Fiber Reinforced Metal Matrix Composites Research Articles

Machining SiC fibre reinforced metal matrix composites – How do different matrix materials affect the cutting performance?

SiC fibre reinforced metal matrix composites find widespread application but show major machining difficulties due to significant variations in constituents' properties. In this sense, while the SiC fibre plays significant strengthening effects, the properties mismatch between the brittle fibre and ductile matrix materials becomes important in their machining performance. Through machining tests, SiC fibre reinforced MMCs with Al (soft) and Ti (hard) matrix alloys are evaluated, showing the variation of interaction between inserts and fibres in cutting due to the different matrix properties. This leads to less tool wear but compromised surface integrity in Al-based composite than in Ti-based one.

Al-Mg-Mn-Zn-Zr alloy with refined grain structure to develop Al-B fiber-reinforced metal matrix composites compacted in superplastic conditions

Homogeneous nanostructured and ultrafine-grained states in an Al-Mg-Mn-Zn-Zr alloy were produced by high pressure torsion at room temperature and by continuous equal channel angular pressing at 200 °C. The alloys with refined grain structure in both states exhibited low temperature and high strain rate superplastic behavior. The nanostructured alloy with enhanced mechanical behavior was used for MMC fabrication under superplastic conditions guided with the help of finite element simulations. Computer-aided “foil-fiber-foil” process using a woven-alike boron fiber network and nanostructured Al alloy provided smooth defect-free compaction of an Al-B fiber-reinforced composite under superplastic conditions at a temperature of 300 °C.

Microstructure and mechanical properties of steel wire reinforced Mg matrix composites fabricated by composite extrusion

The Steel/Mg composites were prepared using the composite extrusion method, where AZ31 Mg alloy was used as the matrix and Zn-coated steel wire as the reinforcement. The microstructure evolution and mechanical properties of these composites were systematically studied. The results show that there is an interdiffusion phenomenon of Mg and Zn elements at the interface of the prepared Steel/Mg composites, and an interdiffusion layer with a width of about 15 μm is formed and MgZn and Mg7Zn3 compounds are produced. The inclusion of steel wire in the Mg alloy matrix can significantly reduce its texture strength. Steel/Mg composites have higher tensile and compressive strength than Mg–R. This study provides a novel, time-saving and low-cost method for the manufacture of continuous fiber reinforced metal matrix composites(CFRMMCs), and expands the application of metal composites.

Modification of the model for calculating the long SiC fibre-reinforced metal matrix composites transverse strength and study for interfacial influences

The transverse strength of long SiC fibre-reinforced metal matrix composites is superior to its longitudinal strength owing to interface factors. To accurately predict the transverse strength of long SiC fibre-reinforced metal matrix composites, a micro-mechanics representative volume element (RVE) model was developed; periodic boundary conditions were applied to the model to ensure its displacement and stress continuity. Taking into account the influence of the stress concentration coefficient of the matrix, the failure strength of long SiC fibre-reinforced metal matrix composites under transverse tensile loads and compressive loads were calculated, where the error between the calculation results of the model and the test results was found to be large. A novel calculation method based on the interfacial cohesion model is proposed herein, to improve the accuracy of the RVE model. It was found that the accuracy of the corrected model calculation has been improved through a comparison with the experimental values. The stress/strain relationship between interfaces of different strengths under tensile and compressive loads was analysed, the failure index of interface strength was extracted, and the relationship between the influence of interface strength on failure was determined.

Development of pressure infiltration preparation of metal matrix composites

<p>This paper summarizes the process of metal matrix composites from pressure infiltration preparation to pressure ultrasonic assisted infiltration to pressure solvent assisted infiltration. The advantages of preparing metal matrix composites by pressure infiltration alone are low cost and convenient for mass production. However, the equipment and process requirements are too high, and the quality of composite materials can not be guaranteed. Because of the high pressure of ultrasound, ultrasonic infiltration has become an auxiliary physical method for the preparation of metal matrix composites by pressure infiltration. But this method tends to damage the fibers. Therefore, the fibers need to be coated. The coating on the fiber surface is divided into metal coating and non-metal coating. Some people mixed SiC particles or whiskers in continuous carbon fibers to prepare aluminum alloy composite materials, forming a hybrid assisted infiltration method. Later, people began to pay attention to the flux-assisted role of pressure infiltration. Therefore, solvent-assisted infiltration of fiber-reinforced metal matrix composites has become an important research field.</p>

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.

Experimental investigations into mechanical response and damage mechanisms of fiber aluminum hierarchical composites

Carbon fiber reinforced aluminum matrix hierarchical composites have attracted the attention as a potential lightweight material for aerospace. Two typical Cf/Al composites were prepared by pressure infiltration method with changing the infiltration pressure. The analysis of microstructure, mechanical properties and failure behavior were carried out to systematically reveal the damage mechanisms of composites to realize their full potential. The results show that the infiltration process and solidification behavior of composites can be revealed by analyzing the evolution law of macrosegregation and microstructures. Compared with the matrix alloy, the bending strength of H-Cf/Al composites increased by 47%, and the compression strength of P-Cf/Al composites increased by 128%. To clarify the crack propagation behaviors of H-Cf/Al composite, toughening mechanisms such as crack deflection, crack bridging, and crack branching are discussed. The shear tests show that the failure characteristics of H-Cf/Al composites are mainly fiber bundle interface cracking, while the strong interlaminar shear strength of P-Cf/Al composites dominated by fiber splitting is attributed to serious interface reaction. In addition, main damage mechanisms affecting the ultimate failure were identified, namely interface splitting cracks, plastic deformation of matrix and fiber damage. This study provides meaningful enlightenment for the preparation and application of fiber-reinforced metal matrix composites.

Machining of long ceramic fibre reinforced metal matrix composites – How could temperature influence the cutting mechanisms?

Metal matrix composites (MMCs) offer a unique set of properties due to the ductile-brittle combination produced by the matrix and the reinforcements. Conventional MMCs are usually particle-reinforced, and their cutting mechanisms have been thoroughly studied, showing that they tend to follow traditional cutting theory as the particles roll within the surface/chip or are pushed in/pulled out of the machined surfaces. However, while the enforcement mechanism is quite unique in fibre reinforced MMCs, very little is known about the cutting mechanisms of this kind of materials. These materials are distinguished for having a, roughly, one-to-one scale alternation of the ductile (i.e., matrix) and hard/brittle (i.e., ceramic fibres) phases; key characteristic that is likely to heavily influence the material removal mechanism. Further, there is an open question on how the (temperature-dependent) stiffness of the matrix would affect the cutting mechanism when considering the hybrid machining process (e.g., heat assisted/cryogenic machining) to improve their machinability. To elucidate these aspects, here, by means of cutting a SiCf/Ti-6Al-4V MMC, the following particularities/peculiarities of the cutting mechanism of these structures are reported: (1) the chip formation includes, up to now unobserved, extrusion of the ductile component of the MMC (Ti-6Al-4V matrix) between the fractured hard phase (SiC); (2) the properties and deformation mechanisms of the matrix (adjusted by temperature control: −180 °C; 24 °C; 400 °C) will affect the crack initiation of the SiC hard/brittle fibre which is manifested underneath the machined surface. Thus, this work is unique in its approach as it opens the understanding of how these complex and heterogeneous structures could be “activated” (e.g., by thermal means to change the stiffness of a particular phase) for improved cutting conditions.

Evaluation on dimensional stability of Cf/AZ91D composite based on the micro-yield strength

The dimensional instability caused by irreversible micro-plastic deformation can be evaluated with the micro-yield strength. Cf/Mg composite material prepared by liquid-solid extrusion following vacuum infiltration(LSEVI) process was taken as testing material and its dimensional stability was evaluated. The load-unload cycle test method is used to explore the stress range for the Cf/Mg composite to generate residuals plastic strain in static conditions. The results show that micro-plastic deformation for Cf/Mg composite material occurred in the stress range between 35 and 45 MPa. When the micro-plastic strain reaches 10−5, the micro-yield strength of the Cf/Mg composite material is evaluated as 79MPa. Compared with matrix alloy, the micro-yield strength has increased by more than 89%, which is the same level as beryllium alloy. This paper provides an effective strategy for characterize the dimensional stability of continuous fibre reinforced metal matrix composites.

Modeling the temperature-dependent Young’s modulus of short fiber reinforced metal matrix composites and its particle hybrid composites

Modeling the temperature-dependent Young’s modulus of short fiber reinforced metal matrix composites and its particle hybrid composites

Numerical Simulation on Thermal Stresses and Solidification Microstructure for Making Fiber-Reinforced Aluminum Matrix Composites.

The fabrication of fiber-reinforced metal matrix composites (MMCs) mainly consists of two stages: infiltration and solidification, which have a significant influence on the properties of MMCs. The present study is primarily focused on the simulation of the solidification process and the effect of the active cooling of fibers with and without nickel coating for making the continuous carbon fiber-reinforced aluminum matrix composites. The thermomechanical finite element model was established to investigate the effects of different cooling conditions on the temperature profile and thermal stress distributions based on the simplified physical model. The predicted results of the temperature distribution agree well with the results of the references. Additionally, a three-dimensional cellular automata (CA) finite element (FE) model is used to simulate the microstructure evolution of the solidification process by using ProCAST software. The results show that adding a nickel coating can make the heat flux smaller in the melt, which is favorable for preventing debonding at the coating/fiber and alloy interface and obtaining a finer microstructure. In the presence of the nickel coating, the number of grains increases significantly, and the average grain size decreases, which can improve the properties of the resultant composite materials. Meanwhile, the predicting results also show that the interfaces of fiber–coating, fiber–melt, and coating–melt experience higher temperature gradients and thermal stresses. These results will lead to the phenomenon of stress concentration and interface failure. Thus, it was demonstrated that these simulation methods could be helpful for studying the solidification of fiber-reinforced MMCs and reducing the number of trial-and-error experiments.

Manufacturing process of short carbon fiber reinforced Al matrix with preformless and their properties

The conventional manufacturing process of fiber-reinforced metal matrix composites via liquid infiltration processes, preform manufacturing using inorganic binders is essential. However, the procedure involves binder sintering, which requires high energy and long operating times. A new fabrication process without preform manufacturing is proposed to fabricate short carbon fiber (SCF)-reinforced aluminum matrix composites using a low-pressure infiltration method. To improve the wettability between fiber and matrix, fibers were plated copper using an electroless plating process. The low-pressure infiltration method with preformless succeeded in manufacturing a composite with a volume fraction of about 30% of carbon fibers.The fiber orientation of the composite material manufactured without preform and the fiber orientation of the composite material manufactured using an inorganic binder was almost the same. The manufactured composites with preformless have high hardness and high thermal conductivity.

Machining of composite materials through advance machining process

This study explores those composite materials are difficult to machinate because of their variability, heat sensitivity, and high abrasiveness. This leads to damages to the material and extremely high tool wear and damage to the tool. A thorough overview of advanced machining techniques for composite materials is presented in this article. There is an emphasis on glass and carbon fiber reinforced polymeric composites and long fiber reinforced metal matrix composites in the area of fiber-reinforced composites. Particulate composites cannot be machined in the same way as metal matrix composites, though conventional machining processes due to their advanced properties. As per the previous research we concluded that advance machining process is used to cut hard material such as ceramics, composites, Titanium, etc. It is the opposite of traditional machining when a wedge-shaped tool is used to remove material in the form of chips by causing friction coefficient. These techniques have been used in a number of ways to remove material. One approach is to produce stresses via various methods but not with a well-directed wedge-shaped instrument in the material. Some of the techniques like ultrasonic machining, water jet machining, and abrasive jet machining, to name a few of them. The thermal effect may also be used to dissolve or evaporate the materials. Successful and cheap, advanced machining techniques are finding application in sectors.

Dual mechanisms of fiber dispersion of CF/Sn50Pb50 composites fabricated by double-layer printing head 3D printing process

Abstract Fiber dispersion was one of the crucial factors, which influenced the mechanical properties of fiber reinforced metal matrix composites (FR-MMCs). The incomprehension of fiber dispersion mechanisms and the lack of control methods limited the developments and further applications of the 3D printed FR-MMCs. In this work, the tensile properties and microstructures of continuous carbon fiber reinforced SnPb matrix composites, which were fabricated by the double-layer printing head 3D printing process (DPP), were measured and observed. The dual mechanisms of capillarity pressure driving and nonuniform interface reaction driving in fiber dispersion were proposed. Besides, the dynamic of fiber dispersion was discussed. It was found that improving wicking performance could increase the dispersion of fibers. This research filled in the blank of fiber dispersion mechanisms of 3D printed FR-MMCs, and provided the methodological supports for further improving the performances of composites.

Temperature dependent ultimate tensile strength model for short fiber reinforced metal matrix composites

In this paper, considering the combined influences of fiber strength and various strengthening mechanisms including load transmitting, dispersion strengthening, residual thermal stress and dislocation strengthening, and their evolution with temperature, a temperature dependent ultimate tensile strength theoretical model of short fiber reinforced metal matrix composites is established. The model is confirmed by comparing with the available experimental results of six different short fiber reinforced metal matrix composites. Then, based on the model we developed, the contribution of various strengthening mechanisms to the ultimate tensile strength of the composites with the evolution of temperature is analyzed. Besides, the quantitative influences of Young’s modulus of fiber and matrix on the ultimate tensile strength evolution with temperature are discussed. Several opinions on the design of short fiber reinforced metal matrix composites are put forward, especially at high temperatures.

A fast numerical method of introducing the strengthening effect of residual stress and strain to tensile behavior of metal matrix composites

Thermal residual stress and strain (TRSS) in particle reinforced metal matrix composites (PRMMCs) are believed to cause strengthening effects, according to previous studies. Here, the representative volume element (RVE) based computational homogenization technique was used to study the tensile deformation of PRMMCs with different particle aspect ratios (AR). The influence of TRSS was assessed quantitatively via comparing simulations with or without the cooling process. It was found that the strengthening effect of TRSS was affected by the particle AR. With the average strengthening effect of TRSS, a fast method of introducing the strengthening effect of TRSS to the tensile behavior of PRMMCs was developed. The new method has reduced the computational cost by a factor 2. The effect of TRSS on continuous fiber-reinforced metal matrix composite was found to have a softening-effect during the entire tensile deformation process because of the pre-yield effect caused by the cooling process.

Tensile and fatigue properties of fiber-reinforced metal matrix composites Cf/5056Al

Fiber-reinforced metal matrix composites have mechanical properties highly dependent on directions, possessing high strength and fatigue resistance in fiber longitudinal direction achieved by weak interface bonding. However, the disadvantage of weak interface combination is the reduction of transversal performances. In this article, tensile and fatigue properties of carbon fiber-reinforced 5056 aluminum alloy matrix (Cf/5056Al) composite under the condition of medium-strength interface combination are carried out. The fatigue damage mechanisms of Cf/5056Al composite under tension–tension and tension–compression loads are not the same, but the fatigue life curves are close, which may be the result of the medium-strength interface combination.

Fiber reinforced metal matrix composites - a review

Modern technology has placed increasing demands on materials. The need of hour is to develop the new materials so as to overcome the limitations of the materials existed presently regarding applications in different fields. The materials with properties such as better wear resistance, high specific strength and stability at high temperatures have been in great demand in the past few decades. The properties of conventional materials can be improved by the method of reinforcing whiskers, fibers and particles in to polymers, metals and ceramics. This has resulted in the manufacturing of composite materials. The mechanical properties of fiber reinforced metal matrix composites (MMCs) make them the suitable choice for applications in the fields of automotive and aerospace etc. The paper outlines the overview of fiber reinforced MMCs. The applications, manufacturing methods and mechanical properties of these composites are discussed. Furthermore, this review describes the single fiber push-out test which is developed in the past years so as to measure quantitatively the properties of the interface between the fiber and the matrix in these fiber reinforced MMCs.

Finite element modeling and simulation of the fiber–matrix interface in fiber reinforced metal matrix composites

The properties of fiber–matrix interface in the fiber reinforced metal matrix composites (MMCs) have been investigated in the past with the use of push-out test. The finite element (FE) analysis which is used to model the push-out test helps the composite’s designer in optimizing the interfacial properties. A two dimensional planar FE model is presented for investigating the properties of interface. Cohesive layer concept is used to model the interface with a specified thickness. The initial response of the cohesive element is assumed to be linear elastic. The maximum nominal stress criterion is used to define the damage initiation and the damage evolution is defined in terms of fracture energy. The simulation results show that the cohesive layer behaves almost like the matrix for the linear elastic deformation prior to damage. It is concluded that the values of Young’s modulus and shear modulus for the cohesive layer can be taken equal to that of the matrix material for the finite element simulation of the debonding behavior of these MMCs. Furthermore, it is observed that the shear stress at which damage initiates can be determined by using the cohesive layer concept for the interface. Once a damage initiation criterion is met, material damage occurs in accordance with the defined damage evolution law. The complete failure of the interface takes place when the stress becomes zero. However, the interface behavior needs to be defined in a more sophisticated way so as to model the stepwise debonding and failure evolution once the complete debonding has occurred.

Role of fiber arrangement in the thermal expanding behavior of unidirectional metal matrix composites

The influence of fiber arrangement on thermal expanding behavior of unidirectional fiber-reinforced metal matrix composites (MMCs) is evaluated using a unit cell micromechanical approach. Both regular and random fiber arrangements are considered in the MMC simulation by extending the number of sub-cells of the representative volume element (RVE). Moreover, the unit cell micromechanical model is used to investigate the role of fiber cross-section on the coefficients of thermal expansion (CTEs) of unidirectional MMCs. The validity of the model is verified by comparing the predictions and those available experimental measurements. The effective axial CTEs are not dependent on the MMC microstructure with different types of fiber arrays and cross-sections. However, the results show that besides the volume fraction, shape and the arrangement type of fibers plays a significant role in the effective transverse CTEs of MMCs. The discrepancy between the transverse predictions of the model with a random fiber arrangement and those of the model with a regular fiber arrangement increases with the rise of difference between the constituent material properties. Also, the effects of different statistical distributions of the random fiber arrangement, the number of RVE sub-cells and fiber orientation on the MMC thermal expanding response are examined.