attuned to match other important materials that finds enormous demand in industrial sectors. Although its application is very common, the physics behind the Al-SiC formation, functionality and behaviors are intricate owing to the temperature gradient of hundreds of degrees, over the volume, occurring on a time scale of a few seconds, involving multiple phases. In this study, various physical, metallurgical and numerical aspects such as equation of continuum for thermal, stress and deformation using finite element (FE matrix formulation, temperature dependent material properties, are analyzed. Modelling and simulation studies of Al/SiC composites are a preliminary attempt to view this research work from computational point of view.

  7. Thermal conductivity of microPCMs-filled epoxy matrix composites

    NARCIS (Netherlands)

    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

  8. Insight of the interface of electroless Ni-P/SiC composite coating on aluminium alloy, LM24

    OpenAIRE

    Franco, M.; Sha, W.; Tan, V.; Malinov, S.

    2015-01-01

    Electroless nickel composite coatings with silicon carbide, SiC, as reinforcing particles deposited with Ni–P onto aluminium alloy, LM24, having zincating as under layer were subjected to heat treatment using air furnace. The changes at the interface were investigated using scanning electron microscope (SEM) and energy dispersive X-ray (EDX) to probe the chemistry changes upon heat treatment. Microhardness tester with various loads using both Knoop and Vickers indenters was used to study the ...

  9. Parametric Study Of A Ceramic-Fiber/Metal-Matrix Composite

    Science.gov (United States)

    Murthy, P. L. N.; Hopkins, D. A.; Chamis, C. C.

    1992-01-01

    Report describes computer-model parametric study of effects of degradation of constituent materials upon mechanical properties of ceramic-fiber/metal-matrix composite material. Contributes to understanding of weakening effects of large changes in temperature and mechanical stresses in fabrication and use. Concerned mainly with influences of in situ fiber and matrix properties upon behavior of composite. Particular attention given to influence of in situ matrix strength and influence of interphase degradation.

  10. Matrix effect on leaching of Bisphenol A diglycidyl ether (BADGE) from epoxy resin based inner lacquer of aluminium tubes into semi-solid dosage forms.

    Science.gov (United States)

    Lipke, Uwe; Haverkamp, Jan Boris; Zapf, Thomas; Lipperheide, Cornelia

    2016-04-01

    To study the impact of different semi-solid dosage form components on the leaching of Bisphenol A (BPA) and Bisphenol A diglycidyl ether (BADGE) from the epoxy resin-based inner lacquer of aluminium tubes, the tubes were filled with different matrix preparations and stored at an elevated temperature. Despite compliance with the European Standards EN 15348 and EN 15766 on porosity and polymerisation of internal coatings of aluminium tubes, the commercially available tubes used in the study contained an increased amount of polymerisation residues, such as unbound BPA, BADGE and BADGE derivatives in the lacquer, as determined by acetonitrile extraction. Storage of Macrogol ointments in these tubes resulted in an almost quantitative migration of the unbound polymerisation residues from the coating into the ointment. In addition, due to alterations observed in the RP-HPLC chromatograms of the matrix spiked with BADGE and BADGE derivatives it is supposed that the leachates can react with formulation components. The contamination of the medicinal product by BPA, BADGE and BADGE derivatives can be precluded by using aluminium tubes with an internal lacquer with a low degree of unbound polymerisation residues. PMID:26724272

  11. Evaluation of thermophysical and thermomechanical properties of aluminium matrix dispersion fuels at BARC

    International Nuclear Information System (INIS)

    Al-U alloy and Al-UAIx, Al-U3O8 and Al-U3Si2 composites are being extensively used all over the world as fuel for small, water-cooled, non-power research reactors. As part of 40 kWt KAMINI and 5 MWt and 10 MWt research reactor fuels development programme at Bhabha Atomic Research Centre (BARC), Bombay, out-of-pile properties of these fuels, namely, hot hardness, high temperature microstructure and thermal conductivity were evaluated in the temperature range of 300-900K. (author)

  12. Composition of microfouling on aluminium and fibre glass panels exposed in Agatti waters (Lakshadweep Island)

    Digital Repository Service at National Institute of Oceanography (India)

    Raveendran, T.V.; Sankaran, P.D.; Wagh, A.B.

    Rate of microfouling build-up was high during the initial periods of exposure of test surfaces but decreased with the increasing duration. Fibre glass surfaces showed higher deposition than those of aluminium. Carbohydrates and lipids were the major...

  13. Test on Sensor Effect of Cement Matrix Piezoelectric Composite

    Institute of Scientific and Technical Information of China (English)

    YANG Xiaoming; LI Zhongxian; DING Yang; LI Zongjin

    2005-01-01

    A novel cement matrix smart piezoelectric composite and its application as sensing element are presented.A cement matrix smart piezoelectric composite piece encapsulated in a cement mortar formed a practical sensor, and it was tested on material test system with cyclic loading.According to the theoretical analysis, the function of the cement matrix piezoelectric sensor output voltage was expressed in terms of the magnitude of the input cyclic loading amplitude and frequency.The curve fitting of gain function that is defined as sensor′s gain factor under different frequencies of input loading was carried out. From the results of curve fitting, it is found that the cement matrix smart piezoelectric composite has a simple relationship between input loading and output voltage.Therefore the cement matrix piezoelectric composite sensor is suitable to be applied in structural health monitoring.

  14. Morphology, thermal, electrical and electrochemical stability of nano aluminium-oxide-filled polyvinyl alcohol composite gel electrolyte

    Indian Academy of Sciences (India)

    Navin Chand; Neelesh Rai; S L Agrawal; S K Patel

    2011-12-01

    In the present work, an attempt has been made to develop nano aluminium oxide (Al2O3)-filled polyvinyl alcohol (PVA) composite gel electrolytes. Surface morphological studies, thermal behaviour, electrochemical stability and electrical characterization of these composite gel electrolytes have been performed. An increase in the concentration of Al2O3 in composite gel electrolytes increases the amorphous characteristics of pure PVA. Bulk conductivity of composite gel electrolytes increases by an order of magnitude on addition of a nano filler. Maximum conductivity of 5.81 × 10-2 S/cm is observed for 6 wt% Al2O3-filled polymer gel composite electrolytes. Temperature dependence of electrical conductivity shows a combination of Arrhenius and Vogel–Tamman–Fulcher (VTF) nature. Maximum current stability during oxidation and reduction cycle is noticed for 6 wt% Al2O3-filled PVA composite electrolyte, viz. ±1.65 V.

  15. Rod extrusion of titanium-aluminum composites; Verbundstrangpressen von Titan-Aluminium-Verbindungen

    Energy Technology Data Exchange (ETDEWEB)

    Grittner, N.; Bormann, D.; Nikolaus, M.; Bach, F.W. [Bereich Biomedizintechnik und Leichtbau (BML), Institut fuer Werkstoffkunde, Leibniz-Universitaet Hannover, Garbsen (Germany); Stelling, O.; Schimanski, K.; von Hehl, A.; Zoch, H.W. [Stiftung Institut fuer Werkstofftechnik, Bremen (Germany); Senden, H. von

    2009-12-15

    The combination of different metals enables the processing of materials with local optimized properties. Thus, the production of metallic composites is associated with high standards in manufacturing technologie. Focus of the following investigations is the rod extrusion process of titanium-aluminum-composites. Besides the mechanical properties, the formation of the bonding zone and the mechanisms of adhesion in the bonding zone were investigated. The influence of specimens' preparation and of different coatings used improve bonding were a matter of particular interest. Whereas coatings of copper or nickel inhibit the formation of a strong bonding due to the formation of oxide layers, sealed titanium cores can reach a mechanical strength of up to 100 MPa after rod extrusion. Compared to other joining technologies, an impairment of the base metal via formation of heat affected zones, pores or grain coarsening does not occur. (Abstract Copyright [2009], Wiley Periodicals, Inc.) [German] Durch die Kombination von unterschiedlichen metallischen Werkstoffen lassen sich massgeschneiderte Konstruktionen mit optimierten Eigenschaften herstellen. Die Herstellung von Werkstoffverbunden ist jedoch haeufig mit hohen Anforderungen an die Fertigungstechnik verbunden. Schwerpunkt dieser Untersuchung ist das Verbundstrangpressen von Aluminium und Titan. Neben den mechanischen Eigenschaften des Verbundes wurden die Ausbildung der Bindungszone sowie die beim Haftungsaufbau wirksamen Bindungsmechanismen untersucht. Hierbei war neben dem Einfluss der Probenvorbereitung vor allem die Wirksamkeit von unterschiedlichen Haftvermittlerschichten von Interesse. Waehrend Schichten aus Kupfer oder Nickel den Haftungsaufbau aufgrund von Oxidschichtbildung verhindern, koennen durch Umformung eingegossener Titankerne Festigkeiten von ueber 100 MPa erreicht werden. Im Vergleich zu alternativen Fuegeverfahren tritt eine Beeintraechtigung des Werkstoffgefueges in Form von Waermeeinflusszonen

  16. Mechanical Properties of Continuous Fiber Reinforced Zirconium Diboride Matrix Composites

    Science.gov (United States)

    Stuffle, Kevin; Creegan, Peter; Nowell, Steven; Bull, Jeffrey D.; Rasky, Daniel J. (Technical Monitor)

    1995-01-01

    Continuous fiber reinforced zirconium diboride matrix composites, SCS-9a-(RBSiCZrB2)matrix, are being developed for leading edge, rocket nozzle and turbine engine applications. Recently, the composite materials have been characterized for tensile properties to 1250 C, the highest temperature tested. The tensile properties are fiber dominated as the matrix is microcracked on fabrication, but favorable failure characteristic are observed. Compression and shear mechanical testing results will be reported if completed. The effects of fiber volume fraction and matrix density on mechanical properties will be discussed. The target applications of the materials will be discussed. Specific testing being performed towards qualification for these applications will be included.

  17. Fabrication of aluminum matrix composite reinforced with carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1.0 wt.% carbon nanotube (CNT) reinforced 2024A1 matrix composite was fabricated by cold isostatic press and subsequent hot extrusion techniques. The mechanical properties of the composite were measured by a tensile test. Meanwhile, the fracture surfaces were examined using field emission scanning electron microscopy. The experimental results show that CNTs are dispersed homogeneously in the composite and that the interfaces of the Al matrix and the CNT bond well. Although the tensile strength and the Young's modulus of the composite are enhanced markedly, the elongation does not decrease when compared with the matrix material fabricated under the same process. The reasons for the increments may be the extraordinary mechanical properties of CNTs, and the bridging and pulling-out role of CNTs in the Al matrix composite.

  18. Continuous fiber ceramic matrix composites for heat engine components

    Science.gov (United States)

    Tripp, David E.

    1988-01-01

    High strength at elevated temperatures, low density, resistance to wear, and abundance of nonstrategic raw materials make structural ceramics attractive for advanced heat engine applications. Unfortunately, ceramics have a low fracture toughness and fail catastrophically because of overload, impact, and contact stresses. Ceramic matrix composites provide the means to achieve improved fracture toughness while retaining desirable characteristics, such as high strength and low density. Materials scientists and engineers are trying to develop the ideal fibers and matrices to achieve the optimum ceramic matrix composite properties. A need exists for the development of failure models for the design of ceramic matrix composite heat engine components. Phenomenological failure models are currently the most frequently used in industry, but they are deterministic and do not adequately describe ceramic matrix composite behavior. Semi-empirical models were proposed, which relate the failure of notched composite laminates to the stress a characteristic distance away from the notch. Shear lag models describe composite failure modes at the micromechanics level. The enhanced matrix cracking stress occurs at the same applied stress level predicted by the two models of steady state cracking. Finally, statistical models take into consideration the distribution in composite failure strength. The intent is to develop these models into computer algorithms for the failure analysis of ceramic matrix composites under monotonically increasing loads. The algorithms will be included in a postprocessor to general purpose finite element programs.

  19. Experimental Test of Stainless Steel Wire Mesh and Aluminium Alloy With Glass Fiber Reinforcement Hybrid Composite

    Directory of Open Access Journals (Sweden)

    Ranga Raj R.,

    2015-05-01

    Full Text Available At present, composite materials are mostly used in aircraft structural components, because of their excellent properties like lightweight, high strength to weight ratio, high stiffness, and corrosion resistance and less expensive. In this experimental work, the mechanical properties of laminate, this is reinforced with stainless steel wire mesh, aluminum sheet metal, perforated aluminum sheet metal and glass fibers to be laminate and investigated. The stainless steel wire mesh and perforated aluminum metal were sequentially stacked to fabricate, hybrid composites. The aluminum metal sheet is also employed with that sequence to get maximum strength and less weight. The tensile, compressive and flexure tests carried out on the hybrid composite. To investigate the mechanical properties and elastic properties of the metal matrix composite laminate of a material we are using experimental test and theoretical calculation. The experimental work consists of Tensile, compressive and flexural test. The expectation of this project results in the tensile and compressive properties of this hybrid composite it is slightly lesser than carbon fibers but it could facilitate a weight reduction compared with CFRP panels. So this hybrid laminates composite material offering significant weight savings and maximum strength over some other GFRP conventional panels.

  20. Ultra-Low-Density (ULD) Polymer Matrix Composites (PMCs) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This NASA Phase I SBIR proposal seeks to demonstrate a new class of ultra-low-density (ULD) polymer matrix composites of high specific modulus and specific strength...

  1. Design Concepts for Cooled Ceramic Matrix Composite Turbine Vanes Project

    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. Laser Assisted Machining of Metal Matrix Composites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Metal matrix composites (MMC's) are of great interest in aerospace applications where their high specific strength provides a weight saving alternative to standard...

  3. OPTIMIZATION OF ELECTRICAL DISCHARGE MACHINING PARAMETERS OF ALUMINIUM HYBRID COMPOSITES USING TAGUCHI METHOD

    Directory of Open Access Journals (Sweden)

    N. RADHIKA

    2014-08-01

    Full Text Available Metal matrix composites utilises the combined properties of the constituent material that finds applications in various fields. The present study investigates the influence of peak current, flushing pressure and pulse-on time on Electrical Discharge Machining of AlSi10Mg alloy reinforced with 3 wt% graphite and 9 wt% alumina hybrid metal matrix composites. Taguchi’s Design of Experiment was used to analyse the machining characteristics of hybrid composites. Analysis of Variance and Signal-to-Noise ratio were used to determine the influence of input process parameters on the surface roughness, material removal rate and tool wear rate. Signal to Noise ratio and Analysis of Variance revealed that peak current was the most influential parameter on surface roughness followed by pulse on time and flushing pressure. For material removal rate, the major parameter was flushing pressure followed by peak current and pulse on time. The most significant parameter of tool wear rate was pulse on time followed by peak current and flushing pressure. Interaction terms also have significant effect on their output responses.

  4. Watermarking Digital Image Using Fuzzy Matrix Compositions and Rough Set

    OpenAIRE

    Sharbani Bhattacharya

    2014-01-01

    Watermarking is done in digital images for authentication and to restrict its unauthorized usages. Watermarking is sometimes invisible and can be extracted only by authenticated party. Encrypt a text or information by public –private key from two fuzzy matrix and embed it in image as watermark. In this paper we proposed two fuzzy compositions Product-Mod-Minus, and Compliment-Product-Minus. Embedded watermark using Fuzzy Rough set created from fuzzy matrix compositions.

  5. Glass matrix composite material prepared with waste foundry sand

    Directory of Open Access Journals (Sweden)

    ZHANG Zhao-shu

    2006-11-01

    Full Text Available The technology of glass matrix of the composite material manufactured through a sintering process and using waste foundry sand and waste glass as the main raw materials was studied. The effects of technological factors on the performance of this material were studied. The results showed that this composite material is formed with glass as matrix, core particulate as strengthening material, it has the performance of glass and ceramics, and could be used to substitute for stone.

  6. Watermarking Digital Image Using Fuzzy Matrix Compositions and Rough Set

    Directory of Open Access Journals (Sweden)

    Sharbani Bhattacharya

    2014-07-01

    Full Text Available Watermarking is done in digital images for authentication and to restrict its unauthorized usages. Watermarking is sometimes invisible and can be extracted only by authenticated party. Encrypt a text or information by public –private key from two fuzzy matrix and embed it in image as watermark. In this paper we proposed two fuzzy compositions Product-Mod-Minus, and Compliment-Product-Minus. Embedded watermark using Fuzzy Rough set created from fuzzy matrix compositions.

  7. Glass matrix composite material prepared with waste foundry sand

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhao-shu; XIA Ju-pei; ZHU Xiao-qin; LIU Fan; HE Mao-yun

    2006-01-01

    The technology of glass matrix of the composite material manufactured through a sintering process and using waste foundry sand and waste glass as the main raw materials was studied. The effects of technological factors on the performance of this material were studied. The results showed that this composite material is formed with glass as matrix, core particulate as strengthening material, it has the performance of glass and ceramics, and could be used to substitute for stone.

  8. 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.

  9. Steel-SiC Metal Matrix Composite Development

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Don D.

    2005-07-17

    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.

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

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    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 preparatior 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.

  11. Microstructure and composition of rare earth-transition metal-aluminium-magnesium alloys

    OpenAIRE

    Lia Maria Carlotti Zarpelon; Eguiberto Galego; Hidetoshi Takiishi; Rubens Nunes Faria

    2008-01-01

    The determination of the microstructure and chemical composition of La0.7-xPr xMg0.3Al 0.3Mn0.4Co0.5 Ni3.8 (0 < x < 0.7) metal hydride alloys has been carried out using scanning electron microscopy (SEM), energy dispersive X ray analysis (EDX) and X ray diffraction analysis (XRD). The substitution of La with Pr changed the grain structure from equiaxial to columnar. The relative atomic ratio of rare earth to (Al, Mn, Co, Ni) in the matrix phase was 1:5 (LaNi5-type structure). Magnesium was de...

  12. Effect of Matrix Composition on Physical Properties of Al3CON In-situ Reaction Reinforced Corundum Composite

    Institute of Scientific and Technical Information of China (English)

    YANG Dingao; YUAN Shouqian; JIANG Mingxue; ZHANG Changxi; ZHENG Jianying; LIANG De'an; ZHANG Qiye

    2008-01-01

    60% white corundum used for aggregate.5% aluminium powder for fixed additions and 35% various additives for matrix were prepared for specimens 1#,2#,3#.They were mixed uniformly with the suitable resin as a binder and pressed under pressure of 315 ton forging press,then dried at 200 ℃ for 24 h.Effects of various additives on 1500 ℃×2 h creep properties of Al3CON reinforced corundum composite were researched,The experimenal results show that creep coefficients of specimens 1#,2#,3# at 1500 ℃×2 h are 1.4×10-4,-9.4×10 4,-22.6×10-4 respectively.Crushing strength of the slide plate added with suitable additive A after fired at 1500 ℃×3 h reaches to 225 MPa,the creep rate is positive all the time from 0% to 0.014% at 1500 ℃ for 2 h.The microstructure result analysis shows that reinforced phases of Al3CON fiber composite have been formed after fired with Al powder in coke at high temperatures for specimen 1#,and the strength of the composite is increased.The hot modulus of rupture is up to 59 MPa at 1400 ℃ and the RUL is obviously higher than that at 1700 ℃.Its service life is two times as that of Al2O3-C slide plate when used in the process of pouring steel.The mechanism of creep rate resistance of the composites can be discovered by means of SEM and EDAX analysis.It is concluded that the active Al3CON and Al2O3 multiphases that were formed by N2 in gas,C,Al and Al2O3 inside the matrix of the composites during in-situ reaction,which gives the composites outstanding creep rate resistance for the dense zone resulting from Al3CON oxidation that inhibits contraction at the high temperature.Besides,the matrix will turn into the multiphase with high refractoriness,N content and its Al3CON reinforced fiber will further increase accordingly.In addition,Al3CON formed by Al2O3 and C,Al in the matrix with N2 in gas will inhibit the creep rate and also greatly improve the creep rate resistance of the composites.

  13. Electrical and Thermal Properties of Glass Matrix-Al/sub 2/TiO/sub 5/ Composites Prepared at Low Temperature

    International Nuclear Information System (INIS)

    In this research, the electrical and thermal properties of glass matrix composites filled with different amounts of aluminium titanate (Al/sub 2/TiO/sub 5/) powder varying from 5 to 15 wt. percent have been investigated. In order to optimize the processing route, some sintering strategies were tested. The densest specimens were obtained by less pressure of the sintering. The composites were characterized by means of SEM micrography, X-ray diffraction (XRD), differential thermal analysis (DTA), dilatometry and impedance spectrometry. XRD results showed that the main crystallization phases were Wollastonite, Aluminium titanate, Rutile, and Alumina in all sintered glass matrix composites. It was also revealed that addition of 15 wt.% aluminium titanate has increased the relative density and decreased thermal expansion coefficient (TEC) (6.9*10/sup -6/degree C) and electrical conductivity (3.1*10/sup -4 Ohm.cm) in comparison with other composites. The results would be explained considering nature and concentration of the formed crystalline phases and their micro-structures. (author)

  14. Fatigue of continuous fiber reinforced titanium matrix composites

    Science.gov (United States)

    Johnson, W. S.

    1991-01-01

    Several lay-ups of SCS-6/Ti-15-3 composites were investigated. Static and fatigue tests were conducted for both notched and unnotched specimens at room and elevated temperatures. Test results indicated that the stress in the 0 fibers is the controlling factor in fatigue life. The static and fatigue strength of these materials is shown to be dependent on the level of residual stresses and the fiber/ matrix interfacial strength. Fatigue tests of notched specimens showed that cracks can initiate and grow many fiber spacings in the matrix material without breaking fibers. These matrix cracks can significantly reduce the residual strength of notched composite.

  15. Use of silica sol as a transient phase for fabrication of aluminium titanate-mullite ceramic composite

    International Nuclear Information System (INIS)

    A novel approach for the fabrication of aluminium titanate-mullite composite via silica sol gelating is described. The bending strength of sintered samples was greatly improved (by up to about 200%) compared with that of samples fabricated by dry pressing and gel-casting. The effect of silica sol on the dispersion behaviour of slurry was revealed. The results from scanning electron microscopy analysis showed that silica sol gel-casting provides a dense microstructure with fine grains, which are responsible for the improvement in bending strength.

  16. Fatigue damage criteria - Matrix, fibers and interfaces of continuous fiber reinforced metal matrix composites

    Science.gov (United States)

    Johnson, W. S.

    1988-01-01

    Continuous fiber reinforced metal matrix composites (MMC) are projected for use in high temperature, stiffness critical parts that will be subjected to cyclic loadings. Depending on the relative fatigue behavior of the fiber and matrix, and the interface properties, the failure modes of MMC can be grouped into four catagories: (1) matrix dominated, (2) fiber dominated, (3) self-similar damage growth, and (4) fiber/matrix interfacial failures. These four types of damage are discussed and illustrated by examples. The emphasis is on the fatigue of unnotched laminates.

  17. 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...

  18. Composite Matrix Systems for Cryogenic Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — As an alternative material to aluminum-lithium, cryotanks developed from fiber reinforced composites can offer significant weight savings in applications for fuel...

  19. Cavitation instabilities between fibres in a metal matrix composite

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2016-01-01

    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...... 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...

  20. Magnesium Matrix Composite Foams—Density, Mechanical Properties, and Applications

    Directory of Open Access Journals (Sweden)

    Kyu Cho

    2012-07-01

    Full Text Available Potential of widespread industrial applications of magnesium has been realized in recent years. A variety of magnesium alloy matrix composites are now being studied for mechanical properties. Since magnesium is the lightest structural metal, it can replace aluminum in existing applications for further weight savings. This review presents an overview of hollow particle filled magnesium matrix syntactic composite foams. Fly ash cenospheres are the most commonly used hollow particles for such applications. Fly ash cenospheres primarily have alumino-silicate composition and contain a large number of trace elements, which makes it challenging to study the interfacial reactions and microstructure in these composites. Microstructures of commonly studied AZ and ZC series magnesium alloys and their syntactic foams are discussed. Although only a few studies are available on these materials because of the nascent stage of this field, a comparison with similar aluminum matrix syntactic foams has provided insight into the properties and weight saving potential of magnesium matrix composites. Analysis shows that the magnesium matrix syntactic foams have higher yield strength at the same level of density compared to most other metal matrix syntactic foams. The comparison can guide future work and set goals that need to be achieved through materials selection and processing method development.

  1. The effect of surface pre-conditioning treatments on the local composition of Zr-based conversion coatings formed on aluminium alloys

    Science.gov (United States)

    Cerezo, J.; Vandendael, I.; Posner, R.; de Wit, J. H. W.; Mol, J. M. C.; Terryn, H.

    2016-03-01

    This study investigates the effect of different alkaline, acidic and thermal pre-conditioning treatments applied to different Al alloy surfaces. The obtained results are compared to the characteristics of Zr-based conversion coatings that were subsequently generated on top of these substrates. Focus is laid on typical elemental distributions on the sample surfaces, in particular on the amount of precipitated functional additives such as Cu species that are present in the substrate matrix as well as in the conversion bath solutions. To this aim, Field Emission Auger Electron spectra, depth profiles and surface maps with superior local resolution were acquired and compared to scanning electron microscopy images of the sample. The results show how de-alloying processes, which occur at and around intermetallic particles in the Al matrix during typical industrial alkaline or acidic cleaning procedures, provide a significant source of crystallization cores for any following coating processes. This is in particular due for Cu-species, as the resulting local Cu structures on the surface strongly affect the film formation and compositions of state-of-the-art Zr-based films. The findings are highly relevant for industrial treatments of aluminium surfaces, especially for those that undergo corrosion protection and painting process steps prior to usage.

  2. Mechanical Behaviour of Aluminium Dispersed Unsaturated Polyester/Jute Composites for Structural Applications

    Science.gov (United States)

    Biswas, Bhabatosh; Chabri, Sumit; Mitra, Bhairab Chandra; Bandyopadhyay, Nil Ratan; Sinha, Arijit

    2016-07-01

    The fibrous filler Jute along with Al particle reinforced unsaturated polyester composites having different filler (both Jute and Al were in equal wt%) were fabricated by compression molding technique. The variation of loading was taken as 2, 5, 10 and 15 wt% in the fabricated composites. In present investigation, it was observed that with fillers (Jute and Al) incorporation the microhardness increases and become optimum at 10 wt% of fillers content followed by slight deterioration at 15 wt%. Structural investigation through scanning electron microscopy and X-ray diffraction confirm the dispersion of the fillers within the composites. An improvement of crystallinity % of the matrix with filler addition was observed as predicted from X-ray diffraction technique. The results of tensile testing shows that the strength and modulus increase monotonically up to 10 wt% of filler addition followed by slight decreases at 15 wt% of the same. The scratch result shows the optimization of strength and toughness of the composites with filler content of 10 wt%.

  3. Development and characterization of 430L matrix composites gradient materials

    Directory of Open Access Journals (Sweden)

    Elisa Maria Ruiz-Navas

    2005-03-01

    Full Text Available This paper deals with a new concept that is Functionally Gradient Materials (FGM. The materials developed in this work are constituted by a 430L matrix core and composite materials with this matrix and gradient concentration with NbC reinforcement, from the core to the surface, through different steps. Composite powders of different content in NbC were produced through high energy milling in order to obtain the gradient composition. The morphology and microhardness of these powders were characterised and subsequently were processed through conventional P/M techniques, pressing and sintering. The materials obtained show improved wear behaviour.

  4. 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...

  5. Dynamic stiffness matrix of partial-interaction composite beams

    Directory of Open Access Journals (Sweden)

    Guangjian Bao

    2015-03-01

    Full Text Available Composite beams have a wide application in building and bridge engineering because of their advantages of mechanical properties, constructability and economic performance. Unlike static characteristics, the methods of studying the dynamic characteristics of partial-interaction composite beams were limited, especially dynamic stiffness matrix method. In this article, the dynamic stiffness matrix of partial-interaction composite beams was derived based on the assumption of the Euler–Bernoulli beam theory, and then it was used to predict the frequencies of the free vibration of the single-span composite beams with various boundary conditions or different axial forces. The corresponding vibration modes and buckling loads were also obtained. From the comparison with the existing results, the numerical results obtained by the proposed method agreed reasonably with those in the literatures. The dynamic stiffness matrix method is an accurate method which can determine natural vibration frequencies and vibration mode shapes in any precision theoretically. As a result, when the higher precision or natural frequencies of higher order are required, the dynamic stiffness matrix method is superior when compared to other approximate and numerical methods. The dynamic stiffness matrix method can also be combined with the finite-element method to calculate the free vibration frequencies and natural mode shapes of composite beams in complex conditions.

  6. Residual stresses in polymer matrix composite laminates

    Science.gov (United States)

    Hahn, H. T.

    1976-01-01

    Residual stresses in composites are induced during fabrication and by environmental exposure. The theory formulated can describe the shrinkage commonly observed after a thermal expansion test. Comparison between the analysis and experimental data for laminates of various material systems indicates that the residual stress-free temperature can be lower than the curing temperature, depending on the curing process. Effects of residual stresses on ply failure including the acoustic emission characteristics are discussed.

  7. Properties and Structure of Magnesium Matrix Composite Reinforced with CNTs

    Institute of Scientific and Technical Information of China (English)

    LI Si-nian; SONG Shou-zhi; YU Tian-qing; CHEN Hui-min; ZHANG You-shou; SHEN Jin-long

    2004-01-01

    By using high pure Magnesium (99.9 wt% )as matrix and multi-walled bended carbonnanotubes ( CNTs ) as reinforced phase, carbon nanotubes/magnesium matrix composite was prepared by thefoundry method under the argon gas protection, and its mechanical properties were tested. The interface structureand component of plating and un-plating carbon nanotubes were analyzed by TEM and EDS, and the action mech-anism was discussed. The experiment results show that the CNTs can strengthen mechanical properties of the nano-tube- reinforced Mg matrix composite, the tensile strength and elongation ratio are greatly improved. Furthermore,the plating CNTs are better than un-plating CNTs in strengthening effects. The tensile strength is inereased by150% and the elongation ratio is increased by 30% than that of matrix when content of CNTs is 0.67 wt% .

  8. Radiation-protective polymer-matrix nanostructured composites

    Energy Technology Data Exchange (ETDEWEB)

    Kaloshkin, S.D.; Tcherdyntsev, V.V. [College of Advanced Materials and Nanotechnologies, National University of Science and Technology ' MISiS' , Leninsky Prospect, 4 Moscow (Russian Federation); Gorshenkov, M.V., E-mail: mvg@misis.ru [College of Advanced Materials and Nanotechnologies, National University of Science and Technology ' MISiS' , Leninsky Prospect, 4 Moscow (Russian Federation); Gulbin, V.N. [College of Advanced Materials and Nanotechnologies, National University of Science and Technology ' MISiS' , Leninsky Prospect, 4 Moscow (Russian Federation); Kuznetsov, S.A. [Russian State Technological University ' MATI' , Orshanskaya 3, Moscow (Russian Federation)

    2012-09-25

    Highlights: Black-Right-Pointing-Pointer Radiation-protective composites were fabricated by solid state intermixing and thermal pressing. Black-Right-Pointing-Pointer The composites based on UHMWPE contain B{sub 4}S and W nanopowders as fillers. Black-Right-Pointing-Pointer The mechanical and {gamma}-radiation protective properties of the polymer-matrix nanocomposites were determined experimentally. Black-Right-Pointing-Pointer For composites containing 12% B{sub 4}C and 12% W the mechanical properties were studied prior to and after the irradiation with fast neutrons. - Abstract: UHMWPE-based nanostructured composites containing B{sub 4}C and W nanopowders were fabricated and studied. The mechanical and {gamma}-radiation protective properties of the polymer-matrix nanocomposites were determined experimentally. For selected composites the mechanical properties were studied prior to and after the irradiation.

  9. Nickel matrix micro/nano SiC composite electrodeposition

    OpenAIRE

    Albert Calbeto, Sònia

    2010-01-01

    Electrochemical codeposition is widely used in the last decade to produce composite metal matrix coatings. Hard particles such as oxides or carbides embedded in a metal matrix coating aim to increase its mechanical and wear properties. The use of nanometric particles could also change the microstructure of the electrodeposits leading to a more compact structure and thus to an increased corrosion resistance. The aim of this work is the production of pure nickel, nickel containing SiC micro-...

  10. Abrasive Wear Performance of Aluminium Modified Epoxy-Glass Fiber Composites

    Science.gov (United States)

    Kamble, Vikram G.; Mishra, Punyapriya; Al Dabbas, Hassan A.; Panda, H. S.; Fernandez, Johnathan Bruce

    2015-07-01

    For a long time, Aluminum filled epoxies molds have been used in rapid tooling process. These molds are very economical when applied in manufacturing of low volume of plastic parts. To improve the thermal conductivity of the material, the metallic filler material is added to it and the glass fiber improves the wear resistance of the material. These two important parameters establish the life of composites. The present work reports on abrasive wear behavior of Aluminum modified epoxy and glass fiber composite with 5 wt.% and 10 wt.% of aluminum particles. Through pin on disc wear testing machine, we studied the wear behaviors of composites, and all these samples were fabricated by using hand layup process. Epoxy resin was used as matrix material which was reinforced with Glass fiber and Aluminum as filler. The composite with 5 wt.% and 10 wt.% of Al was cast with dimensions 100 × 100 × 6 mm. The specimens were machined to a size of 6 × 6 × 4 mm for abrasive testing. Abrasive tests were carried out for different grit paper sizes, i.e., 150, 320, 600 at different sliding distance, i.e., 20, 40, 60 m at different loads of 5, 10 and 15 N and at constant speed. The weight loss due to wear was calculated along with coefficient of friction. Hardness was found using Rockwell hardness machine. The SEM morphology of the worn out surface wear was analyzed to understand the wear mechanism. Results showed that the addition of Aluminum particles was beneficial for low abrasive conditions.

  11. Research and development of advanced aluminium/graphite composites for thermal management applications

    CERN Document Server

    Wyszkowska, Edyta; Bertarelli, Alessandro

    Thermal management materials are continuously gaining importance as a consequence of everlasting evolution in performance of electronic and electric devices. In particular, by improving the heat exchanger’s materials' properties (i.e. thermal conductivity) it is possible to boost further performance and miniaturization of such devices. Due to their high thermal conductivity, Copper and Aluminium are currently the most commonly used materials for thermal management applications. However, the mismatch in thermal expansion between Cooper/Aluminium and Silicon is limiting the heat transfer at the interface between the electronic chip and the heat exchanger. Furthermore, Copper is indeed characterized by a high thermal conductivity but at the same time its high density (8.9 g/cm3) increases weight of the final product, which in most of the cases does not meet specific application requirements. High cost of these materials is another constraint which limits their application. Due to aforementioned facts, monolith...

  12. Obtainment, machining and wear of metal matrix composites processed by powder metallurgy

    International Nuclear Information System (INIS)

    The aim of this investigation was the obtainment of metal matrix composites (MMC) by the route of powder metallurgy, and the valuation of these materials with relation to their machining and wear characteristics. Firstly, were obtained pure commercial aluminium matrix composites materials, with 5, 10 and 15% volumetric fraction of silicon carbide particles. Was also obtained a material without reinforcement particles in order to verify by comparison, the influence of addition of reinforcement particles. The obtained materials were characterized physics (hydrostatic density), mechanics (hardness and tensile tests) and microstructurally (optical microscopy and scanning electron microscopy). The results showed a homogeneous distribution of reinforcement particles in the composite, and improvement in the mechanical properties, mainly tensile strength (UTS) in comparison to the unreinforced material. After, tests were made to verify the materials behavior during machining and to check the performance of several tool materials (cemented carbide, ceramics and polycrystalline diamond). In these tests, values of the cutting force were measured by instrumented tool-holders. Phenomena such as tool wear, built-up edge formation and mechanism of chip formation were also observed and evaluated. The results from the cemented carbide tool tests, were utilised for the machinability index determination of each material. These results were applied to the Taylor equation and the equation constants for each material and test conditions were determined. The results showed that the inclusion of silicon carbide particles made extremely difficult the machining of the composites, and only with diamond tool, satisfactory results were obtained. At last, wear tests were performed to verify the influence of the reinforcement particles in the characteristics of wear resistance of the materials. The results obtained were utilized in the wear coefficient determination for each material. The

  13. 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 are...... discussed. For distributed matrix micro cracking a continuum damage model is used as the basis for describing the associated stress-strain behavior. A simplified analysis of frictional sliding at the fiber/matrix inter face is made to elucidate its effect on the stress-strain response....

  14. Extracellular matrix composition of the cricopharyngeus muscle.

    Science.gov (United States)

    Tavares, Raquel Aguiar; Sennes, Luiz Ubirajara; Mauad, Thais; Imamura, Rui; da Silva, Luiz Fernando Ferraz; Carrau, Ricardo Luis

    2012-06-01

    The aim of this study was to analyze the presence and distribution of total collagen, type I and type III collagen, elastic fibers, fibronectin, and versican in the endomysium of cricopharyngeus muscles from adults of various ages. The study was a cross-sectional analysis of human cricopharyngeus muscles. Twenty-seven muscles obtained from autopsies of men and women ranging in age from 28 to 92 years were analyzed with the Picrosirius method, oxidized Weigert resorcin-fuchsin, immunohistochemistry, and image analysis. Collagen had the highest density among the analyzed components. Elastic fibers surrounded each muscle cell; they were aligned longitudinally by their long axis and associated with traversing fibers, thereby forming a fiber network with embedded muscle cells. The fibronectin and versican contents varied widely among the specimens. We found no statistically significant differences between the proportion of extracellular matrix (ECM) components and factors such as gender and race. We conclude that the higher proportion of type I and type III collagen is compatible with the cricopharyngeus muscle's sphincteric behavior, and the arrangement of the elastic fibers may also contribute to the muscle's elasticity. We found no statistically significant correlation between the ECM components and age. PMID:21874509

  15. Corrosion Behavior of Silicon Carbide/7091 Aluminum Matrix Composites

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Wooseung [Inha Technical College, Incheon (Korea, Republic of)

    2012-04-15

    The effects of volume fraction (15-30%) of SiC particulate reinforcements on the corrosion behavior of SiCp/7091 Al composites in the 3.5% NaCl solution were studied by electrochemical techniques and scanning electron microscopy. The results showed that the amount of SiC particulate reinforcements did not cause much difference in the corrosion behavior of SiCp/7091 Al composites but the corrosion rate was proportional to the amount of SiCp reinforcement. And numerous pits and severe dissolution of the matrix was observed probably due to the discontinuities and galvanic effects between Al matrix and SiC reinforcements.

  16. Ductility of a continuous fiber reinforced aluminum matrix composite

    Science.gov (United States)

    Jansson, S.; Leckie, Frederick A.

    1991-01-01

    The transverse properties of an aluminum alloy metal matrix composite reinforced by continuous alumina fibers have been investigated. The composite is subjected to both mechanical and cyclic thermal loading. The ductility can vary by an order of magnitude according to the operating conditions. For high mechanical and low thermal loading the ductility is small, for low mechanical and high thermal loading the ductility is an order of magnitude higher. Experiments on a beam in bending confirm that the ductility is strongly dependent on the loading conditions. The observations suggest a means of utilizing the inherent ductility of the matrix.

  17. 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.

  18. Electron beam curing of polymer matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Janke, C.J. [Lockheed Martin Energy Systems, Inc., Oak Ridge, TN (United States); Wheeler, D. [Sandia National Lab., Albuquerque, NM (United States); Saunders, C. [AECL Technologies, Inc., Rockville, MD (United States)] [and others

    1998-01-08

    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.

  19. Electron beam curing of polymer matrix composites

    International Nuclear Information System (INIS)

    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

  20. Microstructure and composition of rare earth-transition metal-aluminium-magnesium alloys

    Directory of Open Access Journals (Sweden)

    Lia Maria Carlotti Zarpelon

    2008-03-01

    Full Text Available The determination of the microstructure and chemical composition of La0.7-xPr xMg0.3Al 0.3Mn0.4Co0.5 Ni3.8 (0 < x < 0.7 metal hydride alloys has been carried out using scanning electron microscopy (SEM, energy dispersive X ray analysis (EDX and X ray diffraction analysis (XRD. The substitution of La with Pr changed the grain structure from equiaxial to columnar. The relative atomic ratio of rare earth to (Al, Mn, Co, Ni in the matrix phase was 1:5 (LaNi5-type structure. Magnesium was detected only in two other phases present. A grey phase revealed 11 at.% Mg and the concentration ratios of other elements indicated the composition to be close to PrMgNi4. A dark phase was very heterogeneous in composition, attributed to the as-cast state of these alloys. The phases identified by XRD analysis in the La0.7Mg0.3Al0.3Mn0.4Co 0.5Ni3.8 alloy were: La(Ni,Co5, LaAl(Ni,Co4, La2(Ni,Co7 and AlMn(Ni,Co2. Praseodymium favors the formation of a phase with a PuNi3-type structure. Cobalt substituted Ni in the structures and yielded phases of the type: Pr(Ni,Co5 and Pr(Ni,Co3.

  1. Experimental Investigation on Active Cooling for Ceramic Matrix Composite

    Institute of Scientific and Technical Information of China (English)

    PENG Li-na; HE Guo-qiang; LIU Pei-jin

    2009-01-01

    Compared with conventional materials, the active cooling ceramic matrix composite used in ramjet or scramjet makes their structures lighter in mass and better in performance. In this paper, an active and a passive cooling refractory composite specimens are designed and tested with an experimental facility composed of multilayer smale scale cooling penel which consists of a water cooling system and a ceramic matrix composite specimen, and a gas generator used for providing lower and higher transfer rate gases to simulate the temperatures in combustion chamber of ramjst. The active cooling specimen can continuously suffer high surface temperature of 2 000K for 30s and that of 3 000 K for 9.3 s, respectively. The experiment results show that the active cooling composite structure is available for high-temperature condition in ramjet.

  2. CONSTITUTIVE RELATION OF DISCONTINUOUS REINFORCED METAL-MATRIX COMPOSITES

    Institute of Scientific and Technical Information of China (English)

    季葆华; 王自强

    2001-01-01

    A micromechanical model is developed to simulate the mechanical behaviors of discontinuous reinforced composites. The analysis for a representative unit cell is based on the assumption of a periodic array of aligned reinforcements.The minimum energy principle is used to determine the unknown coefficients of the displacement field of the unit cell. The constitutive behavior of composites is studied to obtain the relationship between the main variables of matrix and reinforcements.It is concluded that the flow strength of composites is strongly influenced by volume fraction, aspect ratio of reinforcement, and the strain hardening exponent of matrix.An analytical constitutive relation of composites is obtained. The predicted results are in agreement with the existing experimental and numerical results.

  3. Influence of Aluminium on Performance of HTPB-based Aluminised PBXs

    Directory of Open Access Journals (Sweden)

    Vinay Prakash

    2004-10-01

    Full Text Available The paper describes the development of aluminised plastic-bonded explosives (PBXs based on aluminium and nitramine explosives using hydroxy-terminated polybutadiene as polymer matrix. The PBXs were processed as per standard procedures. Compositions with different formulations were prepared by varying the percentages of aluminium and RDX and their explosive properties, including velocity of detonation (VOD, peak overpressure, duration, impulse and sensitivity to different types of stimuli, were studied. The experimental and theoretical values of the VOD have been compared. It is observed that about 15 per cent aluminium content in the aluminised PBXs shows the optimum VOD.

  4. Thermosetting polymer-matrix composites for structural repair applications

    Science.gov (United States)

    Goertzen, William Kirby

    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 incorporation 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.

  5. 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.

  6. Separation of matrix alloy and reinforcement from aluminum metal matrix composites scrap by salt flux addition

    Indian Academy of Sciences (India)

    K R Ravi; R M Pillai; B C Pai; M Chakraborty

    2007-08-01

    Separation of matrix alloy and reinforcements from pure Al–SiCp composite scrap by salt flux addition has been theoretically predicted using interface free energies. Experiments performed confirm the theoretical prediction. Complete separation of matrix aluminum and reinforcement from metal matrix composites (MMCs) scrap has been achieved by addition of 2.05 wt% of equimolar mixture of NaCl–KCl salt flux with a metal and particle yield of 84 and 50%, respectively. By adding 5 wt% of NaF to equimolar mixture of NaCl–KCl, metal and particle yield improved to 91 and 73%, respectively. Reusability of both the matrix aluminum and the SiC separated from Al–SiCp scraps has been analysed using XRD, SEM and DTA techniques. The matrix alloy separated from Al–SiCp scraps can be used possibly as a low Si content Al–Si alloy. However, the interfacial reaction that occurred during the fabrication of the composites had degraded the SiC particles.

  7. Nickel and nickel-phosphorous matrix composite electrocoatings

    Institute of Scientific and Technical Information of China (English)

    Nicolas SPYRELLIS; Evangelia A. PAVLATOU; Styliani SPANOU; Alexandros ZOIKIS-KARATHANASIS

    2009-01-01

    Nickel and nickel-phosphorous matrix composite coatings reinforced by TiO2, SiC and WC particles were produced under direct and pulse current conditions from an additive-free Watts' type bath. The influence of the variable electrolysis parameters (type of current, frequency of current pulses and current density) and the reinforcing particles properties (type, size and concentration in the bath) on the surface morphology and the structure of the deposits was examined. It is demonstrated that the embedding of ceramic particles modifies in various ways the nickel electrocrystallisation process. On the other hand, Ni-P amorphous matrix is not affected by the occlusion of the particles. Overall, the imposition of pulse current conditions leads to composite coatings with increased embedded percentage and more homogenous distribution of particles in the matrix than coatings produced under direct current regime.

  8. Caracterisation du composite titanium diboride-carbone avec l'aluminium liquide et le bain cryolithique des cuves d'electrolyse de l'aluminium

    Science.gov (United States)

    Dionne, Martin

    with the carbon matrix to form a TiB2/Al4 C3 composite sealing the surface to further penetration. (Abstract shortened by UMI.)

  9. 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...

  10. Fracture criteria for discontinuously reinforced metal matrix composites

    Science.gov (United States)

    Rack, H. J.; Goree, J. G.; Albritton, J.; Ratnarparkhi, P.

    1988-01-01

    The effect of sample configuration on the details of initial crack propagation in discontinuously whisker reinforced aluminum metal matrix composites was investigated. Care was taken to allow direct comparison of fracture toughness values utilizing differing sample configurations and orientations, holding all materials variables constant, e.g., extrusion ration, heat treatment, and chemistry.

  11. Review on Fabrication Methods of in situ Metal Matrix Composites

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper deals with a series of novel processing techniques based on the in situ production of metal matrix composites (MMCs). In situ techniques involve a chemical reaction resulting in the formation of a very fine and thermodynamically stable reinforcing ceramic phase within a metal matrix. As a result, this provides thermodynamic compatibility at the matrix-reinforcement interface. The reinforcement surfaces are also likely to be free of contamination and, therefore, a stronger matrix-dispersion bond can be achieved. Some of these technologies including DIMOXTM, XD, PRIMEXTM, reactive gas infiltration, high-temperature self-propagating synthesis (SHS), and liquid-solid, or solid-gas-liquid reactions as well as plasma in situ MMCs are expressed in this paper.

  12. An Facile High-Density Polyethylene - Exfoliated Graphite - Aluminium Hydroxide Composite: Manufacture, Morphology, Structure, Antistatic and Fireproof Properties

    Directory of Open Access Journals (Sweden)

    Jihui LI

    2014-09-01

    Full Text Available Graphite intercalation compounds (GIC and exfoliated graphite (EG as raw materials were prepared with flake graphite, concentrated sulphuric acid (H2SO4, potassium bichromate (K2Cr2O7 and peracetic acid (CH3CO3H and characterized. Then, high-density polyethylene-exfoliated graphite (HDPE-EG composites were fabricated with HDPE and EG via in situ synthesis technique in the different mass ratio, and their resistivity values (ohms/sq were measured. Based on the resistivity values, it was discovered that HDPE-EG composite with the antistatic property could be fabricated while the mass ratio was 5.00 : 0.30. Last, HDPE-EG-aluminium hydroxide (HDPE-EG-Al(OH3 composites were manufactured with HDPE, GIC and Al(OH3 via the in situ synthesis-thermal expansion technique, and their resistivity values and limiting oxygen index (LOI values were measured. Based on the resistivity values and LOI values, it was discovered that HDPE-EG-Al(OH3 composite with the antistatic and fireproof property could be manufactured while HDPE, GICs and Al(OH3 of mass ratio was 5.00 : 0.30 : 1.00. Otherwise, the petal-like morphology and structure of HDPE-EG-Al(OH3 composite were characterized, which consisted of EG, HDPE and Al(OH3. DOI: http://dx.doi.org/10.5755/j01.ms.20.3.4275

  13. Synthesis of nano-crystalline zirconium aluminium oxynitride (ZrAlON) composite films by dense plasma Focus device

    International Nuclear Information System (INIS)

    Zirconium aluminium oxynitride multiphase composite film is deposited on zirconium substrate using energetic nitrogen ions delivered from dense plasma Focus device. X-ray diffractometer (XRD) results show that five Focus shots are sufficient to initiate the nucleation of ZrN and Al2O3 whereas 10 Focus shots are sufficient to initiate the nucleation of AlN. XRD results reveal that crystal growth of nitrides/oxides increases by increasing Focus shots (up to 30 Focus shots) and resputtering of the previously deposited film is taken place by further increase in Focus shots (40 Focus shots). Scanning electron microscopic (SEM) results indicate the uniform distribution of spherical grains (∼35 nm). A smoother surface is observed for 20 Focus shots at 0 deg. angular position. SEM results also show a net-type microstructure (thread like features) of the sample treated for 30 Focus shots whereas rough surface morphology is observed for 40 Focus shots. Energy dispersive spectroscopic profiles show the distribution of different elements present in the deposited composite films. A typical microhardness value of the deposited composite films is 5255 ± 10 MPa for 10 grams imposed load which is 3.3 times than the microhardness values of unexposed sample. The microhardness values of the exposed samples increases with increasing Focus shots (up to 30 Focus shots) and decreases for 40 Focus shots treatment due to resputtering of the previously deposited composite film. The microhardness values of the composite films decreases by increasing the sample's angular position.

  14. Wear Studies on Metal Matrix Composites: a Taguchi Approach

    Institute of Scientific and Technical Information of China (English)

    S. Basavarajappa; G. Chandramohan

    2005-01-01

    An attempt has been made to study the influence of wear parameters like applied load, sliding speed, sliding distance and percentage of reinforcement on the dry sliding wear of the metal matrix composites. A plan of experiments,based on techniques of Taguchi, was pedormed to acquire data in controlled way. An orthogonal array and the analysis of variance were employed to investigate the influence of process parameters on the wear of composites. The objective is to establish a correlation between dry sliding wear of composites and wear parameters. These correlations were obtained by multiple regressions. Finally, confirmation tests were conducted to verify the experimental results foreseen from the mentioned correlations.

  15. Dual-nanoparticulate-reinforced aluminum matrix composite materials

    Science.gov (United States)

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

    2012-06-01

    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 (Al4C3) was observed by TEM analysis and quantified using x-ray diffraction. The composite with the highest hardness values contained some nanosized Al4C3. Along with the CNT and the nano-SiC, Al4C3 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.

  16. Metallographic investigations of composite structures of aluminium foam with thermally sprayed coatings; Metallographische Untersuchungen an Verbundstrukturen aus Aluminiumschaum mit thermisch aufgespritzten Schichten

    Energy Technology Data Exchange (ETDEWEB)

    Maurer, M.; Koch, D.; Zhao Lidong; Lugscheider, E. [Werkstoffwissenschaften, RWTH Aachen, Aachen (Germany)

    2005-01-01

    Aluminium foams are on the brink of industrial use. Many new fields of use could be found for these new materials if a defined, wear and corrosion resistant coating could be applied. This is quite possible using thermally sprayed coatings, but the metallographical examination of this type of composite structure is extremely difficult as the very hard coatings have completely different properties to the soft open porous structure of the aluminium foam. This article introduces the concept of aluminium foams and the spraying techniques which can be used to improve their surfaces, and more centrally the methods of metallographical preparation which can be used to examine them and the problems which can occur. (orig.)

  17. Processing of continuous fiber composites using thermoplastic polyimide matrix resins

    Energy Technology Data Exchange (ETDEWEB)

    Kranjc, M.D.

    1993-01-01

    Composites have been produced which contain a solvent resistant polyimide matrix with favorable physical properties. The polyimide matrix resin has been designated as P12. The prepegs used to produce the composite contain a low molecular weight resin which is the polyamic acid precursor to P12. Polymerization and imidization of the precursor resin occurs in-situ during processing. Similar commercial systems are often processed in an autoclave and pressure is used at high temperatures to obtain consolidation between prepreg laminates. Pressure is generally applied after polymerization and imidization are complete and at temperatures above the melting point of the polymer. In this research a significant decrease in composite void content was obtained by applying pressure earlier in the cure. Obtaining composites with low void content with these types of systems can be difficult. This is due in part to the generation of low molecular weight reaction by products, water and methanol. High void content results in a decrease in the physical properties of the composite structure. This is especially true for fracture properties. An empirical equation was used to describe the rate of resin removal from the composite to the bleeder cloth during processing. This equation is based on Springer-Loos resin flow model. The conditions in which this model does not apply were also determined. Determining resin removal rates is helpful in producing composites with consistent fiber/resin ratios. In addition, conditions which favor void growth can be prevented.

  18. 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.

  19. 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.

  20. Analyzing the Effect of Machining Parameters Setting to the Surface Roughness during End Milling of CFRP-Aluminium Composite Laminates

    Directory of Open Access Journals (Sweden)

    M. Nurhaniza

    2016-01-01

    Full Text Available The quality of the machining is measured from surface finished and it is considered as the most important aspect in composite machining. An appropriate and optimum machining parameters setting is crucial during machining operation in order to enhance the surface quality. The objective of this research is to analyze the effect of machining parameters on the surface quality of CFRP-Aluminium in CNC end milling operation with PCD tool. The milling parameters evaluated are spindle speed, feed rate, and depth of cut. The L9 Taguchi orthogonal arrays, signal-to-noise (S/N ratio, and analysis of variance (ANOVA are employed to analyze the effect of these cutting parameters. The analysis of the results indicates that the optimal cutting parameters combination for good surface finish is high cutting speed, low feed rate, and low depth of cut.

  1. Wear performance optimization of stir cast Al-TiB2 metal matrix composites using Taguchi design of experiments

    Science.gov (United States)

    Poria, Suswagata; Sahoo, Prasanta; Sutradhar, Goutam

    2016-09-01

    The present study outlines the use of Taguchi parameter design to minimize the wear performance of Al-TiB2 metal matrix composites by optimizing tribological process parameters. Different weight percentages of micro-TiB2 powders with average sizes of 5-40 micron are incorporated into molten LM4 aluminium matrix by stir casting method. The wear performance of Al-TiB2 composites is evaluated in a block-on-roller type Multitribo tester at room temperature. Three parameters viz. weight percentage of TiB2, load and speed are considered with three levels each at the time of experiment. A L27 orthogonal array is used to carry out experiments accommodating all the factors and their levels including their interaction effects. Optimal combination of parameters for wear performance is obtained by Taguchi analysis. Analysis of variance (ANOVA) is used to find out percentage contribution of each parameter and their interaction also on wear performance. Weight percentage of TiB2 is forced to be the most effective parameter in controlling wear behaviour of Al-TiB2 metal matrix composite.

  2. Microstructural characterization of interpenetrating light weight metal matrix composites

    International Nuclear Information System (INIS)

    Interpenetrating metal matrix composites, MMCs, were fabricated successfully by infiltrating of porous ceramic preforms with Al and Mg alloys by a pressure supported casting process. Open porosity of the preforms varied from 50 to 60%, the pore diameters were in the range of 1-10 μm. The microstructure of the materials was characterized using light optical-, scanning electron-, transmission electron microscopy and X-ray diffraction. Several observations indicate the formation of a thin MgAl2O4 spinel at the interface Al2O3 to Mg matrix alloy.

  3. Rapid Prototyping of Continuous Fiber Reinforced Ceramic Matrix Composites

    Science.gov (United States)

    Vaidyanathan, R.; Green, C.; Phillips, T.; Cipriani, R.; Yarlagadda, S.; Gillespie, J. W., Jr.; Effinger, M.; Cooper, K. C.

    2003-01-01

    For ceramics to be used as structural components in high temperature applications, their fracture toughness is improved by embedding continuous ceramic fibers. Ceramic matrix composite (CMC) materials allow increasing the overall operating temperature, raising the temperature safety margins, avoiding the need for cooling, and improving the damping capacity, while reducing the weight at the same time. They also need to be reliable and available in large quantities as well. In this paper, an innovative rapid prototyping technique to fabricate continuous fiber reinforced ceramic matrix composites is described. The process is simple, robust and will be widely applicable to a number of high temperature material systems. This technique was originally developed at the University of Delaware Center for Composite Materials (UD-CCM) for rapid fabrication of polymer matrix composites by a technique called automated tow placement or ATP. The results of mechanical properties and microstructural characterization are presented, together with examples of complex shapes and parts. It is believed that the process will be able to create complex shaped parts at an order of magnitude lower cost than current chemical vapor infiltration (CVI) and polymer impregnation and pyrolysis (PIP) processes.

  4. Reinforcement/matrix interaction in SiC fiber-reinforced Ni3Al matrix composites

    International Nuclear Information System (INIS)

    This paper presents an investigation of the interfacial reaction characteristics of two different types of SiC fibers with Ni3Al (Ni-Al-Cr-Zr-B) matrix. The microstructure and chemical compositions across the reaction zone have been analyzed quantitatively using microscopy and electron probe microanalysis. In both types of SiC/Ni3Al composites, it was found that Ni was the dominant diffusing species responsible for the overall reaction. The C-rich layer outside the SCS-6 fiber provided an incubation period, but could not stop the inward diffusion of Ni. It could, however, effectively stop the diffusion of Al,Zr and Cr. No significant increase in reaction zone thickness after exposure at temperatures below 900 degrees C for up to 100 hours was observed. When the C-rich layer was depleted, a rapid increase in reaction zone thickness and the formation of multilayer reaction products occurred. In the case of Sigma/Ni3Al composite, extensive reaction between the fiber and the matrix occurred at all the temperatures studied. Diffusion barrier coating for both types of fibers is required to develop nickel aluminide matrix composites

  5. Fiber-Matrix Interface Studies on Electron Beam Cured Composites

    Energy Technology Data Exchange (ETDEWEB)

    Drazel, L.T.; Janke, C.J.; Yarborough, K.D.

    1999-05-23

    The recently completed Department of Energy (DOE) and industry sponsored Cooperative Research and Development Agreement (CRADA) entitled, ''Electron Beam Curing of Polymer Matrix Composites,'' determined that the interlaminar shear strength properties of the best electron beam cured IM7/epoxy composites were 19-28% lower than autoclave cured IM7/epoxy composites (i.e. IM7/977-2 and IM7/977-3). Low interlaminar shear strength is widely acknowledged as the key barrier to the successful acceptance and implementation of electron beam cured composites in the aircraft/aerospace industry. The objective of this work was to improve the interlaminar shear strength properties of electron beam cured composites by formulating and evaluating several different fiber sizings or coating materials. The researchers have recently achieved some promising results by having discovered that the application of epoxy-based, electron beam compatible sizings or coatings onto surface-treated, unsized IM7 carbon fibers improved the composite interlaminar shear strength properties by as much as 55% versus composites fabricated from surface-treated, unsized IM7 fibers. In addition, by applying these same epoxy-based sizings or coatings onto surface-treated, unsized IM7 fibers it was possible to achieve an 11% increase in the composite interlaminar shear strength compared to composites made from surface-treated, GP-sized IM7 fibers. Work is continuing in this area of research to further improve these properties.

  6. A honeycomb composite of mollusca shell matrix and calcium alginate.

    Science.gov (United States)

    You, Hua-jian; Li, Jin; Zhou, Chan; Liu, Bin; Zhang, Yao-guang

    2016-03-01

    A honeycomb composite is useful to carry cells for application in bone, cartilage, skin, and soft tissue regenerative therapies. To fabricate a composite, and expand the application of mollusca shells as well as improve preparing methods of calcium alginate in tissue engineering research, Anodonta woodiana shell powder was mixed with sodium alginate at varying mass ratios to obtain a gel mixture. The mixture was frozen and treated with dilute hydrochloric acid to generate a shell matrix/calcium alginate composite. Calcium carbonate served as the control. The composite was transplanted subcutaneously into rats. At 7, 14, 42, and 70 days after transplantation, frozen sections were stained with hematoxylin and eosin, followed by DAPI, β-actin, and collagen type-I immunofluorescence staining, and observed using laser confocal microscopy. The composite featured a honeycomb structure. The control and composite samples displayed significantly different mechanical properties. The water absorption rate of the composite and control group were respectively 205-496% and 417-586%. The composite (mass ratio of 5:5) showed good biological safety over a 70-day period; the subcutaneous structure of the samples was maintained and the degradation rate was lower than that of the control samples. Freezing the gel mixture afforded control over chemical reaction rates. Given these results, the composite is a promising honeycomb scaffold for tissue engineering.

  7. The influence of alloy composition on residual stresses in heat treated aluminium alloys

    International Nuclear Information System (INIS)

    The as quenched properties of eight different heat treatable aluminium alloys are related to residual stress magnitudes with the objective being to establish if there is a relationship between the residual stress and the as quenched alloy hardness and strength. Near surface residual stresses were assessed with X-ray diffraction using both the established sin2ψ method and the more recent cos α technique. Through thickness residual stresses were also characterised using neutron diffraction. The alloys were chosen to encompass a wide range of strengths. The low to medium strength alloys were 6060 and 6082, medium to high strength 2618A, 2014A, 7075, 7010 and two variants of 7449, while the very high strength alloy was the powder metallurgy alloy N707. To assess the as quenched strength, dynamic hardness and tensile properties were determined from samples tested immediately after quenching to minimise the influence of precipitation hardening by natural aging. In addition, hot hardness measurements were made in situ on samples cooled to simulate quench paths. Within the experimental constraints of the investigation, the distribution of residual stress through the thickness was found to follow the same pattern for all the alloys investigated, varying from tensile in the interior to surface compression. The influence of alloy strength was manifested as a change in the observed residual stress magnitudes, and surface residual stresses were found to vary linearly with as quenched hardness and strength. - Highlights: • As quenched aluminium alloys contain high magnitude residual stresses. • Surface is compressive balance by a tensile core. • As quenched surface residual stress is linear function of alloy strength. • In situ hot hardness demonstrates rapid change in intrinsic hardness during rapid cooling

  8. The influence of alloy composition on residual stresses in heat treated aluminium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, J.S., E-mail: jeremy.robinson@ul.ie [Department of Mechanical, Aeronautical and Biomedical Engineering, University of Limerick (Ireland); Redington, W. [Materials and Surface Science Institute, University of Limerick (Ireland)

    2015-07-15

    The as quenched properties of eight different heat treatable aluminium alloys are related to residual stress magnitudes with the objective being to establish if there is a relationship between the residual stress and the as quenched alloy hardness and strength. Near surface residual stresses were assessed with X-ray diffraction using both the established sin{sup 2}ψ method and the more recent cos α technique. Through thickness residual stresses were also characterised using neutron diffraction. The alloys were chosen to encompass a wide range of strengths. The low to medium strength alloys were 6060 and 6082, medium to high strength 2618A, 2014A, 7075, 7010 and two variants of 7449, while the very high strength alloy was the powder metallurgy alloy N707. To assess the as quenched strength, dynamic hardness and tensile properties were determined from samples tested immediately after quenching to minimise the influence of precipitation hardening by natural aging. In addition, hot hardness measurements were made in situ on samples cooled to simulate quench paths. Within the experimental constraints of the investigation, the distribution of residual stress through the thickness was found to follow the same pattern for all the alloys investigated, varying from tensile in the interior to surface compression. The influence of alloy strength was manifested as a change in the observed residual stress magnitudes, and surface residual stresses were found to vary linearly with as quenched hardness and strength. - Highlights: • As quenched aluminium alloys contain high magnitude residual stresses. • Surface is compressive balance by a tensile core. • As quenched surface residual stress is linear function of alloy strength. • In situ hot hardness demonstrates rapid change in intrinsic hardness during rapid cooling.

  9. Composite orthogonal projection methods for large matrix eigenproblems

    Institute of Scientific and Technical Information of China (English)

    贾仲孝

    1999-01-01

    For classical orthogonal projection methods for large matrix eigenproblems, it may be much more difficult for a Ritz vector to converge than for its corresponding Ritz value when the matrix in question is non-Hermitian. To this end, a class of new refined orthogonal projection methods has been proposed. It is proved that in some sense each refined method is a composite of two classical orthogonal projections, in which each refined approximate eigenvector is obtained by realizing a new one of some Hermitian semipositive definite matrix onto the same subspace. A priori error bounds on the refined approximate eigenvector are established in terms of the sine of acute angle of the normalized eigenvector and the subspace involved. It is shown that the sufficient conditions for convergence of the refined vector and that of the Ritz value are the same, so that the refined methods may be much more efficient than the classical ones.

  10. Method of thermal strain hysteresis reduction in metal matrix composites

    Science.gov (United States)

    Dries, Gregory A. (Inventor); Tompkins, Stephen S. (Inventor)

    1987-01-01

    A method is disclosed for treating graphite reinforced metal matrix composites so as to eliminate thermal strain hysteresis and impart dimensional stability through a large thermal cycle. The method is applied to the composite post fabrication and is effective on metal matrix materials using graphite fibers manufactured by both the hot roll bonding and diffusion bonding techniques. The method consists of first heat treating the material in a solution anneal oven followed by a water quench and then subjecting the material to a cryogenic treatment in a cryogenic oven. This heat treatment and cryogenic stress reflief is effective in imparting a dimensional stability and reduced thermal strain hysteresis in the material over a -250.degree. F. to +250.degree. F. thermal cycle.

  11. EFFECT OF RICE HUSKS AS FILLER IN POLYMER MATRIX COMPOSITES

    Directory of Open Access Journals (Sweden)

    K. Hardinnawirda

    2012-06-01

    Full Text Available In this study, rice husk-filled polyester composites were produced with rice husks (RH as the filler and unsaturated polyester resin (UPR as the matrix. Several percentages of filler loadings were used (10, 15, 20 and 25 wt % in order to gain insights into the effect of filler content on the mechanical properties and water intake of the composites. The tensile strength of the RH-filled UPR composites was found to decrease as the filler loading increased; however, as it reached 25 wt %, the strength showed a moderate increase. The Young’s modulus showed a remarkable increase for 15 wt % of RH but decreased as the RH percentage increased further to 25 wt %. A water absorption test was conducted and the results showed that the composites absorb more water as the percentage weight of RH increased, which is attributed to the ability of the RH filler to absorb water.

  12. 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.

  13. Damping behaviors of metal matrix composites with interface layer

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A novel technique of designing the interface layer in metal matrix composites of high damping capacity was developed via different CVD coatings on carbon fibers in Cf/Al composites. It was shown that the interface layer improved the tensile strength, elastic modulus and damping capacity of the Cf/Al composites. A carbon layer showed the highest improvement and a silicon layer the lowest, while a mixed carbon and silicon layer exhibited an intermediate effect. Moreover, the thickness of interface layer also influences the damping capacity. A thicker carbon layer produced a better damping capacity because the dependence of damping capacity on strain amplitude was increased. It is suggested that a micro-sliding action occurring in the interface layer is the main mechanism responsible for the high damping capacity of the composites.

  14. Preparation of SiC Fiber Reinforced Nickel Matrix Composite

    Institute of Scientific and Technical Information of China (English)

    Lu Zhang; Nanlin Shi; Jun Gong; Chao Sunt

    2012-01-01

    A method of preparing continuous(Al+Al2O3)-coated SiC fiber reinforced nickel matrix composite was presented,in which the diffusion between SiC fiber and nickel matrix could be prevented.Magnetron sputtering is used to deposit Ni coating on the surface of the(Al+Al2O3)-coated SiC fiber in preparation of the precursor wires.It is shown that the deposited Ni coating combines well with the(Al+Al2O3) coating and has little negative effect on the tensile strength of(Al+Al2O3)-coated SiC fiber.Solid-state diffusion bonding process is employed to prepare the(Al+Al2O3)-coated SiC fiber reinforced nickel matrix with 37% fibers in volume.The solid-state diffusion bonding process is optimized and the optimum parameters are temperature of 870,pressure of 50 MPa and holding time of 2 h.Under this condition,the precursor wires can diffuse well,composite of full density can be formed and the(Al+Al2O3) coating is effective to restrict the reaction between SiC fiber and nickel matrix.

  15. Analytical Scanning and Transmission Electron Microscopy of Laboratory Impacts on Stardust Aluminium Foils: Interpreting Impact Crater Morphology and the Composition of Impact Residues.

    Energy Technology Data Exchange (ETDEWEB)

    Kearsley, A T; Graham, G A; Burchell, M J; Cole, M J; Dai, Z R; Teslich, N; Chater, R; Wozniakiewicz, P A; Spratt, J; Jones, G

    2006-10-19

    The known encounter velocity (6.1kms{sup -1}) between the Stardust spacecraft and the dust emanating from the nucleus of comet Wild 2 has allowed realistic simulation of dust collection in laboratory experiments designed to validate analytical methods for the interpretation of dust impacts on the aluminium foil components of the Stardust collector. In this report we present information on crater gross morphology, the pre-existing major and trace element composition of the foil, geometrical issues for energy dispersive X-ray analysis of the impact residues in scanning electron microscopes, and the modification of dust chemical composition during creation of impact craters as revealed by analytical transmission electron microscopy. Together, these observations help to underpin the interpretation of size, density and composition for particles impacted upon the Stardust aluminium foils.

  16. Cure shrinkage effects in epoxy and polycyanate matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Spellman, G.P.

    1995-12-22

    A relatively new advanced composite matrix, polycyanate ester, was evaluated for cure shrinkage. The chemical cure shrinkage of composites is difficult to model but a number of clever experimental techniques are available to the investigator. In this work the method of curing a prepreg layup on top of a previously cured laminate of identical ply composition is utilized. The polymeric matrices used in advanced composites have been primarily epoxies and therefore a common system of this type, Fiberite 3501-6, was used as a base case material. Three polycyanate matrix systems were selected for the study. These are: Fiberite 954-2A, YLA RS-3, and Bryte Technology BTCy-1. The first three of these systems were unidirectional prepreg with carbon fiber reinforcement. The Bryte Technology material was reinforced with E-glass fabric. The technique used to evaluate cure shrinkage results in distortion of the flatness of an otherwise symmetric laminate. The first laminate is cured in a conventional fashion. An identical layup is cured on this first laminate. During the second cure all constituents are exposed to the same thermal cycles. However, only the new portion of the laminate will experience volumetric changes associate with matrix cure. The additional strain of cure shrinkage results in an unsymmetric distribution of residual stresses and an associated warpage of the laminate. The baseline material, Fiberite 3501-6, exhibited cure shrinkage that was in accordance with expectations. Cure strains were {minus}4.5E-04. The YLA RS-3 material had cure strains somewhat lower at {minus}3.2E-04. The Fiberite 954-2A cure strain was {minus}1.5E-04 that is 70% lower than the baseline material. The glass fabric material with the Bryte BTCy-1 matrix did not result in meaningful results because the processing methods were not fully compatible with the material.

  17. Tensile and compressive test results for metal matrix composites

    Science.gov (United States)

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

    1977-01-01

    Experimental results of the mechanical behavior of two metal matrix composite systems at room temperature are presented. Ultimate stress, ultimate strain, Poisson's ratio, and initial Young's Modulus are documented for BORSIC/Aluminum in uniaxial tension and Boron/Aluminum in uniaxial tension and compression. Poisson's ratio is used for nonlinear stress-strain behavior. A comparison of compression results for B/Al as obtained from sandwich beam compression specimens and IITRI coupon compression specimens is presented.

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

    Energy Technology Data Exchange (ETDEWEB)

    Janke, C. J. [ORNL; Howell, Dave [ORNL; Norris, Robert E. [ORNL

    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.

  19. Micromechanical modelling of thermoplastic elastomer composite with a Polypropylene matrix

    OpenAIRE

    Parenteau, Thomas

    2009-01-01

    Due to their high consumption, the vulcanized elastomeric products are an important source of waste. One way of recycling these materials is their reuse under the form of particles in polymer matrix composites to reduce stiffness and increase their resistance to low-energy impacts. This study is born of a collaboration between the LIMATB and the Technische Universität Chemnitz, which develops this concept of materials.The aim of this study is to conduct experimental characterization and to de...

  20. Investigation of Product Performance of Al-Metal Matrix Composites Brake Disc using Finite Element Analysis

    Science.gov (United States)

    Fatchurrohman, N.; Marini, C. D.; Suraya, S.; Iqbal, AKM Asif

    2016-02-01

    The increasing demand of fuel efficiency and light weight components in automobile sectors have led to the development of advanced material parts with improved performance. A specific class of MMCs which has gained a lot of attention due to its potential is aluminium metal matrix composites (Al-MMCs). Product performance investigation of Al- MMCs is presented in this article, where an Al-MMCs brake disc is analyzed using finite element analysis. The objective is to identify the potentiality of replacing the conventional iron brake disc with Al-MMCs brake disc. The simulation results suggested that the MMCs brake disc provided better thermal and mechanical performance as compared to the conventional cast iron brake disc. Although, the Al-MMCs brake disc dissipated higher maximum temperature compared to cast iron brake disc's maximum temperature. The Al-MMCs brake disc showed a well distributed temperature than the cast iron brake disc. The high temperature developed at the ring of the disc and heat was dissipated in circumferential direction. Moreover, better thermal dissipation and conduction at brake disc rotor surface played a major influence on the stress. As a comparison, the maximum stress and strain of Al-MMCs brake disc was lower than that induced on the cast iron brake disc.

  1. Mechanical Properties and Corrosion Behaviour of Aluminium Hybrid Composites Reinforced with Silicon Carbide and Bamboo Leaf Ash

    Directory of Open Access Journals (Sweden)

    K.K. Alaneme

    2013-03-01

    Full Text Available The viability of developing low cost – high performance Al matrix hybrid composites with the use of bamboo leaf ash (an agro waste ash and silicon carbide as complementing reinforcements was investigated. Silicon carbide (SiCparticulates added with 0, 2, 3, and 4 wt% bamboo leaf ash (BLA were utilized to prepare 10 wt% of the reinforcing phase with Al-Mg-Si alloy as matrix using two-step stir casting method. Microstructural characterization, mechanical properties evaluation and corrosion behaviour were used to assess the performance of the composites. The results show that the hardness, ultimate tensile strength, and percent elongation of the hybrid composites decrease with increase in BLA content. The fracture toughness of the hybrid composites were however superior to that of the single reinforced Al - 10 wt% SiC composite. Only the 2 wt % BLA containing hybrid composite had specific strength value comparable to that of the single reinforced composite. In 5wt% NaCl solution, it was observed that the 2 and 3 wt % BLA containing hybrid composites had higher corrosion resistance in comparison to the single reinforced Al - 10 wt% SiC composite but the reverse trend was observed in 0.3M H2SO4 solution where the single reinforced had superior corrosion resistance.

  2. Composite materials based on AlMg1SiCu aluminium alloy reinforced with halloysite particles

    OpenAIRE

    Tomiczek, B.; L.A. Dobrzański

    2013-01-01

    Purpose: The present work describes microstructure and technological, as well as mechanical properties of AlMg1SiCu matrix composite materials reinforced with halloysite particles by powder metallurgy techniques and hot extrusion. Design/methodology/approach: Mechanical milling, compacting and hot extrusion successively are considering as a method for manufacturing metal composite powders with a controlled fine microstructure and enhanced mechanical properties. Findings:...

  3. Wear Behaviour of Al-6061/SiC Metal Matrix Composites

    Science.gov (United States)

    Mishra, Ashok Kumar; Srivastava, Rajesh Kumar

    2016-06-01

    Aluminium Al-6061 base composites, reinforced with SiC particles having mesh size of 150 and 600, which is fabricated by stir casting method and their wear resistance and coefficient of friction has been investigated in the present study as a function of applied load and weight fraction of SiC varying from 5, 10, 15, 20, 25, 30, 35 and 40 %. The dry sliding wear properties of composites were investigated by using Pin-on-disk testing machine at sliding velocity of 2 m/s and sliding distance of 2000 m over a various loads of 10, 20 and 30 N. The result shows that the reinforcement of the metal matrix with SiC particulates up to weight percentage of 35 % reduces the wear rate. The result also show that the wear of the test specimens increases with the increasing load and sliding distance. The coefficient of friction slightly decreases with increasing weight percentage of reinforcements. The wear surfaces are examined by optical microscopy which shows that the large grooved regions and cavities with ceramic particles are found on the worn surface of the composite alloy. This indicates an abrasive wear mechanism, which is essentially a result of hard ceramic particles exposed on the worn surfaces. Further, it was found from the experimentation that the wear rate decreases linearly with increasing weight fraction of SiC and average coefficient of friction decreases linearly with increasing applied load, weight fraction of SiC and mesh size of SiC. The best result has been obtained at 35 % weight fraction and 600 mesh size of SiC.

  4. Effect of TiN particulate reinforcement on corrosive behaviour of aluminium 6061 composites in chloride medium

    Indian Academy of Sciences (India)

    H C Ananda Murthy; V Bheema Raju; C Shivakumara

    2013-11-01

    In the present investigation, the corrosive behaviour of Al 6061–TiN particulate composites prepared by liquidmetallurgy has been studied in chloride medium using electroanalytical techniques such as Tafel, cyclic polarization and electrochemical impedance spectroscopy (EIS). Surface morphology of the sample electrodes was examined using scanning electron micrography and energy dispersive X-ray methods. X-ray diffraction technique was used to confirm inclusion of TiN particulates in the matrix alloy and identify the alloying elements and intermetallic compounds in the Al 6061 composites. Polarization studies indicate an increase in the corrosion resistance in composites compared to the matrix alloy. EIS study reveals that the polarization resistance (p) increases with increase in TiN content in composites, thus confirming improved corrosion resistance in composites. The observed decrease in corrosion rate in the case of composites is due to decoupling between TiN particles and Al 6061 alloy. It is understood that after the initiation of corrosion, interfacial corrosion products may have decoupled the conducting ceramic TiN from Al 6061 matrix alloy thus eliminating the galvanic effect between them.

  5. Ultrafine-grained Aluminm and Boron Carbide Metal Matrix Composites

    Science.gov (United States)

    Vogt, Rustin

    Cryomilling is a processing technique used to generate homogenously distributed boron carbide (B4C) particulate reinforcement within an ultrafine-grained aluminum matrix. The motivation behind characterizing a composite consisting of cryomilled aluminum B4C metal matrix composite is to design and develop a high-strength, lightweight aluminum composite for structural and high strain rate applications. Cryomilled Al 5083 and B4C powders were synthesized into bulk composite by various thermomechanical processing methods to form plate and extruded geometries. The effects of processing method on microstructure and mechanical behavior for the final consolidated composite were investigated. Cryomilling for extended periods of time in liquid nitrogen has shown to increase strength and thermal stability. The effects associated with cryomilling with stearic acid additions (as a process-control agent) on the degassing behavior of Al powders is investigated and results show that the liberation of compounds associated with stearic acid were suppressed in cryomilled Al powders. The effect of thermal expansion mismatch strain on strengthening due to geometrically necessary dislocations resulting from quenching is investigated and found not to occur in bulk cryomilled Al 5083 and B 4C composites. Previous cryomilled Al 5083 and B4C composites have exhibited ultrahigh strength associated with considerable strain-to-failure (>14 pct.) at high strain rates (>103/s) during mechanical testing, but only limited strain-to-failure (˜0.75 pct.) at quasi-static strain rates (10-3/s). The increased strain to failure at high strain rates is attributed to micro-flaw developments, including kinking, extensive axial splitting, and grain growth were observed after high strain rate deformation, and the significance of these mechanisms is considered.

  6. Effect of aluminium phosphate as admixture on oxychloride cement

    Indian Academy of Sciences (India)

    M P S Chandrawat; R N Yadav

    2000-02-01

    The effect of admixing of aluminium phosphate on oxychloride cement in the matrix has been investigated. It is shown that aluminium phosphate retards the setting process of the cement and improves water-tightness.

  7. Ultrasonic assessment of interfacial oxidation damage in ceramic matrix composites

    Science.gov (United States)

    Chu, Y. C.; Rokhlin, S. I.; Baaklini, G. Y.

    1993-01-01

    A new approach to characterizing oxidation damage in ceramic matrix composites using ultrasonic techniques is proposed. In this approach, the elastic constants of the composite are determined nondestructively by measuring the angular dependence of both longitudinal and transverse wave velocities. A micromechanical model for composites with anisotropic constituents is used to find the anisotropic properties of an effective fiber, which is a combination of the fiber and the interface. Interfacial properties are extracted from the properties of this effective fiber by analyzing the difference between effective and actual fiber properties. Unidirectional /0/28 SiC/Si3N4 composites with 30 percent fiber volume fraction and 30 percent matrix porosity are used. The samples are exposed in a flowing oxygen environment at elevated temperatures, up to 1400 C, for 100 hours and then measured by ultrasonic methods at room temperature. The Young's modulus in the fiber direction of the sample oxidized at 600 C decreased significantly but it was unchanged for samples oxidized at temperatures above 1200 C. The transverse moduli obtained from ultrasonic measurements decrease continuously up to 1200 C. The shear stiffnesses show behavior similar to the transverse moduli. The effective elastic moduli of the interfacial carbon coating are determined from the experimental data, and their change due to thermal oxidation is discussed.

  8. Experimental investigation on mechanical behaviour, modelling and optimization of wear parameters of B4C and graphite reinforced aluminium hybrid composites

    International Nuclear Information System (INIS)

    Highlights: • Aluminium alloy reinforced with boron carbide and graphite through liquid casting. • The high hardness and elongation obtained in the AA 7075 hybrid composite. • SEM, EDS observations were used to evaluate the worn surface. • MINITAB software was used to analyse the wear rate and develop the map. - Abstract: Aluminium alloy (AA) 6061 and 7075 were reinforced with 10 wt.% of boron carbide (B4C) and 5 wt.% of graphite through liquid casting technique. The Scanning Electron Microscope (SEM) and Energy Dispersive Spectrum (EDS) were used for the characterization of composites. The wear experiment was carried out by using a pin-on-disc apparatus with various input parameters like applied load (10, 20, and 30 N), sliding speed (0.6, 0.8, and 1.0 m/s) and sliding distance (1000, 1500, and 2000 m). Response Surface Methodology (RSM) using MINITAB 14 software was used to analyse the wear rate of hybrid composites and aluminium alloys. The worn surfaces of hybrid composites and base alloys were studied through SEM and EDS systems and some useful conclusions were made

  9. 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.

  10. Effect of plasma spraying conditions on structure and properties of Al-B hot pressed composites

    International Nuclear Information System (INIS)

    Composition and properties of composite matrixes obtained by plasmic sputtering of aluminium alloys have been studied. The effect of sputtering conditions on properties of boron and boron-silicon fibres is described. Formation of the matrix strong contact with the fibres during hot pressing has been studied. Plasmic sputtering is shown to be able of controlling the structure and properties of composite metal matrixes

  11. X-ray microtomography of ceramic and metal matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Baaklini, G.Y.; Bhatt, R.T.; Eckel, A.J. [National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center; Engler, P.; Rauser, R.W. [Cleveland State Univ., OH (United States); Castelli, M.G. [NYMA, Inc., Cleveland, OH (United States)

    1995-09-01

    Capabilities and limitations of X-ray computed microtomography (CT) in characterizing relevant composite material issues as identified during manufacturing processes were investigated. Damage in engine subcomponents was evaluated and compared with damage detected in pedigreed coupon type specimens. The system used is a newly developed state-of-the-art X-ray computed tomography system capable of providing digital radiography, computed tomography, and computed laminography. CT was found viable for characterizing processing defects and coating effect in thermally shocked carbon fiber reinforced silicon carbide matrix (C/SiC) samples. CT results from mechanically tested silicon carbide fiber reinforced reaction bonded silicon nitride (SiC/RBSN) matrix sample were evaluated and compared to engine tested SiC/RBSN turbine vanes. Thermomechanically cycled SiC (SCS-6) fiber reinforced Timetal 21S samples showed viability of CT in detecting composite constituents and limitations of CT in detecting matrix and fiber cracking. Also an engineering analysis approach was proposed to continuously integrate nondestructive evaluation modalities in the design-manufacturing-prototyping cycle of engine components.

  12. Hot extruded carbon nanotube reinforced aluminum matrix composite materials

    Science.gov (United States)

    Kwon, Hansang; Leparoux, Marc

    2012-10-01

    Carbon nanotube (CNT) reinforced aluminum (Al) matrix composite materials were successfully fabricated by mechanical ball milling followed by powder hot extrusion processes. Microstructural analysis revealed that the CNTs were well dispersed at the boundaries and were aligned with the extrusion direction in the composites obtained. Although only a small quantity of CNTs were added to the composite (1 vol%), the Vickers hardness and the tensile strength were significantly enhanced, with an up to three-fold increase relative to that of pure Al. From the fractography of the extruded Al-CNT composite, several shapes were observed in the fracture surface, and this unique morphology is discussed based on the strengthening mechanism. The damage in the CNTs was investigated with Raman spectroscopy. However, the Al-CNT composite materials were not only strengthened by the addition of CNTs but also enhanced by several synergistic effects. The nanoindentation stress-strain curve was successfully constructed by setting the effective zero-load and zero-displacement points and was compared with the tensile stress-strain curve. The yield strengths of the Al-CNT composites from the nanoindentation and tensile tests were compared and discussed. We believe that the yield strength can be predicted using a simple nanoindentation stress/strain curve and that this method will be useful for materials that are difficult to machine, such as complex ceramics.

  13. Hot extruded carbon nanotube reinforced aluminum matrix composite materials

    International Nuclear Information System (INIS)

    Carbon nanotube (CNT) reinforced aluminum (Al) matrix composite materials were successfully fabricated by mechanical ball milling followed by powder hot extrusion processes. Microstructural analysis revealed that the CNTs were well dispersed at the boundaries and were aligned with the extrusion direction in the composites obtained. Although only a small quantity of CNTs were added to the composite (1 vol%), the Vickers hardness and the tensile strength were significantly enhanced, with an up to three-fold increase relative to that of pure Al. From the fractography of the extruded Al–CNT composite, several shapes were observed in the fracture surface, and this unique morphology is discussed based on the strengthening mechanism. The damage in the CNTs was investigated with Raman spectroscopy. However, the Al–CNT composite materials were not only strengthened by the addition of CNTs but also enhanced by several synergistic effects. The nanoindentation stress–strain curve was successfully constructed by setting the effective zero-load and zero-displacement points and was compared with the tensile stress–strain curve. The yield strengths of the Al–CNT composites from the nanoindentation and tensile tests were compared and discussed. We believe that the yield strength can be predicted using a simple nanoindentation stress/strain curve and that this method will be useful for materials that are difficult to machine, such as complex ceramics. (paper)

  14. Development of a Precipitation-Strengthened Matrix for Non-quenchable Aluminum Metal Matrix Composites

    Science.gov (United States)

    Vo, Nhon Q.; Sorensen, Jim; Klier, Eric M.; Sanaty-Zadeh, Amirreza; Bayansan, Davaadorj; Seidman, David N.; Dunand, David C.

    2016-07-01

    Recent developments in metal matrix composite-encapsulated ceramic armor show promise in lightweight armor technology. The system contains ceramic tiles, such as alumina, sandwiched between unreinforced aluminum or aluminum metal matrix composite (Al-MMC), which has a better toughness compared to the ceramic tiles. The sandwich structures should not be quenched during the fabrication, as the large mismatch in the coefficients of thermal expansion between the ceramic tiles and the unreinforced aluminum or Al-MMC creates internal stresses high enough to fracture the ceramic tiles. However, slow cooling of most commercial alloys creates large precipitates making solute unavailable for the formation of fine precipitates during aging. Here, we develop a non-quenched, high-strength metal matrix utilizing dilute Al-Sc-Zr alloys. We demonstrate that the dilute Al-0.09 Sc-0.045 Zr at.% alloy and the same alloy containing 0-4 vol.% alumina short fibers do not result in precipitation upon slow cooling from a high temperature, and can thereafter be aged to increase their strength. They exhibit a moderate strength, but improved ductility and toughness as compared to common armor aluminum alloys, such as AA5083-H131, making them attractive as armor materials and hybrid armor systems.

  15. Thermal Fatigue Limitations of Continuous Fiber Metal Matrix Composites

    Science.gov (United States)

    Halford, Gary R.; Arya, Vinod K.

    1997-01-01

    The potential structural benefits of unidirectional, continuous-fiber, metal matrix composites (MMC's) are legendary. When compared to their monolithic matrices, MMC's possess superior properties such as higher stiffness and tensile strength, and lower coefficient of thermal expansion in the direction of the reinforcing fibers. As an added bonus, the MMC density will be lower if the fibers are less dense than the matrix matErial they replace. The potential has been demonstrated unequivocally both analytically and experimentally, especially at ambient temperatures. Successes prompted heavily-funded National efforts within the United States (USAF and NASA) and elsewhere to extend the promise of MMC's into the temperature regime wherein creep, stress relaxation, oxidation, and thermal fatigue damage mechanisms lurk. This is the very regime for which alternative high-temperature materials are becoming mandatory, since further enhancement of state- of-the-art monolithic alloys is rapidly approaching a point of diminishing returns.

  16. LDEF results for polymer-matrix composite experiment AO 180

    International Nuclear Information System (INIS)

    This report represents a summary of the results obtained to-date on a polymer matrix composite experiment (AO 180) located at station D-12, about 82 deg off the 'ram' direction. Different material systems comprised of graphite, boron, and aramid (Kevlar) fiber reinforcements were studied. Although previous results were presented on in-situ thermal-vacuum cycling effects, particularly dimensional changes associated with outgassing, additional comparative data will be shown from ground-based tests on control and flight samples. The system employed was fully automated for thermal-vacuum cycling using a laser interferometer for monitoring displacements. Erosion of all three classes of materials due to atomic oxygen (AO) will also be discussed, including angle of incidence effects. Data from this experiment will be compared to published results for similar materials in other LDEF experiments. Composite materials' erosion yields will be presented on an AO design nomogram useful for estimating total material loss for given exposure conditions in low Earth orbit (LEO). Optical properties of these materials will also be compared with control samples. A survey of the damage caused by micrometeoroids/debris impacts will be addressed as they relate to polymer matrix composites. Correlations between hole size and damage pattern will be given. Reference to a new nomogram for estimating the number distribution of micrometeoroid/debris impacts for a given space structure as a function of time in LEO will be addressed based on LDEF data

  17. Rapid Fabrication of Carbide Matrix/Carbon Fiber Composites

    Science.gov (United States)

    Williams, Brian E.; Bernander, Robert E.

    2007-01-01

    Composites of zirconium carbide matrix material reinforced with carbon fibers can be fabricated relatively rapidly in a process that includes a melt infiltration step. Heretofore, these and other ceramic matrix composites have been made in a chemical vapor infiltration (CVI) process that takes months. The finished products of the CVI process are highly porous and cannot withstand temperatures above 3,000 F (approx.1,600 C). In contrast, the melt-infiltration-based process takes only a few days, and the composite products are more nearly fully dense and have withstood temperatures as high as 4,350 F (approx.2,400 C) in a highly oxidizing thrust chamber environment. Moreover, because the melt- infiltration-based process takes much less time, the finished products are expected to cost much less. Fabrication begins with the preparation of a carbon fiber preform that, typically, is of the size and shape of a part to be fabricated. By use of low-temperature ultraviolet-enhanced chemical vapor deposition, the carbon fibers in the preform are coated with one or more interfacial material(s), which could include oxides. The interfacial material helps to protect the fibers against chemical attack during the remainder of the fabrication process and against oxidation during subsequent use; it also enables slippage between the fibers and the matrix material, thereby helping to deflect cracks and distribute loads. Once the fibers have been coated with the interfacial material, the fiber preform is further infiltrated with a controlled amount of additional carbon, which serves as a reactant for the formation of the carbide matrix material. The next step is melt infiltration. The preform is exposed to molten zirconium, which wicks into the preform, drawn by capillary action. The molten metal fills most of the interstices of the preform and reacts with the added carbon to form the zirconium carbide matrix material. The zirconium does not react with the underlying fibers because they

  18. Classification and Preparation of Ocean Engineering Metal Matrix Composite%海洋工程金属基复合材料的分类与制备

    Institute of Scientific and Technical Information of China (English)

    贺毅强

    2011-01-01

    介绍了海洋环境的特点,综述了海洋工程金属基复合材料的发展现状,介绍了海洋工程金属基复合材料的分类与特点,着重介绍了铁基、铝基、钛基及铜基复合材料;综述了金属基复合材料制备技术的发展历程;概述了液态法、扩散粘结法、形变法、沉积法、多层喷射沉积法以及原位合成法等工艺;展望了海洋工程金属基复合材料的产业化发展趋势,提出了海洋工程金属材料朝金属基复合材料的方向发展,而采用防腐蚀涂层和镀层将进一步提高复合材料的耐腐蚀性.%The characteristic of ocean environment was introduced. The current status of ocean engineering metal matrix composite was introduced, and Ferrum matrix, aluminium matrix, titanium matrix and copper matrix composite were recommended specially. The preparation technology development of ocean engineering metal matrix composite was summarized. Specially liquid method, diffusion bonding, deforming method, deposition method, multi-layer spray deposition and in-situ composition were presented. Industrialization and development tendency were summarized. And it is considered that ocean engineering metals develop to the direction of ocean engineering metal matrix composite, and the corrosion resistance of the composite can be improved by anti-corrosion coating and film.

  19. Analytical Micromechanics Modeling Technique Developed for Ceramic Matrix Composites Analysis

    Science.gov (United States)

    Min, James B.

    2005-01-01

    Ceramic matrix composites (CMCs) promise many advantages for next-generation aerospace propulsion systems. Specifically, carbon-reinforced silicon carbide (C/SiC) CMCs enable higher operational temperatures and provide potential component weight savings by virtue of their high specific strength. These attributes may provide systemwide benefits. Higher operating temperatures lessen or eliminate the need for cooling, thereby reducing both fuel consumption and the complex hardware and plumbing required for heat management. This, in turn, lowers system weight, size, and complexity, while improving efficiency, reliability, and service life, resulting in overall lower operating costs.

  20. Fatigue In Continuous-Fiber/Metal-Matrix Composites

    Science.gov (United States)

    Johnson, William S.

    1992-01-01

    Report describes experimental approaches to quantification of fatigue damage in metal-matrix composites (MMC's). Discusses number of examples of development of damage and failure along with associated analytical models of behavior of MMC. Objectives of report are twofold. First, present experimental procedures and techniques for conducting meaningful fatigue tests to detect and quantify fatigue damage in MMC's. Second, present examples of how fatigue damage initiated and grows in various MMC's. Report furnishes some insight into what type of fatigue damage occurs and how damage quantified.

  1. Machinability of Al-SiC metal matrix composites using WC, PCD and MCD inserts

    Directory of Open Access Journals (Sweden)

    Beristain, Jokin

    2014-03-01

    Full Text Available The aim of this work is the study of the machinability of aluminium-silicon carbide Metal Matrix Composites (MMC in turning operations. The cutting tools used were hard metal (WC with and without coating, different grades and geometries of Poly-Crystalline Diamond (PCD and Mono-Crystalline Diamond (MCD. The work piece material was AMC225xe, composed of aluminium-copper alloy AA 2124 and 25% wt of SiC, being the size of the SiC particles around 3 μm. Experiments were conducted at various cutting speeds and cutting parameters in facing finishing operations, measuring the surface roughness, cutting forces and tool wear. The worn surface of the cutting tool was examined by Scanning Electron Microscope (SEM. It was observed that the Built Up Edge (BUE and stuck material is higher in the MCD tools than in the PCD tools. The BUE acts as a protective layer against abrasive wear of the tool.El objetivo de este trabajo es el estudio de la maquinabilidad del material compuesto de matriz metálica aluminio-carburo de silicio en operaciones de torneado. Las herramientas de corte utilizadas han sido de metal duro con y sin recubrimiento, diferentes grados de diamante policristalino (PCD y diamante monocristalino (MCD. El material mecanizado ha sido AMC225xe, compuesto de la aleación de aluminio AA 2124 con un 25% en peso de partículas de SiC con un tamaño medio de 3 μm. Los experimentos se han realizado con diferentes velocidades de corte en una operación de refrentado, midiendo la rugosidad superficial, las fuerzas y el desgaste de la herramienta. La superficie desgastada de la herramienta ha sido examinada en el microscopio electrónico (SEM. Se ha observado que el filo recrecido y el material adherido son mayores en el caso de las herramientas de MCD que en las de PCD. El filo recrecido actúa como una capa protectora contra la abrasión.

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

    International Nuclear Information System (INIS)

    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

  3. Direct digital radiography for the detection of defects in a standard aluminium test object through composite resin restorative materials.

    Science.gov (United States)

    Golubow, N A; Farman, A G; von Fraunhofer, J A; Kelly, M S

    1994-05-01

    While the RVG 32000 (Trophy Radiologie, Vincennes, France) is in wide use for direct digital intraoral radiography in dentistry, there is a dearth of information in the literature concerning the system's sensitivity to small changes in radiographic density consistent with initial and recurrent dental caries. A standardized 7 mm aluminium test block was used as a phantom for perceptibility testing of density changes, both with and without the superimposition of composite resin sheets of various thicknesses. Defects in the block were randomly positioned and varied from 0.1 to 1.5 mm. Thermal prints were used for evaluation. Standard linear images, with no enhancement, were compared with three enhanced modes, standard mode with gradient enhancement (enhanced standard), standard X-function and zoom high resolution (ZHR). Sensitivity improved in the following sequence: standard 0.58 < enhanced standard 0.75 < X-function 0.94 < ZHR 0.95. Accuracy improved in the following sequence: standard 0.45 < enhanced standard 0.58 < X-function 0.73 < ZHR 0.74. Specificity was 1.0 both for X-function and for ZHR. These two modes both proved significantly better (P < 0.05) for the detection of 0.1 mm defects than the other two modes tested. No significant difference was found between X-function and ZHR. As ZHR requires four times the radiation exposure as standard exposures with the X-function, the latter is preferred for the task described in this study.

  4. 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.

  5. Laser Machining of Melt Infiltrated Ceramic Matrix Composite

    Science.gov (United States)

    Jarmon, D. C.; Ojard, G.; Brewer, D.

    2012-01-01

    As interest grows in considering the use of ceramic matrix composites for critical components, the effects of different machining techniques, and the resulting machined surfaces, on strength need to be understood. This work presents the characterization of a Melt Infiltrated SiC/SiC composite material system machined by different methods. While a range of machining approaches were initially considered, only diamond grinding and laser machining were investigated on a series of tensile coupons. The coupons were tested for residual tensile strength, after a stressed steam exposure cycle. The data clearly differentiated the laser machined coupons as having better capability for the samples tested. These results, along with micro-structural characterization, will be presented.

  6. Manufacturing process of a multifunctional composite panel with nanocharged matrix

    Science.gov (United States)

    Volponi, R.; Spena, P.; De Nicola, F.; Guadagno, L.; Raimondo, M.; Vietri, U.

    2016-05-01

    This paper proposes an effective manufacturing process developed to overcome drawbacks that can occur using a nanofilled resin as matrix in aeronautical composites. Nanoparticles embedded in epoxy resins impregnating carbon fibers are able to improve a composite with new desired functionalities. As soon as the nanoparticles are dispersed in a resin, the viscosity dizzily rises and usually, the traditional manufacturing processes are not suitable to obtain a good quality of the manufactured panels. An alternative method has been developed starting from the Resin Film Infusion (RFI) process. This method has been firstly tested on several flat panels, and then it has been transferred on a more complex shaped panel with three stringers. In this work, a flame resistant resin based on a tetrafunctional epoxy precursor filled with carbon nanotubes to increase electrical conductivity, has been used for the panel manufacturing.

  7. Modeling oxidation damage of continuous fiber reinforced ceramic matrix composites

    Institute of Scientific and Technical Information of China (English)

    Cheng-Peng Yang; Gui-Qiong Jiao; Bo Wang

    2011-01-01

    For fiber reinforced ceramic matrix composites (CMCs), oxidation of the constituents is a very important damage type for high temperature applications. During the oxidizing process, the pyrolytic carbon interphase gradually recesses from the crack site in the axial direction of the fiber into the interior of the material. Carbon fiber usually presents notch-like or local neck-shrink oxidation phenomenon, causing strength degradation. But, the reason for SiC fiber degradation is the flaw growth mechanism on its surface. A micromechanical model based on the above mechanisms was established to simulate the mechanical properties of CMCs after high temperature oxidation. The statistic and shearlag theory were applied and the calculation expressions for retained tensile modulus and strength were deduced, respectively. Meanwhile, the interphase recession and fiber strength degradation were considered. And then, the model was validated by application to a C/SiC composite.

  8. Microstructure of a cement matrix composite reinforced with polypropylene fibers

    Directory of Open Access Journals (Sweden)

    Rincón, J. M.

    2004-06-01

    Full Text Available The present investigation deals with the microstructural characterization of a composite material, which is comprised of polypropylene fibers in an cement matrix, by means of environmental scanning electron microscopy (ESEM and field emission scanning electron microscopy (FESEM. The microstructure of the different phases that compose the matrix is very heterogeneous, though there is a uniform distribution of the fibers inside it. The surface of this composite is different after setting, cured and hardening depending if the zone is or not in touch with the walls of the mould. The interface between the different crystalline regions of the cement matrix and the dispersed fibers shows compatibility between the matrix and the polymeric fibers. The mechanical properties (compression and bending strength have also been evaluated. The use of melamine formaldehyde as additive leads to a reinforcement of the cement matrix and to the improvement of the mechanical properties.

    Se ha llevado a cabo una observacíón microestructural detallada de un material compuesto de fibras de polipropileno embebidas en una matriz de cemento usando los nuevos tipos de microscopía electrónica de barrido, tales como: un microscopio electrónico medioambiental (acrónimo en inglés: ESEM y uno de emisión de campo (acrónimo en inglés: FESEM. La microestructura de las diferentes fases que componen la matriz es muy heterogénea, aunque hay una distribución uniforme de las fibras dentro de ellas. La superficie de este material compuesto es diferente después del fraguado, curado y endurecimiento según qué zonas estén o no en contacto con las paredes del molde. La interfase entre las diferentes fases cristalinas de la matriz de cemento y las fibras dispersadas se ha observado a diferentes aumentos, comprobándose compatibilidad entre la matriz y las fibras poliméricas. Las propiedades de resistencia mecánica (tanto a flexión como a compresión han sido tambi

  9. Orthorhombic Titanium Matrix Composite Subjected to Simulated Engine Mission Cycles

    Science.gov (United States)

    Gabb, Timothy P.

    1997-01-01

    Titanium matrix composites (TMC's) are commonly made up of a titanium alloy matrix reinforced by silicon carbide fibers that are oriented parallel to the loading axis. These composites can provide high strength at lower densities than monolithic titanium alloys and superalloys in selected gas turbine engine applications. The use of TMC rings with unidirectional SiC fibers as reinforcing rings within compressor rotors could significantly reduce the weight of these components. In service, these TMC reinforcing rings would be subjected to complex service mission loading cycles, including fatigue and dwell excursions. Orthorhombic titanium aluminide alloys are of particular interest for such TMC applications because their tensile and creep strengths are high in comparison to those of other titanium alloys. The objective of this investigation was to assess, in simulated mission tests at the NASA Lewis Research Center, the durability of a SiC (SCS-6)/Ti-22Al-23Nb (at.%) TMC for compressor ring applications, in cooperation with the Allison Engine Company.

  10. Metal-Matrix Composites Prepared by Paper-Manufacturing Technology

    Science.gov (United States)

    Wenzel, Claudia; Aneziris, Christos G.; Pranke, Katja

    2016-01-01

    In this work, metal-matrix composites were prepared via paper-manufacturing technology using metastable austenitic steel powder of type 16-7-3 (Cr-Mn-Ni in wt pct) and magnesia partially stabilized zirconia reinforcing particles. The influence of the process parameters on the paper web formation and the resulting properties of the MMCs were studied and solids retention of >90 wt pct was achieved. During filtration of the aqueous fiber-filler suspension, the steel particles were incorporated in the fiber network, and steel clusters were formed. Calendering had a positive influence on the porosity, bulk density, and tensile strength of the green paper sheets. Within this contribution, the debinding process for the metal-matrix paper sheets was in focus. A debinding rate of 0.5 K/min to 733 K (460 °C) with a dwell time of 90 minutes was sufficient to completely remove cellulose fibers. The sintered composites attained a tensile strength of up to 177 N/mm2 at a total porosity of 66 pct.

  11. AN EXACT ELASTO-PLASTIC SOLUTION OF METAL-MATRIX COMPOSITE CANTILEVER BEAM LOADED BY A SINGLE FORCE AT ITS FREE END

    Directory of Open Access Journals (Sweden)

    Onur SAYMAN

    2001-03-01

    Full Text Available In the present study, an elastic-plastic stress analysis is carried out in a metal matrix composite cantilever beam loaded by a single force at its free end. A composite consisting of stainless-steel reinforced aluminium was produced for this work. The orientation angle of the fibers is chosen as 0°, 30°, 45°, 60° and 90°. The material is assumed to be perfectly plastic in the elasto-plastic solution. An analytical solution is performed for satisfying both the governing differential equation in the plane stress case and boundary conditions for small plastic deformations. The solution is carried out under the assumption of the Bernoulli-Navier hypotheses. The composite material is assumed as hardening linearly. The Tsai-Hill theory is used as a yield criterion.

  12. 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

  13. Experimental Test of Stainless Steel Wire Mesh and Aluminium Alloy With Glass Fiber Reinforcement Hybrid Composite

    OpenAIRE

    Ranga Raj R.,; Velmurugan R

    2015-01-01

    At present, composite materials are mostly used in aircraft structural components, because of their excellent properties like lightweight, high strength to weight ratio, high stiffness, and corrosion resistance and less expensive. In this experimental work, the mechanical properties of laminate, this is reinforced with stainless steel wire mesh, aluminum sheet metal, perforated aluminum sheet metal and glass fibers to be laminate and investigated. The stainless steel wire mesh and...

  14. Ultrasonic location for core end of Al-Li alloy and aluminium composite tube

    International Nuclear Information System (INIS)

    The locating method of the core end of Al-Li alloy is studied by ultrasonic wave time-frequency analysis. Adopting the high frequency and narrow pulse emission the composite metal tube can be located by means of the states of longitudinal wave and transverse wave. The dissection of the sample proves that the core end thickness is 0.1 mm and the location precision is 2 mm

  15. Friction behaviour of aluminium composites mixed with carbon fibers with different orientations

    Science.gov (United States)

    Caliman, R.

    2016-08-01

    The primary goal of this study work it was to distinguish a mixture of materials with enhanced friction and wearing behaviour. The composite materials may be differentiated from alloys; which can contain two more components but are formed naturally through different processes such as casting. The load applied on the specimen during the tests, is playing a very important role regarding friction coefficient and also the wearing speed. Sintered composites are gaining importance because the reinforcement serves to reduce the coefficient of thermal expansion and increase the strength and modulus. The friction tests are carried out, at the room temperature in dry condition, on a pin-on-disc machine. The exponentially decreasing areas form graphs, represented to the curves coefficient of friction, are attributed to the formation of lubricant transfer film and initial polishing surface samples. The influence of the orientation of the carbon fibers on the friction properties in the sintered polymer composites may be studied by the use of both mechanical wear tests by microscopy and through the use of phenomenological models.

  16. 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.

  17. Nondestructive damage evaluation in ceramic matrix composites for aerospace applications.

    Science.gov (United States)

    Dassios, Konstantinos G; Kordatos, Evangelos Z; Aggelis, Dimitrios G; Matikas, Theodore E

    2013-01-01

    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.

  18. Nondestructive evaluation of a ceramic matrix composite material

    Science.gov (United States)

    Grosskopf, Paul P.; Duke, John C., Jr.

    1992-01-01

    Monolithic ceramic materials have proven their usefulness in many applications, yet, their potential for critical structural applications is limited because of their sensitivity to small imperfections. To overcome this extreme sensitivity to small imperfections, ceramic matrix composite materials have been developed that have the ability to withstand some distributed damage. A borosilicate glass reinforced with several layers of silicon-carbide fiber mat has been studied. Four-point flexure and tension tests were performed not only to determine some of the material properties, but also to initiate a controlled amount of damage within each specimen. Acousto-ultrasonic (AU) measurements were performed periodically during mechanical testing. This paper will compare the AU results to the mechanical test results and data from other nondestructive methods including acoustic emission monitoring and X-ray radiography. It was found that the AU measurements were sensitive to the damage that had developed within the material.

  19. Measuring time-dependent diffusion in polymer matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Pilli, Siva Prasad; Smith, Lloyd V.; Shutthanandan, V.

    2014-11-01

    Moisture plays a significant role in influencing the mechanical behavior and long-term durability of polymer matrix composites (PMC’s). The common methods used to determine the moisture diffusion coefficients of PMCs are based on the solution of Fickian diffusion in the one-dimensional domain. Fick’s Law assumes that equilibrium between the material surface and the external vapor is established instantaneously. A time dependent boundary condition has been shown to improve correlation with some bulk diffusion measurements, but has not been validated experimentally. The surface moisture content in a Toray 800S/3900-2B toughened quasi-isotropic laminate system, [0/±60]s, was analyzed experimentally using Nuclear Reaction Analysis (NRA). It was found that the surface moisture content showed a rapid increase to an intermediate concentration C0, followed by a slow linear increase to the saturation level.

  20. Measuring time-dependent diffusion in polymer matrix composites

    Science.gov (United States)

    Pilli, Siva P.; Smith, Lloyd V.; Vaithiyalingam, Shutthanandan

    2014-11-01

    Moisture plays a significant role in influencing the mechanical behavior and long-term durability of polymer matrix composites (PMCs). The common methods used to determine the moisture diffusion coefficients of PMCs are based on the solution of Fickian diffusion in the one-dimensional domain. Fick's Law assumes that equilibrium between the material surface and the external vapor is established instantaneously. A time-dependent boundary condition has been shown to improve correlation with some bulk diffusion measurements, but has not been validated experimentally. The surface moisture content in a Toray 800S/3900-2B toughened quasi-isotropic laminate system, [0/±60] s , was analyzed experimentally using Nuclear Reaction Analysis (NRA). It was found that the surface moisture content showed a rapid increase to an intermediate concentration C 0, followed by a slow linear increase to the saturation level.

  1. 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.

  2. Creep Test of Polymer-matrix 3-D Braided Composites

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The long-term creep behavior of polymer-matrix 3-D braided composites was studied by using the tensile creep test method, and the effect of braiding structure, braiding angle and fiber volume fraction were discussed. The creep curve appears as expected, and can be defimed two phases,namely, the primary phase and the secondary phase. For each sample, strain increases with time rapidly, and then the strain rate decreases and appears to approach a constant rate of change (steady-state creep). The experiment results show that the creep resistant properties are improved while the braiding angle decreases or the fiber volume fraction increases, and that the five-directional braiding structure offers better creep resistant properties than the fourdirectional braiding structure.

  3. 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.

  4. Condensation Dynamics on Mimicked Metal Matrix Hydrophobic Nanoparticle-Composites

    Science.gov (United States)

    Damle, Viraj; Sun, Xiaoda; Rykaczewski, Konrad

    2014-11-01

    Use of hydrophobic surfaces promotes condensation in the dropwise mode, which is significantly more efficient than the common filmwise mode. However, limited longevity of hydrophobic surface modifiers has prevented their wide spread use in industry. Recently, metal matrix composites (MMCs) having microscale hydrophobic heterogeneities dispersed in hydrophilic metal matrix have been proposed as durable and self-healing alternative to hydrophobic surface coatings interacting with deposited water droplets. While dispersion of hydrophobic microparticles in MMC is likely to lead to surface flooding during condensation, the effect of dispersion of hydrophobic nanoparticles (HNPs) with size comparable to water nuclei critical radii and spacing is not obvious. To this end, we fabricated highly ordered arrays of Teflon nanospheres on silicon substrates that mimic the top surface of the MMCs with dispersed HNPs. We used light and electron microscopy to observe breath figures resulting from condensation on these surfaces at varied degrees of subcooling. Here, we discuss the relation between the droplet size distribution, Teflon nanosphere diameter and spacing, and condensation mode. KR acknowledges startup funding from ASU.

  5. DEVELOPMENT OF LIGNIN EPOXIDE—A POTENTIAL MATRIX OF RESIN MATRIX COMPOSITE

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    To develop new kinds of matrix resin of composite and utilize lignosulfonate in large scale and high value, a kind of lignosulfonate was modified into epoxide in this paper. Two kinds of phenolized lignosulfonic acid and two kinds of lignin epoxides were prepared. The lignin epoxides and a kind of bisphenol-A epoxy resin were mixed respectively with a kind of liquid anhydride (MNA) to be measured by DSC technology. Both of these two kinds of epoxides can be cured by MNA, and curing exotherm of the liquid one is more than that of the solid one. Samples of the phenolized lignosulfonic acid and the epoxides were all analyzed by IR spectroscopy to find relations between them. It is suggested that the phenolation decide the type and the yield of the lignin epoxides.

  6. 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

  7. Oxidation Behavior of C/C-SiC Gradient Matrix Composites

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Oxidation behavior of C/C-SiC gradient matrix composites and C/C composites were compared in stationary air. The results show that oxidation threshold of C-SiC materials increases with the amount of SiC particles in the codeposition matrix. Oxidation rate of C/C-SiC gradient matrix composites is significantly lower than that of C/C material. The micro-oxidation process was observed by SEM.

  8. 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

  9. CNT-based Reinforcing Polymer Matrix Composites for Lightweight Structures Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Carbon Polymer Matrix Composites (PMCs) are attractive structural materials for NASA applications due to their high strength to weight ratio, mechanical properties...

  10. 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.

  11. A study of the composition and microstructure of aluminum matrix composites reinforced with alumina fibers

    Science.gov (United States)

    Zolotova, D.; Serpova, V.; Prokofiev, M.; Rabinskiy, L.; Shavnev, A.

    2016-04-01

    This article presents the results of a study of the microstructure and the composition of aluminum-based metal matrix composites (MMC) reinforced with continuous alumina fibers. An Al-Mg-Cu alloy similar to that of AA 2024 was used. X-ray diffraction and X-ray fluorescence analyses were used for investigation of a probable volume fraction of a spinel phase in MMC. Scanning electron microscopy and an X-ray microanalysis were used to study a change of the elemental composition of the composites microstructure on the polished cross sections. The constant mass fractions of magnesium (0.65 wt. %) and copper (1.25 wt. %) were found in the interphase area within radius of 1 μm around fibers.

  12. High-temperature mechanical properties of aluminium alloys reinforced with boron carbide particles

    Energy Technology Data Exchange (ETDEWEB)

    Onoro, J. [Dept. Ingenieria y Ciencia de los Materiales, ETSI Industriales, Universidad Politecnica de Madrid, c/Jose Gutierrez Abascal 2, 28006 Madrid (Spain)], E-mail: javier.onoro@upm.es; Salvador, M.D. [Dept. Ingenieria Mecanica y de Materiales, ETSI Industriales, Universidad Politecnica de Valencia, Camino de Vera s/n, 46071 Valencia (Spain); Cambronero, L.E.G. [Dept. Ingenieria de Materiales, ETSI Minas, Universidad Politecnica de Madrid, c/Rios Rosas 21, 28003 Madrid (Spain)

    2009-01-15

    The mechanical properties of particulate-reinforced metal-matrix composites based on aluminium alloys (6061 and 7015) at high temperatures were studied. Boron carbide particles were used as reinforcement. All composites were produced by hot extrusion. The tensile properties and fracture analysis of these materials were investigated at room temperature and at high temperature to determine their ultimate strength and strain to failure. The fracture surface was analysed by scanning electron microscopy.

  13. 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.

  14. Polymer matrix composites research: A survey of federally sponsored programs

    Energy Technology Data Exchange (ETDEWEB)

    1990-06-01

    This report identifies research conducted by agencies of the federal government other than the Department of Energy (DOE) in the area of advanced polymer matrix composites (PMCs). DOE commissioned the report to avoid duplicating other agencies' efforts in planning its own research program for PMCs. PMC materials consist of high-strength, short or continuous fibers fused together by an organic matrix. Compared to traditional structural metals, PMCs provide greater strength and stiffness, reduced weight and increased heat resistance. The key contributors to PMC research identified by the survey are the Department of Defense (DOD), the National Aeronautics and Space Administration (NASA), the National Science Foundation (NSF), and the Department of Transportation (DOT). The survey identified a total of 778 projects. More than half of the total projects identified emphasize materials research with a goal toward developing materials with improved performance. Although an almost equal number of identified materials projects focus on thermosets and thermoplastics receive more attention because of their increased impact resistance and their easy formability and re-formability. Slightly more than one third of projects identified target structures research. Only 15 percent of the projects identified focus on manufacturing techniques, despite the need for efficient, economical methods manufacturing products constructed of PMCs--techniques required for PMCs to gain widespread acceptance. Three issues to be addressed concerning PMCs research are economy of use, improvements in processing, and education and training. Five target technologies have been identified that could benefit greatly from increased use of PMCs: aircraft fuselages, automobile frames, high-speed machinery, electronic packaging, and construction.

  15. Numerical studies of fibrous composites from the view point of fiber-matrix interface and fiber-matrix bonding

    Science.gov (United States)

    Yilmaz, Yahya Ilyas

    In the present research, the micromechanics of fibrous composites was studied numerically. The effects of the fiber/matrix interphase region and fiber/matrix bonding were the main goals of this research. Throughout the research NASTRAN finite element analyses were used. First we investigated the effect of the interphase region on the stress field by varying the thickness of the interphase region and the material properties in the interphase region. Second, we numerically simulated the bonding qualities between the fiber and the matrix by the implementation of the fiber/matrix interphase region. The change for bonding between the fiber and the matrix were simulated through a periodic material property change in the interphase region. Third, we developed a bi-dimensional concentric cylindrical model for stress transfer between the fiber and the matrix model in case of a broken fiber or short fiber composites. This model is unique in accounting for the real non-linear stress-strain relationship for the matrix material. The stress transfer between the fiber and the matrix was also analyzed by finite element models. Toward this end finite element analysis proved a useful tool to help us evaluate key model parameters, most importantly the radius of fiber influence. This parameter is also a key parameter of simple models upon which the new model is based. Finally we applied our stress transfer model to analyze single fiber fragmentation test data obtained at Kansas State University.

  16. Matrix-filler interfaces and physical properties of metal matrix composites with negative thermal expansion manganese nitride

    Science.gov (United States)

    Takenaka, Koshi; Kuzuoka, Kota; Sugimoto, Norihiro

    2015-08-01

    Copper matrix composites containing antiperovskite manganese nitrides with negative thermal expansion (NTE) were formed using pulsed electric current sintering. Energy dispersive X-ray spectroscopy revealed that the chemically reacted region extends over 10 μm around the matrix-filler interfaces. The small-size filler was chemically deteriorated during formation of composites and it lost the NTE property. Therefore, we produced the composites using only the nitride particles having diameter larger than 50 μm. The large-size filler effectively suppressed the thermal expansion of copper and improved the conductivity of the composites to the level of pure aluminum. The present composites, having high thermal conductivity and low thermal expansion, are suitable for practical applications such as a heat radiation substrate for semiconductor devices.

  17. Deformation behavior of SiC particle reinforced Al matrix composites based on EMA model

    Institute of Scientific and Technical Information of China (English)

    CHENG Nan-pu; ZENG Su-min; YU Wen-bin; LIU Zhi-yi; CHEN Zhi-qian

    2007-01-01

    Effects of the matrix properties, particle size distribution and interfacial matrix failure on the elastoplastic deformation behavior in Al matrix composites reinforced by SiC particles with an average size of 5 μm and volume fraction of 12% were quantitatively calculated by using the expanded effective assumption(EMA) model. The particle size distribution naturally brings about the variation of matrix properties and the interfacial matrix failure due to the presence of SiC particles. The theoretical results coincide well with those of the experiment. The current research indicates that the load transfer between matrix and reinforcements, grain refinement in matrix, and enhanced dislocation density originated from the thermal mismatch between SiC particles and Al matrix increase the flow stress of the composites, but the interfacial matrix failure is opposite. It also proves that the load transfer, grain refinement and dislocation strengthening are the main strengthening mechanisms, and the interfacial matrix failure and ductile fracture of matrix are the dominating fracture modes in the composites. The mechanical properties of the composites strongly depend on the metal matrix.

  18. Residual stress measurements in an SiC continuous fiber reinforced Ti matrix composite

    NARCIS (Netherlands)

    Willemse, P.F.; Mulder, F.M.; Wei, W.; Rekveldt, M. Th.; Knight, K.S.

    2000-01-01

    During the fabrication of ceramic fiber reinforced metal matrix composites mismatch stresses will be introduced due to differences in thermal expansion coefficients between the matrix and the fibers. Calculations, based on a coaxial cylinder model, [1 and 2] predict that, for a Ti matrix SiC continu

  19. Reliability-analysis on damage of unidirectional composites matrix polymers

    Directory of Open Access Journals (Sweden)

    Khiat M. A.

    2014-04-01

    Full Text Available This work presents an analytical model to predict the strength of the unidirectional carbon epoxy composite using micromechanical techniques. This model supposes that a group of broken fibres surrounded by a number of intact fibres with hexagonal arrangement. The mathematical developments used are presented to justify the distribution form of the stresses around broken fibre and adjacent intact fibres. To follow the evolution of the damage in regions of debonding and local plasticity; we proceeded to a progressive increase in the fiber volume fraction and tensile external load. This, procedure enable us to evaluate the extension of the region locally plasticized, the ineffective region, the stress concentration and the longitudinal displacement of broken and intact fibres, in function of broken fibres number and specimen length. As fiber breaks are intrinsically random, the variability of input data allows us to describe the probabilistic model by using the Monte-Carlo method. The sensitivities of the mechanical response are evaluated regarding the uncertainties in design variables such as Young’s modulus of fibers and matrix, fiber reference strength, shear yield stress, fiber volume fraction and shear parameter defining the shear stress in the inelastic region.

  20. Fatigue damage growth mechanisms in continuous fiber reinforced titanium matrix composites

    Science.gov (United States)

    Johnson, W. S.; Naik, R. A.; Pollock, W. D.

    1990-01-01

    The role of fiber/matrix interface strength, residual thermal stresses, and fiber and matrix properties on fatigue damage accumulation in continuous fiber metal matrix composites (MMC) will be discussed. Results from titanium matrix/silicon-carbide fiber composites will be the primary topic of discussion. Results have been obtained from both notched and unnotched specimens at room and elevated temperatures. The stress in the 0 deg fibers has been indentified as the controlling factor in fatigue life. Fatigue of the notched specimens indicated that cracks can grow many fiber spacings in the matrix materials without breaking fibers.

  1. Allylhydridopolycarbosilane (AHPCS) as matrix resin for C/SiC ceramic matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Sreeja, R. [Ceramic Matrix Products Division, Propellants and Special Chemicals Group, PCM Entity, Vikram Sarabhai Space Center, Thiruvananthapuram 695022 (India); Swaminathan, B., E-mail: swami1423@gmail.co [Ceramic Matrix Products Division, Propellants and Special Chemicals Group, PCM Entity, Vikram Sarabhai Space Center, Thiruvananthapuram 695022 (India); Painuly, Anil; Sebastian, T.V.; Packirisamy, S. [Ceramic Matrix Products Division, Propellants and Special Chemicals Group, PCM Entity, Vikram Sarabhai Space Center, Thiruvananthapuram 695022 (India)

    2010-04-15

    In present study, partially allyl-substituted hydridopolycarbosilane (5 mol% allyl) [AHPCS] has been characterized by spectral techniques and thermal analysis. The DSC studies show that, the polymer is self-cross-linking at lower temperatures without any incorporation of cross-linking agents. The spectral and thermal characterizations carried out at different processing stages indicate the possibility of extensive structural rearrangement accompanied by the loss of hydrogen and other reactions of C and Si containing species resulting in the conversion of the branched chain segment into a 3D SiC network structure. AHPCS gave ceramic residue of 72% and 70% at 900 and 1500 deg. C respectively in argon atmosphere. XRD pattern of 1500 deg. C heat-treated AHPCS, indicates the formation of silicon carbide with the particle size of 3-4 nm. AHPCS was used as matrix resin for the preparation of C/SiC composite without any interfacial coating over the T-300 carbon fabric reinforcement. Flexural strength value of 74-86 MPa for C/SiC specimen with density of 1.7 g/cm{sup 3} was obtained after four infiltration and pyrolysis cycles.

  2. Neutron diffraction measurements and modeling of residual strains in metal matrix composites

    Science.gov (United States)

    Saigal, A.; Leisk, G. G.; Hubbard, C. R.; Misture, S. T.; Wang, X. L.

    1996-01-01

    Neutron diffraction measurements at room temperature are used to characterize the residual strains in tungsten fiber-reinforced copper matrix, tungsten fiber-reinforced Kanthal matrix, and diamond particulate-reinforced copper matrix composites. Results of finite element modeling are compared with the neutron diffraction data. In tungsten/Kanthal composites, the fibers are in compression, the matrix is in tension, and the thermal residual strains are a strong function of the volume fraction of fibers. In copper matrix composites, the matrix is in tension and the stresses are independent of the volume fraction of tungsten fibers or diamond particles and the assumed stress free temperature because of the low yield strength of the matrix phase.

  3. Heat Treatment Parameters to Optimize Friction and Wear behavior of Novel Hybrid Aluminium Composites Using Taguchi Technique

    Directory of Open Access Journals (Sweden)

    V.C.Uvaraja

    2014-05-01

    Full Text Available In the present study, an Al 7075 alloy is used as the matrix and varying weight percentage of Silicon Carbide (SiC and constant weight percentage of Boron Carbide (B4C as the reinforcing material. The composite is produced using stir casting technique. The composite thus formed is termed as hybrid composite. The samples are prepared for heat treatment process by subjecting to solutionizing temperature of 530o C for 1 hr followed by quenching in water. Further the specimens are subjected to artificial aging for durations of 4, 6 and 8 hr at a temperature of 175°C. The mechanical and tribological properties of composites before and after heat treatment are examined by Vickers hardness test machine and pin-on-disc test machine respectively. The wear rate and friction co-efficient of heat treatment parameters are evaluated based on Taguchi technique. The analysis is further extended to the optimization of test parameters using Design of Experiment (DoE based on L9 orthogonal array. The developed Analysis of Variance (ANOVA and the regression equations is obtained through MINITAB R16 are used to investigate the influence of parameters like sliding speed, applied load, sliding time, and percentage of reinforcement on the dry sliding wear and friction co-efficient of the composites. The wear surface morphology and wear mechanism of the pins are investigated using Scanning Electron Microscope (SEM and are correlated them with wear test results. Finally, confirmation tests are carried out to verify the experimental results.

  4. 注凝成型制备莫来石-钛酸铝复相陶瓷%PREPARATION OF MULLITE-ALUMINIUM TITANATE CERAMIC COMPOSITES VIA GELCASTING

    Institute of Scientific and Technical Information of China (English)

    陆洪彬; 陈建华; 冯春霞; 焦宝祥; 孟祥康

    2009-01-01

    The mullite-aluminium titanate (MAT) ceramic composites were prepared via the gelcasting or dry pressing processes us- ing industrial mullite and aluminium titanate (Al2TiO5) powders with different mass ratios, that titanate was synthesized by doping the bi-component additive of 10% (in mole, the same below) MgO and 15% SiO2 relative to Al2O3. Effects of the bi-component additive on the phase composition and thermal stabilization of aluminium titanate powder were analyzed by X-ray diffraction and the micro- structures of MAT ceramic composites were characterized by scanning electron microscopy. The effects of aluminium titanate content on the bending strength and average thermal expansion coefficient (room temperature-1000 ℃) of the MAT ceramic composites pre- pared by dry pressing or gelcasting shaping processes were also investigated. The results show that the bi-component additive of MgO and SiO2 can promote the formation of Al2TiO5 and enhance its thermal stabilization. The MAT ceramic composites prepared by gel- casting process obtain more homogenous structure and higher bending strength than that prepared by dry pressing process. The MAT ceramic composite prepared by gelcasting process and containing 10% (mass fraction) Al2TiO5 has the maximum bending strength of 110.05 MPa.%引入10%(摩尔分数,相对于A12O3,下同)MgO和15%SiO2双组分添加剂合成了钛酸铝粉体.采用不同质量比的钛酸铝粉体和工业莫来石,用干压和注凝成型工艺制备了莫来石-钛酸铝(mullite-aluminium titanate,MAT)复相陶瓷.用X射线衍射分析了双组分添加剂对钛酸铝相组成和热稳定性的影响.通过扫描电镜表征了MAT复相陶瓷的微结构.研究了钛酸铝含量对采用于压、注凝2种成型工艺制备的MAT复相陶瓷的弯曲强度和平均热膨胀系数(室温~1 000℃)的影响.结果表明:MgO和SiO2双组分添加剂促进了钛酸铝的形成,增强了钛酸铝的热稳定性.通过注凝成型制备

  5. Automotive Aluminium Recycling

    Energy Technology Data Exchange (ETDEWEB)

    Gelas, B. des

    2000-07-01

    This paper aims at providing an overview on the contribution of aluminium recycling in the supply of new aluminium for automotive applications. Based on a presentation on how the global European automotive aluminium supply requirements are met, an analysis of the present and future contribution of automotive aluminium recycling is first presented. Current situation and future developments for automotive aluminium recycling practices are then commented, together with an outline on design principles for easier aluminium recycling. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-01-15

    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.

  7. A Micro Raman Investigation of Viscoelasticity in Short Fibre Reinforced Polymer Matrix Composites

    DEFF Research Database (Denmark)

    Schjødt-Thomsen, Jan

    The purpose of the present Ph.D. project is to investigate the load transfer mechanisms between the fibre and matrix and the stress/strain fields in and around single fibres in short fibre reinforced viscoelastic polymer matrix composites subjected to various loading histories. The materials...... considered are high modulus carbon fibres embedded in a polypropylene matrix. The polypropylene matrix displays nonlinear viscoelasticity and its constitutive behaviour is modelled using the Schapery model....

  8. Approach to microstructure-behavior relationships for ceramic matrix composites reinforced by continuous fibers

    OpenAIRE

    Lamon Jacques

    2015-01-01

    Ceramic matrix composites (CMCs) reinforced with continuous fibers exhibit several features that differentiate them from homogeneous unreinforced materials. The microstructure consists of various distinct constituents: fibres, matrix, and fiber/matrix interfaces or interphases. Several entities at micro- and mesoscopic length scales can be defined depending on fiber arrangement. Furthermore, the CMCs contain flaw populations that govern matrix cracking and fiber failures. The paper describes ...

  9. Structure and properties of a pulp fibre-reinforced composite with regenerated cellulose matrix

    Science.gov (United States)

    Gindl, W.; Schöberl, T.; Keckes, J.

    2006-04-01

    Fully bio-based cellulose cellulose composites were produced by partly dissolving beech pulp fibres in lithium chloride/dimethylacetamide (LiCl/DMAc) and subsequent regeneration of matrix cellulose in the presence of undissolved fibres. Compared to cellulose epoxy composites produced from the same fibres, a two-fold increase in tensile strength and elastic modulus was observed for cellulose cellulose composites. From scanning electron microscopy and nanoindentation it is concluded that changes in the fibre cell wall during LiCl/DMAc treatment, improved matrix properties of regenerated cellulose compared to epoxy, and improved fibre matrix adhesion are responsible for the superior properties of cellulose cellulose composites.

  10. 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.

  11. In situ (Al3Zr + Al2O3np)/2024Al metal matrix composite with novel reinforcement distributions fabricated by reaction hot pressing

    International Nuclear Information System (INIS)

    Highlights: •(Al3Zr + Al2O3np)/2024Al MMC with a novel network distribution was tailored. •Al3Zr and Al2O3np were in situ synthesized at 740 °C using the 2024Al–ZrO2 system. •The effect of sintering parameters on Al3Zr morphology was investigated. •Influence of Al3Zr morphology on tensile properties of the composite was studied. -- Abstract: In situ hybrid (Al3Zr + Al2O3np)/2024Al metal matrix composites with unique controlled reinforcement distributions were fabricated using low energy ball milling and reactive hot pressing. The reaction system between 2024Al and ZrO2 was studied using differential thermal analysis (DTA). In situ formed aluminium oxide (Al2O3) and zirconium tri-aluminide (Al3Zr) with varying morphology and sizes were produced under different fabricating conditions. Al3Zr with varying morphologies such as particle, plate and flakes were observed. With a total 10 vol.% of reinforcements, the composite containing a three-dimensional network of closely spaced in situ synthesized Al3Zr and Al2O3 particles had a YS of 175 MPa and a UTS of 261 MPa, effectively strengthening the 2024Al matrix. The effect of different sintering conditions on the microstructure and tensile properties of the composite was systematically investigated

  12. High-pressure direct synthesis of aluminium nitride

    CERN Document Server

    Bockowski, M; Grzegory, I; Krukowski, S; Wróblewski, M; Porowski, S

    2002-01-01

    We report the results of direct synthesis of aluminium nitride (AlN) under high nitrogen pressure up to 1 GPa and temperatures up to 2000 K. At pressure from 10 to 650 MPa we observe the combustion synthesis of AlN. As the result of the combustion process one can obtain the AlN sintered powder or AlN/Al metal matrix composites. For N sub 2 pressure higher than 650 MPa the crystal growth of AlN from the solution of atomic nitrogen in aluminium is possible. Both needle-like and bulk AlN single crystals, up to 1 cm and 1 mm, respectively, have been obtained.

  13. Microstructural characterization of a silicon carbide whisker reinforced 2014 aluminum metal matrix composite

    International Nuclear Information System (INIS)

    Microstructural development in a powder metallurgy 2014 aluminum alloy -SiC whisker composite subject to controled and systematic aging treatments was investigated using analytical transmission electron microscopy and matrix microhardness measurements. In order to build a basis for comparison, the precipitation characteristics of the unreinforced matrix material with an identical processing history were also examined. The results indicate that the matrix of the composite material has a much greater density of dislocations than the control alloy. This high density of dislocations is due to the substantial difference on thermal expansion of Al matrix with respect to the SiC particles. (orig.)

  14. Morphology, chemical composition and nanostructure of single carbon-rich particles studied by transmission electron microscopy: source apportionment in workroom air of aluminium smelters.

    Science.gov (United States)

    Weinbruch, Stephan; Benker, Nathalie; Kandler, Konrad; Ebert, Martin; Ellingsen, Dag G; Berlinger, Balázs; Thomassen, Yngvar

    2016-02-01

    Sources of C-rich particles at work places in two aluminium smelters in Norway were studied by transmission electron microscopy and energy-dispersive X-ray microanalysis. Based on morphology, nanostructure and chemistry, three different types of C-rich particles are distinguished: (a) chain-like agglomerates (70-100% by number, relative to the sum of C-rich particles) consisting of primary particles with typical onion-shell structure of graphene layers, (b) multi-walled carbon nanotube particles (≈3%) and (c) spheres or agglomerates of amorphous C-rich particles (0-30%). Chain-like agglomerates are interpreted as diesel soot in accordance with literature data on primary particle diameter, chemical composition and nanostructure of primary particles. The source of the observed multi-walled carbon nanotubes is not known. The amorphous C-rich particles most likely consist of organic carbon species which cannot be characterized further by X-ray microanalysis. Unaltered graphitic electrode material was not found among the C-rich particles. The high fraction of diesel soot particles indicates that elemental carbon is generally suited as proxy for diesel soot in aluminium smelters. However, due to the presence of carbon nanotubes and amorphous C-rich particles, detailed characterization of sources of carbon-rich particles by electron microscopy is recommended for accurate assessment of adverse health effects. PMID:26637216

  15. Microstructure and mechanical behavior of metallic glass fiber-reinforced Al alloy matrix composites.

    Science.gov (United States)

    Wang, Z; Georgarakis, K; Nakayama, K S; Li, Y; Tsarkov, A A; Xie, G; Dudina, D; Louzguine-Luzgin, D V; Yavari, A R

    2016-01-01

    Metallic glass-reinforced metal matrix composites are an emerging class of composite materials. The metallic nature and the high mechanical strength of the reinforcing phase offers unique possibilities for improving the engineering performance of composites. Understanding the structure at the amorphous/crystalline interfaces and the deformation behavior of these composites is of vital importance for their further development and potential application. In the present work, Zr-based metallic glass fibers have been introduced in Al7075 alloy (Al-Zn-Mg-Cu) matrices using spark plasma sintering (SPS) producing composites with low porosity. The addition of metallic glass reinforcements in the Al-based matrix significantly improves the mechanical behavior of the composites in compression. High-resolution TEM observations at the interface reveal the formation of a thin interdiffusion layer able to provide good bonding between the reinforcing phase and the Al-based matrix. The deformation behavior of the composites was studied, indicating that local plastic deformation occurred in the matrix near the glassy reinforcements followed by the initiation and propagation of cracks mainly through the matrix. The reinforcing phase is seen to inhibit the plastic deformation and retard the crack propagation. The findings offer new insights into the mechanical behavior of metal matrix composites reinforced with metallic glasses.

  16. Microstructure and mechanical behavior of metallic glass fiber-reinforced Al alloy matrix composites

    Science.gov (United States)

    Wang, Z.; Georgarakis, K.; Nakayama, K. S.; Li, Y.; Tsarkov, A. A.; Xie, G.; Dudina, D.; Louzguine-Luzgin, D. V.; Yavari, A. R.

    2016-04-01

    Metallic glass-reinforced metal matrix composites are an emerging class of composite materials. The metallic nature and the high mechanical strength of the reinforcing phase offers unique possibilities for improving the engineering performance of composites. Understanding the structure at the amorphous/crystalline interfaces and the deformation behavior of these composites is of vital importance for their further development and potential application. In the present work, Zr-based metallic glass fibers have been introduced in Al7075 alloy (Al-Zn-Mg-Cu) matrices using spark plasma sintering (SPS) producing composites with low porosity. The addition of metallic glass reinforcements in the Al-based matrix significantly improves the mechanical behavior of the composites in compression. High-resolution TEM observations at the interface reveal the formation of a thin interdiffusion layer able to provide good bonding between the reinforcing phase and the Al-based matrix. The deformation behavior of the composites was studied, indicating that local plastic deformation occurred in the matrix near the glassy reinforcements followed by the initiation and propagation of cracks mainly through the matrix. The reinforcing phase is seen to inhibit the plastic deformation and retard the crack propagation. The findings offer new insights into the mechanical behavior of metal matrix composites reinforced with metallic glasses.

  17. Microstructure and mechanical behavior of metallic glass fiber-reinforced Al alloy matrix composites

    Science.gov (United States)

    Wang, Z.; Georgarakis, K.; Nakayama, K. S.; Li, Y.; Tsarkov, A. A.; Xie, G.; Dudina, D.; Louzguine-Luzgin, D. V.; Yavari, A. R.

    2016-01-01

    Metallic glass-reinforced metal matrix composites are an emerging class of composite materials. The metallic nature and the high mechanical strength of the reinforcing phase offers unique possibilities for improving the engineering performance of composites. Understanding the structure at the amorphous/crystalline interfaces and the deformation behavior of these composites is of vital importance for their further development and potential application. In the present work, Zr-based metallic glass fibers have been introduced in Al7075 alloy (Al-Zn-Mg-Cu) matrices using spark plasma sintering (SPS) producing composites with low porosity. The addition of metallic glass reinforcements in the Al-based matrix significantly improves the mechanical behavior of the composites in compression. High-resolution TEM observations at the interface reveal the formation of a thin interdiffusion layer able to provide good bonding between the reinforcing phase and the Al-based matrix. The deformation behavior of the composites was studied, indicating that local plastic deformation occurred in the matrix near the glassy reinforcements followed by the initiation and propagation of cracks mainly through the matrix. The reinforcing phase is seen to inhibit the plastic deformation and retard the crack propagation. The findings offer new insights into the mechanical behavior of metal matrix composites reinforced with metallic glasses. PMID:27067824

  18. 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.

  19. A new route for fibre management in powder injection molded metal matrix composites

    International Nuclear Information System (INIS)

    The properties of short fibre reinforced metal matrix composites can be enhanced by controlling the directionality of the fibers. In the reported research, the multiple live feed injection moulding technique was successfully used for controlling the orientation of short fibers in powder injection molded metal matrix composites. A range of heavily loaded short fibre reinforced metal matrix compounds were injection molded by both parameters. The level of fibre orientation achieved in injection molded components was assessed by calculation of the orientation factor. One result of this investigation was identification of the moulding composition to achieve the highest level of fibre orientation in a preferred direction. (author)

  20. Aluminium in human sweat.

    Science.gov (United States)

    Minshall, Clare; Nadal, Jodie; Exley, Christopher

    2014-01-01

    It is of burgeoning importance that the human body burden of aluminium is understood and is measured. There are surprisingly few data to describe human excretion of systemic aluminium and almost no reliable data which relate to aluminium in sweat. We have measured the aluminium content of sweat in 20 healthy volunteers following mild exercise. The concentration of aluminium ranged from 329 to 5329μg/L. These data equate to a daily excretion of between 234 and 7192μg aluminium and they strongly suggest that perspiration is the major route of excretion of systemic aluminium in humans.

  1. Mechanisms controlling fatigue damage development in continuous fiber reinforced metal matrix composites

    Science.gov (United States)

    Johnson, W. S.

    1989-01-01

    Damage in continuous fiber reinforced metal matrix composite materials can be quite complex since there are a number of different constituents (fiber, matrix, and the fiber/matrix interface) that can fail. Multidirectional lay-ups have an even greater number of possible damage orientations and mechanisms. Based on the simplifying assumption of equivalent constituent strain states in the absence of damage, a strain based failure criteria may be applied to determine when and where initial damage will occur. Based on the relative strain to fatigue failure of the fiber and matrix, the possible damage mechanisms of an MMC can be grouped into three categories: (1) matrix dominated, (2) fiber dominated, and (3) self-similar damage growth. A fourth type of damage development, fiber/matrix interface failure, is dependent on the relative strength of the fiber/matrix interface and the matrix yield strength. These four types of damage are discussed and illustrated by examples.

  2. Matrix-filler interfaces and physical properties of metal matrix composites with negative thermal expansion manganese nitride

    Energy Technology Data Exchange (ETDEWEB)

    Takenaka, Koshi, E-mail: takenaka@nuap.nagoya-u.ac.jp [Department of Applied Physics, Nagoya University, Nagoya 464-8603 (Japan); Department of Crystalline Materials Science, Nagoya University, Nagoya 464-8603 (Japan); Kuzuoka, Kota [Department of Applied Physics, Nagoya University, Nagoya 464-8603 (Japan); Sugimoto, Norihiro [Department of Crystalline Materials Science, Nagoya University, Nagoya 464-8603 (Japan)

    2015-08-28

    Copper matrix composites containing antiperovskite manganese nitrides with negative thermal expansion (NTE) were formed using pulsed electric current sintering. Energy dispersive X-ray spectroscopy revealed that the chemically reacted region extends over 10 μm around the matrix–filler interfaces. The small-size filler was chemically deteriorated during formation of composites and it lost the NTE property. Therefore, we produced the composites using only the nitride particles having diameter larger than 50 μm. The large-size filler effectively suppressed the thermal expansion of copper and improved the conductivity of the composites to the level of pure aluminum. The present composites, having high thermal conductivity and low thermal expansion, are suitable for practical applications such as a heat radiation substrate for semiconductor devices.

  3. Aluminium structural elements

    OpenAIRE

    Švent, Nejc

    2016-01-01

    This thesis focuses on the structural analysis of aluminium structural members in accordance with the SIST EN 1999-1-1 standard. In the introduction, historical development of aluminium is summarized, as well as the processes of structural aluminium production and manufacture. Predominantly, resistance control checks of aluminium structural members are covered, with special attention to the major contrasts between aluminium and steel structural analyses. Finally, fundamental examples of resis...

  4. Constitutive model of ferroelectric composites with a viscoelastic and dielectric relaxation matrix Ⅰ——Theory

    Institute of Scientific and Technical Information of China (English)

    江冰; 方岱宁; 黄克智

    1999-01-01

    Based on micromechanics and Laplace transformation, a constitutive model of ferroelectric composites with a linear elastic and linear dielectric matrix is developed and extended to the ferroelectric composites with a viscoelastic and dielectric relaxation matrix. Thus, a constitutive model for ferroelectric composites with a viscoelastic and dielectric relaxation matrix has been set up.

  5. Improvement of interface and mechanical properties in carbon nanotube reinforced Cu–Cr matrix composites

    International Nuclear Information System (INIS)

    Highlights: ► Cr is used to improve the interfacial bonding of CNT/Cu composites. ► The addition of Cr greatly enhances the interfacial bonding of CNT/Cu composites. ► The addition of Cr greatly enhances the strength of CNT/Cu composites. -- Abstract: An effective approach is utilized to establish a strong interface between the carbon nanotube (CNT) and the Cu matrix by introducing the matrix-alloying chromium (Cr) element. The interface microstructure and mechanical properties of the composites are characterized by high-resolution transmission electron microscopy (HRTEM), hardness and tensile tests, respectively. Compared to CNT/Cu composites, CNT/CNT–Cr composites show evenly improved interfacial bonding and enhanced mechanical properties, which is ascribed to the formation of thin intermediate Cr3C2 transition layer between CNTs and Cu–Cr matrix.

  6. 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.

  7. IMPROVEMENTS IN WOOD THERMOPLASTIC MATRIX COMPOSITE MATERIALS PROPERTIES BY PHYSICAL AND CHEMICAL TREATMENTS

    Directory of Open Access Journals (Sweden)

    Irena Zivkovic

    2016-03-01

    Full Text Available This paper presents a short overview of the developments made in the field of wood thermoplastic composites in terms of surface treatment, flammability, matrix/reinforcement model, properties and application of recycled polymer matrices. The usage of lignocellulosic fibers as reinforcement in composite materials demands well formed interface between the fiber and the matrix. Because of the different nature of reinforcement and matrix components some physical and chemical treatment methods which improve the fiber matrix adhesion were introduced, as well as the improvements of lignocellulosic fibers and thermoplastic polymer matrix based composites flammability characteristics. These physical and chemical treatments influence the hydrophilic character of the lignocellulosic fibers, and therefore change their physical and mechanical properties.

  8. 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.

  9. Matrix Cracking in Four Different 2D SiC/SiC Composite Systems

    Science.gov (United States)

    Morscher, Gregory N.

    2003-01-01

    Silicon carbide fiber reinforced, silicon carbide matrix composites are some of the most advanced composite systems for high-temperature, high-stress applications in oxidizing environments. A basic area that needs to be understood for the purpose of material behavior modeling and optimization is the architectural, constituent, and mechanistic factors that contribute to non-linear stress-strain behavior. The mechanism that causes non-linear stress-strain in dense-matrix composites is the formation and propagation of bridged matrix cracks. In addition, the occurrence and propagation of matrix cracks controls the time-dependent strength-properties of these materials in oxidizing environments at elevated temperatures. A modal acoustic emission technique has been used to monitor and estimate the stress-dependent matrix cracking. Two different SiC matrix systems, chemical vapor infiltrated (CVI) and melt-infiltrated (MI), with two different SiC fiber reinforcement, Hi-Nicalon (trademark) and Sylramic (trademark) were compared. Even though the averages of the range where matrix cracking occurred for the composites varied by more than 0.1% in strain and almost 200 MPa in stress, the range or distribution for matrix cracking could be reduced to a narrow band of stress for CVI SiC and MI SiC composites if it were assumed that all matrix cracks emanate outside of the load-bearing fiber, interphase, CVI preform minicomposite. A simple relationship was determined to describe stress-dependent matrix cracking which can then be used to estimate the onset of large, bridged matrix cracks or for material behavior models.

  10. Reduction of thermal stresses in continuous fiber reinforced metal matrix composites with interface layers

    Science.gov (United States)

    Jansson, S.; Leckie, F. A.

    1992-01-01

    The potential of using interface layer to reduce thermal stresses in the matrix of composites with a mismatch in coefficients of thermal expansion of fiber and matrix has been investigated. It was found that compliant layers, with properties of readily available materials, do not have the potential to reduce thermal stresses significantly. However, interface layers with high coefficient of thermal expansion can compensate for the mismatch and reduce thermal stresses in the matrix significantly.

  11. Improved Foreign Object Damage Performance for 3D Woven Ceramic Matrix Composites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — As the power density of advanced engines increases, the need for new materials that are capable of higher operating temperatures, such as ceramic matrix composites...

  12. The mechanical properties measurement of multiwall carbon nanotube reinforced nanocrystalline aluminum matrix composite

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Manjula, E-mail: manjula.physics@gmail.com; Pal, Hemant; Sharma, Vimal [Department of Physics, NIT Hamirpur (HP) - 177005 (India)

    2015-05-15

    Nanocrystalline aluminum matrix composite containing carbon nanotubes were fabricated using physical mixing method followed by cold pressing. The microstructure of the composite has been investigated using X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy techniques. These studies revealed that the carbon nanotubes were homogeneously dispersed throughout the metal matrix. The consolidated samples were pressureless sintered in inert atmosphere to further actuate a strong interface between carbon nanotubes and aluminum matrix. The nanoindentation tests carried out on considered samples showed that with the addition of 0.5 wt% carbon nanotubes, the hardness and elastic modulus of the aluminum matrix increased by 21.2 % and 2 % repectively. The scratch tests revealed a decrease in the friction coefficient of the carbon nanotubes reinforced composite due to the presence of lubricating interfacial layer. The prepared composites were promising entities to be used in the field of sporting goods, construction materials and automobile industries.

  13. Low-Cost Innovative Hi-Temp Fiber Coating Process for Advanced Ceramic Matrix Composites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — MATECH GSM (MG) proposes 1) to demonstrate a low-cost innovative Hi-Temp Si-doped in-situ BN fiber coating process for advanced ceramic matrix composites in order...

  14. Improved Foreign Object Damage Performance for 2D Woven Ceramic Matrix Composites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — As the power density of advanced engines increases, the need for new materials that are capable of higher operating temperatures, such as ceramic matrix composites...

  15. Characterization of SiC (SCS-6) Fiber Reinforced Reaction-Formed Silicon Carbide Matrix Composites

    Science.gov (United States)

    Singh, Mrityunjay; Dickerson, Robert M.

    1995-01-01

    Silicon carbide (SCS-6) fiber reinforced-reaction formed silicon carbide matrix composites were fabricated using NASA's reaction forming process. Silicon-2 at a percent of niobium alloy was used as an infiltrant instead of pure silicon to reduce the amount of free silicon in the matrix after reaction forming. The matrix primarily consists of silicon carbide with a bi-modal grain size distribution. Minority phases dispersed within the matrix are niobium disilicide (NbSi2), carbon and silicon. Fiber push-out tests on these composites determined a debond stress of approx. 67 MPa and a frictional stress of approx. 60 MPa. A typical four point flexural strength of the composite is 297 MPa (43.1 KSi). This composite shows tough behavior through fiber pull out.

  16. Characterization of SiC Fiber (SCS-6) Reinforced-Reaction-Formed Silicon Carbide Matrix Composites

    Science.gov (United States)

    Singh, M.; Dickerson, R. M.

    1996-01-01

    Silicon carbide fiber (SCS-6) reinforced-reaction-formed silicon carbide matrix composites were fabricated using a reaction-forming process. Silicon-2 at.% niobium alloy was used as an infiltrant instead of pure silicon to reduce the amount of free silicon in the matrix after reaction forming. The matrix primarily consists of silicon carbide with a bimodal grain size distribution. Minority phases dispersed within the matrix are niobium disilicide (NbSi2), carbon, and silicon. Fiber pushout tests on these composites determined a debond stress of approximately 67 MPa and a frictional stress of approximately 60 MPa. A typical four-point flexural strength of the composite is 297 MPa (43.1 KSi). This composite shows tough behavior through fiber pullout.

  17. Electrical Percolation of Carbon Black Filled Poly (ethylene oxide) Composites in Relation to the Matrix Morphology

    Institute of Scientific and Technical Information of China (English)

    Gen Shui CHENG; Ji Wen HU; Ming Qiu ZHANG; Ming Wei LI; Ding Shu XIAO; Min Zhi RONG

    2004-01-01

    The present work studies the electrical conduction performance of carbon black (CB)filled poly(ethylene oxide) (PEO) composites. The addition of CB leads to reduced matrix crystallinity as the fillers which are partly situated inside the lamellae and hinder the growth of PEO crystallites. As a result, the electrical percolation behavior is related with the matrix morphology.

  18. Fabrication and Microstructure of BN Matrix Composites with Electrical Conductivity

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    BN ceramic is an advanced engineering ceramics with excellent thermal shock resistance, good workability and excellent dielectricity.TiB2 ceramic has excellent electric conductivity,high melting points, and corrosion resistance to molten metal.Therefore,the composite consisting of BN and TiB2 ceramics is expected to have a combination of above-mentioned properties,thereby can be used as self- heating crucible.In this paper,hot pressing technology was used to fabricate the high performance BN-TiB2 composite materials.microstructure and electric conducting mechanism were studied,and the relationship between the microstructure and physical property was discussed.The results show that the microstructure of composites has a great influence on the physical property of composites.The BN-TiB2 composites with excellent mechanical strength and stable resistivity can be obtained by optimizing the processing parameter and controlling the microstructure of composites.

  19. Debonding of short fibres among particulates in a metal matrix composite

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2003-01-01

    A numerical analysis is carried out for the development of damage by fibre-matrix debonding in aluminium reinforced by aligned, short SiC fibres. A unit cell-model that has earlier been applied to study materials with arrays of transversely staggered fibres is here extended to contain a number...... of differently shaped fibres or particulates in each unit cell. thus representing debonding of a relatively long discontinuous fibre among particulates that do not debond. Interfacial failure is modelled in terms of a cohesive zone model that accounts for decohesion by normal separation as well as by tangential...... separation. It is found that the evolution of failure can depend rather strongly on the distribution of particulates around a fibre subject to debonding. (C) 2003 Elsevier Ltd. All rights reserved....

  20. 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.

  1. Corrosion rates and electrochemical studies of a depleted uranium alloy tungsten fiber metal matrix composite

    International Nuclear Information System (INIS)

    The corrosion rates of a tungsten reinforced depleted uranium alloy metal matrix composite have been measured, by immersion tests, in three environments (laboratory air, distilled water, and 3.5% NaCl) and compared to the rates of the matrix alloy (DU-0.75 Ti) alone. The corrosion rates of both specimens are negligible in laboratory air, increase in distilled water, and are greatest in NaCl for a 30 day period. In all environments the matrix allo is preferentially attacked. In distilled water the corrosion rate of the matrix alloy is 3 times greater than the composite whereas in NaCl the corrosion rate of the composite is 1.3 times greater than the matrix. In electrochemical tests the composite was simulated by coupling separate samples of the fiber and matrix and the short-circuit (galvanic) currents were measured. A comparison of the corrosion rates calculated from the galvanic currents and from immersio tests shows the principal reaction of the composite in NaCl is galvanic coupling of the matrix and fiber

  2. Finite element analysis of stress transfer in carbon nanotube reinforced magnesium matrix composites

    OpenAIRE

    Li, Sinian; Wang, Yang; Rümmeli, M. H.; Vlček, Jaroslav; Pištora, Jaromír; Lesňák, Michal

    2010-01-01

    A simplified finite element model was established to simulate deformation of carbon nanotubes (CNTs) reinforcing magnesium matrix composites during the tensile test. The stress and strain of matrix and reinforcement agent and the effect of interface on mechanical behaviour of composites were specially studied. The simulation results showed that for uniformly distributed CNTs a stress concentration occurs from the fibre axis towards the interface. The simulations proved that the destruction of...

  3. Nanomodeling of Nonlinear Thermoelastic Behavior of AA5454/ Silicon Nitride Nanoparticulate Metal Matrix Composites

    Directory of Open Access Journals (Sweden)

    Chennakesava R Alavala

    2016-01-01

    Full Text Available The aim of the present work was to estimate non-linear thermoelastic behavior of three-phase AA5454/silicon nitride nanoparticle metal matrix composites. The thermal loading was varied from subzero temperature to under recrystallization temperature. The RVE models were used to analyze thermo-elastic behavior. The AA5454/silicon nitride nanoparticle metal matrix composites have gained the elastic modulus below 0oC and lost at high temperatures.

  4. Neutron irradiation damage of graphite, C/C and metal matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Iseki, Michio (Nagoya Univ. (Japan). Faculty of Engineering)

    1992-06-01

    Graphite and carbon-carbon composites or other carbide composites are considered to be candidate for plasma facing materials or structural material of fusion reactors because of their low atomic number, high thermal conductivity, stability under irradiation etc. This report briefly summarizes the mechanical properties, physical properties and microstructure changes of graphite, carbon composites and metal matrix composites after neutron irradiation. Generally, the effects of neutron irradiation are quite remarkable on physical properties of the graphite materials. (author).

  5. Fibrous monoliths: Economic ceramic matrix composites from powders [Final report

    Energy Technology Data Exchange (ETDEWEB)

    Rigali, Mark; Sutaria, Manish; Mulligan, Anthony; Creegan, Peter; Cipriani, Ron

    1999-05-26

    The project was to develop and perform pilot-scale production of fibrous monolith composites. The principal focus of the program was to develop damage-tolerant, wear-resistant tooling for petroleum drilling applications and generate a basic mechanical properties database on fibrous monolith composites.

  6. 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.

  7. Simplified prediction model for elastic modulus of particulate reinforced metal matrix composites

    Institute of Scientific and Technical Information of China (English)

    WANG Wen-ming; PAN Fu-sheng; LU Yun; ZENG Su-min

    2006-01-01

    Some structural parameters of the metal matrix composite, including particulate shape and distribution do not influence the elastic modulus. A prediction model for the elastic modulus of particulate reinforced metal matrix Al composite was developed and improved. Expressions of rigidity and flexibility of the rule of mixing were proposed. A five-zone model for elasticity performance calculation of the composite was proposed. The five-zone model is thought to be able to reflect the effects of the MMC interface on elastic modulus of the composite. The model overcomes limitations of the currently-understood rigidity and flexibility of the rule of mixing. The original idea of a five-zone model is to propose particulate/interface interactive zone and matrix/interface interactive zone. By integrating organically with the law of mixing, the new model is found to be capable of predicting the engineering elastic constants of the MMC composite.

  8. Influence of Sea Water Aging on the Mechanical Behaviour of Acrylic Matrix Composites

    Science.gov (United States)

    Davies, P.; Le Gac, P.-Y.; Le Gall, M.

    2016-07-01

    A new matrix resin was recently introduced for composite materials, based on acrylic resin chemistry allowing standard room temperature infusion techniques to be used to produce recyclable thermoplastic composites. This is a significant advance, particularly for more environmentally-friendly production of large marine structures such as boats. However, for such applications it is essential to demonstrate that composites produced with these resins resist sea water exposure in service. This paper presents results from a wet aging study of unreinforced acrylic and glass and carbon fibre reinforced acrylic composites. It is shown that the acrylic matrix resin is very stable in seawater, showing lower property losses after seawater aging than those of a commonly-used epoxy matrix resin. Carbon fibre reinforced acrylic also shows good property retention after aging, while reductions in glass fibre reinforced composite strengths suggest that specific glass fibre sizing may be required for optimum durability.

  9. Composite materials with uncured epoxy matrix exposed in stratosphere during NASA stratospheric balloon flight

    CERN Document Server

    Kondyurin, Alexey; Bilek, Marcela

    2010-01-01

    A cassette of uncured composite materials with an epoxy resin matrix was exposed in the stratosphere (40 km altitude) over 3 days. Temperature variations of -76...+32.50C 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 polycondensation 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 composite in a free space environment during an orbital space flight.

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

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    1998-01-01

    the computations are continued through the mechanically unstable regime, where an open crack forms near the ends of the fibers by the coalescence of voids in the matrix. Comparison of predictions for an isotropic hardening model and a kinematic hardening model are used to evaluate the effect of a metal that forms...

  11. Ultrasonic evaluation of initiation and development of oxidation damage in ceramic-matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Y.C.; Lavrentyev, A.I.; Rokhlin, S.I. [Ohio State Univ., Columbus, OH (United States). Nondestructive Evaluation Program; Baaklini, G.Y.; Bhatt, R.T. [NASA Lewis Research Center, Cleveland, OH (United States)

    1995-07-01

    In this paper the authors report on the development of a method for ultrasonic nondestructive characterization of oxidation damage in ceramic-matrix composites. The method is based on ultrasonic measurement of elastic moduli of the composite, which are then used to determine the elastic moduli of the fiber-matrix interphase. Thus the interphasial damage may be estimated quantitatively. As a model system they used, to demonstrate applicability of the method, a unidirectional SiC-fiber-reinforced reaction-bonded silicon nitride matrix composite (SiC/RBSN). The composite samples were oxidized in flowing oxygen for 0.1, 1, 10, and 100 h at 600, 900, 1200, and 1400 C. The ultrasonic phase velocity in the composite was measured at room temperature before and after oxidation; the data were then used to find the composite moduli, which quantify the induced damage. significant changes in ultrasonic velocities and composite moduli, which quantify the induced damage. Significant changes in ultrasonic velocities and composite moduli were found as a result of oxidation. Fiber-matrix interphasial moduli were determined by multiphase micromechanical analysis. They found that oxidation of the carbon interphasial layer is the dominant mechanism in decreasing the elastic moduli of the composite. The critical exposure time for transition from the nondamaged to the damage state of different oxidation temperatures has been determined.

  12. Hardness and wear resistance of carbon nanotube reinforced aluminum-copper matrix composites.

    Science.gov (United States)

    Nam, Dong Hoon; Kim, Jae Hwang; Cha, Seung Il; Jung, Seung Il; Lee, Jong Kook; Park, Hoon Mo; Park, Hyun Dal; Hong, Hyung

    2014-12-01

    Recently, carbon nanotubes (CNTs) have been attracted to reinforcement of composite materials due to their extraordinary mechanical, thermal and electrical properties. Many researchers have attempted to develop CNT reinforced metal composites with various fabrication methods and have shown possibilities for structural and functional applications. Among them, CNT reinforced Al matrix composites have become very attractive due to their huge structural application in industry. In this study, CNT reinforced Al-Cu matrix composites with a microstructure of homogeneous dispersion of CNTs in the Al-Cu matrix are investigated. The CNT/Al-Cu composites are fabricated by mixing of CNT/Cu composite powders and Al powders by high energy ball mill process followed by hot extrusion process. The hardness and wear resistance of the CNT/Al-Cu composites are enhanced by 1.4 and 3 times, respectively, compared to those values for the Al-Cu matrix. This remarkable enhancement mainly originates from the homogeneous dispersion of CNTs in Al-Cu matrix and self-lubricant effect of CNTs. PMID:25971024

  13. The Mechanical Properties of Castor Seed Shell-polyester Matrix Composites

    Directory of Open Access Journals (Sweden)

    S.C. Nwigbo

    2013-05-01

    Full Text Available A composite with a polyester matrix reinforced with chemically modified shells of castor seed (Ricinus communis was produced. The effect of the shell (filler on the mechanical properties of the composite was experimentally quantified. A preliminary study was earlier carried out the shell in terms of their chemical constituents, functional group and mechanical strength. The shell was ground and chemically treated to enhance good bonding and adhesion to the matrix. Composites were fabricated using a hand lay-up or contact mould method for different percentage compositions of the filler. Tests, with respect to the mechanical properties (i.e., tensile, flexural and creep response were carried out. The result obtained was compared with the unreinforced polyester plate. It was observed that the inclusion of the filler (shell added strength to the composite. Scanning Electron Microscopy (SEM was taken on the composite samples to study the morphology of the composites.

  14. Role of segregation and precipitates on interfacial strengthening mechanisms in metal matrix composites when subjected to thermo-mechanical processing

    OpenAIRE

    Myriounis, Dimitrios

    2009-01-01

    Metal Matrix ceramic-reinforced composites are rapidly becoming strong candidates as structural materials for many high temperatures and aerospace applications. Metal matrix composites combine the ductile properties of the matrix with a brittle phase of the reinforcement, leading to high stiffness and strength with a reduction in structural weight. The main objective of using a metal matrix composite system is to increase service temperature or improve specific mechanical prope...

  15. Fabrication and properties of Al matrix composites strengthened by in situ alumina particulates

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    New aluminum matrix composites strengthened by Al2O3 particulates through stirring cast by adding NH4Al(SO4)2 to the molten aluminum have been fabricated. TEM observation shows that in-situ Al2O3 particulates are generally spherical and they are uniformly distributed in the Al matrix. Dry sliding wear test results show that the volume loss of the unreinforced Al matrix is about three times that of the Al2O3 reinforced metal matrix composite (MMC) and the volume loss of the MMC fabricated by adding Al2O3 is larger than that of the MMC by adding NH4Al(SO4)2. Lubricating sliding wear test results show that the volume loss of the MMCs increases more slowly than that of the matrix with the increasing of the load.

  16. Influence of four-point bending fatigue on the residual stress state of a pressure-rolled, particulate-reinforced metal matrix composite

    Energy Technology Data Exchange (ETDEWEB)

    Hanus, E. [Linkoeping Univ. (Sweden). Div. of Eng. Mater.; Ericsson, T. [Linkoeping Univ. (Sweden). Div. of Eng. Mater.

    1995-05-01

    In this work, the influence of fatigue on the residual stress state of a pressure-rolled metal matrix composite has been investigated. The three-dimensional stress state measured in both matrix and reinforcement has been determined by X-ray diffraction. To estimate the efficiency of the pressure rolling treatment, Woehler curves were derived for both the heat-treated (to maximum hardness) (T6) and further rolled composites. To study the stability of the induced residual stress field, four-point bending fatigue tests were performed on a 2014 aluminium alloy reinforced with 15% SiC particles. It was found that pressure rolling increased the fatigue strength by 30% in the high-cycle region. Macrostress relaxation occurs during cyclic loading: the higher the applied load, the larger the relaxation. A more pronounced effect is observed on the compression-loaded side. As regards the microstresses, a reduction, creation and/or stabilization during cycling may occur according to the loading and metallurgical conditions. ((orig.))

  17. Niobium matrix composites for high temperature turbine blades, phase 2

    Science.gov (United States)

    Heng, Sangvavann; Laferla, Raffaele; Tuffias, Robert H.

    1991-01-01

    This program demonstrated the feasibility of fabricating fiber-reinforced MMC (niobium matrix) turbine blades to net shape by chemical vapor infiltration (CVI). A controllable, repeatable niobium infiltration process was developed, and the kinetics of both deposition and infiltration were studied. Several continuous refractory fibers (Nicalon, Nextel 440, FP-Al2O3, HPZ, and tungsten mesh) were investigated as potential reinforcements for strengthening niobium. Thermodynamic and experimental evaluation indicated FP-Al2O3 and tungsten to be the most chemically compatible with niobium, while Nicalon, FP-Al2O3, and tungsten were found to be best with regard to reinforcing capability. Finally, a protective coating for iridium was found to provide substantial oxidation protection to the niobium blade matrix.

  18. Multifunctional Metal Matrix Composite Filament Wound Tank Liners Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Composite Overwrapped Pressure Vessels (COPVs) are used for storing pressurized gases on board spacecraft when mass saving is a key requirement. All future mass...

  19. Concurrent micromechanical tailoring and fabrication process optimization for metal-matrix composites

    Science.gov (United States)

    Morel, M.; Saravanos, D. A.; Chamis, Christos C.

    1990-01-01

    A method is presented to minimize the residual matrix stresses in metal matrix composites. Fabrication parameters such as temperature and consolidation pressure are optimized concurrently with the characteristics (i.e., modulus, coefficient of thermal expansion, strength, and interphase thickness) of a fiber-matrix interphase. By including the interphase properties in the fabrication process, lower residual stresses are achievable. Results for an ultra-high modulus graphite (P100)/copper composite show a reduction of 21 percent for the maximum matrix microstress when optimizing the fabrication process alone. Concurrent optimization of the fabrication process and interphase properties show a 41 percent decrease in the maximum microstress. Therefore, this optimization method demonstrates the capability of reducing residual microstresses by altering the temperature and consolidation pressure histories and tailoring the interphase properties for an improved composite material. In addition, the results indicate that the consolidation pressures are the most important fabrication parameters, and the coefficient of thermal expansion is the most critical interphase property.

  20. Combined micromechanical and fabrication process optimization for metal-matrix composites

    Science.gov (United States)

    Morel, M.; Saravanos, D. A.; Chamis, C. C.

    1991-01-01

    A method is presented to minimize the residual matrix stresses in metal matrix composites. Fabrication parameters such as temperature and consolidation pressure are optimized concurrently with the characteristics (i.e., modulus, coefficient of thermal expansion, strength, and interphase thickness) of a fiber-matrix interphase. By including the interphase properties in the fabrication process, lower residual stresses are achievable. Results for an ultra-high modulus graphite (P100)/copper composite show a reduction of 21 percent for the maximum matrix microstress when optimizing the fabrication process alone. Concurrent optimization of the fabrication process and interphase properties show a 41 percent decrease in the maximum microstress. Therefore, this optimization method demonstrates the capability of reducing residual microstresses by altering the temperature and consolidation pressure histories and tailoring the interphase properties for an improved composite material. In addition, the results indicate that the consolidation pressures are the most important fabrication parameters, and the coefficient of thermal expansion is the most critical interphase property.

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

    OpenAIRE

    Renata Angeli; da Paz, Nathalia V. N.; Maciel, Jackeline C.; Flávia F. B. Araújo; Paiva, Patrícia M. G.; Glícia M. T. Calazans; Ana Paula Valente; Almeida, Fábio C. L.; Coelho, Luana C. B. B.; Carvalho, Luiz B; Silva, Maria da Paz C.; Maria Tereza dos Santos Correia

    2009-01-01

    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 ammon...

  2. Research on polyamide matrix composites filled with hard coal

    OpenAIRE

    M. Rojek; J. Stabik; M. Szymiczek; Ł. Suchoń; K. Mrowiec

    2012-01-01

    Purpose: The aim of this paper is to present the summary results of studies on polyamide composites filled with hard coal. Research on the use of coal as a filler of polymers are conducted for many years in Division of Metallic and Polymeric Materials Processing, Silesian University of Technology. This paper summarizes results obtained in different research programmes preformed in recent years. Described materials are polyamide 6 composites filled with modified and unmodified hard coal powde...

  3. Stereological characterization of crack path transitions in ceramic matrix composites

    Indian Academy of Sciences (India)

    Parag Bhargava; B R Patterson

    2001-04-01

    All ceramic composites involve a mismatch in physical properties the extent of which differs from one composite to another. Mismatch in thermal expansion ( ) and elastic modulus (E) is known to produce stresses that influence the path of a propagating crack. Thus, the relative effect of thermal and elastic mismatch on the crack path is expected to change with change in stress intensity. We propose that the crack path in ceramic composites should undergo a transition with the crack being strongly influenced by the thermal mismatch stresses at low stress intensity and elastic mismatch stresses at high stress intensities. Thus, a material in use under different applications each with its own loading conditions is expected to exhibit different crack propagation tendencies which may be reflected in the – characteristics of the composite material. In the present work several model composites with different combinations of thermal and elastic mismatch have been considered. Cracks propagating at different sub-critical stress intensities (velocities) were generated by a novel indentation technique. Each indentation was performed at a constant displacement rate and a peak load. A range of displacement rates were used to produce cracks propagating at different velocities. The indentations were made using a Vickers indentor fitted in a universal mechanical testing machine. The crack paths in composites were quantified by stereological technique and the proposed theory was verified.

  4. X-ray and neutron diffraction studies of syntactic metal foams and metal matrix composites

    Science.gov (United States)

    Balch, Dorian Kenneth

    2002-11-01

    Synchrotron x-ray and neutron diffraction can provide both the in-situ elastic phase strains and the phases present in metal matrix composites subjected to thermo-mechanical loading by measuring the lattice spacings parallel and perpendicular to the loading axis, as well as changes in the crystalline structure of the composite constituents. Such measurements can give insight into load transfer between phases, the onset of matrix or reinforcement plasticity or damage, and thermally or mechanically induced phase transformations. Four composite systems are presented: (a) bulk metallic glass composites containing low volume fractions of tungsten and tantalum particles, (b) bulk metallic composites containing low volume fractions of both tantalum particles and crystallized matrix inclusions, (c) copper composites containing high volume fractions of particles of the negative thermal expansion ceramic zirconium tungstate, and (d) aluminum matrix syntactic foams containing high volume fractions of hollow ceramic spheres. In the bulk metallic glass composites, plasticity of the metallic reinforcement was observed during mechanical cycling, leading to residual stresses that may alter the subsequent composite behavior. The zirconium tungstate present in the low thermal expansion copper composites was observed to undergo both thermal and stress induced transformations during thermal cycling, confirming the interpretation of ex-situ thermal expansion measurements. In the aluminum syntactic foams, matrix plasticity and ceramic microsphere damage were seen, as well as relative unloading of the matrix during mechanical testing and an improvement in elastic properties due to presence of the hollow spheres. For all systems, continuum mechanical modeling using the Eshelby method was performed, with good agreement found between predictions and measurements.

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

    Energy Technology Data Exchange (ETDEWEB)

    Pinholt, E.M.; Solheim, E. (Institute for Surgical Research, Rikshospitalet, University of Oslo (Norway)); Bang, G. (Department of Oral Pathology and Forensic Odontology, University of Bergen (Norway)); Sudmann, E. (Hagavik Orthopedic Hospital, University of Bergen (Norway))

    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 {sup 85}Sr uptake. The composite implant was technically easier to use than DBM alone. (author).

  6. Analysis of the progressive failure of brittle matrix composites

    Science.gov (United States)

    Thomas, David J.

    1995-01-01

    This report investigates two of the most common modes of localized failures, namely, periodic fiber-bridged matrix cracks and transverse matrix cracks. A modification of Daniels' bundle theory is combined with Weibull's weakest link theory to model the statistical distribution of the periodic matrix cracking strength for an individual layer. Results of the model predictions are compared with experimental data from the open literature. Extensions to the model are made to account for possible imperfections within the layer (i.e., nonuniform fiber lengths, irregular crack spacing, and degraded in-situ fiber properties), and the results of these studies are presented. A generalized shear-lag analysis is derived which is capable of modeling the development of transverse matrix cracks in material systems having a general multilayer configuration and under states of full in-plane load. A method for computing the effective elastic properties for the damaged layer at the global level is detailed based upon the solution for the effects of the damage at the local level. This methodology is general in nature and is therefore also applicable to (0(sub m)/90(sub n))(sub s) systems. The characteristic stress-strain response for more general cases is shown to be qualitatively correct (experimental data is not available for a quantitative evaluation), and the damage evolution is recorded in terms of the matrix crack density as a function of the applied strain. Probabilistic effects are introduced to account for the statistical nature of the material strengths, thus allowing cumulative distribution curves for the probability of failure to be generated for each of the example laminates. Additionally, Oh and Finney's classic work on fracture location in brittle materials is extended and combined with the shear-lag analysis. The result is an analytical form for predicting the probability density function for the location of the next transverse crack occurrence within a crack bounded

  7. 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.

  8. Composite Nickel Coatings Produced on 6XXX Series Aluminium Alloys with the Addition of Vanadium / Kompozytowe Powłoki Niklowe Wytwarzane Na Stopach Aluminum Serii 6XXX Z Dodatkiem Wanadu

    Directory of Open Access Journals (Sweden)

    Nowak M.

    2015-12-01

    Full Text Available Studies of composite nickel coatings electrolytically deposited on aluminium alloys with different content of vanadium were described. Composite coatings were deposited from a Watts bath containing fine-dispersed SiC powder particles in an amount of 20 g/l and organic matters such as saccharin and sodium laurate. The morphology, structure and thickness of the obtained composite coatings were presented. The corrosion resistance of produced coatings was examined by electrochemical method. Basing on the results of studies it was found that coatings obtained with the sole addition of saccharin were characterized by numerous surface defects. The addition of sodium laurate eliminated the occurrence of defects caused by hydrogen evolution and the resulting coatings were continuous with good adhesion to the substrate. The distribution of the ceramic SiC phase in coatings was fairly uniform for all the examined variants of aluminium alloys. SEM examinations did not reveal the phenomenon of the ceramic particles agglomeration.

  9. Effect of deformation temperature on the hot compressive behavior of metal matrix composites with misaligned whiskers

    Institute of Scientific and Technical Information of China (English)

    LI Aibin; MENG Qingyuan; GENG Lin; DENG Chunfeng; YAN Yiwu

    2007-01-01

    A multi-inclusion cell model is used to investigate the effect of deformation temperature and whisker rotation on the hot compressive behavior of metal matrix composites with misaligned whiskers. Numerical results show that deformation temperature influences the work-hardening behavior of the matrix and the rotation behavior of the whiskers. With increasing temperature, the work hardening rate of the matrix decreases, but the whisker rotation angle increases. Both whisker rotation and the increase of deformation temperature can induce reductions in the load supported by whisker and the load transferred from matrix to whisker. Additionally, it is found that during large strain deformation at higher temperatures, the enhancing of deformation temperature can reduce the effect of whisker rotation. Meanwhile, the stress-strain behavior of the composite is rather sensitive to deformation temperature. At a relatively lower temperature (150℃), the composite exhibits work hardening due to the matrix work hardening, but at relatively higher temperatures (300℃ and above),the composite shows strain softening due to whisker rotation. It is also found that during hot compression at higher temperatures, the softening rate of the composite decreases with increasing temperature. The predicted stress-strain behavior of the composite is approximately in agreement with the experimental results.

  10. Recent advances in the field of ceramic fibers and ceramic matrix composites

    Science.gov (United States)

    Naslain, R.

    2005-03-01

    Progress achieved during the last decade in the field of ceramic fibers and related ceramic matrix composites is reviewed. Both SiC-based and alumina-based fine fibers have been improved in terms of thermal stability and creep resistance with temperature limit of about 1400 and 1200 ° C, respectively. Two concepts for achieving damage-tolerant ceramic matrix composites have been identified : (i) that of non-oxide composites with a dense matrix in which matrix cracks formed under load are deflected and arrested in a weak fiber coating referred to as the interphase and (ii) that of all-oxide composites with a highly porous matrix with no need of any fiber coating. The lifetime under load of non-oxide composites in oxidizing atmospheres, is improved through the use of multilayered self-healing interphases and matrices deposited from gaseous precursors by chemical vapor infiltration (CVI). Lifetime ranging from 1000 to 10,000 hours at 1200 ° C under cyclic loading in air are foreseen. Alumina-based composites although attractive for long term exposures in oxidizing atmospheres up to ≈1200 ° C, are still experimental materials.

  11. Mechanical Behavior of Sapphire Reinforced Alumina Matrix Composites at Elevated Temperatures

    Science.gov (United States)

    Jaskowiak, Martha H.; Eldridge, Jeffrey I.; Setlock, John A.; Gyekenyesi, John Z.

    1997-01-01

    Zirconia coated sapphire reinforced alumina matrix composites have been tested both after heat treatment to 1400 C and at temperatures ranging from 800 C to 1200 C in. air. Interfacial shear stress has also been measured with fiber pushout tests performed in air at room temperature, 800 C and 1OOO C. Matrix crack spacing was measured for the tensile tested composites and used to estimate interfacial shear stress up to 1200 C. Electron microscopy was used to determine the source of fiber fracture and to study interfacial failure within the composite.

  12. The oxidative stability of carbon fibre reinforced glass-matrix composites

    Science.gov (United States)

    Prewo, K. M.; Batt, J. A.

    1988-01-01

    The environmental stability of carbon fibre reinforced glass-matrix composites is assessed. Loss of composite strength due to oxidative exposure at elevated temperatures under no load, static load and cyclic fatigue as well as due to thermal cycling are all examined. It is determined that strength loss is gradual and predictable based on the oxidation of carbon fibres. The glass matrix was not found to prevent this degradation but simply to limit it to a gradual process progressing from the composite surfaces inward.

  13. Processing, structure and flexural strength of CNT and carbon fibre reinforced, epoxy-matrix hybrid composite

    Indian Academy of Sciences (India)

    K Chandra Shekar; M Sai Priya; P K Subramanian; Anil Kumar; B Anjaneya Prasad; N Eswara Prasad

    2014-05-01

    Advanced materials such as continuous fibre-reinforced polymer matrix composites offer significant enhancements in variety of properties, as compared to their bulk, monolithic counterparts. These properties include primarily the tensile stress, flexural stress and fracture parameters. However, till date, there are hardly any scientific studies reported on carbon fibre (Cf) and carbon nanotube (CNT) reinforced hybrid epoxy matrix composites (unidirectional). The present work is an attempt to bring out the flexural strength properties along with a detailed investigation in the synthesis of reinforced hybrid composite. In this present study, the importance of alignment of fibre is comprehensively evaluated and reported. The results obtained are discussed in terms of material characteristics, microstructure and mode of failure under flexural (3-point bend) loading. The study reveals the material exhibiting exceptionally high strength values and declaring itself as a material with high strength to weight ratio when compared to other competing polymer matrix composites (PMCs); as a novel structural material for aeronautical and aerospace applications.

  14. Synthesis and Characterization of Multi Wall Carbon Nanotubes (MWCNT) Reinforced Sintered Magnesium Matrix Composites

    Science.gov (United States)

    Vijaya Bhaskar, S.; Rajmohan, T.; Palanikumar, K.; Bharath Ganesh Kumar, B.

    2016-04-01

    Metal matrix composites (MMCs) reinforced with ceramic nano particles (less than 100 nm), termed as metal matrix nano composites (MMNCs), can overcome those disadvantages associated with the conventional MMCs. MMCs containing carbon nanotubes are being developed and projected for diverse applications in various fields of engineering like automotive, avionic, electronic and bio-medical sectors. The present investigation deals with the synthesis and characterization of hybrid magnesium matrix reinforced with various different wt% (0-0.45) of multi wall carbon nano tubes (MWCNT) and micro SiC particles prepared through powder metallurgy route. Microstructure and mechanical properties such as micro hardness and density of the composites were examined. Microstructure of MMNCs have been investigated by scanning electron microscope, X-ray diffraction and energy dispersive X-ray spectroscopy (EDS) for better observation of dispersion of reinforcement. The results indicated that the increase in wt% of MWCNT improves the mechanical properties of the composite.

  15. Computational Simulation of Continuous Fiber-Reinforced Ceramic Matrix Composites Behavior

    Science.gov (United States)

    Murthy, Pappu L. N.; Chamis, Christos C.; Mital, Subodh K.

    1996-01-01

    This report describes a methodology which predicts the behavior of ceramic matrix composites and has been incorporated in the computational tool CEMCAN (CEramic Matrix Composite ANalyzer). The approach combines micromechanics with a unique fiber substructuring concept. In this new concept, the conventional unit cell (the smallest representative volume element of the composite) of the micromechanics approach is modified by substructuring it into several slices and developing the micromechanics-based equations at the slice level. The methodology also takes into account nonlinear ceramic matrix composite (CMC) behavior due to temperature and the fracture initiation and progression. Important features of the approach and its effectiveness are described by using selected examples. Comparisons of predictions and limited experimental data are also provided.

  16. Research on toughening mechanisms of alumina matrix ceramic composite materials improved by rare earth additive

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xihua; LIU Changxia; LI Musen; ZHANG Jianhua

    2008-01-01

    Mixed rare earth elements were incorporated into alumina ceramic materials. Hot-pressing was used to fabricate alumina matrix composites in nitrogen atmosphere protection. Microstructures and mechanical properties of the composites were tested. It was indicated that the bending strength and fracture toughness of alumina matrix ceramic composites sintered at 1550℃ and 28 Mpa for 30 min were improved evidently. Besides mixed rare earth elements acting as a toughening phase, AlTiC master alloys were also added in as sintering assistants, which could prompt the formation of transient liquid phase, and thus nitrides of rare earth elements were produced. All of the above were beneficial for improving the mechanical properties of alumina matrix ceramic composites.

  17. Mechanical behavior and properties of fiber reinforced ceramic matrix composites for high temperature use

    Institute of Scientific and Technical Information of China (English)

    Chongdu Cho; Qiang Pan; Sangkyo Lee

    2007-01-01

    Ceramics can keep their mechanical characteristics up to 2 000℃ or higher.In this paper,A model to predict ultimate strength of continuous fiber-reinforced brittle matrix composites is developed.A statistical theory for the strength of a uni-axially fiber-reinforced brittle matrix composite is presented.Also a semi-empirical frictional heating method for estimating in-situ interfacial shear in fiber-reinforced ceramic matrix composites was improved.Local uneven fiber packing variation as well as uneven micro-damage during fatigue can be expected to have effects on the composites:generation of frictional heating,thermal gradients,and residual stresses around local fiber breaks.This study examined those engineering interests by the finite element method.

  18. 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.

  19. Ferromagnetic levan composite: an affinity matrix to purify lectin.

    Science.gov (United States)

    Angeli, Renata; da Paz, Nathalia V N; Maciel, Jackeline C; Araújo, Flávia F B; Paiva, Patrícia M G; Calazans, Glícia M T; Valente, Ana Paula; Almeida, Fábio C L; Coelho, Luana C B B; Carvalho, Luiz B; Silva, Maria da Paz C; dos Santos Correia, Maria Tereza

    2009-01-01

    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. PMID:19547713

  20. Strain measurements and imaging of metal matrix composites using high-energy X-rays

    Science.gov (United States)

    Young, Marcus L.

    Metal matrix composites (MMCs) are of technological importance for a variety of applications [1, 2]. One important aspect of MMCs is their unique mechanical behavior, which is controlled by the load transfer occurring between matrix and reinforcement. Load transfer is affected by the mismatch in stiffness between matrix and reinforcement, by plastic deformation of the metallic matrix and by damage of the ceramic reinforcement or its interface with the matrix. The goal of this thesis is to study the micromechanics of load transfer in MMC by a combination of x-ray diffraction and imaging, using high-energy synchrotron x-rays in conjunction with in-situ mechanical loading. Diffraction was used for direct measurements of internal elastic strains of all phases within the bulk (rather than near surface) of MMCs during in-situ mechanical loading. Imaging was done using an edge-enhanced, phase-contrast technique providing high spatial resolution radiographic images providing insight into the macro- and micro-mechanical evolution of damage. Three MMC systems with widely different architectures, composition, and end-use were studied: ultrahigh-carbon steels, superconducting fiber composites, and co-continuous composites. First, ultrahigh-carbon steels exhibiting spherical Fe3C particles in a Fe matrix are characterized by no load transfer in the elastic range, followed by marked load transfer in the plastic range of the matrix. Second, superconducting composites consisting of continuous MgB2 fibers in a Mg matrix show mostly elastic (and somewhat plastic) load transfer from matrix to reinforcement, which is complicated by the presence of cracks and a WB4 core in the fibers. Finally, a complex three-dimensional (3-D) Al2O3 preform infiltrated with an Al matrix, like the superconducting composites, show mostly elastic load transfer from matrix to reinforcement. For the latter two composites, differences were found between average bulk measurements and spatially

  1. Superelement methods applications to micromechanics of high temperature metal matrix composites

    Science.gov (United States)

    Caruso, J. J.; Chamis, C. C.

    1988-01-01

    Adaptation of the superelement finite-element method for micromechanics of continuous fiber high temperature metal matrix composites (HT-MMC) is described. The method is used to predict the thermomechanical behavior of P100-graphite/copper composites using MSC/NASTRAN and it is also used to validate those predicted by using an in-house computer program designed to perform micromechanics for HT-MMC. Typical results presented in the paper include unidirectional composite thermal properties, mechanical properties, and microstresses.

  2. "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.

  3. 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.

  4. Sliding Wear Behavior of TiC-Reinforced Cu-4 wt.% Ni Matrix Composites

    Science.gov (United States)

    Jha, Pushkar; Gautam, R. K.; Tyagi, Rajnesh; Kumar, Devendra

    2016-10-01

    The present investigation explores the effect of TiC content on the sliding wear properties of Cu-4 wt.% Ni matrix composites. Cu-4 wt.% Ni - x wt.% TiC ( x = 0, 2, 4 and 8 wt.%) metal matrix composites were developed by powder metallurgy route. Their friction and wear was studied under dry sliding at different loads of 5, 7.5 and 10 N and constant sliding speed of 2 m/s using a pin-on-disk machine. The metallographic observations showed an almost uniform distribution of TiC particles in the matrix. Hardness of the composites increased with increasing TiC content (up to 4 wt.%). Friction and wear results of TiC-reinforced composites show better wear resistance than unreinforced matrix alloy. However, the optimum wear resistance was observed for 4 wt.% TiC-reinforced composites. Worn surfaces of specimens indicated the abrasion as the primary mechanism of wear in all the materials investigated in the study. The observed behavior has been explained on the basis of (1) the hardness which results in a decrease in real area of contact in composites containing TiC particles and (2) the formation of a transfer layer of wear debris on the surface of the composites which protects underlying substrate by inhibiting metal-metal contact.

  5. Wear behaviour of Zr-based in situ bulk metallic glass matrix composites

    Indian Academy of Sciences (India)

    X F WU; G A ZHANG; F F WU

    2016-06-01

    Zr-based bulk metallic glass (BMG) and its in situ BMG matrix composites with diameter of 3 mm were fabricated by conventional Cu-mould casting method and the dry sliding wear behaviour of the BMG and composites was investigated. Compared to the pure BMG, the composites exhibited a markedly improved wear resistance from 10 to 48% due to the existence of various volume fractions of the ductile $\\beta$-Zr dendritic phase embedded in the glassy matrix. The composites showed lower friction coefficient and wear rate than the pure BMG. Meanwhile, the surface wearing of the composite with a proper amount of $\\beta$-Zr dendrites was less severe compared to that of the pure BMG. The worn surface of the composite was covered with mild grooves and some fine wear debris, which exhibited the characteristic of a mild abrasive wear. The improvement of the wear resistance of the composite with the proper amount of $\\beta$-Zr crystalline phase is attributed to the fact that the $\\beta$-Zr crystalline phase distributed in the amorphous matrix has some effective load bearing, plastic deformation and work hardening ability to decrease strain accumulation and the release of strain energy in the glassy matrix, restrict the expanding of shear bands and cracks, and occur plastic deformation homogeneously.

  6. 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. PMID:27567779

  7. 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.

  8. Resin Matrix/Fiber Reinforced Composite Material,Ⅲ:Simulating Results

    Institute of Scientific and Technical Information of China (English)

    Li Chensha(李辰砂); Jiao Caishan; Liu Ying; Wang Zhengping; Wang Hongjie; Cao Maosheng

    2004-01-01

    According to the mathematical model which describes the curing process of composites constructed from continuous fiber-reinforced, thermosetting resin matrix prepreg materials, and the consolidation of the composite, the computer code calculates the data of the process variables of the flat-plate composites cured by a specified cure cycle, provides the variation of temperature distribution, the cure degree process, the resin variation and fibers stress inside the composite, the void variation and the residual stress distribution. The mechanism of curing process is illustrated and the cure cycle of composite material is optimized.

  9. Probabilistic simulation of long term behavior in polymer matrix composites

    Science.gov (United States)

    Shah, A. R.; Singhal, S. N.; Murthy, P. L. N.; Chamis, C. C.

    1995-04-01

    A methodology to compute cumulative probability distribution functions (CDF) of fatigue life for different ratios, r of applied stress to the laminate strength based on first ply failure criteria has been developed and demonstrated. Degradation effects due to long term environmental exposure and mechanical cyclic loads are considered in the simulation process. A unified time-stress dependent multi-factor interaction equation model developed at NASA Lewis Research Center has been used to account for the degradation/aging of material properties due to cyclic loads. Fast probability integration method is used to perform probabilistic simulation of uncertainties. Sensitivity of fatigue life reliability to uncertainties in the primitive random variables are computed and their significance in the reliability based design for maximum life is discussed. The results show that the graphite/epoxy (0/+45/90) deg laminate with ply thickness 0.125 in. has 500,000 cycles life for applied stress to laminate strength ratio of 0.6 and a reliability of 0.999. Also, the fatigue life reliability has been found to be most sensitive to the ply thickness and matrix tensile strength. Tighter quality controls must therefore be enforced on ply thickness and matrix strength in order to achieve high reliability of the structure.

  10. Non-destructive diagnostic methods of polymer matrix composites degradation

    Directory of Open Access Journals (Sweden)

    G. Wróbel

    2008-11-01

    Full Text Available Purpose: The aim of this paper is to present results of application of ultrasonic and termovision techniques to non-destructive evaluation of the degree of thermal degradation of fibre reinforced polymer composites. a model describing heat transfer taking place during Thermographic tests were undertaken to identify thermal properties of searched material and to correlate them with operational characteristics. In the same manner ultrasounds propagation characteristics were correlated with strength properties.Design/methodology/approach: Epoxy-glass composites were exposed to thermal ageing and subsequently tested using thermography and ultrasounds. Finally destructive bending test was performed. Material characteristics evaluated in these test were compared and related to elaborate diagnostic relations.Findings: The most essential result of the project is the methodology of applying thermovision and ultrasonic testing to diagnose the state of thermal degradation of polymeric composites.Research limitations/implications: Results showed the possibility of non-destructive diagnosis of the degree of thermal degradation manifested by strength capacity deterioration of wide class of materials, namely polymeric composites.Practical implications: Results of presented project together with results of planned experimental programme devoted to elaboration of diagnostic relations enable to apply thermography and ultrasonic testing directly to the state of polymeric structural materials assessment. Especially the degree of material degradation may be estimated.Originality/value: Originality of the project is based on possibility of practical application of the thermovison and ultrasonic testing to non-destructive diagnosis of kinematics of degradation processes.

  11. Aluminum-matrix composite materials with shungite rock fillers

    Science.gov (United States)

    Kalashnikov, I. E.; Kovalevski, V. V.; Chernyshova, T. A.; Bolotova, L. K.

    2010-11-01

    A method is proposed for the introduction of shungite rocks into aluminum melts by mechanical mixing with carriers, namely, aluminum granules and reactive titanium powders taking part in exothermic in situ reactions. The structures of composite materials with shungite rock additions are studied, and a stabilizing effect of these additions on dry sliding friction is revealed.

  12. Steam generated conversion coating on aluminium alloys

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Jellesen, Morten Stendahl; Ambat, Rajan

    and growth of oxide film on different intermetallic particles and corrosion behaviour of such alloys.Surface morphology was observed by using FEG-SEM, EDX and FIB-SEM. Metal oxide surface characterization and compositional depth profiling were investigated by using XPS and GD-OES respectively......Aluminium and its alloys are widely used in aerospace industry owing to their high strength to weight ratio. The surface of aluminium under normal conditions has a thin oxide film (2.5-10 nm) responsible for its inherent corrosion resistance. This oxide film can further be converted or transformed......) depending on the preparation parameters/conditions. Moreover, with the knowledge of factors controlling film growth, composition and morphology, such oxide layers carry huge potential for practical applications. Pure aluminium (AA1090, 99.94 wt. %) and other aluminium alloy surfaces were exposed to high...

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

    International Nuclear Information System (INIS)

    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.

  14. 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.

  15. Aluminium surface treatment with ceramic phases using diode laser

    Science.gov (United States)

    Labisz, K.; Tański, T.; Brytan, Z.; Pakieła, W.; Wiśniowski, M.

    2016-07-01

    Ceramic particles powder feeding into surface layer of engineering metal alloy is a well-known and widely used technique. New approach into the topic is to obtain finely distributed nano-sized particles involved in the aluminium matrix using the traditional laser technology. In this paper are presented results of microstructure investigation of cast aluminium-silicon-copper alloys surface layer after heat treatment and alloying with ceramic carbides of WC and ZrO2 using high-power diode laser. The surface layer was specially prepared for the reason of reducing the reflectivity, which is the main problem in the up-to-date metal matrix composites production. With scanning electron microscopy, it was possible to determine the deformation process and distribution of WC and ZrO2 ceramic powder phase. Structure of the surface after laser treatment changes, revealing three zones—remelting zone, heat-affected zone and transition zone placed over the Al substrate. The structural changes of ceramic powder, its distribution and morphology as well as microstructure of the matrix material influence on functional properties, especially wear resistance and hardness of the achieved layer, were investigated.

  16. Multiple strengthening mechanisms in nanoparticle-reinforced copper matrix composites

    Indian Academy of Sciences (India)

    D Bozic; J Stasic; B Dimcic; M Vilotijevic; V Rajkovic

    2011-04-01

    The multiple hardening mechanisms of a copper matrix have been presented and discussed. The prealloyed ball milled Cu–3 wt.%Al and the atomized Cu–0.6 wt.%Ti–2.5 wt.%TiB2 powders have been used as starting materials. Dispersoid particles Al2O3 and TiB2 were formed in situ. The powders have been hot consolidated. Optical microscopy, SEM, TEM, and X-ray diffraction analysis were performed for microstructural characterization. Increase in microhardness of Cu–3 wt.%Al compacts is a consequence of the crystallite size refinement and the presence of Al2O3 particles. High hardening of Cu–0.6 wt.%Ti–2.5 wt.%TiB2 is a consequence of the presence of modular structure, Cu4Ti$_{(m)}$, and TiB2 particles.

  17. Performance of the Cement Matrix Composite Material With Rubber Powder

    Institute of Scientific and Technical Information of China (English)

    SONG Shao-min; LIU Juan-hong; ZHANG Xi-qing

    2004-01-01

    The effect of the deferent rubber content substituted for fine aggregate on the mortar performancewas studied. The effects of the rubber coated with the coating materials on the mortar compressive strength, bendingstrength and impact work were discussed. The optimum rubber powder content and the suitable coating materialwere found. Through the electrical probe test- BEI, SEI and calcium ion distribution, and the slight crack and theinterface between the rubber and cement matrix are analyzed. The results show that the rubber powder coated withthe surface treatment materials A, B and C bas the capability of absorbing a large amount of energy under thecompressive and flexural load and the slight cracks of R- C were controlled and restrained.

  18. Freeform fabrication of polymer-matrix composite structures

    Energy Technology Data Exchange (ETDEWEB)

    Kaufman, S.G.; Spletzer, B.L.; Guess, T.L.

    1997-05-01

    The authors have developed, prototyped, and demonstrated the feasibility of a novel robotic technique for rapid fabrication of composite structures. Its chief innovation is that, unlike all other available fabrication methods, it does not require a mold. Instead, the structure is built patch by patch, using a rapidly reconfigurable forming surface, and a robot to position the evolving part. Both of these components are programmable, so only the control software needs to be changed to produce a new shape. Hence it should be possible to automatically program the system to produce a shape directly from an electronic model of it. It is therefore likely that the method will enable faster and less expensive fabrication of composites.

  19. Polymer-matrix Composites for High-temperature Applications

    Directory of Open Access Journals (Sweden)

    P.D. Mangalgiri

    2005-04-01

    Full Text Available Over the last decade, applications of fibre-reinforced composites using polymer matrices have seen tremendous growth. In spite of the complexity of their behaviour and the unconventionalnature of fabrication and other aspects, the usage of such composites, even for primary loadbearing structures in military fighters and transport aircraft, and satellites and space vehicles has been beneficially realised. Most of such usage constituted structural applications (such as in airframe where service temperatures are not expected to he beyond 120 'C. Attention is now focussed on expanding the usage of such composites to other areas where temperatures could be higher-in the range 200400 "C. The intended applications are structural and non-structural parts on or around the aero-engines and airframe components for supersonic or hypersonic aircraft. The development of polymer matrices-such as bismaleimides, polyimides, cyanates, and liquid crystalline polymers and others-has brought such applications within the realm of practicability. The associated problems have been in terms of suitable processing technologies and in balancing the requirements of the performance with those of the processing. This paper describes briefly such developments and reviews the potential application scenario.

  20. Characterization and Damage Evaluation of Coal Tar Pitch Carbon Matrix Used in Carbon/Carbon Composites

    Science.gov (United States)

    Bhagat, Atul Ramesh; Mahajan, Puneet

    2016-09-01

    Flexure, compressive, and shear properties of the carbon matrix in carbon/carbon (C/C) composites made via a pitch impregnation method have been determined. The pitch carbon matrix was made using the same densification cycle used in making the C/C composite. Cyclic compression tests were performed on the matrix specimens. While unloading, a reduction in modulus was observed and residual strains were observed on complete unloading. These features were attributed to the presence of damage and plasticity in the densified matrix. A J 2 plasticity model with damage was used to simulate this behavior numerically. The parameters required for plasticity and damage model were evaluated iteratively by comparing the results in experiments with simulation.

  1. Simplification and improvement of prediction model for elastic modulus of particulate reinforced metal matrix composite

    Institute of Scientific and Technical Information of China (English)

    WANG Wen-ming; PAN Fu-sheng; LU Yun; ZENG Su-min

    2006-01-01

    In this paper, we proposed a five-zone model to predict the elastic modulus of particulate reinforced metal matrix composite. We simplified the calculation by ignoring structural parameters including particulate shape, arrangement pattern and dimensional variance mode which have no obvious influence on the elastic modulus of a composite, and improved the precision of the method by stressing the interaction of interfaces with pariculates and maxtrix of the composite. The five- zone model can reflect effects of interface modulus on elastic modulus of composite. It overcomes limitations of expressions of rigidity mixed law and flexibility mixed law. The original idea of five zone model is to put forward the particulate/interface interactive zone and matrix/interface interactive zone. By organically integrating the rigidity mixed law and flexibility mixed law,the model can predict the engineering elastic constant of a composite effectively.

  2. Ablation and radar-wave transmission performances of the nitride ceramic matrix composites

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The 2.5 dimensional silica fiber reinforced nitride matrix composites (2.5D SiO2f/Si3N4-BN) were prepared through the preceramic polymer impregnation pyro- lysis (PIP) method. The ablation and radar-wave transparent performances of the composite at high temperature were evaluated under arc jet. The composition and ablation surface microstructures were studied by X-ray diffraction (XRD) and scanning electron microscope (SEM). The results show that the 2.5D SiO2f/Si3N4-BN composites have a linear ablation rate of 0.33 mm/s and high radar-wave trans- parent ratio of 98.6%. The fused layer and the matrix are protected by each other, and no fused layer accumulates on the ablation surface. The nitride composite is a high-temperature ablation resistivity and microwave transparent material.

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Dobrzanski, L.A. [Mechanical Engineering Faculty, Institute of Engineering Materials and Biomaterials, Silesian University of Technology, ul. Konarskiego 18A Street, Gliwice 44-100 (Poland); Nowosielski, R. [Mechanical Engineering Faculty, Institute of Engineering Materials and Biomaterials, Silesian University of Technology, ul. Konarskiego 18A Street, Gliwice 44-100 (Poland); Konieczny, J. [Mechanical Engineering Faculty, Institute of Engineering Materials and Biomaterials, Silesian University of Technology, ul. Konarskiego 18A Street, Gliwice 44-100 (Poland)]. E-mail: jk@zmn.mt.polsl.gliwice.pl; PrzybyI, A. [Faculty of Materials Processing Technology and Applied Physics, Czestochowa University of Technology, Armii Krajowej 19 Street, Czestochowa 42-200 (Poland); WysIocki, J. [Faculty of Materials Processing Technology and Applied Physics, Czestochowa University of Technology, Armii Krajowej 19 Street, Czestochowa 42-200 (Poland)

    2005-04-15

    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.

  5. Preparation and properties of Cu matrix composite reinforced by carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiao-hua; LI Wen-hua; CHEN Chuan-sheng; XU Long-shan; YANG Zhi; HU Jing

    2005-01-01

    Cu matrix composites reinforced by carbon nanotubes(CNTs) were prepared. The effect of carbon nanotubes on mechanical and tribological properties of the Cu matrix composites were investigated. The chemical method for coating CNTs was reported. The morphology of the fracture surfaces and worn surface were examined by SEM.The results show that Cu/coated-CNTs composites have higher hardness, much better wear resistance and antifriction properties than those of the reference Cu alloy (Cu-10Sn) and Cu/uncoated-CNTs composite sintered under the same conditions. The optimal mechanical properties of the composites occurred at 2. 25% (mass fraction) of CNTs. The excellent wear resistance and anti-friction properties are attributed to the fiber strengthening effect of CNTs and the effect of the spherical wear debris containing carbon nanotubes on the tribo-surface.

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

    Science.gov (United States)

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

    2012-03-01

    In the present work a nanocrystalline Ni-W metallic matrix was used to fabricate Ni-W/Al2O3 composite coatings. The MMC (metal matrix composite) coatings with inert α-Al2O3 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/Al2O3 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/Al2O3 composite coatings have been determined.

  7. Corrosion resistance of the sintered composite materials with the EN AW-AlCu4Mg1(a alloy matrix reinforced with ceramic particles

    Directory of Open Access Journals (Sweden)

    A. Włodarczyk-Fligier

    2010-09-01

    Full Text Available Purpose: the aim of the project was to evaluate of the effect of heat treatment and the reinforcing Al2O3 and Ti(C,N particles content on the corrosion resistance in the NaCl water solution environment on the EN AW-AlCu4Mg1(A aluminium alloy matrix composite.Design/methodology/approach: Powders of the starting materials were wet mixed in the laboratory vibratory ball mill to obtain the uniform distribution of the reinforcement particles in the matrix. The mixed powders were then dried in the air. The components were initially compacted at cold state in a die with the diameter of Ø 26 mm in the laboratory vertical unidirectional press – with a capacity of 350 kN. The selected compacting load was sufficient to obtain prepregs which would not crumble and at the same time would not be deformed too much, which would also have the adverse effect on their quality, as the excessive air pressure in the closed pores causes breaking the prepreg up when it is taken out from the die. The obtained PM compacts were heated to a temperature of 480-500˚C and finally extruded – with the extrusion pressure of 500 kN. Some of the composite materials were hyperquenched for 0.5 h at the temperature of 495ºC with the subsequent cooling in water, and were quench aged next for 6 h at 200°C. Corrosion tests were made in 5% water NaCl solution.Findings: Composite materials were examined without heat treatment and after heat treatment carried out to improve their corrosion resistance. The corrosion susceptibility of the investigated composite materials determined using the potentiodynamic method in the 3% water solution of NaCl depends on the volume fraction of the reinforcing particles and also on the heat treatment status.Practical implications: Tested composite materials can be applicate among the others in automotive industry but it requires additional researches.Originality/value: It was demonstrated corrosion resistance of the extruded composite materials with

  8. Damage Mechanisms of a TiB2-Reinforced Steel Matrix Composite for Lightweight Automotive Application

    Science.gov (United States)

    Li, Y. Z.; Luo, Z. C.; Yi, H. L.; Huang, M. X.

    2016-09-01

    The microscopic strain-and-stress fields related to primary and eutectic particles in a lightweight steel matrix composite (SMC) produced by in situ precipitation of TiB2 particles during solidification were investigated by means of microscale digital image correlation and finite element method. The damage process in this SMC is a sequential process of primary particles cracking, the fracture of the surrounding eutectic particles, and finally the growth and coalescence of voids in the ferrite matrix.

  9. Investigation of Coating Layer to Reduce Thermal Stresses in Steel Fiber Reinforced Aluminum Metal Matrix Composite

    OpenAIRE

    OKUMUŞ, Fuat

    2011-01-01

    In this study, by using coating layers to reduce thermal stresses in the metal matrix composites with a mismatch in coefficients of thermal expansions of fiber and matrix is investigated. The thermoelastic solutions based on a three cylinder model are deformed. It is shown that the effectiveness of the layer can be defined by the product of its cofficients of thermal expansions and thickness and that a compensating layer with a sufficiently high coefficient of thermal expansions can reduce th...

  10. Damage Mechanisms of a TiB2-Reinforced Steel Matrix Composite for Lightweight Automotive Application

    Science.gov (United States)

    Li, Y. Z.; Luo, Z. C.; Yi, H. L.; Huang, M. X.

    2016-05-01

    The microscopic strain-and-stress fields related to primary and eutectic particles in a lightweight steel matrix composite (SMC) produced by in situ precipitation of TiB2 particles during solidification were investigated by means of microscale digital image correlation and finite element method. The damage process in this SMC is a sequential process of primary particles cracking, the fracture of the surrounding eutectic particles, and finally the growth and coalescence of voids in the ferrite matrix.

  11. The high frequency fatigue behavior of continuous-fiber-reinforced ceramic matrix composites

    Science.gov (United States)

    Chawla, Nikhilesh

    Many potential applications for continuous fiber ceramic matrix composites (CFCMCs), such as gas turbines and heat exchangers, will involve high frequency cyclic loading (75 Hz or higher). While most of the work in the area of fatigue of CFCMCs has concentrated on low frequency behavior, it has been shown that fatigue at high frequencies can exacerbate the accumulation of microstructural damage and significantly decrease fatigue life. "Soft" matrix composites with strong interface bonding provided superior resistance to high frequency fatigue damage. Nicalon/SiCON composites with strong interfacial bonding between the fibers and matrix exhibited very little internal heating during high frequency fatigue loading. This composite system exhibited excellent fatigue life, with fatigue runout at 10sp7 cycles occurring for stresses close to 80% of the ultimate strength (at a loading frequency of 100 Hz). Thick fiber coatings may be more effective in reducing the amount of fiber wear and damage which occur during high frequency fatigue. More effective lubrication at the fiber/matrix interface was achieved with thicker carbon coatings in Nicalon/C/SiC composites subjected to high frequency fatigue loading. Composites with thicker coatings exhibited substantially lower frictional heating and had much higher fatigue lives. The effect of laminate stacking sequence had a significant effect on the high frequency fatigue behavior of CFCMCs. In SCS-6/Sisb3Nsb4 composites, frictional heating in angle-ply laminates (±45) was substantially higher than that in cross-ply laminates (0/90). Since the angle-ply had a lower stiffness, matrix microcracking in this composite was more predominant. Finally, preliminary fatigue damage mechanism maps for CFCMCs were developed. These maps provided a means to identify which fatigue mechanisms were operating at a given stress level and number of cycles.

  12. Microcracking mechanisms and interface toughening of semi-IPN polyimide matrix composites

    Science.gov (United States)

    Lee, Byung L.; Pater, R.

    1990-01-01

    A new research program was initiated as a preliminary phase. The following three objectives are being pursued for the overall program: to elucidate the mechanisms of microcracking for graphite fiber-reinforced semi-IPN polyimide matrix composites under mechanical and thermal cyclic loading; to devise material engineering solutions for possible improvement of fatigue damage resistance (or the increase of fatigue endurance strength) of semi-IPN matrix composites by tailoring of modulus and toughness of fiber-resin interface region; and to assess processing characteristics of the composites and their roles in controlling the resistance of composites to microcracking and the effectiveness of interface toughening. The main emphasis was placed upon the initial screening of material systems and optimization of processing conditions for semi-IPN matrix composites with tailored interface. As a first set of control material systems to study, the composites were prepared with unsized Celion 6000 graphite fiber reinforcement and the following resin matrices of varied fracture toughness: PMR-15 thermoset polyimide, semi-IPN of PNR-15 thermoset polyimide and NR150B2 thermoplastic polyimide in 75/25 ratio, and semi-IPN of PMR-15 and NR150B2 in 50/50 ratio. For the composites with the resin matrix of semi-IPN in 75/25 ratio, interface tailoring was attempted by using graphite fibers coated with the resins of systematically varied fracture toughness. In the continuing work, a broad range of interlayer toughness will be achieved by coating the fibers with reactants of semi-IPN having lower or higher content of thermoplastic constituent in comparison with the composition of surrounding resin matrix. In pursuing the objectives of the overall research program, the respective roles and interaction of critical parameters were defined.

  13. Matrix density effects on the mechanical properties of SiC/RBSN composites

    Science.gov (United States)

    Bhatt, Ramakrishna T.; Kiser, James D.

    1990-01-01

    The room temperature mechanical properties were measured for SiC fiber reinforced reaction-bonded silicon nitride composites (SiC/RBSN) of different densities. The composites consisted of approx. 30 vol percent uniaxially aligned 142 micron diameter SiC fibers (Textron SCS-6) in a reaction-bonded Si3N4 matrix. The composite density was varied by changing the consolidation pressure during RBSN processing and by hot isostatically pressing the SiC/RBSN composites. Results indicate that as the consolidation pressure was increased from 27 to 138 MPa, the average pore size of the nitrided composites decreased from 0.04 to 0.02 microns and the composite density increased from 2.07 to 2.45 gm/cc. Nonetheless, these improvements resulted in only small increases in the first matrix cracking stress, primary elastic modulus, and ultimate tensile strength values of the composites. In contrast, HIP consolidation of SiC/RBSN resulted in a fully dense material whose first matrix cracking stress and elastic modulus were approx. 15 and 50 percent higher, respectively, and ultimate tensile strength values were approx. 40 percent lower than those for unHIPed SiC/RBSN composites. The modulus behavior for all specimens can be explained by simple rule-of-mixture theory. Also, the loss in ultimate strength for the HIPed composites appears to be related to a degradation in fiber strength at the HIP temperature. However, the density effect on matrix fracture strength was much less than would be expected based on typical monolithic Si3N4 behavior, suggesting that composite theory is indeed operating. Possible practical implications of these observations are discussed.

  14. Computational modeling of structure of metal matrix composite in centrifugal casting process

    Science.gov (United States)

    Zagórski, Roman

    2007-04-01

    The structure of alumina matrix composite reinforced with crystalline particles obtained during centrifugal casting process are studied. Several parameters of cast process like pouring temperature, temperature, rotating speed and size of casting mould which influent on structure of composite are examined. Segregation of crystalline particles depended on other factors such as: the gradient of density of the liquid matrix and reinforcement, thermal processes connected with solidifying of the cast, processes leading to changes in physical and structural properties of liquid composite are also investigated. All simulation are carried out by CFD program Fluent. Numerical simulations are performed using the FLUENT two-phase free surface (air and matrix) unsteady flow model (volume of fluid model — VOF) and discrete phase model (DPM).

  15. Thermal expansion of laminated, woven, continuous ceramic fiber/chemical-vapor-infiltrated silicon carbide matrix composites

    Science.gov (United States)

    Eckel, Andrew J.; Bradt, Richard C.

    1990-01-01

    Thermal expansions of three two-dimensional laminate, continuous fiber/chemical-vapor-infiltrated silicon carbide matrix composites reinforced with either FP-Alumina (alumina), Nextel (mullite), or Nicalon (Si-C-O-N) fibers are reported. Experimental thermal expansion coefficients parallel to a primary fiber orientation were comparable to values calculated by the conventional rule-of-mixtures formula, except for the alumina fiber composite. Hysteresis effects were also observed during repeated thermal cycling of that composite. Those features were attributed to reoccurring fiber/matrix separation related to the micromechanical stresses generated during temperature changes and caused by the large thermal expansion mismatch between the alumina fibers and the silicon carbide matrix.

  16. Micromechanical modeling of damage growth in titanium based metal-matrix composites

    Science.gov (United States)

    Sherwood, James A.; Quimby, Howard M.

    1994-01-01

    The thermomechanical behavior of continuous-fiber reinforced titanium based metal-matrix composites (MMC) is studied using the finite element method. A thermoviscoplastic unified state variable constitutive theory is employed to capture inelastic and strain-rate sensitive behavior in the Timetal-21s matrix. The SCS-6 fibers are modeled as thermoplastic. The effects of residual stresses generated during the consolidation process on the tensile response of the composites are investigated. Unidirectional and cross-ply geometries are considered. Differences between the tensile responses in composites with perfectly bonded and completely debonded fiber/matrix interfaces are discussed. Model simulations for the completely debonded-interface condition are shown to correlate well with experimental results.

  17. Obtainment, machining and wear of metal matrix composites processed by powder metallurgy; Obtencao, usinagem e desgaste de materiais compositos de matriz metalica processados via metalurgia do po

    Energy Technology Data Exchange (ETDEWEB)

    Jesus, Edilson Rosa Barbosa de. E-mail: erbjesus@usp.br

    1998-07-01

    The aim of this investigation was the obtainment of metal matrix composites (MMC) by the route of powder metallurgy, and the valuation of these materials with relation to their machining and wear characteristics. Firstly, were obtained pure commercial aluminium matrix composites materials, with 5, 10 and 15% volumetric fraction of silicon carbide particles. Was also obtained a material without reinforcement particles in order to verify by comparison, the influence of addition of reinforcement particles. The obtained materials were characterized physics (hydrostatic density), mechanics (hardness and tensile tests) and microstructurally (optical microscopy and scanning electron microscopy). The results showed a homogeneous distribution of reinforcement particles in the composite, and improvement in the mechanical properties, mainly tensile strength (UTS) in comparison to the unreinforced material. After, tests were made to verify the materials behavior during machining and to check the performance of several tool materials (cemented carbide, ceramics and polycrystalline diamond). In these tests, values of the cutting force were measured by instrumented tool-holders. Phenomena such as tool wear, built-up edge formation and mechanism of chip formation were also observed and evaluated. The results from the cemented carbide tool tests, were utilised for the machinability index determination of each material. These results were applied to the Taylor equation and the equation constants for each material and test conditions were determined. The results showed that the inclusion of silicon carbide particles made extremely difficult the machining of the composites, and only with diamond tool, satisfactory results were obtained. At last, wear tests were performed to verify the influence of the reinforcement particles in the characteristics of wear resistance of the materials. The results obtained were utilized in the wear coefficient determination for each material. The

  18. 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.

  19. 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...

  20. Giant enhancement of magnetocaloric effect in metallic glass matrix composite

    Institute of Scientific and Technical Information of China (English)

    WANG YongTian; BAI HaiYang; PAN MingXiang; ZHAO DeQian; WANG WeiHua

    2008-01-01

    The magnetocaloric effect (MCE) has made great success in very low temperature refrigeration, which is highly desirable for application to the extended higher tem-perature range. Here we report the giant enhancement of MCE in the metallic glass composite. The large magnetic refrigerant capacity (RC) up to 103 J·kg-1 is more than double the RC of the well-known crystalline magnetic refrigerant compound Gd5Si2Ge1.9Fe0.1 (357 J·kg-1) and MnFeP0.45As0.55 (390 J·kg-1)(containing either ex-orbitant-cost Ge or poisonous As). The full width at half maximum of the magnetic entropy change (△Sm) peak almost spreads over the whole low-temperature range (from 303 to 30 K), which is five times wider than that of the Gd5Si2Ge1.9Fe0.1 and pure Gd. The maximum △Sm approaches a nearly constant value in a wide tem-perature span over 100 K, and however, such a broad table-like region near room temperature has seldom been found in alloys and compounds. In combination with the intrinsic amorphous nature, the metallic glass composite may be potential for the ideal Ericsson-cycle magnetic refrigeration over a broad temperature range near room temperature.

  1. Giant enhancement of magnetocaloric effect in metallic glass matrix composite

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The magnetocaloric effect (MCE) has made great success in very low temperature refrigeration, which is highly desirable for application to the extended higher tem-perature range. Here we report the giant enhancement of MCE in the metallic glass composite. The large magnetic refrigerant capacity (RC) up to 103 J·kg-1 is more than double the RC of the well-known crystalline magnetic refrigerant compound Gd5Si2Ge1.9Fe0.1 (357 J·kg-1) and MnFeP0.45As0.55 (390 J·kg-1)(containing either ex-orbitant-cost Ge or poisonous As). The full width at half maximum of the magnetic entropy change (ΔSm) peak almost spreads over the whole low-temperature range (from 303 to 30 K), which is five times wider than that of the Gd5Si2Ge1.9Fe0.1 and pure Gd. The maximum ΔSm approaches a nearly constant value in a wide tem-perature span over 100 K, and however, such a broad table-like region near room temperature has seldom been found in alloys and compounds. In combination with the intrinsic amorphous nature, the metallic glass composite may be potential for the ideal Ericsson-cycle magnetic refrigeration over a broad temperature range near room temperature.

  2. Residual stresses in continuous graphite fiber Al metal matrix composites

    Science.gov (United States)

    Park, Hun Sub; Zong, Gui Sheng; Marcus, Harris L.

    1988-01-01

    The residual stresses in graphite fiber reinforced aluminum (Gr/Al) composites with various thermal histories are measured using X-ray diffraction (XRD) methods. The XRD stress analysis is based on the determination of lattice strains by precise measurements of the interplanar spacings in different directions of the sample. The sample is a plate consisting of two-ply P 100 Gr/Al 6061 precursor wires and Al 6061 overlayers. Prior to XRD measurement, the 6061 overlayers are electrochemically removed. In order to calibrate the relationship between stress magnitude and lattice spacing shift, samples of Al 6061 are loaded at varying stress levels in a three-point bend fixture, while the stresses are simultaneously determined by XRD and surface-attached strain gages. The stresses determined by XRD closely match those determined by the strain gages. Using these calibrations, the longitudinal residual stresses of P 100 Gr/Al 6061 composites are measured for various heat treatments, and the results are presented.

  3. Modeling the Tensile Strength of Carbon Fiber - Reinforced Ceramic - Matrix Composites Under Multiple Fatigue Loading

    Science.gov (United States)

    Li, Longbiao

    2016-06-01

    An analytical method has been developed to investigate the effect of interface wear on the tensile strength of carbon fiber - reinforced ceramic - matrix composites (CMCs) under multiple fatigue loading. The Budiansky - Hutchinson - Evans shear - lag model was used to describe the micro stress field of the damaged composite considering fibers failure and the difference existed in the new and original interface debonded region. The statistical matrix multicracking model and fracture mechanics interface debonding criterion were used to determine the matrix crack spacing and interface debonded length. The interface shear stress degradation model and fibers strength degradation model have been adopted to analyze the interface wear effect on the tensile strength of the composite subjected to multiple fatigue loading. Under tensile loading, the fibers failure probabilities were determined by combining the interface wear model and fibers failure model based on the assumption that the fiber strength is subjected to two - parameter Weibull distribution and the loads carried by broken and intact fibers satisfy the Global Load Sharing criterion. The composite can no longer support the applied load when the total loads supported by broken and intact fibers approach its maximum value. The conditions of a single matrix crack and matrix multicrackings for tensile strength corresponding to multiple fatigue peak stress levels and different cycle number have been analyzed.

  4. Shape and vibration control of a smart composite plate with matrix cracks

    International Nuclear Information System (INIS)

    This paper addresses the interaction between the health monitoring and control functions of a smart structure. A finite element model is developed for a composite plate with surface mounted piezoceramic actuators and matrix cracks by integrating a classical laminate plate theory approach with a matrix crack model. The effect of matrix cracks in a cantilevered smart composite plate with different electrical and mechanical loadings is studied for several different laminate types and ply angles. It is observed that matrix crack saturation depends on the loading conditions, applied voltage, laminate type, and ply angles. It is found that the static and dynamic behavior of the plate changes significantly due to matrix cracking. Changes in deflection caused by loss of stiffness due to matrix cracks can be compensated by applied voltage. A negative velocity feedback control algorithm is used for active control of damping, and it is found that there is a change in the decay rate of the response due to matrix cracks and that this change can be compensated by increasing the control gain of the active damping algorithm. Different applied voltages and control gains can be used to interrogate the structure at varying loading conditions, which creates more data for structural damage detection. The model developed in this work is useful for structural health monitoring applications

  5. Biomechanical characteristics of polymeric UHMWPE composites with hybrid matrix and dispersed fillers

    Science.gov (United States)

    Panin, Sergey; Kornienko, Lyudmila; Shilko, Sergey; Thuc, Nguyen Xuan; Korchagin, Mikhail; Chaikina, Marina

    2015-11-01

    In order to develop artificial joint implants some biomechanical properties of composites with UHMWPE and hybrid (polymer-polymeric) "UHMWPE+PTFE" matrix with dispersed fillers were studied. A comparative analysis of the effectiveness of adding hydroxyapatite micron- and nanopowders as a biocompatible filler was carried out. It was shown that under dry sliding friction the wear rate of nanocomposites with the hybrid matrix is lower as compared with composites with the non-hybrid one. Mechanical activation of components further enhances the durability of nano- and microcomposites to almost double it without any significant reduction in the strength characteristics.

  6. 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.

  7. Stiffness Transfer Matrix Method (STMM) for stable dispersion curves solution in anisotropic composites

    Science.gov (United States)

    Kamal, Ayman; Giurgiutiu, Victor

    2014-03-01

    This paper discusses combined transfer matrix method (TMM) with stiffness matrix method (SMM) for obtaining a stable solution for dispersion curves of Lamb wave propagation in non-isotropic layers. TMM developed by Thomson and Haskell experiences numerical deficiency at high frequency thickness simulations. SMM was proposed by different researchers to solve the instability issue of TMM. This study shows that stable SMM is good at high frequencies, and TMM needs to be combined with SMM to obtain stable and robust behavior over the frequency range. Numerical simulations of dispersion curves are presented for wave propagation in orthotropic unidirectional fiber composites and cross ply composites. The paper ends with conclusions and future work.

  8. Thixoforming of SiC ceramic matrix composites in pseudo-semi-solid state

    Institute of Scientific and Technical Information of China (English)

    CHENG Yuan-sheng; LUO Shou-jing; DU Zhi-ming

    2005-01-01

    A new forming process, ceramic matrix composites thixoforming in pseudo-semi-solid state, was proposed based on powder metallurgy technology combined with the semi-solid metal forming process. The satellite angle-frames were prepared by this technology with Alp and SiCp materials mixed with different volume fractions. It is proved that it is feasible for the forming of the ceramic matrix composites by this technology through metallographic analyses and tensile tests. The results also show that the microstructures of samples are homogeneous and they have high hardness and certain plasticity.

  9. Resin Matrix/Fiber Reinforced Composite Material, Ⅱ: Method of Solution and Computer Code

    Institute of Scientific and Technical Information of China (English)

    Li Chensha(李辰砂); Jiao Caishan; Liu Ying; Wang Zhengping; Wang Hongjie; Cao Maosheng

    2003-01-01

    According to a mathematical model which describes the curing process of composites constructed from continuous fiber-reinforced, thermosetting resin matrix prepreg materials, and the consolidation of the composites, the solution method to the model is made and a computer code is developed, which for flat-plate composites cured by a specified cure cycle, provides the variation of temperature distribution, the cure reaction process in the resin, the resin flow and fibers stress inside the composite, the void variation and the residual stress distribution.

  10. PREDICTION OF MECHANICAL PROPERTY OF WHISKER REINFORCED METAL MATRIX COMPOSITE: PART-Ⅰ. MODEL AND FORMULATION

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Based on study of strain distribution in whisker reinforced metal matrix composites, an explicit precise stiffness tensor is derived. In the present theory, the effect of whisker orientation on the macro property of composites is considered, but the effect of random whisker position and the complicated strain field at whisker ends are averaged. The derived formula is able to predict the stiffness modulus of composites with arbitrary whisker orientation under any loading condition. Compared with the models of micro-mechanics, the present theory is competent for modulus prediction of actual engineering composites. The verification and application of the present theory are given in a subsequent paper published in the same issue.

  11. Influence of Carbon & Glass Fiber Reinforcements on Flexural Strength of Epoxy Matrix Polymer Hybrid Composites

    Directory of Open Access Journals (Sweden)

    T.D. Jagannatha

    2015-04-01

    Full Text Available Hybrid composite materials are more attracted by the engineers because of their properties like stiffness and high specific strength which leads to the potential application in the area of aerospace, marine and automobile sectors. In the present investigation, the flexural strength and flexural modulus of carbon and glass fibers reinforced epoxy hybrid composites were studied. The vacuum bagging technique was adopted for the fabrication of polymer hybrid composite materials. The hardness, flexural strength and flexural modulus of the hybrid composites were determined as per ASTM standards. The hardness, flexural strength and flexural modulus were improved as the fiber reinforcement contents increased in the epoxy matrix material.

  12. Numerical Simulation of Dynamic Response of Fiber Reinforced Ceramic Matrix Composite Beam with Matrix Cracks Using Multiscale Modeling

    Institute of Scientific and Technical Information of China (English)

    Gao Xiguang; Song Yingdong; Sun Zhigang; Hu Xuteng

    2010-01-01

    A multiscale method for simulating the dynamic response of ceramic matrix composite (CMC) with matrix cracks is developed.At the global level,the finite element method is employed to simulate the dynamic response ofa CMC beam.While at the local level,the multiscale mechanical method is used to estimate the stress/strain response of the material.A distributed computing system is developed to speed up the simulation.The simulation of dynamic response of a Nicalon/CAS-Ⅱ beam being subjected to harmonic loading is performed as a numerical example.The results show that both the stress/strain responses under tension and compressive loading are nonlinear.These conditions result in a different response compared with that of elastic beam,such as:1) the displacement response is not symmetric about the axis of time;2) in the condition of small external load,the response at first order natural frequency is limited within a finite range;3) decreasing the matrix crack space will increase the displacement response of the beam.

  13. In situ fabrication and microstructure of Al2O3 particles reinforced aluminum matrix composites

    International Nuclear Information System (INIS)

    Al2O3p/Al composites were prepared by direct melt reaction process. The thermodynamics of in situ chemical reactions between molten aluminum and CeO2 powder was studied. The XRD results show that the components of the as-prepared composites consist of Al2O3 and Al phases. For the as-cast composite specimens, SEM, EDX, TEM and SAD were used to analyze the reinforcement phases and interface characters of composites. The results show that the in situ generated Al2O3 particles, whose sizes are 100-200 nm, have various irregular shapes and disperse uniformly in matrix. TEM observation shows that the interface between particle and matrix is clean. Furthermore, there is no fixed orientation relationship between Al2O3 particles and aluminum matrix. Only [12-bar 10]//[111] orientation parallel relationship with low exponent is found. Therefore, the composites have isotropic properties. Besides characters mentioned above, there are large amount of high density dislocations and the generated extensive fine subgrains around Al2O3 particles. These features are favorable for improving composite performances. As a result, the composites are comprehensively strengthened not only by Al2O3 particles, but also by the high density dislocations and fine subgrains.

  14. Production of Decorative Cast Metal Matrix Composites with a Complex Relief and Nonmetal Reinforcement Phase

    Directory of Open Access Journals (Sweden)

    Daniela Spasova

    2016-02-01

    Full Text Available The present paper is relevant to the research of possibilities for the production of decorative complex relief metal matrix composites (MMCs of the “invitro” type, with unformed and unchanging reinforcement (strengthening phase in the process of creating a composite. The research on the methods of metal matrix composites development in this paper has been brought to the application of different space vacuum schemes for composite synthesisof vacuuming the space for composites synthesis by using the notion of the “capillary forming”. In this method the metal matrix (copper alloy melt was infiltrated in the space between the pellets of reinforcement phase (quartz particles – SiO2, whereas the classical method adopted for the obtaining MMCs “in vitro”, uses a mechanism of forced insertion of the reinforcement phase into the ready for use melt, followed by homogenization of the composite structure. In the particular case, because the obtained composite will have a complex relief three-dimensional surface, the conditions for compacting the building phases in the three directions x, y, z should be virtually equalized. In order to accomplish the task set, a laboratory system is developed. The experiments were conducted with laboratory equipment elaborated on the base of another equipment for "capillary forming" with extra vacuum. The structures of the obtained MMCs were tested by metallographic analysis.

  15. 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.

  16. Investigation of Creep Phenomenon in Metal Matrix Composites with Whiskers

    Directory of Open Access Journals (Sweden)

    Vahid Monfared

    2012-09-01

    Full Text Available A new mathematical model based on the exponential, logarithmic and polynomial (mixed functions is presented for determination of some unknowns such as displacement rate in outer surface of unit cell and strain rate of short fiber (whisker composites with elastic fiber in steady state creep under axial loading. In addition, effective factor or effect coefficient is introduced for determination of creep displacement rate in outer surface. Also, radial, axial displacement rates, equivalent and shear stresses will be determined by new method. Aim of this study is using the mathematical modeling instead of time consuming and costly experimental methods. On the other hand, unknowns are determined by polynomial, exponential and logarithmic functions instead of some theories, simply. These analytical results are then validated by the Finite Element Analysis (FEA. Interestingly, good agreements are found between analytical and numerical predictions for creep strain rate and displacement rate.

  17. Evaluation of Impact Damage Tolerance in Carbon Fabric/epoxy-matrix Composites by Electrical Resistance Measurement

    Institute of Scientific and Technical Information of China (English)

    LI Zhipeng; XIE Xiaolin; HONG Zhen; LU Chao; WANG Gaochao

    2012-01-01

    Impact damage tolerance is provided in intensity design on composites.The compression intensity of impacted composites requires more than 60% of its original intensity.The influence of impact on compressive intensity and electrical resistance of carbon fabric/epoxy-matrix composites was studied in this paper.The experimental results shows that impact can cause damage in composites,degenerate compressive intensity,and increase resistance.The electrical resistance change rate was used as an evaluation indicator of impact damage tolerance of composites.Impact damage,which results from the applying process of composites,can be identified in time by electrical resistance measurement.So,the safety performance of composites can also be improved.

  18. A Preliminary Investigation of Ductility-Enhancement Mechanism through In Situ Nanofibrillation in Thermoplastic Matrix Composites

    Directory of Open Access Journals (Sweden)

    Bhaskar Patham

    2013-01-01

    Full Text Available A preliminary investigation of interrelationships between tensile stress-strain characteristics and morphology evolution during deformation is conducted on a commercially available thermoplastic composite with a low-surface-energy nanofibrillating poly(tetrafluoroethylene (PTFE additive. In this class of composites, the deformation-associated nanofibrillation of the low-surface-energy additive has been hypothesized to provide an additional dissipation mechanism, thereby enhancing the ductility of the composite. This class of composites offers potential for automotive light weighting in exterior and interior body and fascia applications; it is therefore of interest to investigate processing-structure-property interrelationships in these materials. This study specifically probes the interrelationships between the plastic deformation within the matrix and the fibrillation of the low-surface-energy additive; tensile tests are carried out at two different temperatures which are chosen so as to facilitate and suppress plastic deformation within the matrix polymer. Based on these preliminary investigations, it is noted that PTFE fibrillation acts synergistically with the ductile deformation of the matrix resin resulting in higher strains to failure of the composite; the results also suggest that the mechanism of fibrillation-assisted enhancement of strains to failure may not operate in the absence of matrix plasticity.

  19. Seamless metal-clad fiber-reinforced organic matrix composite structures and process for their manufacture

    Science.gov (United States)

    Bluck, Raymond M. (Inventor); Bush, Harold G. (Inventor); Johnson, Robert R. (Inventor)

    1990-01-01

    A metallic outer sleeve is provided which is capable of enveloping a hollow metallic inner member having continuous reinforcing fibers attached to the distal end thereof. The inner member is then introduced into outer sleeve until inner member is completely enveloped by outer sleeve. A liquid matrix member is then injected into space between inner member and outer sleeve. A pressurized heat transfer medium is flowed through the inside of inner member, thereby forming a fiber reinforced matrix composite material. The wall thicknesses of both inner member and outer sleeve are then reduced to the appropriate size by chemical etching, to adjust the thermal expansion coefficient of the metal-clad composite structure to the desired value. thereby forming a fiber reinforced matrix composite material. The wall thicknesses of both inner member and outer sleeve are then reduced to the appropriate size by chemical etching, to adjust the thermal expansion coefficient of the metal-clad composite structure to the desired value. The novelty of this invention resides in the development of a efficient method of producing seamless metal clad fiber reinforced organic matrix composite structures.

  20. Corn gluten meal as a biodegradable matrix material in wood fibre reinforced composites

    International Nuclear Information System (INIS)

    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

  1. PARTICULATE SIZE EFFECTS IN THE PARTICLE-REINFORCED METAL-MATRIX COMPOSITES

    Institute of Scientific and Technical Information of China (English)

    魏悦广

    2001-01-01

    The influences of particle size on the mechanical properties of the particulate metal matrix composite are obviously displayed in the experimental observations. However, the phenomenon can not be predicted directly using the conventional elastic-plastic theory. It is because that no length scale parameters are involved in the conventional theory. In the present research, using the strain gradient plasticity theory, a systematic research of the particle size effect in the particulate metal matrix composite is carried out. The roles of many composite factors, such as: the particle size, the Young's modulus of the particle, the particle aspect ratio and volume fraction, as well as the plastic strain hardening exponent of the matrix material,are studied in detail. In order to obtain a general understanding for the composite behavior, two kinds of particle shapes, ellipsoid and cylinder, are considered to check the strength dependence of the smooth or non-smooth particle surface. Finally,the prediction results will be applied to the several experiments about the ceramic particle-reinforced metal-matrix composites. The material length scale parameter is predicted.

  2. 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.

  3. 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

  4. The Role of Particles in Fatigue Crack Propagation of Aluminum Matrix Composites and Casting Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    Zhenzhong CHEN; Ping HE; Liqing CHEN

    2007-01-01

    Fatigue crack propagation (FCP) behaviors were studied to understand the role of SiC particles in 10 wt pct SiCp/A2024 composites and Si particles in casting aluminum alloy A356. The results show that a few particles appeared on the fracture surfaces in SiCp/Al composites even at high AK region, which indicates that cracks propagated predominantly within the matrix avoiding SiC particles due to the high strength of the particles and the strong particle/matrix interface. In casting aluminum alloy, Si particle debonding was more prominent.Compared with SiCp/Al composite, the casting aluminum alloy exhibited lower FCP rates, but had a slight steeper slope in the Paris region. Crack deflection and branching were found to be more remarkable in the casting aluminum alloy than that in the SiCp/Al composites, which may be contributed to higher FCP resistance in casting aluminum alloy.

  5. Fracture Analysis of Particulate Reinforced Metal Matrix Composites

    Science.gov (United States)

    Min, James B.; Cornie, James A.

    2013-01-01

    A fracture analysis of highly loaded particulate reinforced composites was performed using laser moire interferometry to measure the displacements within the plastic zone at the tip of an advancing crack. Ten castings were made of five different particulate reinforcement-aluminum alloy combinations. Each casting included net-shape specimens which were used for the evaluation of fracture toughness, tensile properties, and flexure properties resulting in an extensive materials properties data. Measured fracture toughness range from 14.1 MPa for an alumina reinforced 356 aluminum alloy to 23.9 MPa for a silicon carbide reinforced 2214 aluminum alloy. For the combination of these K(sub Ic) values and the measured tensile strengths, the compact tension specimens were too thin to yield true plane strain K(sub Ic) values. All materials exhibited brittle behavior characterized by very small tensile ductility suggesting that successful application of these materials requires that the design stresses be below the elastic limit. Probabilistic design principles similar to those used with ceramics are recommended when using these materials. Such principles would include the use of experimentally determined design allowables. In the absence of thorough testing, a design allowable stress of 60 percent of the measured ultimate tensile stress is recommended.

  6. THE RECYCLING OF OMC'S CARBON REINFORCEMENT BY SOLVOLYSING THERMOSET MATRIX. A WAY OF SUSTAINABILITY FOR COMPOSITES

    OpenAIRE

    PRINCAUD, Marion; Pompidou, Stéphane; Perry, Nicolas; SONNEMANN, Guido; Aymonier, Cyril; SERANI, Anne

    2014-01-01

    International audience; Originally developed for high-tech applications, carbon fibre/thermoset matrix composites have been increasingly used in leisure and sports industries, for several years. But the carbon reinforcement is the most expensive constituent, and also the most environmentally impacting in the elaboration of a composite part. To this day, no end-of-life solution or recycling process efficiently exists. This paper aims at demonstrating that recovering the carbon reinforcement is ...

  7. Study on Mechanical Behavior of Bio-Fiber Reinforced Polymer Matrix Composite

    OpenAIRE

    V.N.Loganathan*; M.Palanisamy; K.Sathish Kumar

    2014-01-01

    Presently polymer matrix composites reinforced with fibers such as glass, carbon, aramid, etc. are being used more because of their favorable mechanical properties in spite of they being more expensive materials. Nowadays natural fibers such as sisal, flax, hemp, jute, coir, bamboo, banana, etc. are widely used for environmental concern on synthetic fibers. This coming generation of engineered bio-composites must provide construction materials and building products that exceed cur...

  8. Durability of polymer matrix composites: Viscoelastic effect on static and fatigue loading

    OpenAIRE

    Guedes, RM

    2007-01-01

    The structural applications of polymer matrix composites (PMC) demand lifetimes of 15, 25 and 50 years. However, the mechanical properties of these composites have a time dependent nature, i.e. strength and stiffness are time-dependent due to the hereditary nature (viscoelasticity) of polymers. In this context lifetime models for viscoelastic materials, i.e. energy-based criteria and fracture mechanics extended to viscoelastic media, are revised. These models are applied to predict the lifeti...

  9. Matrix free fiber reinforced polymeric composites via high-temperature high-pressure sintering

    Science.gov (United States)

    Xu, Tao

    2004-11-01

    A novel manufacturing process called high-temperature high-pressure sintering was studied and explored. Solid fiber reinforced composites are produced by consolidating and compacting layers of polymeric fabrics near their melting temperature under high pressure. There is no need to use an additional matrix as a bonding material. Partial melting and recrystallization of the fibers effectively fuse the material together. The product is called a "matrix free" fiber reinforced composite and essentially a one-polymer composite in which the fiber and the matrix have the same chemical composition. Since the matrix is eliminated in the process, it is possible to achieve a high fiber volume fraction and light weight composite. Interfacial adhesion between fibers and matrix is very good due to the molecular continuity throughout the system and the material is thermally shapeable. Plain woven Spectra RTM cloth made of SpectraRTM fiber was used to comprehensively study the process. The intrinsic properties of the material demonstrate that matrix free SpectraRTM fiber reinforced composites have the potential to make ballistic shields such as body armor and helmets. The properties and structure of the original fiber and the cloth were carefully examined. Optimization of the processing conditions started with the probing of sintering temperatures by Differential Scanning Calorimetry. Coupled with the information from structural, morphological and mechanical investigations on the samples sintered at different processing conditions, the optimal processing windows were determined to ensure that the outstanding original properties of the fibers translate into high ballistic performance of the composites. Matrix free SpectraRTM composites exhibit excellent ballistic resistance in the V50 tests conducted by the US Army. In the research, process-structure-property relationship is established and correlations between various properties and structures are understood. Thorough knowledge is

  10. 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

  11. Effect of reinforcement type and porosity on strength of metal matrix composite

    Science.gov (United States)

    Kulkarni, S. G.; Lal, Achchhe; Menghani, J. V.

    2016-05-01

    In the present work, experimental investigation and the numerical analysis are carried out for strength analysis of A356 alloy matrix composites reinforced with alumina, fly ash and hybrid particle composites. The combined strengthening effect of load bearing, Hall-Petch, Orowan, coefficient of thermal expansion mismatch and elastic modulus mismatch is studied for predicting accurate uniaxial stress-strain behavior of A356 based alloy matrix composite. The unit cell micromechanical approach and nine noded isoparametric finite element analysis (FEA) is used to investigate the yield failure load by considering material defect of porosity as fabrication errors in particulate composite. The Ramberg-Osgood approach is considered for the linear and nonlinear relationship between stress and strain of A356 based metal matrix composites containing different amounts of fly ash and alumina reinforcing particles. A numerical analysis of material porosity on the stress strain behavior of the composite is performed. The literature and experimental results exhibit the validity of this model and confirm the importance of the fly ash as the cheapest and low density reinforcement obtained as a waste by product in thermal power plants.

  12. Deformation features of aluminium in tensile tests

    International Nuclear Information System (INIS)

    It is presented a method to analyse stress-strain curves. Plastic and elastic strains were studied. The strains were done by tensile tests in four types of materials: highly pure aluminium, pure aluminium, commercially pure aluminium and aluminium - uranium. The chemical compositions were obtained by spectroscopy analysis and neutron activation analysis. Tensile tests were carried out at three strain rates, at room temperature, 100,200, 300 and 4000C, with knives extensometer and strain-gages to studied the elastic strain region. A multiple spring model based on two springs model to analyse elastic strain caused by tests without extensometers, taking in account moduli of elasticity and, an interactive analysis system with graphic capability were developed. It was suggested a qualitative model to explain the quantized multielasticity of Bell. (M.C.K.)

  13. Fatigue testing and damage development in continuous fiber reinforced metal matrix composites

    Science.gov (United States)

    Johnson, W. S.

    1989-01-01

    A general overview of the fatigue behavior of metal matrix composites (MMC) is presented. The first objective is to present experimental procedures and techniques for conducting a meaningful fatigue test to detect and quantify fatigue damage in MMC. These techniques include interpretation of stress-strain responses, acid etching of the matrix, edge replicas of the specimen under load, radiography, and micrographs of the failure surfaces. In addition, the paper will show how stiffness loss in continuous fiber reinforced metal matrix composites can be a useful parameter for detecting fatigue damage initiation and accumulation. Second, numerous examples of how fatigue damage can initiate and grow in various MMC are given. Depending on the relative fatigue behavior of the fiber and matrix, and the interface properties, the failure modes of MMC can be grouped into four categories: (1) matrix dominated, (2) fiber dominated, (3) self-similar damage growth, and (4) fiber/matrix interfacial failures. These four types of damage will be discussed and illustrated by examples with the emphasis on the fatigue of unnotched laminates.

  14. 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...

  15. Al-Al2O3 core-shell composite by microwave induced oxidation of aluminium powder

    International Nuclear Information System (INIS)

    Microwave processing is gaining importance in the preparation of composite materials mainly because of its predominance in the improvement of uniformity for different phases formed. In the present study, commercial Al powder was heat treated using microwave radiation to synthesize Al-Al2O3 core-shell composite powder. The as received Al powder and the microwave heated Al powders were characterized by X-ray diffractometry (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis and zeta potential measurement. XRD data confirmed the formation of Al-Al2O3 composite. FTIR studies indicated the core-shell type Al-Al2O3 composite formation. SEM observations suggested the formation of Al-Al2O3 core-shell composite. TEM images, corresponding selected area electron diffraction (SAED) patterns and EDX analysis confirmed the Al-Al2O3 core-shell composite development. Zeta potential measurements also indicated that Al core particles were surrounded with Al2O3 shell.

  16. Sliding Wear Properties of Hybrid Aluminium Composite Reinforced by Particles of Palm Shell Activated Carbon and Slag

    Directory of Open Access Journals (Sweden)

    Zamri Yusoff

    2011-09-01

    Full Text Available In present work, dry sliding wear tests were conducted on hybrid composite reinforced with natural carbon based particles such as palm shell activated carbon (PSAC and slag. Hybrid composites containing 5 -20 wt.% of both reinforcements with average particles sizes about 125μm were prepared by conventional powder metallurgy technique, which involves the steps of mixing, compacting and sintering. Dry sliding experiments were conducted in air at room temperature using a pin-on-disc self-built attach to polisher machine. The disc which acted as the mating surface material was made of mild steel (120 HV cut from commercial mild steel sheet (2 mm thickness into 100mm diameter. The influence of the applied load was investigated under a constant sliding velocity of 0.1m/s with the applied loads at 3N, 11N and 51N. The contribution of the reinforcement content and the applied load as well as the sliding distance on the wear process and the wear rate have been investigated. The contribution of synergic factors such as applied load, sliding distance and reinforcement content (wt.% have been studied using analysis of variance (ANOVA. All synergic factors contribute to the wear process of all tested composites. Among synergic factors, the applied load is the highest contribution to wear process on both composites (Al/PSAC and Al/Slag and hybrid composite. The degree of improvement of wear resistance of hybrid composite is strongly dependent on the reinforcement content.

  17. Preparation of Aluminum Metal Matrix Composite with Novel In situ Ceramic Composite Particulates, Developed from Waste Colliery Shale Material

    Science.gov (United States)

    Venkata Siva, S. B.; Sahoo, K. L.; Ganguly, R. I.; Dash, R. R.; Singh, S. K.; Satpathy, B. K.; Srinivasarao, G.

    2013-08-01

    A novel method is adapted to prepare an in situ ceramic composite from waste colliery shale (CS) material. Heat treatment of the shale material, in a plasma reactor and/or in a high temperature furnace at 1673 K (1400 °C) under high vacuum (10-6 Torr), has enabled in situ conversion of SiO2 to SiC in the vicinity of carbon and Al2O3 present in the shale material. The composite has the chemical constituents, SiC-Al2O3-C, as established by XRD/EDX analysis. Particle sizes of the composite range between 50 nm and 200 μm. The shape of the particles vary, presumably rod to spherical shape, distributed preferably in the region of grain boundaries. The CS composite so produced is added to aluminum melt to produce Al-CS composite (12 vol. pct). For comparison of properties, the aluminum metal matrix composite (AMCs) is made with Al2O3 particulates (15 vol. pct) with size <200 μm. The heat-treated Al-CS composite has shown better mechanical properties compared to the Al-Al2O3 composite. The ductility and toughness of the Al-CS composite are greater than that of the Al-Al2O3 composite. Fractographs revealed fine sheared dimples in the Al-CS composite, whereas the same of the Al-Al2O3 composite showed an appearance of cleavage-type facets. Abrasion and frictional behavior of both the composites have been compared. The findings lead to the conclusion that the in situ composite developed from the colliery shale waste material has a good future for its use in AMCs.

  18. The effect orientation of features in reconstructed atom probe data on the resolution and measured composition of T1 plates in an A2198 aluminium alloy.

    Science.gov (United States)

    Mullin, Maria A; Araullo-Peters, Vicente J; Gault, Baptiste; Cairney, Julie M

    2015-12-01

    Artefacts in atom probe tomography can impact the compositional analysis of microstructure in atom probe studies. To determine the integrity of information obtained, it is essential to understand how the positioning of features influences compositional analysis. By investigating the influence of feature orientation within atom probe data on measured composition in microstructural features within an AA2198 Al alloy, this study shows differences in the composition of T1 (Al2CuLi) plates that indicates imperfections in atom probe reconstructions. The data fits a model of an exponentially-modified Gaussian that scales with the difference in evaporation field between solutes and matrix. This information provides a guide for obtaining the most accurate information possible.

  19. 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.

  20. 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)

  1. Significance of Shrinkage Induced Clamping Pressure in Fiber-Matrix Bonding in Cementitious Composite Materials

    DEFF Research Database (Denmark)

    Stang, Henrik

    1996-01-01

    The present paper accesses the significance of shrinkage inducedclamping pressure in fiber/matrix bonding mechanisms incementitious composite materials. The paper contains a description of an experimental setup whichallows mbox{measurement} of the clamping pressure which develops on anelastic...... inhomogeneity embedded in a matrix consisting of acementitious material undergoing shrinkage during hydration(autogenous shrinkage). Furthermore, the paperpresents the analysis necessary to perform an interpretation of the experimental results and which allows for thedetermination of the clamping pressure...... 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...

  2. Fiber optic sensor for monitoring atomic oxygen erosion of polymer matrix composites

    Science.gov (United States)

    Li, Linda; Tennyson, Rod C.; Morison, W. D.; Alavie, A. Tino

    1996-10-01

    An economical, fiber optic sensor which monitors atomic oxygen erosion of polymer matrix composites has been developed into a functional prototype. The self-contained prototype featuring automated data collection has been tested in two different atomic oxygen beam facilities. Results show very good correlation of the sensor's response under different operating conditions.

  3. Composite biomaterials with chemical bonding between hydroxyapatite filler particles and PEG/PBT copolymer matrix

    NARCIS (Netherlands)

    Liu, Qing; Wijn, de Joost R.; Blitterswijk, van Clemens A.

    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) confi

  4. Oxidation resistant coating for titanium alloys and titanium alloy matrix composites

    Science.gov (United States)

    Brindley, William J. (Inventor); Smialek, James L. (Inventor); Rouge, Carl J. (Inventor)

    1992-01-01

    An oxidation resistant coating for titanium alloys and titanium alloy matrix composites comprises an MCrAlX material. M is a metal selected from nickel, cobalt, and iron. X is an active element selected from Y, Yb, Zr, and Hf.

  5. 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

  6. Emerging Implications for Extracellular Matrix-Based Technologies in Vascularized Composite Allotransplantation

    OpenAIRE

    Ricardo Londono; Vijay S Gorantla; Badylak, Stephen F.

    2015-01-01

    Despite recent progress in vascularized composite allotransplantation (VCA), limitations including complex, high dose immunosuppression regimens, lifelong risk of toxicity from immunosuppressants, acute and most critically chronic graft rejection, and suboptimal nerve regeneration remain particularly challenging obstacles restricting clinical progress. When properly configured, customized, and implemented, biomaterials derived from the extracellular matrix (ECM) retain bioactive molecules and...

  7. Finite element implementation and numerical issues of strain gradient plasticity with application to metal matrix composites

    DEFF Research Database (Denmark)

    Frederiksson, Per; Gudmundson, Peter; Mikkelsen, Lars Pilgaard

    2009-01-01

    quadrilateral type are examined and a few numerical issues are addressed related to these elements as well as to strain gradient plasticity theories in general. Numerical results are presented for an idealized cell model of a metal matrix composite under shear loading. It is shown that strengthening due to...

  8. In situ crack growth observation and fracture behavior of short carbon fiber reinforced geopolymer matrix composites

    International Nuclear Information System (INIS)

    The crack initiation and propagation of short carbon fiber reinforced geopolymer matrix composites (Cf/geopolymer composites) during bending test were observed in situ by environmental scanning electron microscope (ESEM). Lots of micro cracks initiate, and then propagate on the side of the beam sample with the increase of the bending load. A nearly elastic response of load-displacement curve and significant deformation of the composites are observed at the initial stages. The propagation of the micro cracks ceases, and these cracks tend to close to some extent while the main crack forms. The fiber bridging effect in the micro and main cracks effectively keeps the composites integrity and makes the composites exhibit a non-catastrophic fracture behavior. A simple mode for the damage behavior of the composites during the bending test is discussed.

  9. Physical and Hydrodynamic Properties of Spherical Cellulose—Titanium Dioxide Composite Matrix for Expanded Bed Adsorption

    Institute of Scientific and Technical Information of China (English)

    雷引林; 林东强; 姚善泾; 刘坐镇; 朱自强

    2003-01-01

    Expanded bed adsorption (EBA) has been widely used in industrial downstream bioprocessing,Solid matrix is the principal pillar supporting the successful application of EBA.A novel spherical ceelulose-titanium dioxide composite matrix was prepared through the method of water-in-oil suspension thermal regeneration.Its typical physical properties were wet density 1.18g.cm-3,,diameters in the range of 100-300μm ,porosity 85.5%,and water content 72.3%.Expansion characteristics and liquid mixing performance of the matrix in expanded bed were investigated using water and 10% (by mass )glycerol solution as mobile phases,The results indicate that the custom-assembled matrix has a stable flow hydrodynamics and exhibits the same degree of liquid-phase mixing or column efficiency as the commercially available Streamline adsorbent.

  10. In-situ Dendrite/Metallic Glass Matrix Composites: A Review

    Institute of Scientific and Technical Information of China (English)

    Junwei Qiao

    2013-01-01

    The advanced fabrication of in-situ dendrite/metallic glass matrix (MGM) composites is reviewed.Herein,the semisolid processing and Bridgman solidification are two methods,which can make the dendrites homogeneously dispersed within the metallic glass matrix.Upon quasi-static compressive loading at room temperature,almost all the in-situ composites exhibit improved plasticity,due to the effective block to the fast propagation of shear bands.Upon quasi-static tensile loading at room temperature,although the composites possess tensile ductility,the inhomogeneous deformation and associated softening dominates.High volume-fractioned dendrites and network structures make in-situ composites distinguishingly plastic upon dynamic compression.In-situ composite exhibits high tensile strength and softening (necking) in the supercooled liquid region,since the presence of high volume-fractioned dendrites lowers the rheology of the viscous glass matrix at high temperatures.At cryogenic temperatures,a distinguishingly-increased maximum strength is available; however,a ductile-to-brittle transition seems to be present by lowering the temperature.Besides,improved tension-tension fatigue limit of 473 MPa and four-point-bending fatigue limit of 567 MPa are gained for Zr58.5Ti14.3Nb5.2Cu6.1Ni4.9Be11.o MGM composites.High volume-fraction dendrites within the glass matrix induce increased effectiveness on the blunting and propagating resistance of the fatigue-crack tip.The fracture toughness of in-situ composites is comparable to those of the toughest steels and crystalline Ti alloys.During steady-state crack-growth,the confinement of damage by in-situ dendrites results in enhancement of the toughness.

  11. Influence of matrix characteristics on fracture toughness of high volume fraction Al2O3 / Al-AlN composites

    OpenAIRE

    Nagendra, N.; Jayaram, V

    2000-01-01

    The role of matrix microstructure on the fracture of Al-alloy composites with 60 % volume of alumina particulates has been studied. The matrix composition and microstructure were systematically varied by changing the infiltration temperature and heat treatment. Characterisation was carried out by a combination of metallography, hardness measurements and fracture studies conducted on compact tension (CT) specimens to study the fracture toughness and crack growth in the composites. The composit...

  12. Stiffness matrix determination of composite materials using lamb wave group velocity measurements

    Science.gov (United States)

    Putkis, O.; Croxford, A. J.

    2013-04-01

    The use of Lamb waves in Non-Destructive Evaluation (NDE) and Structural Health Monitoring (SHM) is gaining popularity due to their ability to travel long distances without significant attenuation, therefore offering large area inspections with a small number of sensors. The design of a Lamb-wave-based NDE/SHM system for composite materials is more complicated than for metallic materials due to the directional dependence of Lamb wave propagation characteristics such as dispersion and group velocity. Propagation parameters can be theoretically predicted from known material properties, specifically the stiffness matrix and density. However, in practice it is difficult to obtain the stiffness matrix of a particular material or structure with high accuracy, hence introducing errors in theoretical predictions and inaccuracies in the resulting propagation parameters. Measured Lamb wave phase velocities can be used to infer the stiffness matrix, but the measurements are limited to the principal directions due to the steering effect (different propagation directions of phase and corresponding group velocities). This paper proposes determination of the stiffness matrix from the measured group velocities, which can be unambiguously measured in any direction. A highly anisotropic carbon-fibre-reinforced polymer plate is chosen for the study. The influence of different stiffness matrix elements on the directional group velocity profile is investigated. Thermodynamic Simulated Annealing (TSA) is used as a tool for inverse, multi variable inference of the stiffness matrix. A good estimation is achieved for particular matrix elements.

  13. Sustainable Aluminium Systems

    Directory of Open Access Journals (Sweden)

    Sergio R. Ermolli

    2010-09-01

    Full Text Available In the present paper, an analytical presentation of some popular aluminium systems that contribute to sustainability of structures is presented. Special emphasis has been given to the properties of aluminium, while the influence of these systems in the overall performance of the structure regarding environment and economy is described. In particular, characteristics of aluminium elements such as high reflectivity and recyclability and their role in life cycle analysis (LCA are analyzed. The connections between energy efficiency and conservation of buildings and aluminium application are also discussed. Building applications such as curtain walls, window frames and facade sheets are presented and thoroughly investigated, considering their environmental and economic aspects. Furthermore, many innovative techniques that use aluminium elements in collaboration with other systems in order to produce renewable energy, such as solar panels and photovoltaics, are introduced. Finally, environmental innovations such as optimized ventilation mechanisms and light and shade management systems based on aluminium members are presented.

  14. An Investigation of Laser Assisted Machining of Al_2O_3 Particle Reinforced Aluminum Matrix Composite

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The Al 2O 3 particles reinforced aluminum matrix composite (Al 2O 3p/Al) are more and more widely used for their excellent physical and chemical properties. However, their poor machinability leads to severe tool wear and bad machined surface. In this paper laser assisted machining is adopted in machining Al 2O 3p/Al composite and good result was obtained. The result of experiment shows in machining Al 2O 3p/Al composites the cutting force is reduced in 30%~50%, the tool wear is reduced in 20%~30% an...

  15. Thermo-oxidative stability studies of PMR-15 polymer matrix composites reinforced with various continuous fibers

    Science.gov (United States)

    Bowles, Kenneth J.

    1990-01-01

    An experimental study was conducted to measure the thermooxidative stability of PMR-15 composites reinforced with various fibers and to observe differences in the way they degrade in air. The fibers studied include graphite and the thermally stable Nicalon and Nextel ceramic fibers. Weight-loss rates for the different composites were assessed as a function of mechanical properties, specimen geometry, fiber sizing, and interfacial bond strength. Differences were observed in rates of weight loss, matrix cracking, geometry dependency, and fiber sizing effects. It was shown that Celion 6000 fiber-reinforced composites do not exhibit a straight-line Arrhenius relationship at temperatures above 316 C.

  16. MS&T'13 Symposium Preview: Metal and Polymer Matrix Composites

    Science.gov (United States)

    Gupta, Nikhil; Paramsothy, Muralidharan

    2013-08-01

    The Metal and Polymer Matrix Composites symposium at Materials Science & Technology 2013 (MS&T'13) conference is planned to provide a platform to researchers working on various aspects of composite materials and capture the state of the art in this area. The dialogue among leading researchers is expected to provide insight into the future of this field and identify the future directions in terms of research, development, and applications of composite materials. In the 2 day program, the symposium includes 34 presentations, including 10 invited presentations. The contributions have come from 16 different countries including USA, Mexico, Switzerland, India, Egypt, and Singapore.

  17. THERMO-MECHANICAL PROPERTIES OF FABRIC REINFORCED COMPOSITES WITH FILED EPOXY MATRIX

    Directory of Open Access Journals (Sweden)

    Igor ROMAN

    2010-10-01

    Full Text Available While the design problem seems to be essential in order to form a high performance composite one may ask more: is it possible to form a material able to give information about its state? Is it possible to control the properties of a composite through alternation of its various layers? Is it possible, finally, to obtain a multifunctional material based on a right design, on a cheap forming technique, on accessible components? This study is about partially answering the above questions. Two types of fiber fabric were used to form composites with filled epoxy matrix and materials bending and thermo-mechanical properties were evaluated using appropriate recommended methods.

  18. An approach for homogeneous carbon nanotube dispersion in Al matrix composites

    International Nuclear Information System (INIS)

    Highlights: • A novel approach was developed on the hot topic of carbon nanotube dispersion in composites. • Homogeneous carbon nanotube dispersion with a large aspect ratio and small damage was obtained. • Strength enhancement by carbon nanotube addition was examined by load transfer mechanism in Al matrix composites. • Al4C3 nano-rods were detected and helpful for load transfer in carbon nanotube/Al composites. - Abstract: Good dispersion of carbon nanotubes (CNTs) was the bottleneck to convert their attractive properties to CNT reinforced composites. In this study, a solution ball milling (SBM) approach was developed to homogeneously disperse CNTs in Al matrix composites (AMCs). The process integrated strategies of solution coating, mechanical ball milling and Al-flake producing into a simple organic unity. The dispersion quality, crystal-structure and strengthening effect of CNTs in AMCs processed by SBM were investigated through scanning electron microscopy, transmission electron microscopy, Raman analysis and tensile tests. Compared with previous methods, the SBM process was simple and effective to obtain a homogeneous CNT dispersion with a large aspect ratio and small CNT damages. Resultantly, the tensile strength of Al matrix was noticeably enhanced by CNT additions agreeing with the potential strengthening effect predicted by the load transfer mechanism

  19. EFFECTS OF MATRIX MOLECULAR WEIGHT ON STRUCTURE AND REINFORCEMENT OF HIGH DENSITY POLYETHYLENE/MICA COMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Li Chen; Yu-fang Xiang; Ke Wang; Qin Zhang; Rong-ni Du; Qiang Fu

    2011-01-01

    Three types of high-density polyethylene (HDPE) with different molecular weights (high, medium and Iow) were adopted to evaluate the influence of matrix molecular weight on the structure-property relation of injection-molded HDPE/mica composites through a combination of SEM, 2d-WAXS, DSC, DMA and tensile testing. Various structural factors including orientation, filler dispersion, interfacial interaction between HDPE and mica, etc., which can impact the macroscopic mechanics, were compared in detail among the three HDPE/mica composites. The transcrystallization of HDPE on the mica surface was observed and it exhibited strong matrix molecular weight dependence. Obvious transcrystalline structure was found in the composite with Iow molecular weight HDPE, whereas it was hard to be detected in the composites with increased HDPE molecular weight. The best reinforcement effect in the composite with low molecular weight HDPE can be understood as mainly due to substantially improved interracial adhesion between matrix and mica filler, which arises from the transerystallization mechanism.

  20. A micro-Raman study of Cu-particulate-filled epoxy matrix composites

    Directory of Open Access Journals (Sweden)

    S. Tognana

    2014-05-01

    Full Text Available A micro-Raman study is carried out to investigate the influence of the filler on the curing process of bisphenol A diglycidyl ether (DGEBA-based epoxy matrix composites. The composites are cured (14 h at 393 K with an anhydride (methyl tetrahydro phthalic anhydride, MTHPA, 100:90 pbw, catalyzed with a tertiary amine (0.7 pbw and filled with a 30% volume of Cu particles of approximately 75 µm in diameter. The experimental results are compared with those obtained for the same epoxy resin unfilled and for the same composite with Cu filler but not catalyzed. The micro-Raman experimental technique is used to search for information on the curing process in different regions of the matrix, near to and far from the copper filler, taking into account the results of differential-scanning-calorimetry measurements performed on the same composites. The results provide information on the influence of the copper filler on the curing process of the epoxy matrix. Differences were observed in the peaks associated with the epoxy ring and the ester group as a function of the distance to the nearest copper particle, but no differences were observed between the different composites.

  1. 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.

  2. Extracellular matrix stiffness and composition jointly regulate the induction of malignant phenotypes in mammary epithelium

    Science.gov (United States)

    Chaudhuri, Ovijit; Koshy, Sandeep T.; Branco da Cunha, Cristiana; Shin, Jae-Won; Verbeke, Catia S.; Allison, Kimberly H.; Mooney, David J.

    2014-10-01

    In vitro models of normal mammary epithelium have correlated increased extracellular matrix (ECM) stiffness with malignant phenotypes. However, the role of increased stiffness in this transformation remains unclear because of difficulties in controlling ECM stiffness, composition and architecture independently. Here we demonstrate that interpenetrating networks of reconstituted basement membrane matrix and alginate can be used to modulate ECM stiffness independently of composition and architecture. We find that, in normal mammary epithelial cells, increasing ECM stiffness alone induces malignant phenotypes but that the effect is completely abrogated when accompanied by an increase in basement-membrane ligands. We also find that the combination of stiffness and composition is sensed through β4 integrin, Rac1, and the PI3K pathway, and suggest a mechanism in which an increase in ECM stiffness, without an increase in basement membrane ligands, prevents normal α6β4 integrin clustering into hemidesmosomes.

  3. Computed tomography evaluation of metal-matrix composites for aeropropulsion engine applications

    Energy Technology Data Exchange (ETDEWEB)

    Yancey, R.N. (Advanced Research and Applications Corp., Dayton, OH (United States)); Baaklini, G.Y. (NASA, Cleveland, OH (United States). Lewis Research Center)

    1994-07-01

    Computed tomography (CT) is a powerful evaluation tool for advanced propulsion engine materials and components. CT uses x-rays nondestructively to produce images of two-dimensional slices or planes through an object. This paper presents data from CT investigations of metal-matrix composite (MMC) ring, rod, and coupon structures. Moderate resolution CT data identified density variations within reinforced sections, which were correlated with fiber packing densities. Also, some composite lay-up features were also imaged. High-resolution CT data provided information on fiber spacing and distribution. Correlation with other NDE techniques and destructive analysis was good. CT proved to provide valuable information on the internal state of these metal-matrix composite components. Use of CT during process development of MMCs and the components made from MMCs is encouraged given the results of this study.

  4. Electroless plating Ni-P matrix composite coating reinforced by carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    邓福铭; 陈小华; 陈卫祥; 李文铸

    2004-01-01

    Ni-P matrix composite coating reinforced by carbon nanotubes (CNTs) was deposited by electroless plating. The most important factors that influence the content of carbon nanotubes in deposits, such as agitation, surfactant and carbon nanotubes concentration in the plating bath were investigated. The surface morphology, structure and properties of the Ni-P-CNTs coating were examined. It is found that the maximum content of carbon nanotubes in the deposits is independent of carbon nanotubes concentration in the plating bath when it is up to 5 mg/L. The test results show that the carbon nanotubes co-deposited do not change the structure of the Ni-P matrix of the composite coating, but greatly increase the hardness and wear resistance and decrease the friction coefficient of the Ni-PCNTs composite coating with increasing content of carbon nanotubes in deposits.

  5. Numerical Simulation of Particle/Matrix Interface Failure in Composite Propellant

    Institute of Scientific and Technical Information of China (English)

    常武军; 鞠玉涛; 韩波; 胡少青; 王政时

    2012-01-01

    Interface debonding between particle and matrix in composite propellant influences its macroscopic mechanical properties greatly. For this, the laws of interface cohesive damage and failure were analyzed. Then, its microscopic computational model was established. The interface mechanical response was modeled by the bitinear cohesive zone model. The effects of interface properties and particle sizes on the macroscopic mechanical behavior were investigated, Numerical simu- lation of debonding damage evolution of composite propellant under finite deformation was carried out. The debonding damage nucleation, propagation mechanism and non-uniform distribution of microscopic stress-strain fields were discussed. The results show that the finite element simulation method based on microstructure model can effectively predict the trend of macroscopic mechanical behavior and particle/matrix debonding evolution process. It can be used for damage simulation and failure assessment of composite propellants.

  6. Hot deformation behavior and microstructure evaluation of hydrogenated Ti-6Al-4V matrix composite

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Junqiang; Qin, Jining; Lu, Weijie; Chen, Yifei; Zhang, Di [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240 (China); Hou, Hongliang [Beijing Aeronautical Manufacturing Technology Research Institute, Beijing 100024 (China)

    2009-11-15

    Ti-6Al-4V matrix composite reinforced with TiB and TiC particulates was prepared and hydrogenated. Isothermal compression tests were carried out at the deformation temperatures ranging from 750 C to 900 C and strain rate ranging from 0.01 s{sup -1} to 1 s{sup -1}. The effects of hydrogen concentration, deformation temperature and strain rate on flow stress-strain curves and microstructure evaluation were studied. Hydrogen decreases the deformation temperature at least 100 C or enables the composite to deform at a higher strain rate at the same flow stress level. Hydrogen improves dynamic recrystallization of {alpha} phase and accommodation deformation between reinforcements and matrix. Optimum hydrogen concentrations at different deformation temperatures were determined. The strain rate sensitivity index and apparent activation energy of the composite with 0 wt.% H and 0.35 wt.% H were calculated and discussed. (author)

  7. 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.

  8. 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.

  9. Micromechanics Fatigue Damage Analysis Modeling for Fabric Reinforced Ceramic Matrix Composites

    Science.gov (United States)

    Min, J. B.; Xue, D.; Shi, Y.

    2013-01-01

    A micromechanics analysis modeling method was developed to analyze the damage progression and fatigue failure of fabric reinforced composite structures, especially for the brittle ceramic matrix material composites. A repeating unit cell concept of fabric reinforced composites was used to represent the global composite structure. The thermal and mechanical properties of the repeating unit cell were considered as the same as those of the global composite structure. The three-phase micromechanics, the shear-lag, and the continuum fracture mechanics models were integrated with a statistical model in the repeating unit cell to predict the progressive damages and fatigue life of the composite structures. The global structure failure was defined as the loss of loading capability of the repeating unit cell, which depends on the stiffness reduction due to material slice failures and nonlinear material properties in the repeating unit cell. The present methodology is demonstrated with the analysis results evaluated through the experimental test performed with carbon fiber reinforced silicon carbide matrix plain weave composite specimens.

  10. Interface Stability of the SiC Particles/Fe Matrix Composite System

    Institute of Scientific and Technical Information of China (English)

    TANG Wenming; ZHENG Zhixiang; WU Yucheng; JIN Zhihao

    2006-01-01

    The interface reaction between the SiC particles (SiCp) and Fe was studied during sintering the SiCp reinforced Fe matrix composites at 1423 K for 1 h. In the composite having 3wt% (weight ratio) SiCp (the 3SiCp/Fe composite), the interface reaction products of Fe3Si, the carbon precipitates, and Fe3C or pearlite were generated. Fe3Si constructs the bright matrix of the reaction zone in the original situation of the SiCp. The carbon precipitates are randomly embedded in the reaction zone. Fe3C or pearlite exists at the grain boundaries of the Fe matrix. As increasing the SiCp concentration in the SiCp/Fe composite, the intensity of the interface reaction between SiCp and Fe increases. After the 10SiCp/Fe composite (having 10wt.% SiCp) sintered at 1423 K for 1 h, all of SiCp are decomposed, and replaced by the reaction zone composed of Fe3Si and the carbon precipitates. No Fe3C or pearlite was generated during the reaction. The effects of the techniques of oxidizing of SiCp, coating SiCp by interaction with the Cr powder, and alloying the Fe matrix by adding the Cr element on the interface stability of the SiCp/Fe composite system were also investigated, respectively. The oxide membrane and the coating layer on SiCp can inhibit the interface reaction between SiCp and Fe by isolating SiCp from the Fe matrix during sintering. The interface reaction does not occur in the 3SiCp/Fe-10Cr composite but in the 3SiCp/Fe-5Cr composite. In the SiCp/Fe-Cr alloy composites, the interface reaction between SiCp and the Fe-Cr alloys is weaker than that between SiCp and Fe. The Cr element behaves as a diluent, it causes a reduction in the interface reaction, which is proportional to the amount of the element added.

  11. Texture and residual strain in SiC/Ti-6-2-4-2 titanium matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Rangaswamy, P.; Bennett, K.; Bourke, M.A.M.; Dreele, R. von; Roberts, J.A. [Los Alamos National Lab., NM (United States). Manuel Lujan Jr. Neutron Scattering Center; Jayaraman, N. [Univ. of Cincinnati, OH (United States). Dept. of Materials Science and Engineering

    1997-11-01

    Residual strain and texture variations were measured in two Titanium matrix composites reinforced with Silicon Carbide fibers (Ti/SiC) having the same composition but fabricated by dramatically different processing routes. In both specimens the Titanium matrix comprised an {alpha}/{beta} alloy (Ti-6242) containing approximately 35% by volume of continuous SiC fibers. In one case the matrix was produced by a plasma spray (PS) route and the other by a wire drawing (WD) process. The resulting textures in the matrix differ significantly, from approximately random for the PS matrix to 6.25X random in the WD matrix. No significant differences in matrix residual strains between the composites prepared by the two procedures were noted. Plane-specific elastic moduli, measured in load tests on the unreinforced matrices also showed little difference.

  12. Evaluation of interfacial bonding in dissimilar materials of YSZ-alumina composites to 6061 aluminium alloy using friction welding

    International Nuclear Information System (INIS)

    Research highlights: → Friction-welding process. → Joining between ceramic composite and metal alloy. → Slip casting of the yttria stabilized zirconia/alumina composite samples. - Abstract: The interfacial microstructures characteristics of alumina ceramic body reinforced with yttria stabilized zirconia (YSZ) was evaluated after friction welding to 6061 aluminum alloy using optical and electron microscopy. Alumina rods containing 25 and 50 wt% yttria stabilized zirconia were fabricated by slip casting in plaster of Paris (POP) molds and subsequently sintered at 1600 deg. C. On the other hand, aluminum rods were machine down to the required dimension using a lathe machine. The diameter of the ceramic and the metal rods was 16 mm. Rotational speeds for the friction welding were varied between 900 and 1800 rpm. The friction pressure was maintained at 7 MPa for a friction time of 30 s. Optical and scanning electron microscopy was used to analyze the microstructure of the resultant joints, particularly at the interface. The joints were also examined with EDX line (energy dispersive X-ray) in order to determine the phases formed during the welding. The mechanical properties of the friction welded YSZ-Al2O3 composite to 6061 alloy were determined with a four-point bend test and Vickers microhardness. The experimental results showed the degree of deformation varied significantly for the 6061 Al alloy than the ceramic composite part. The mechanical strength of friction-welded ceramic composite/6061 Al alloy components were obviously affected by joining rotational speed selected which decreases in strength with increasing rotational speed.

  13. Measurement of Interfacial Porosity and Finite Element Ana lysis of Stress Distribution in Al2O3-Fiber-Reinforced Aluminium Alloy Composites%Al2O3纤维增强Al合金复合材料界面孔隙率测定及复合材料应力分布有限元计算

    Institute of Scientific and Technical Information of China (English)

    陈志武; 张喜燕; 张继红

    2001-01-01

    利用挤压铸造法制备了Al2O3纤维增强Al合金复合材料,对其界面孔隙率进行了测定,结合拉伸强度数据,讨论孔隙率对复合材料强度的影响;并通过有限元计算,分析了与拉伸轴平行、成45°及与拉伸轴垂直的3种纤维模型,得出纤维、基体、界面处应力分布。%Al2O3-fiber-reinforced aluminium alloy composites were preparedusing squeeze cast method, and porosity of the composites was me asured. The influence of the porosity on tensile strength of the composites is discussed. Three models of the composites (fiber being parallel, perpendicular and at an angle of 45° to tensile axis) are analyzed using finite element, and the stress distribution in fiber, matrix and at interface are discussed in detail.

  14. Dynamic nanomechanics of individual bone marrow stromal cells and cell-matrix composites during chondrogenic differentiation.

    Science.gov (United States)

    Lee, BoBae; Han, Lin; Frank, Eliot H; Grodzinsky, Alan J; Ortiz, Christine

    2015-01-01

    Dynamic nanomechanical properties of bovine bone marrow stromal cells (BMSCs) and their newly synthesized cartilage-like matrices were studied at nanometer scale deformation amplitudes. The increase in their dynamic modulus, |E(*)| (e.g., 2.4±0.4 kPa at 1 Hz to 9.7±0.2 kPa at 316 Hz at day 21, mean±SEM), and phase angle, δ, (e.g., 15±2° at 1 Hz to 74±1° at 316 Hz at day 21) with increasing frequency were attributed to the fluid flow induced poroelasticity, governed by both the newly synthesized matrix and the intracellular structures. The absence of culture duration dependence suggested that chondrogenesis of BMSCs had not yet resulted in the formation of a well-organized matrix with a hierarchical structure similar to cartilage. BMSC-matrix composites demonstrated different poro-viscoelastic frequency-dependent mechanical behavior and energy dissipation compared to chondrocyte-matrix composites due to differences in matrix molecular constituents, structure and cell properties. This study provides important insights into the design of optimal protocols for tissue-engineered cartilage products using chondrocytes and BMSCs. PMID:25468666

  15. Enhancement of wear and ballistic resistance of armour grade AA7075 aluminium alloy using friction stir processing

    Directory of Open Access Journals (Sweden)

    I. Sudhakar

    2015-03-01

    Full Text Available Industrial applications of aluminium and its alloys are restricted because of their poor tribological properties. Thermal spraying, laser surfacing, electron beam welding are the most widely used techniques to alter the surface morphology of base metal. Preliminary studies reveal that the coating and layering of aluminium alloys with ceramic particles enhance the ballistic resistance. Furthermore, among aluminium alloys, 7075 aluminium alloy exhibits high strength which can be compared to that of steels and has profound applications in the designing of lightweight fortification structures and integrated protection systems. Having limitations such as poor bond integrity, formation of detrimental phases and interfacial reaction between reinforcement and substrate using fusion route to deposit hard particles paves the way to adopt friction stir processing for fabricating surface composites using different sizes of boron carbide particles as reinforcement on armour grade 7075 aluminium alloy as matrix in the present investigation. Wear and ballistic tests were carried out to assess the performance of friction stir processed AA7075 alloy. Significant improvement in wear resistance of friction stir processed surface composites is attributed to the change in wear mechanism from abrasion to adhesion. It has also been observed that the surface metal matrix composites have shown better ballistic resistance compared to the substrate AA7075 alloy. Addition of solid lubricant MoS2 has reduced the depth of penetration of the projectile to half that of base metal AA7075 alloy. For the first time, the friction stir processing technique was successfully used to improve the wear and ballistic resistances of armour grade high strength AA7075 alloy.

  16. Enhancement of wear and ballistic resistance of armour grade AA7075 aluminium alloy using friction stir processing

    Institute of Scientific and Technical Information of China (English)

    I. SUDHAKAR; V. MADHU; G. MADHUSUDHAN REDDY; K. SRINIVASA RAO

    2015-01-01

    Industrial applications of aluminium and its alloys are restricted because of their poor tribological properties. Thermal spraying, laser surfacing, electron beam welding are the most widely used techniques to alter the surface morphology of base metal. Preliminary studies reveal that the coating and layering of aluminium alloys with ceramic particles enhance the ballistic resistance. Furthermore, among aluminium alloys, 7075 aluminium alloy exhibits high strength which can be compared to that of steels and has profound applications in the designing of lightweight fortification structures and integrated protection systems. Having limitations such as poor bond integrity, formation of detrimental phases and interfacial reaction between reinforcement and substrate using fusion route to deposit hard particles paves the way to adopt friction stir processing for fabricating surface composites using different sizes of boron carbide particles as reinforcement on armour grade 7075 aluminium alloy as matrix in the present investigation. Wear and ballistic tests were carried out to assess the performance of friction stir processed AA7075 alloy. Significant improvement in wear resistance of friction stir processed surface composites is attributed to the change in wear mechanism from abrasion to adhesion. It has also been observed that the surface metal matrix composites have shown better ballistic resistance compared to the substrate AA7075 alloy. Addition of solid lubricant MoS2 has reduced the depth of penetration of the projectile to half that of base metal AA7075 alloy. For the first time, the friction stir processing technique was successfully used to improve the wear and ballistic resistances of armour grade high strength AA7075 alloy.

  17. Improvement of thermal conductivity of ceramic matrix composites for 4. generation nuclear reactors

    International Nuclear Information System (INIS)

    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)

  18. 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.

  19. Mechanical properties of several neat polymer matrix materials and unidirectional carbon fiber-reinforced composites

    Science.gov (United States)

    Coguill, Scott L.; Adams, Donald F.

    1989-01-01

    The mechanical and physical properties of three neat matrix materials, i.e., PEEK (polyetheretherketone) thermoplastic, Hexcel F155 rubber-toughened epoxy and Hercules 8551-7 rubber-toughened epoxy, were experimentally determined. Twelve unidirectional carbon fiber composites, incorporating matrix materials characterized in this or earlier studies (with one exception; the PISO(sub 2)-TPI matrix itself was not characterized), were also tested. These composite systems included AS4/2220-1, AS4/2220-3, T500/R914, IM6/HX1504, T300/4901A (MDA), T700/4901A (MDA), T300/4901B (MPDA), T700/4901B (MPDA), APC2 (AS4/PEEK, ICI), APC2 (AS4/PEEK, Langley Research Center), AS4/8551-7, and AS4/PISO(sub 2)-TPI. For the neat matrix materials, the tensile, shear, fracture toughness, coefficient of thermal expansion, and coefficient of moisture expansion properties were measured as a function of both temperature and moisture content. For the unidirectional composites, axial and transverse tensile, longitudinal shear, coefficient of thermal expansion, and coefficient of moisture expansion properties were determined, at room temperature and 100 C.

  20. Matrix Resin Characterization in Cured Graphite Composites Using Diffuse Reflectance-Ftir

    Science.gov (United States)

    Young, P. R.; Chang, A. C.

    1984-01-01

    The chemical characterization of cured graphite fiber reinforced polymer matrix composites is complicated by the fact that the resins are insoluble and the composites are apaque. Standard analyses which depend either on the ability to dissolve the sample or to detect transmitted radiation are impossible. As a result, data reported on environmentally exposed composites primarily concern macroscopic information such as weight loss or changes in selected mechanical properties. Diffuse reflectance in combination with fourier transform infrared spectroscopy was developed to gain a basic chemical understanding of composite and adhesive behavior. Several composite and adhesive materials were characterized before and after environmental exposure. In each case significant changes in resin molecular structure were observed and correlated with changes in mechanical properties, providing new insights into material performance.