Showing papers on "Ceramic matrix composite published in 2022"

Si-based polymer-derived ceramics for energy conversion and storage

Abstract: Abstract Since the 1960s, a new class of Si-based advanced ceramics called polymer-derived ceramics (PDCs) has been widely reported because of their unique capabilities to produce various ceramic materials (e.g., ceramic fibers, ceramic matrix composites, foams, films, and coatings) and their versatile applications. Particularly, due to their promising structural and functional properties for energy conversion and storage, the applications of PDCs in these fields have attracted much attention in recent years. This review highlights the recent progress in the PDC field with the focus on energy conversion and storage applications. Firstly, a brief introduction of the Si-based polymer-derived ceramics in terms of synthesis, processing, and microstructure characterization is provided, followed by a summary of PDCs used in energy conversion systems (mainly in gas turbine engines), including fundamentals and material issues, ceramic matrix composites, ceramic fibers, thermal and environmental barrier coatings, as well as high-temperature sensors. Subsequently, applications of PDCs in the field of energy storage are reviewed with a strong focus on anode materials for lithium and sodium ion batteries. The possible applications of the PDCs in Li-S batteries, supercapacitors, and fuel cells are discussed as well. Finally, a summary of the reported applications and perspectives for future research with PDCs are presented.

Oxidation behaviors of carbon fiber reinforced multilayer SiC-Si3N4 matrix composites

Abstract: Abstract Oxidation behaviors of carbon fiber reinforced SiC matrix composites (C/SiC) are one of the most noteworthy properties. For C/SiC, the oxidation behavior was controlled by matrix microcracks caused by the mismatch of coefficients of thermal expansion (CTEs) and elastic modulus between carbon fiber and SiC matrix. In order to improve the oxidation resistance, multilayer SiC-Si 3 N 4 matrices were fabricated by chemical vapor infiltration (CVI) to alleviate the above two kinds of mismatch and change the local stress distribution. For the oxidation of C/SiC with multilayer matrices, matrix microcracks would be deflected at the transition layer between different layers of multilayer SiC-Si 3 N 4 matrix to lengthen the oxygen diffusion channels, thereby improving the oxidation resistance of C/SiC, especially at 800 and 1000 °C. The strength retention ratio was increased from 61.9% (C/SiC-SiC/SiC) to 75.7% (C/SiC-Si 3 N 4 /SiC/SiC) and 67.8% (C/SiC-SiC/Si 3 N 4 /SiC) after oxidation at 800 °C for 10 h.

A systematic approach for horizontal and vertical scale up of sintered Ultra-High Temperature Ceramic Matrix Composites for aerospace – Advances and perspectives

Abstract: Ultra-High Temperature Ceramic Matrix Composites (UHTCMCs) are the next generation composites developed for application in the harsh environment of aerospace. Qualification of these materials requires the manufacturing of demonstrators for testing in relevant environments, which in turn, requires to scale them up. This paper illustrates the systematic approach adopted for the scale-up of UHTCMCs based on carbon fibre reinforced zirconium diboride plus silicon carbide from laboratory to industrial scale dimensions. The scale-up process covered a period of three years and concerned an increase in diameter of ∼10 times (from 40 to 400 mm), and in thickness of ∼30 times (from 5 to 160 mm). Small-scale products were consolidated by hot pressing at ISTEC whilst larger samples were consolidated by an industrial spark plasma sintering facility (NanokerResearch, Spain). After each scale-up step, reproducibility of composition, microstructure and properties was carefully checked. Thanks to the homogenous fibre distribution and sapient dosing of secondary phases, composites with different diameters and thickness were successfully consolidated by both techniques with little adjustment of sintering parameters up to the maximum size of available industrial furnaces . The large discs produced allowed production of 170 mm long bars for tensile testing and large tiles for hypersonic wind tunnel tests . Thick samples were useful to machine complex shapes such as screws and nuts, vertical bars for characterization of properties along the composite thickness and nozzle demonstrators. • ZrB 2 -Cf composites were scaled-up 10 times in diameter, 30 times in thickness. • A manufact of UHTCMC material weighting 11 kg was produced for the first time. • The same mechanisms were efficient for scale-up in diameter and thickness. • Reproducible microstructure-properties were assessed from lab to industrial scale. • Large components such as plates, nozzle inserts, screw and nuts were fabricated.

Thermal conductivity and bending strength of SiC composites reinforced by pitch-based carbon fibers

Abstract: Abstract In this work, pitch-based carbon fibers were utilized to reinforce silicon carbide (SiC) composites via reaction melting infiltration (RMI) method by controlling the reaction temperature and resin carbon content. Thermal conductivities and bending strengths of composites obtained under different preparation conditions were characterized by various analytical methods. Results showed the formation of SiC whiskers (SiC w ) during RMI process according to vapor—solid (VS) mechanism. SiC w played an important role in toughening the C pf /SiC composites due to crack bridging, crack deflection, and SiC w pull-out. Increase in reaction temperature during RMI process led to an initial increase in thermal conductivity along in-plane and thickness directions of composites, followed by a decline. At reaction temperature of 1600 °C, thermal conductivities along the in-plane and thickness directions were estimated to be 203.00 and 39.59 W/(m·K), respectively. Under these conditions, bending strength was recorded as 186.15±3.95 MPa. Increase in resin carbon content before RMI process led to the generation of more SiC matrix. Thermal conductivities along in-plane and thickness directions remained stable with desirable values of 175.79 and 38.86 W/(m·K), respectively. By comparison, optimal bending strength improved to 244.62±3.07 MPa. In sum, these findings look promising for future application of pitch-based carbon fibers for reinforcement of SiC ceramic composites.

Long-term ceramic matrix composite for aeroengine

Abstract: Abstract Three strategies were proposed to prolong the service life of continuous fiber-reinforced silicon carbide ceramic matrix composite (CMC-SiC), which served as thermal-structure components of aeroengine at thermo-mechanical-oxygenic coupling environment. As for some thermal-structure components with low working stress, improving the degree of densification was crucial to prolong the service life, and the related process approaches were recited. If the thermal-structure components worked under moderate stress, the matrix cracking stress ( σ mc ) should be improved as far as possible. The fiber preform architecture, interface shear strength, residual thermal stress, and matrix strengthening were associated with σ mc in this review. Introducing self-healing components was quite significant with the appearance of matrix microcracks when CMC-SiC worked at more severe environment for hundreds of hours. The damage can be sealed by glass phase originating from the reaction between self-healing components and oxygen. The effective self-healing temperature range of different self-healing components was first summarized and distinguished. The structure, composition, and preparation process of CMC-SiC should be systematically designed and optimized to achieve long duration target.

Research progress of ceramic matrix composites for high temperature stealth technology based on multi-scale collaborative design

Abstract: Thermal structural materials integrated with specific electromagnetic function have arised great attention in recent years. Driven by the urgent demand of multi-functional composites involving oxidation resistance, high strength and strong microwave attenuation in application of future high speed stealth vehicle, ceramics and their derivative architectures have considered to be a promising candidate in the field of high-temperature microwave absorption (HTMA) owning to tunable dielectric properties as well as intrinsic excellent thermo-physical properties. This article mainly systematically summarizes state-of-art research progress of high temperature stealth performance of ceramic matrix composites from multi-scale collaborative design. Specifically, the influence on microstructure of SiC fibers, interfaces, matrix and meta-structure design on the microwave absorbing are summarized. Besides, compatibility design over microwave and infrared range of ceramic matrix absorbing composites are summarized. Finally, the prospects in the future challenges and guidelines are provided to design more novel functional high temperature stealth materials. Looking forward to the development trend of high-temperature stealth technology of ceramic matrix composites, it is proposed that the more attention should be devoted to combination of structural and functional performance in terms of compatibility stealth materials with strong absorption, wide frequency bandwidth, multi-frequency absorption, high temperature resistance and low density in application of high temperature stealth materials in the future.

Fracture behaviour of SiC/SiC ceramic matrix composite at room temperature

Abstract: Ceramic matrix composites are promising materials for structural applications at high temperature due to their excellent thermo-mechanical properties. Despite all their advantages, standardised methods for the characterisation of fracture toughness have not been established yet. Therefore, it is necessary to develop an understanding of their fracture behaviour. In this study, the fracture behaviour of silicon carbide (SiC) materials reinforced by SiC fibres is investigated using notched beams in flexural and tensile tests. The toughening mechanisms were identified. The work of fracture ranges between 4.0 and 24.6 kJ.m −2 and the fracture toughness K IC ranges between 3.2 and 5.5 MPa.m 1/2 . An equivalent fracture toughness K eq that reflects to some extent the degree of extrinsic toughening was defined and values range between 23.5 and 27.9 MPa.m 1/2 . K IC and the work of fracture decrease with increasing displacement rate while the strength was not affected. K IC measurements reveal the material’s anisotropy, higher values were obtained for the out-of-plane fibres orientation. • Fracture of SiC/SiC CMC involves a complex fracture process. • Toughening mechanisms responsible of toughness of SiC/SiC CMC were identified. • K IC is found to be sensitive to strain rate and fibre orientation. • Flexural work of fracture is found to be sensitive to strain rate. • Deviation from linearity does not reflect the crack initiation in SiC/SiC CMC.

Additive manufacturing of carbon fiber reinforced ceramic matrix composites based on fused filament fabrication

Abstract: For the first time, carbon fiber reinforced ceramic matrix composites (CMC) were successfully fabricated by additive manufacturing (AM) using the fused filament fabrication (FFF) technology, filaments (“CF-PEEK”) with thermoplastic polyetheretherketone (PEEK) as the matrix and C-precursor, and carbon short-fibers (< 250 μm) as reinforcements. In order to prevent a re-melting of the as-printed CFRPs (C-fiber reinforced plastics) during pyrolysis at 1000 °C in N2ensuring the freedom of design and complex parts, a prior crosslinking step at 325 °C with a dwell time of 48 h in air was introduced to stabilize and crosslink the CFRP. Due to the stabilization and the printing of degassing channels for the pyrolysis, near net shape and complex CMC parts with different C-fiber orientations (0°; ±45°; 90°) were obtained by the liquid siliconization infiltration process (LSI). The manufactured C/C-SiC parts were characterized regarding their microstructure and mechanical properties. The reinforcing C-fibers were successfully protected during the LSI-process and flexural strengths of almost 60 MPa were obtained.

Characterization of cyclic loading/unloading damage behavior in fiber-reinforced ceramic-matrix composites using inverse tangent modulus

Abstract: Under cyclic loading/unloading, the mechanical hysteresis appears in fiber-reinforced ceramic-matrix composites (CMCs) due to multiple micro damage mechanisms. In this paper, the cyclic loading/unloading damage evolution in different CMCs is analyzed using the inverse tangent modulus (ITMs). Experimental micro damage mechanisms are observed using the X-ray computed tomography (XCT) and scanning electron microscopy (SEM). Based on the damage mechanisms’ analysis, a damage-based micromechanical constitutive model is developed to predict the cyclic loading/unloading curves and related damage parameters. Effects of composite’s constitutive properties, peak stress, damage state and interface properties on the cyclic loading/unloading damage evolution are discussed. For the 1D and 2D SiC/SiC, and 3D C/SiC composites, the evolution curves of ITMs can be divided into two regions. In region I, the increasing rate of the ITMs is constant and depends on the composite’s constitutive properties; and in region II, the increasing rate of the ITMs decreases as the interface slip range approaches the interface debonding tip.

Low temperature fabrication of Cf/BNi/(Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C-SiCm high entropy ceramic matrix composite by slurry coating and laminating combined with precursor infiltration and pyrolysis

Abstract: In this study, the low temperature fabrication of a Cf/BNi/(Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C-SiCm high entropy ceramic (HEC) ceramic matrix composite (CMC) was achieved through slurry coating and laminating (SCL) combined with precursor infiltration and pyrolysis (PIP). Firstly, the (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)C HEC powder was synthesized by pressureless sintering and ball milling. Then, a Cf/BNi/HECm CMC preform was obtained by the SCL process. At last, the composite was densified by PIP of SiC at 1200 °C and a Cf/BNi/HEC-SiCm CMC was the final result. The density and open porosity of the HEC-CMC were 2.7 g/cm3 and 10%, respectively. The composite had a relatively high flexural strength (269 ± 25 MPa) and flexural modulus (53.3 ± 7.9 GPa). Fiber degradation was scarcely detected and fiber pullout was clearly observed. Most importantly, the fabrication method is simple and the fabrication temperature is rather low. This study opens a new insight for high entropy ceramic matrix composites fabrication.

Rare earth monosilicates as oxidation resistant interphase for SiCf/SiC CMC: Investigation of SiCf/Yb2SiO5 model composites

Abstract: Abstract Model composites consisting of SiC fiber and Yb 2 SiO 5 were processed by the spark plasma sintering (SPS) method. The mechanical compatibility and chemical stability between Yb 2 SiO 5 and SiC fiber were studied to evaluate the potential application of Yb monosilicate as the interphase of silicon carbide fiber reinforced silicon carbide ceramic matrix composite (SiC f /SiC CMC). Two kinds of interfaces, namely mechanical and chemical bonding interfaces, were achieved by adjusting sintering temperature. SiC f /Yb 2 SiO 5 interfaces prepared at 1450 and 1500 °C exhibit high interface strength and debond energy, which do not satisfy the crack deflection criteria based on He-Hutchison diagram. Raman spectrum analyzation indicates that the thermal expansion mismatch between Yb 2 SiO 5 and SiC contributes to high compressive thermal stress at interface, and leads to high interfacial parameters. Amorphous layer at interface in model composite sintered at 1550 °C is related to the diffusion promoted by high temperature and DC electric filed during SPS. It is inspired that the interfacial parameters could be adjusted by introducing Yb 2 Si 2 O 7 −Yb 2 SiO 5 interphase with controlled composition to optimize the mechanical fuse mechanism in SiC f /SiC CMC.

A Review on Si-Based Ceramic Matrix Composites and their Infiltration Based Techniques

Abstract: This review paper aims to look at silicon-based ceramic matrix composites and infiltration-based approaches for them. There are many different types of infiltration-based manufacturing processes, each with its own set of features. The best technique is chosen depending on the needs and desired attributes. With these considerations in mind, any type of infiltration might be selected to meet the requirements. Silicon-based ceramics has been highly used in the fields of aerospace, medical, automobile, electronics, and other various industries so it is important to study about their applications as well. This review outlines the evolution of composites from early 7000 BCE to composites today and discussed about various infiltration techniques for manufacturing silicon based ceramic matrix composites. This article also gives the comprehensive review of general characteristics and mechanical properties of silicon-based composites used in a variety of engineering sectors. The application section entails the wide range of engineering fields with consideration of infiltration techniques, which would be helpful for researchers to study and correlate the different infiltration techniques for end applications.

Oxidation of SiC/BN/SiC Ceramic Matrix Composites in Dry and Wet Oxygen at Intermediate Temperatures

Abstract: The oxidation behavior of SiC/BN/SiC ceramic matrix composites (CMCs) was evaluated from 400° to 800 °C in 100% O2 and 50% H2O/50% O2 gas mixtures. Thermogravimetric analysis (TGA) was utilized to measure weight change during controlled environment exposures at elevated temperatures for 1 and 50 hours. Oxidized CMCs and their oxides were studied post-exposure with scanning electron microscopy and energy dispersive spectroscopy. The oxidation onset and composition transition temperatures were evaluated. Key observations include oxide composition, oxide wetting, oxygen solubility in Hi-Nicalon SiC fibers and BN fiber coating oxidation and volatility behavior as a function of temperature. Degradation in wet environments at 600 °C was most extensive due to the formation of a non-wetting, non-protective surface oxide, allowing oxidant access to the BN fiber coatings followed by oxidation and volatilization. Implications of the CMC oxidation behavior are discussed for CMCs in service.

Modeling of fatigue failure for SiC/SiC ceramic matrix composites at elevated temperatures and multi-scale experimental validation

Abstract: The fatigue failure of ceramic matrix composites at elevated temperatures was predicted using the micromechanics method. Multiple micro-damage models were developed to describe the evolution processes of matrix cracking, interface wear, and fiber fracture during fatigue loading. On this basis, the fatigue life was calculated. To validate the fatigue failure model, multi-scale experiments were conducted. In the macroscale, the S-N curve was obtained by the fatigue test. In the microscale, multiple in-situ measuring methods were developed through which the matrix crack density, the interfacial shear stress, and the percentage of fracture fibers were obtained. Both the macroscale and microscale experimental results were in good agreement with the predicted results. Therefore, the fatigue failure model developed in the present work is accurate.

The mechanical, thermophysical and electromagnetic properties of UD SiCf/SiC composites in different directions

Abstract: Unidirectional (UD) silicon carbide (SiC) fiber-reinforced SiC matrix (UD SiCf/SiC) composites with CVI BN interphase were fabricated by polymer infiltration-pyrolysis (PIP) process. The effects of the anisotropic distribution of SiC fibers on the mechanical properties, thermophysical properties and electromagnetic properties of UD SiCf/SiC composites in different directions were studied. In the direction parallel to the axial direction of SiC fibers, SiC fibers bear the load and BN interphase ensures the interface debonding, so the flexural strength and the fracture toughness of the UD SiCf/SiC composites are 813.0 ± 32.4 MPa and 26.1 ± 2.9 MPa·m1/2, respectively. In the direction perpendicular to the axial direction of SiC fibers, SiC fibers cannot bear the load and the low interfacial bonding strengths between SiC fiber/BN interphase (F/I) and BN interphase/SiC matrix (I/M) both decrease the matrix cracking stress, so the corresponding values are 36.6 ± 6.9 MPa and 0.9 ± 0.5 MPa∙m1/2, respectively. The thermal expansion behaviors of UD SiCf/SiC composites are similar to those of SiC fibers in the direction parallel to the axial direction of SiC fibers, and are similiar to those of SiC matrix in the direction perpendicular to the axial direction of SiC fibers. The total electromagnetic shielding effectiveness (EM SET) of UD SiCf/SiC composites attains 32 dB and 29 dB when the axial direction of SiC fibers is perpendicular and parallel to the electric field direction, respectively. The difference of conductivity in different directions is the main reason causing the different SET. And the dominant electromagnetic interference (EMI) shielding mechanism is absorption for both studied directions.

Preparation and characterization of Nextel TM 720/ alumina ceramic matrix composites via an improved prepreg process

Abstract: In this work, the Nextel 720 continuous fiber reinforced alumina ceramic matrix composites (CMCs) were prepared by an improved prepreg process. The alumina matrix was derived from aqueous slurry, which consisted of organic glue, alumina sol, nanometer alumina powders, and micrometer alumina powders. This design provided a densely packed matrix for the CMC, and made the whole process relatively simple. The ratio of different alumina components in aqueous slurry was optimized to obtain good sintering activity, high thermal resistance, and excellent mechanical properties simultaneously. Furthermore, a preceramic polymer of mullite was used to strengthen the ceramic matrix through a multiple infiltration process. The final CMC sample achieved a high flexural strength of 255 MPa and a good high-temperature stability. After 24 h of heat treatment at 1100°C, 85% of the maximum flexural strength still had been retained.

Advancements in carbon fibre reinforced ultra-refractory ceramic composites: effect of rare earth oxides addition

Abstract: Continuous carbon fibre ceramic matrix composites capable of tolerating multiple thermal-shock cycles and resisting ablation are needed for aerospace and hypersonic systems. Carbon fibre around 50 vol% and ultra-refractory matrices are fundamental parameters. The influence of rare earth (RE) oxides on the microstructure and mechanical properties of carbon fibre-ZrB2/SiC composites was investigated. Materials were produced by slurry infiltration and hot pressing. The addition of Y2O3, La2O3 and CeO2 led to the formation of lamellar boro-carbides that improved the densification, while Sc2O3 promoted the formation of (Zr,Sc)B2 solid solutions in the matrix. All these composites exhibited improved mechanical properties compared to a RE-free baseline, with room temperature strengths and toughness above 330 MPa and 9 MPa m0.5, respectively, and strengths above 600 MPa at 1500 °C. The lamellar phase was identified as a fibre by-product with general formula REB2C2. Only CeO2 was detrimental on the long run due to its high reactivity with humidity which induced swelling and jeopardized the structural stability of the composite. This study revealed new fundamental insights into the microstructure evolution of carbon-fibre refractory composites and its impact on the mechanical properties, which will contribute to the development of new generation of reusable ceramic matrix composites for harsh environments.

Analysis of failure mechanisms of Oxide - Oxide ceramic matrix composites

Abstract: The failure mechanisms of Oxide-Oxide ceramic matrix composites AS-N610 were studied at both room temperature and high temperature using tensile and fatigue tests with and without lateral and laminar notches. The unnotched coupons had an average tensile strength of 423 MPa with elastic modulus of 97 GPa at room temperature showing a perfect elastic behaviour whereas the laminar notched samples shown similar strength of 425 MPa with elastic modulus (98 GPa) revealing pseudo-ductile behaviour. A reduction in tensile strength of the oxide ceramic matrix composites was observed at high temperatures. Thermal shock experiments revealed that the retained strength of the samples quenched from 1100 °C deteriorated by ∼10 % (395 ± 15 MPa). In all samples, fracture origin was observed on the mid-plane showing a higher degree of fiber pull-out, delamination and pseudo ductile behaviour. Finite element analysis confirmed higher stress concentration on the areas of failures.