Carbon Fiber Reinforced Metal Matrix Research Articles

Highly thermal conductive Csf/Mg composites by in-situ constructing the unidirectional configuration of short carbon fibers

Lightweight, low cost, and high thermal conductivity (TC) are crucial targets for thermal management material development. Short carbon fiber reinforced metal matrix composites (MMCs) have attracted extensive attention due to the aforementioned superiorities. Despite compositing short carbon fibers capable of improving the TC of metals to a certain extent, the enhancement efficiency is not satisfactory till now due to the significant anisotropy of fibers. Inspired by the pressure stacking phenomenon of short fibers and using an independently designed preform-forming mold, combined with the Liquid-solid extrusion following vacuum infiltration (LSEVI) technique, we propose a novel technique that could in situ construct the short carbon fiber unidirectional configuration in the AZ91D matrix. According to micro-CT test results and using image processing technology, the high TC of 106.7 W/mK was achieved due to the highly aligned short carbon fibers, which is equivalent to 122.2% enhancement compared to the AZ91D matrix. And the specific TC enhancement efficiency (σ) is significantly higher than that of the prior reports. Furthermore, the short carbon fiber reinforced magnesium (Csf/Mg) composites possess excellent heat conduction capacity compared to the AZ91D magnesium alloy, according to the thermal management capability test experiment. Our results not only chalk up a record value σ for short carbon fiber reinforced MMCs, but also provide a road map for future employing the Csf/Mg composites in the field of thermal management.

Micro-debond Experiment and Analytical Model for Interfacial Fracture Toughness between Single Carbon Fiber and TiO2 Micro-droplet

To improve mechanical behaviors of the carbon fiber-reinforced metal matrix composites, TiO2-coated carbon fibers are usually used in the composites to protect the fiber from degradation. Thus, it is crucial to maintain both strong interfacial bonding at carbon fiber–TiO2 interlayer interface and high interfacial fracture toughness, which influence the damage tolerance of the composites as well as their energy absorption capacity. In this study, different single carbon fiber/TiO2 systems with and without modified carbon fiber were prepared at heat treatment temperatures of 80 and 700 °C, respectively, and an analytical modeling for evaluating interfacial fracture toughness from the micro-debond tests by using the tests that record only the debond and friction force as a function of the TiO2 micro-droplet length was implemented first, and then, the interfacial adhesion forces, interfacial fracture toughness and the influence of friction force and thermal residual stress on the fracture toughness of the systems were discussed in detail. From the experimental and theoretical results, heat treatment temperature and local strong bonding sites have a significant effect on the interfacial fracture toughness, while the interfacial morphology and functional groups are dominant in determining the interfacial adhesion forces. Meanwhile, the dominant factor of the interfacial fracture toughness will change as the heat treatment temperature increases. The friction force is a major contributor to the interfacial fracture toughness of the systems treated under lower temperature (80 °C), while the residual thermal stress is responsible for the toughness of the systems treated under higher temperature (700 °C). The results in this study can serve as reliable input data in multi-scale simulation of the carbon fiber-reinforced light metal matrix composites and offer exciting opportunities for further investigation of the microscopic deformation mechanisms in the composites.

Carbon Fibre Reinforced Composite Material: Review of Properties and Processing for various Metal Matrix Materials

Carbon Fibres (CF) are used as a reinforcing material from past few decades. Carbon Fibres are reinforced in Metal matrix composites (MMC), Ceramic matrix composites (CMC) & polymer matrix composites (PMC). Numerous Research work was done on Carbon Fiber Reinforced Polymer Composites (CFRP), but Carbon Fiber Reinforced Metal Matrix Composites (CFMMC) & Carbon Fiber Reinforced Ceramic Matrix Composites (CF-CMC) have wide scope to explore. This Paper reviews effect of Carbon Fibre reinforcement on Mechanical, Tribological and Morphological Properties of various Metal Matrix Materials. This paper also presents various processing techniques of Carbon Fibre Reinforced Composite Material.

STUDIES OF IMPRESSION CREEP BEHAVIOR OF ALUMINUM (7079) BASED CARBON FIBER REINFORCED METAL MATRIX COMPOSITES

This current work aims to is to assess the impression creep behavior of Aluminum based Carbon Fiber reinforced Metal Matrix Composites for three different temperature namely, room temperature, 100oC and 200oC under a constant load of 2 Kg and to find the steady-state creep rates and creep mechanism occurring. In this test, a cylindrical indenter with a flat end is allowed under the action of stress to make a shallow impression on the surface of the specimen. Penetration depth at given stress is measured as a function of time to obtain an impression creep curve. At constant stress similarity can be seen between impression creep curve and normal creep curve. The same procedure is repeated for different temperature conditions. The impression creep curve explains creep characteristics of the specimens. Four different grade carbon specimens are used for testing. Deflection readings are noted for a time interval of 30 seconds. Impression creep curve will be plotted to find the creep behavior.

Electroless carbon fibers: A new route for improving mechanical property and wettability of composites

For carbon fiber reinforced metal matrix composites, there are many potential problems such as severe agglomeration of carbon fibers (CFs), their poor interfacial wettability with the matrix, and poor mechanical strength. To solve these problems, we proposed to use electroless plating to coat a layer of Ni onto the CFs, and then studied their interfacial structures, fracture strain/strength and wettability. The coated Ni layer was uniformly distributed onto and well bonded with the CFs. The maximum strain of the CFs coated with the Ni layer was increased by 23.4%, though their average fracture strength was slightly decreased from 3.5 GPa to 2.25 GPa. The wettability of the Ni-coated fiber was significantly improved, verified from testing results using both a dip coating method and a fiber reinforced composite simulation test.

Application of Composite Materials in Engine

This paper analyzes the technical and demand problems of the current automotive and aviation engines, andintroduces the applications of carbon fiber reinforced metal matrix composites and resin matrix composites in thepiston and connecting rods of automobile engines. Composite materials and ceramic matrix composites on civilaircraft engines, as well as composite materials and composites in military aerospace engines (solid rocket motors andtranscendental ramjet) applications, and some of the composite materials The application raises key questions andsuggestions.

Effect of Coating Parameters on Coating Rate of Carbon Fibers by Electroless Nickel Plating

The coating quality of nickel is important factor in improvement of wettability of carbon fibers to be used as reinforcing material in the production of carbon fiber reinforced metal matrix composites. In this research work, Polyacrylonitile (PAN) based carbon fibers have been Ni coated in Sodium hypophosphite reduced acidic bath by electroless plating method. These carbon fibers are coated using 4, 4.5, 5 and 5.5 pH values for 5, 10, 15, 20, 25 and 30minutes. Coating thickness is found to increase with time linearly. Nickel deposition rate per unit time increases with pH, however it reaches a maxima and then declines. The surface condition of fibers reveals that coating becomes more and more rough due to non uniform coating, as coating time and pH goes on increasing.

Tribological characteristics of innovative Al6061–carbon fiber rod metal matrix composites

Rods made of continuous carbon fibers are being extensively used as structural materials in light weight micro-air vehicles owing to their excellent specific modulus and strength. Further, they possess excellent tribological characteristics – low friction and wear coupled with high conductivity making them an ideal reinforcement in developing light weight, high strength aluminum based metal matrix composites. In the last three decades, researchers have focused mainly on the study of mechanical and tribological behavior of discontinuous carbon fiber reinforced metal matrix composites. However, no information is available regarding the tribological behavior of carbon fibers rod reinforced metal matrix composites, although it is interesting and will result in expanding the applications of metal matrix composites (MMC) where tribological failures are expected.In the light of the above, the present work focuses on development of innovative Al6061–carbon fiber rods composites by casting route and assessing their tribological characteristics. Carbon fiber rods of 4mm and 6mm diameters were surface sensitized to achieve electro less nickel coating. Copper plating on the electro less nickel coated carbon fiber rods were carried out. The copper plated carbon fiber rods were arranged in cylindrical array in the metallic mold to which molten Al6061 alloy after degassing was poured at a temperature of 700°C. The developed innovative composites were subjected to density tests, microstructure studies, hardness, friction and wear tests. A pin on disk configuration was used with hardened steel as the counter face. Load was varied from 20N to 60N while the sliding velocity was varied between 0.12m/s and 0.62m/s. Scanning electron microscopy (SEM) studies on worn surfaces and wear debris have been carried out to validate the wear mechanism. The developed innovative composites (11Vol.% & 25Vol.%) have exhibited lower coefficient of friction and wear rates when compared with matrix alloy.

Fluidity and Mechanical Properties of Open Cell AZ31 Mg Alloy Foam

Abstract 발포금속은 초경량 재료로서 폐기공과 개기공의 두 가지 형태의 구조를 지니고 있으며 폐기공은 내충격성, 흡음성, 단열성의 기능을 지니고 있고, 개기공은 필터, 생체지지대, 촉매재, 열방출재 등으로 사용되고 있다. 개기공발포재는 삼차원구조모양으로 프리커서를 이용한 압력정밀주조나 기공입자용출법으로 제조하고 있으나 기공의 크기나 셀의 형상, 두께 등을 조절하기에 어려움이 있다. 이를 해결하기 위하여 환경친화적인 펄라이트를 사용하여 목적하는 크기의 그래뉼을 제조한 후, 용융마그네슘합금을 감압주조법으로 주조하여 그래뉼의 크기로 기공율을 조절하고, 주형의 온도와 압력에 따른 유동의 길이를 측정하였다. 그래뉼 직경이 2.3 mm ∅ 일때에 주형의 온도300 o C 이상, 압력이 5000 Pa 이상에서 유동길이6.5 cm이상을 얻었다.Key words: Open-cell foam, Metal foam, Mg alloy, Gravity casting method, Infiltration, Fluidity.(Received March 23, 2012 ; Accepted June 22, 2012) 1. Introduction Metal foam is revolutionary materials that exhibitdifferent attractive characteristics when compared to theirsolid material counterparts [1]. The pores can be sealed(closed-cell foam), or they can form an interconnectednetwork (open-cell foam). Open-cell metal foam is a newclass of materials with low densities and novel physical,mechanical, thermal, electrical, and acoustic properties[2,3]. They offer potential for thermal management, catalystsupport, filtration, steam generation, energy absorption,acoustic absorption, and filters. Al and Al alloy foams havebeen developed successfully and have been employed inthe new generation of crash boxes. Mg and Mg alloy foamsare denitely expected to be particularly advantageous due tolower densities of their metal matrix, which are approximatelytwo thirds that of Al and good mechanical properties [4,5].Many methods for their manufacture, characterization andapplication are being developed [6,7]. In this research, weused investment casting method. It was simple and low costto cast by vacuum pump. A. Jinnapat and A. Kennedy studied on open cell Al foamsmade by infiltration molten al into porous salt [8]. M. Grohnand C. Hintz. investigated determination of parameters ofinfiltrated metallic foam composites. The open cell structurereticulated polyurethane foams were used [9]. I. N. Orbulov,A. Nemeth and J. Dobranszky carried out composite produc-tion made by pressure infiltration. Open cell foams, syntacticfoams and carbon fiber reinforced metal matrix compositeswere produced by pressure infiltration method [10]. Fluidity isan important factor for the successful production of castings,and yet the study on the fluidity of open cell AZ31 Mg alloyfoam is empty in the world [11]. So in the present work, experiments were performed in orderto determine the importance of parameters on fluidity of opencell AZ31 alloy metal foam. The inuence of characteristic wasinvestigated along with the inuence of vacuum assistance andthe preheat temperatures of mould. The mechanical propertiesand energy absorption were investigated and discussed.

Electrochemical Properties of NiCl2 ‐ Intercalated and Reduced ‐ NiCl2 ‐ Intercalated Graphite

The feasibility of modifying graphite, by intercalation, to reduce galvanic reactions in carbon fiber reinforced metal matrix composites is investigated. A nickel chloride intercalation compound and a reduced nickel chloride intercalation compound were prepared, and their electrochemical properties studied in deaerated 0.1 N . The open‐circuit potential of is about 0.500 V more positive than that of natural graphite while that of is about 700 V more negative than that of natural graphite. In the latter case, the potential difference relative to aluminum is reduced by about 50%. Distinct changes in the cathodic behavior of graphite upon intercalation and reduction are also observed. Results are discussed in terms of the effects of these changes on galvanic interactions with aluminum alloy Al 6061‐T6.

4737382 Carbide coatings for fabrication of carbon-fiber-reinforced metal matrix composites

A carbon fiber reinforced metal matrix composite is produced by carbide coating the surface of the fibers by passing the fibers through an organometallic solution followed by pyrolysis of the organometallic compounds. The carbide coated fibers, so produced are readily wettable without degradation when immersed in a molten bath of metal matrix material containing an active alloying element.

Interface characterization of metal matrix composites by transmission electron microscopy

Carbon fiber reinforced metal matrix composites (MMC's) are an attractive class of materials for automotive and aerospace structural applications because of their high strength and stiffness to weight ratios and their low coefficients of thermal expansion. Successful development of these new materials demands a thorough understanding of the structure/property/processing relationships and, in particular, a detailed understanding of the fiber/matrix interface since this region strongly influences the final mechanical properties of the system. This interface is affected by many factors including the manufacturing method, heat treatment, matrix alloy composition and wettability of the fibers but, since it is a region which is typically much less than lμm wide, it is inaccessible to direct detailed observation by any means other than transmission electron microscopy.

TEM observations of a Ni-coated carbon fiber reinforced metal matrix composite

TEM observations of a Ni-coated carbon fiber reinforced metal matrix composite