Fiber Reinforced Metal Matrix Composites Research Articles

Force model based on heterogeneous components decoupling and machining behaviors of ultrasonic grinding continuous fiber-reinforced MMCs

Continuous fiber-reinforced metal matrix composites (CFMMCs), such as SiC fiber-reinforced TC17 matrix composites (SiCf/TC17), are renowned for their exceptional mechanical properties. However, their heterogeneous compositions present significant machining challenges, including fiber pullout, matrix cracking, and accelerated tool wear. Ultrasonic vibration-assisted grinding (UVAG) has proven to be an effective technique for overcoming these challenges. The material removal mechanisms in UVAG, especially in composites with both ductile and brittle phases, remain poorly understood. To explore these issues, UVAG and conventional grinding (CG) experiments were conducted on SiCf/TC17 along two grinding directions: fiber’s transverse direction (FT) and fiber’s longitudinal direction (FL). This paper aims to provide a new dynamic mechanical model and shed light on the complex removal mechanisms in CFMMCs, which are characterized by a near one-to-one alternation of ductile and brittle phases. The findings reveal that UVAG reduces fiber damage and surface roughness compared to CG, especially when grinding along FT. UVAG lowers normal (Fn) and tangential grinding forces (Ft) by 15.3% and 12.3%, respectively. This highlights UVAG’s potential for improving the machinability of complex materials like CFMMCs. The proposed grinding force model closely matches the experimental results. This paper hopes to support the precision abrasive machining of CFMMCs, a kind of complex and highly anisotropic composite material, and promote their application in the fields such as aerospace.

Heterogeneous components removal mechanism and grinding force model from energy aspect in ultrasonic grinding continuous fiber reinforced metal matrix composites

Continuous fiber reinforced metal matrix composites (CFMMCs) offer higher specific strength, specific modulus, and operating temperature than matrix metals due to the unique enforcement mechanism of the one-to-one scale arrangement of matrix and reinforced phases. Due to the heterogeneous characteristics between the plastic matrix and brittle fibers, the removal mechanism of CFMMCs during processing is exceptionally complex. Ultrasonic vibration-assisted grinding (UVAG) shows great advantages in machining difficult-to-cut materials (i.e., ceramics and composites) by changing the motion trajectory between grains and workpieces, effectively reducing grinding force and improving machining quality. However, little is known about the removal mechanism of UVAG for CFMMCs composed of the ductile (i.e., metal matrix) and brittle (i.e., SiC fiber) phases with highly anisotropic structure characteristics. This raises the question of how CFMMCs with heterogeneous components perform under abrasive processing and how to predict their processing forces. Hence, UVAG and conventional grinding (CG) experiments with single CBN grain were carried out on SiC fiber reinforced TC17 matrix composites (SiCf/TC17) in this work. A grinding force model considering both phases and materials structure from energy aspect was proposed. A theoretical model for suppressing SiC fiber damage has been proposed, which is expected to guide low-damage processing of brittle materials. According to the results, the removal models of CFMMCs are revealed including: i) macro fracture of SiC fiber, ii) neat fracture of SiC fiber, and iii) TC17 matrix massive adhesion on the SiC fiber. Besides, no cracks crossing fibers are observed on the subsurface of SiC fiber under both UVAG and CG due to the good support of the TC17 matrix on SiC fibers. The grinding force predicted model error decreases as ap increases. When ap is 50 μm, the errors between predicted and experimental values are 7.8 % and 9.1 % for normal forces (Fn) and tangential forces (Ft), respectively. Ultrasound suppresses the severe wear behavior of grains, thereby improving the tool life. This paper aims to comprehensively reveal the characteristics of abrasive processing of CFMMCs from various aspects (surface morphology, subsurface features, grinding force prediction, and tool wear), which will promote the industrial application of CFMMCs.

Continuous Casting Preparation Process of Helical Fiber-Reinforced Metal Matrix Composites

To improve the strength of the metal while maintaining good plasticity, helical fibers are added to the metal matrix. How to form helical fiber and control its parameters in the preparation process are urgent problems to be solved in the study of helical fiber-reinforced metal matrix composites. In this paper, the continuous casting process of helical fiber-reinforced metal matrix composites was proposed. To reduce the difficulty of the experiment, the formation process of helical fiber on metal matrix and the relationship between the continuous casting process parameters and helical shape fiber parameters were studied by preparing helical carbon fiber-reinforced lead matrix composites with a low-melting-point metal matrix. The results show that this process can produce helical fiber-reinforced metal matrix composite stably and continuously, and the helical shape parameters of the composite can be controlled by changing the process parameters of continuous casting. To further improve the practical application of this process, helical carbon fiber-reinforced aluminum matrix composites were prepared. The test result in terms of mechanical property shows that the tensile strength and elongation of the composite were improved. This indicates that the reinforced phase of the helical structure of the metal matrix composite has higher strength and toughness compared with the matrix metal.

Design of self-healing materials for the integration of structural health monitoring (SHM^2)

Integration of the complementary fields of structural health monitoring in self-healing materials (SHM2) has the potential to transform the traditional engineering concepts of fail safe and damaged tolerant design. Structural health monitoring seeks to embed and automate sensing capabilities within structures to determine their state and to detect degradation or damage. Once degradation or damage is detected, additional decisions and potential action are required. Reducing operational envelopes can prevent further damage accumulation or catastrophic failure or repairs can be performed to correct the degradation. Typical repair requires active involvement of personnel and potentially down time. Self-healing materials seek to avoid maintenance needs and down time through the creation of structures and materials with an imbued capability to repair damage. Together SHM^ 2 has the potential to create a closed loop where damage is detected using embedded sensors and automated analysis that can then initiate self-healing. The highly structured and controlled nature of self-healing materials presents an opportunity to design structures that additionally support health monitoring capabilities. This paper presents recent research and results informing the design of shape memory alloy (SMA) fiber reinforced metal matrix composites (MMCs) to optimize self-healing capabilities and structural health monitoring (SHM^2). Fiber pull tests were performed to analyze the strength of the interface between the SMA fibers and matrix allowing for sizing to complement both composite design and healing capabilities. Analysis was performed to understand complex failure mechanisms occurring at the interface between detwinning shape memory alloys and the metal matrix. And novel composite design was performed to support both the self-healing and damage detection capabilities of the material structure.

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.