Carbon Fiber Reinforced Aluminum Matrix Research Articles

Microstructure of a carbon fiber-reinforced aluminum matrix composite fabricated by spark plasma sintering in various pulse conditions

Carbon fiber-reinforced aluminum composites were produced by spark plasma sintering in various pulse conditions. The pulse condition of spark plasma sintering affected the aluminum particle boundaries and aluminum/carbon fiber interfaces; the different fracture morphologies of aluminum oxide were observed on aluminum particles and interfacial aluminum carbide formation. We demonstrated the control of the quantity of aluminum carbide crystals by the alteration of pulse conditions. Finally, we propose the mechanism of local temperature increase in the spark plasma sintering process.

Continuous Carbon Fiber Reinforced Aluminum Matrix Composites - A Review

The physical and mechanical properties that can be obtained with metal matrix composites (MMCs) have made them attractive candidate materials for aerospace, automotive and numerous other applications. In this paper, the current fabrication methods of continuous fiber reinforced aluminum matrix composites are briefly described.

Effect of specific pressure on fabrication of 2D-Cf/Al composite by vacuum and pressure infiltration

Carbon fiber reinforced aluminum matrix (Cf/Al) composite has many excellent properties, and it has received more and more attention. Two-dimensional (2D) Cf/Al composites were fabricated by vacuum and pressure infiltration, which was an integrated technique and could provide high vacuum and high infiltration pressure. The effect of specific pressure on the infiltration quality of the obtained composites was comparatively evaluated through microstructure observation. The experimental results show that satisfied Cf/Al composites could be fabricated at the specific pressure of 75 MPa. In this case, the preform was infiltrated much more completely by aluminum alloy liquid, and the residual porosity was seldom found. It is found that the ultimate tensile strength of the obtained Cf/Al composite reached maximum at the specific pressure of 75 MPa, which was improved by 138.9% compared with that of matrix alloy.

Fabrication of Continuous Nickel-Coated Carbon Fiber Reinforced Aluminum Matrix Composites Using Low Gas Pressure Infiltration Method

Based on the principle of vacuum counter-pressure casting, a low gas pressure infiltration technology was developed to fabricate the Ni-coated carbon fiber reinforced A357 alloy composites. The soundness and microstructure of the as-cast composites were investigated. The results show the relative density increases with the increase of melt temperature, while it firstly increases and then declines as the fiber temperature and infiltration pressure increased. The enhancement of melt and fiber temperature can eliminate the incomplete infiltration defects and improve the uniformity of fiber distribution. The insufficient infiltration pressure leads to some micro-pores in the matrix alloy. However, the over high fiber temperature and infiltration pressure may result in the separation of nickel coating and the fiber aggregation respectively, both of which are responsible for the partial un-infiltrated or insufficient filling defects. The appropriate infiltration parameters identified in this study could provide a reference for inhibition of the hazard interfacial reactions by optimizing the low gas pressure infiltration process.

Fabrication of carbon fiber reinforced aluminum matrix composites via a titanium-ion containing flux

Here we show that carbon fiber (CF) reinforced aluminum (Al) matrix composite with homogenously dispersed (57±11 vol.%) carbon fibers can be fabricated without any external pressure, although usually some external pressure is needed to fabricate such composites due to their non-wetting character. CFs were transferred into liquid Al using a special flux (molten salt), containing K2TiF6 dissolved in NaCl–KCl. This flux ensures the removal of oxides from the interfaces and the formation of a wettable TiC layer at the interfaces. The oxide-free and in situ TiC-coated CF showed perfect wettability by the de-oxidized liquid Al under the same flux, and thus the composite was formed in a spontaneous way, i.e. without applying any external pressure or mixing.

Modification Process of Carbon Fiber Reinforcement for Aluminum Matrix Composite

Modification process of carbon fiber reinforcement was investigated so as to produce aluminum matrix composite on a large scale. A series of pretreatment technologies could acquire chemical deposition silver, which became the base of copperplating on the surface of carbon fibers. The optimum conditions of electroless plating copper, including components, adding amount of carbon fibers, temperature, pH value, and mixing method, were determined to obtain a perfect copper layer on the surface of carbon fibers. The control of copper deposition and repeating utilization of many technology solutions were realized to reduce the costs. The results laid a foundation of mass production for carbon fiber reinforced aluminum matrix composite.

Preparation and Characterization of Carbon Fibre Reinforced Aluminium Matrix Composite

Driven by the increasing requirements from aircraft producers, aluminium alloy matrix composites with carbon fiber reinforcement have been largely used in the modern industry. The method of traditional preparation of carbon fiber reinforced aluminum matrix composites is not only high cost and complex to produce but also difficult to apply in the civilian. The present paper focuses on exploratory study on the preparation of carbon-fiber- reinforced aluminum composites, the intensifying material is continuous long carbon fiber. In order to avoid any interfacial reactions in the carbon fiber reinforced composites, the carbon fibers were coated with copper. We made The tensile samples were made by using the mould, the tensile properties determined, the strengthening mechanism studied, and the carbon fiber in the matrix observed with the microscope.

Interface and thermal expansion of carbon fiber reinforced aluminum matrix composites

Two kinds of unidirectional PAN M40 carbon fiber (55%, volume fraction) reinforced 6061Al and 5A06Al composites were fabricated by the squeeze-casting technology and their interface structure and thermal expansion properties were investigated. Results showed that the combination between aluminum alloy and fibers was well in two composites and interface reaction in M40/5A06Al composite was weaker than that in M40/6061Al composite. Coefficients of thermal expansion (CTE) of M40/Al composites varied approximately from (1.45–2.68)×10 −6 K −1 to (0.35–1.44)×10 −6 K −1 between 20 °C and 450 °C, and decreased slowly with the increase of temperature. In addition, the CTE of M40/6061Al composite was lower than that of M40/5A06Al composite. It was observed that fibers were protruded significantly from the matrix after thermal expansion, which demonstrated the existence of interface sliding between fiber and matrix during the thermal expansion. It was believed that weak interfacial reaction resulted in a higher CTE. It was found that the experimental CTEs were closer to the predicted values by Schapery model.

Infiltration Characteristics of Carbon Fiber Reinforced MMCs

Carbon fiber reinforced aluminum matrix composite blocks and a pipe (as semi-product) were produced by pressure infiltration technique. In this paper the authors deal with the production method and investigations of the blocks and the pipe. In our composites AlSi12 eutectic aluminium-silicon alloy was used as matrix material. The reinforcements were ‘A’ and ‘B’ type carbon fibers (‘A’ having lower amorphous carbon content than ‘B’). The volume fraction of the fibers was outstanding – at least 55 vol%. Scanning electron microscopic investigations were done in order to observe the rather rough surface of the carbon fibres. X-ray diffraction and energy dispersive spectrometry was done in order to estimate the quantity of Al4C3 intermetallic phase at the carbon fiber/matrix interface region. The measurements showed that the quantity of Al4C3 strongly depends on the amorphous carbon quantity in carbon fibers. Much more Al4C3 was formed in the case of ‘A’ type reinforcement (less amorphous carbon), than in the case of ‘B’ type reinforcement (more amorphous carbon). The presence of Al4C3 crystals caused large scatter in the mechanical properties, the UTS was decreased, while the compressive strength was increased. Fracture surfaces were investigated: the composite showed rigid fracture.

A Finite Element Model to Simulate the Cutting of Carbon Fiber Reinforced Composite Materials

In the present study, the finite element model of machining carbon fiber reinforced aluminum matrix composites with representative fiber orientation of 90 degree is established with the following developments: (i) a Johnson-Cook constitutive model of each component in the multi-phase composite materials; (ii) a failure model of the composite material based on physical separation criterion; (iii) the interface between fiber and matrix defined by a interaction. This simulating method can be developed to each kind of fiber reinforced composite materials.

Mechanical and Thermal Properties of Vapor-Grown Carbon Fiber Reinforced Aluminum Matrix Composites by Plasma Sintering

Vapor-grown carbon fiber (VGCF) reinforced aluminum matrix composites were fabricated by plasma sintering method, and their mechanical and thermal properties were investigated. The aluminum powders with average diameters of 1 μm, 3 μm and 30 μm were chosen as the matrix. The monolithic aluminum blocks were also fabricated by plasma sintering method in order to comparing with the composites. As decreasing the aluminum powder size, VGCFs became to disperse more uniformly in composites. Compared with the monolithic aluminum block, Vickers hardness of the composites was enhanced remarkably. For 1 μm aluminum powders, the increment rate of Vickers hardness of the composites to monolithic aluminum was as high as 78.3%. While the tensile strength of the composites was lower than that of the monolithic aluminum. In contrast, the coefficient of thermal expansion of composites with 1 μm or 3 μm and 30 μm aluminum powders were decreased and increased, respectively, compared with the aluminium blocks with their powder. The thermal conductivity of the composites also increased compared with that of the monolithic aluminum blocks, but was not dependent on the size of aluminum powders.

Development and characterization of liquid carbon fibre reinforced aluminium matrix composite

The progress and developments in materials technology have resulted in several new materials like metal–matrix composites (MMCs). On account of excellent physical, mechanical and development properties, MMCs are applied widely in aircraft and automobile technology. The present paper deals with the development of aluminium matrix composite reinforced with carbon preform having a volume fraction of 20–25% using squeeze casting infiltration process. Hardness, impact and tension test on the squeeze cast matrix and the composite was conducted to study the improvement in properties compare to that of matrix. Even though ultimate tensile strength of composite is found to be decreased, an increased Brinell hardness number and a four-fold improvement in toughness are noticed. Characterization of the materials done using optical and scanning electron microscope (SEM) revealed that the carbon fibers are evenly distributed in the matrix and the alloy is appeared to have smaller dendrite size. The lack of observed fibre pull-out on fracture and improved mechanical properties resulted due to the good wetting of the fibers by the liquid alloy.

Influence of Fiber Surface Structure on Interfacial Structure between Fiber and Matrix in Vapor Grown Carbon Fiber Reinforced Aluminum Matrix Composites

Vapor grown carbon fiber reinforced pure aluminum matrix composites were fabricated by the hot-pressing method below the melting temperature of pure aluminum. The surface structures of the vapor grown carbon fibers and the interfacial structures between the fibers and the matrix in the composite were observed. The precipitation mechanism of crystalline aluminum carbide was also investigated. An interlayer with an amorphous-like structure formed at the interface between the carbon surface structure and the aluminum matrix. This interlayer between the wave or irregular carbon structure and the matrix grew more rapidly than that formed between the linear carbon surface structure and the matrix. The thickness of the interlayer increased with the increased fabrication temperature of the composite. Crystalline aluminum carbide could not easily be precipitated in the composite fabricated below 933 K owing to the thicker interlayer separating the vapor grown carbon fibers and aluminum. By either extending the heat-treatment time to 18 ks or increasing the fabrication temperature to 933 K, we could promote the precipitation of crystalline aluminum carbide in the composite. After heat-treating the composite produced at 933 K, aluminum carbide crystals precipitated from the stacked carbon lamellae at the interface between the fibers and the matrix. [doi:10.2320/matertrans.MRA2008350]

Friction and wear properties of short carbon fiber reinforced aluminum matrix composites

The friction and wear properties of short carbon fibers (SCFs) reinforced aluminum matrix composite were studied. The influences of the fiber volume fraction, load applied, rotating speed, and wear mechanism were discussed. The results indicated that SCFs/Al composite had better tribological properties than Al alloy. The friction coefficient and wear mass loss decreased with the fiber volume fraction increased, but increased as the load and rotating speed increased, respectively. SCF reduced direct contact between the matrix and counterpart and improved the wear resistance of SCFs/Al composite greatly. The wear displayed a linear evolution in all the range of load. Surfaces before and after wear tests were characterized using scanning electron microscopy (SEM) and energy-dispersive analysis of X-ray (EDAX) spectroscopy.

The effects of volume percent and aspect ratio of carbon fiber on fracture toughness of reinforced aluminum matrix composites

Carbon fiber reinforced aluminum matrix composites are used as advanced materials in aerospace and electronic industries. In order to investigate role of aspect ratio of carbon fiber on fracture toughness of aluminum matrix composite, the composite was produced using stir casting. Al–8.5%Si–5%Mg selected as a matrix. The samples were prepared with three volume fractions (1, 2 and 3) and three aspect ratios (300, 500 and 800). Three-point bending test was performed on the specimens to evaluate the fracture toughness of the materials. The results showed that the fracture toughness of composites depends on both fiber volume fraction and aspect ratio. Scanning electron microscopy (SEM) was employed to elucidate the fracture behavior and crack deflection of composites. The study also, showed that the toughening mechanism depends strongly on fiber volume fraction, aspect ratio and the degree of wetting between fiber and matrix.

Effect of copper electroless coatings on the interaction between a molten Al–Si–Mg alloy and coated short carbon fibres

Abstract The role of electroless copper coatings applied on short carbon fibres on the interaction between an aluminium alloy (Al–Si–Mg) and coated fibres has been studied to get useful information for the fabrication of carbon fibre reinforced aluminium matrix composites by liquid or semi-liquid processing. The conditions used for electroless were optimized to obtain a uniform and continuous layer of copper. After characterization, uncoated and Cu coated carbon fibres were mixed with AA 6061 aluminium powders, compacted and heated at temperatures from 650 to 950 °C to study the reactivity and the resulting interface. To complete this study, differential thermal analysis (DTA) were carried out on compacted mixtures of aluminium alloy powders with Cu coated and uncoated carbon fibres, applying similar thermal cycles than for the composite manufacturing. The results show an important improving of reinforcement wetting by molten matrix when copper coatings are applied, jointly with a reduction of the alloying elements microsegregation in the matrix, unlike the composites manufactured with uncoated fibres. Additional microhardness and nanoindentation tests were carried out to study the effect of the copper incorporation from the coating to the matrix on the matrix response to the ageing hardening.

Interfacial microstructure and forming mechanism of brazing C f/Al composite with Al–Si filler

Using Al–Si–Cu and Al–Si–Cu–Zn filler alloy, at the temperature between 500 and 570 °C, the brazing technology of the carbon fiber-reinforced aluminum matrix composite was investigated. The results showed that the component elements Si and Cu diffused into the base metal. The infiltrating filler alloy, the aluminum base and the carbon fiber reacted, and interfacial reaction products like Al 4C 3, SiC, and CuAl 2 were generated. The bond between filler and the aluminum base was perfect. When using the Al–28Cu–6Si and Al–4Cu–10Si filler alloy, brazed without pressure and flux, the shear strength of the brazing joint was 65 and 75 MPa, respectively. The shear fracture occurred at the interface between brazing alloy and base metal.

TEM study of carbon fibre reinforced aluminium matrix composites: influence of brittle phases and interface on mechanical properties

The microstructure of A357 aluminium alloy (7 wt% Si+0.6 wt% Mg) reinforced by 1D-M40J carbon fibres is characterised using different techniques of transmission electron microscopy (diffraction, HRTEM, EDX, EELS). The microstructure of the high modulus PAN based fibre and of the pyrolytic carbon coating (Cp) is fully characterised. Silicon and Mg 2Si grains which determine matrix-reinforcement adhesion are investigated. On the basis of the microstructural features, the mechanical properties of the composites are discussed. The mechanical behaviour of composites prepared with and without Cp interphases corresponds to a brittle matrix reinforced by brittle fibres. In the case of the composite without Cp interphase, the most influent parameter is the high resistance to sliding at the interface between silicon and fibres which leads to a strong fibre-matrix “bonding” and thus, to a weak and brittle material. The interfacial resistance to decohesion and to sliding is lower in the composite with Cp interphase resulting in higher strength and limited pull out. This lower interfacial resistance is due to the successive microporous and layered microstructures of the pyrolytic carbon coating.

Transverse Shear Strength of Unidirectional Carbon Fiber Reinforced Aluminum Matrix Composite under Static and Dynamic Loadings

The static and dynamic transverse shear strength of a unidirectional carbon fiber reinforced cast aluminum alloy matrix composite (C f/A356.0) and aluminum alloy were studied with Instron-1195 testing machine and a split Hopkinson pressure bar, respectively. The results indicate that the transverse shear strength of the composite is about half that of the aluminum matrix. Both the composite and the matrix show almost the same rate effect, namely a slight increase in the shear strength with increasing strain rate. This may be an indication that the rate effect of the unidirectional Cf/A356.0 composite is mainly controlled by the A356.0 aluminum alloy matrix. Moreover, the shear failure mechanisms of the composite are discussed.

A combined process of coating and hybridizing for the fabrication of carbon fiber reinforced aluminum matrix composites

A process which combines fiber coating and particles hybridizing has been utilized for the fabrication of carbon fiber reinforced aluminum matrix composite. Ceramic SiC coating was derived by Sol-gel method and SiC particle hybridizing was processed in Sol-gel solution simultaneously. Squeeze-cast process was used to get bulk composite materials. SEM analysis of the material showed a good fiber distribution in the Al matrix by particles hybridizing. HRTEM works indicated the coating to be an effective barrier of the C/Al interfacial reaction and had reduced the interfacial shear strength noticeably. Mechanical properties of the composite were improved especially for the axial strength. C/Al interfacial reaction was also studied which revealed that PAN-based carbon fiber reacted heavily with aluminum matrix. The nucleation and growth of the reactants were dominantly a random process.