Fiber-reinforced Ceramic Matrix Composites Research Articles

Damage development and lifetime prediction of fiber-reinforced ceramic-matrix composites subjected to cyclic loading at 1300 °C in vacuum, inert and oxidative atmospheres

In this paper, the fatigue damage development and lifetime of C/SiC and SiC/SiC ceramic-matrix composites (CMCs) under cyclic loading at an elevated temperature of 1300°C in vacuum, in inert, in air and in steam atmospheres are investigated. The damage evolution versus applied cycles of C/SiC and SiC/SiC composites are analyzed through fatigue hysteresis-based damage parameters and fiber/matrix interface shear stress. The Global Load Sharing (GLS) criterion is used to determine the stress distribution between intact and broken fibers. The fibers failure probability of oxidized and unoxidized fibers in the oxidation region, fibers in the interface debonded region and interface bonded region are determined considering the damage mechanisms of interface wear, interface oxidation and fiber oxidation. The effects of fatigue peak stress, testing condition and fiber preforms on the damage evolution and lifetime are discussed. The fatigue life S–N curves and fatigue limit stresses of C/SiC and SiC/SiC composites at 1300°C under different testing conditions are predicted. In the inert atmosphere, the fatigue limit stress is about 92% tensile strength for 3D C/SiC in vacuum atmosphere, 82% tensile strength for 2D C/SiC in argon atmosphere, 37% tensile strength for 2D SiC/SiC in N2 atmosphere, and 32% tensile strength for 2D SiC/SiC in argon atmosphere, the fatigue limit stress of C/SiC is much higher than that of SiC/SiC; however, in air and in steam atmospheres, the fatigue limit stress of SiC/SiC composite is higher than that of C/SiC.

Time-dependent damage and fracture of fiber-reinforced ceramic-matrix composites at elevated temperatures

ABSTRACTIn this paper, the time-dependent damage and fracture of fiber-reinforced ceramic-matrix composites (CMCs) are investigated considering fiber oxidation and fracture at an elevated temperature. The shear-lag model combined with the fiber/matrix interface oxidation model, the interface debonding criterion, fiber strength degradation model and fiber failure model is adopted to analyze the microstress field in the damaged composite. The relationships between the first steady-state matrix cracking stress, composite tensile strength, fiber/matrix interface debonding and sliding, oxidation temperature and oxidation time are established. The effects of fiber volume fraction, fiber/matrix interface shear stress, fiber strength and oxidation temperature on the evolution of first steady-state matrix cracking stress and composite tensile strength versus the oxidation time are analyzed. The first steady-state matrix cracking stress and composite tensile strength of 2D C/SiC and 2D C/[SiC-B4C] composites after oxidation at 700°C, 1200°C and 1300°C in air atmosphere are predicted for different oxidation time.

Research progresses on multi-functional integration MAX phases modified continuous fiber-reinforced ceramic matrix composites

Research progresses on multi-functional integration MAX phases modified continuous fiber-reinforced ceramic matrix composites

A hysteresis energy dissipation based model for multiple loading damage in continuous fiber-reinforced ceramic-matrix composites

In this paper, a hysteresis energy dissipation based damage model for fiber-reinforced ceramic-matrix composites (CMCs) subjected to multiple loading stress levels is developed. Considering the combination effects of multiple loading sequences and multiple fatigue damage mechanisms, i.e., matrix cracking, fiber/matrix interface debonding and interface wear, the evolution of the fiber/matrix interface debonding and sliding, fatigue hysteresis loops, fatigue hysteresis dissipated energy and fatigue hysteresis modulus changing with increasing applied cycles are analyzed. The effects of fiber volume fraction, matrix crack spacing, fatigue peak stress and fatigue stress range on the damage development inside of CMCs are discussed. The difference of the fiber/matrix interface shear stress existed between the interface wear region and new interface debonded region affects the fiber/matrix interface debonded length and loading carrying ability of intact and broken fibers. The damage evolution for C/SiC and SiC/SiC composites subjected to multiple fatigue loading sequences are predicted using the hysteresis energy dissipation damage model. Under multiple loading stress, the fatigue hysteresis dissipated energy increases when high peak stress and stress range increases due to the increase of fiber/matrix interface sliding range. However, when the low peak stress increases, the evolution of fatigue hysteresis dissipated energy depends on the interface debonding and sliding state.

Strengthening of C/SiC Composites by Electrophoretic Deposition of CNTs on a SiC Coating

The current study reports the enhancement of mechanical properties of carbon fiber-reinforced silicon carbide ceramic matrix composites (C/SiC CMCs) by the application of a carbon nanotube/silicon carbide (CNT/SiC) coating. CNTs were deposited on the surfaces of C/SiC composites using electrophoretic deposition (EPD), after which infiltration by SiC was achieved through a chemical vapor infiltration process. An EPD duration of 5 min was associated with a 40% increase in the ultimate flexural strength relative to that of composites with a pure SiC coating. The observed enhancement was rationalized by the microstructural observations of SiC infiltration into the porous CNT morphology and the subsequent formation of CNT/SiC layers on the surfaces of the composites and by the inherent toughness of the SiC whiskers. The flexural strength decreased with EPD durations greater than 5 min due to the formation of thick CNT meshes, which decreased the open porosity and thereby obstructed further SiC infiltration. This is a viable methodology for the improvement of mechanical properties of CMCs by the introduction of a ceramic coating containing CNT.

Modeling Multiple-Step Loading Damage Evolution in Continuous Fiber-Reinforced Ceramic-Matrix Composites at Room and Elevated Temperatures

AbstractIn this paper, the multiple-step loading damage evolution in two-dimensional (2D) SiC/SiC ceramic-matrix composites (CMCs) at room and elevated temperatures and subjected to different appli...

Thermomechanical fatigue damage development of continuous carbon fiber-reinforced ceramic-matrix composites subjected to different loading sequences and phase angles

Under thermomechanical fatigue (TMF) loading of fiber-reinforced ceramic-matrix composites (CMCs), the multiple TMF damage mechanisms of matrix multicracking, fiber/matrix interface debonding, and sliding are affected by the loading sequence and phase angle. In this paper, the TMF damage development of carbon fiber-reinforced CMCs is investigated corresponding to different loading sequences and phase angles. The TMF damage evolution subjected to different loading sequences (i.e., constant fatigue peak stress, low-high fatigue peak stress, and high-low fatigue peak stress) and phase angles (i.e., θ = 0, π/3, π/2, and π) are analyzed. The effects of fiber volume fraction, matrix crack spacing, fiber/matrix interface debonded energy, initiate/steady-state fiber/matrix interface shear stress, and thermal cycle temperature on the TMF damage evolution are discussed. The experimental TMF damage evolution of fatigue peak strain and hysteresis modulus versus applied cycles curves of 2D and 2.5D C/SiC composites at elevated temperatures of 550 and 800 °C in air condition are predicted.

Durability Modeling Review of Thermal- and Environmental-Barrier-Coated Fiber-Reinforced Ceramic Matrix Composites Part I.

This paper is a Part I of a literature review documentation describing the currently available and used techniques that are being explored by material scientists and researchers in the field of materials characterizations and testing for both thermal and environmental barrier coatings (TBCs and EBCs, respectively). This review contains relevant information regarding the most common coating applications and their impact on the durability and life of both the coatings and the substrate materials. It also includes a description of the methodologies of coating applications and their pros and cons. A discussion of the applicability, failure modes and modeling approaches that are presently available and utilized by active researchers in the field is also included. Part II will illustrate an in-depth assessment of various aspects of the available and developing life prediction models for both TBC and EBC and the influence of intrinsic and extrinsic factors on their thermal and mechanical stability.

Temperature-dependent dielectric and microwave absorption properties of silicon carbide fiber-reinforced oxide matrices composite

Simultaneous improvement of mechanical and microwave absorption properties of the composites at high temperatures still undergoes considerable challenges. We have investigated the high-temperature microwave absorbing properties of the silicon carbide fiber-reinforced oxide matrices (SiCf/mullite–SiO2) composite on the basis of our previous work. Results indicate that the complex permittivity increases from 8.19 − j5.09 to 16.39 − j9.83 at 10 GHz with the temperature rising from 200 to 600 °C. The SiCf/mullite–SiO2 composite has relatively high tanδ values indicating superior microwave attenuation ability. The reflection loss (RL) values of the composite increase with rising thickness. It can be noticed that the RL response curves of different thicknesses are basically consistent at 200 and 400 °C. In addition, the RL value of the composite is less than − 5 dB in the whole X band when the thickness is under 2.9 mm and the temperature is below 400 °C. The hybrid oxide matrices of mullite and SiO2 are beneficial to improve the dielectric properties, especially high-temperature microwave absorption properties of the SiC fiber-reinforced ceramic matrix composite. The superior microwave absorption properties indicate that the SiCf/mullite–SiO2 composite is a promising candidate in aircraft engine nozzle and aerodynamic heating parts of aircrafts at high temperatures.

Synergistic effects of hold time and cyclic loading on fatigue hysteresis loops of fiber-reinforced ceramic-matrix composites at elevated temperatures in oxidizing atmosphere

In this paper, the synergistic effects of the hold time and cyclic loading on the fatigue hysteresis loops of fiber-reinforced ceramic-matrix composites (CMCs) at elevated temperatures in air condition are investigated. Based on the analysis of relative frictional sliding between fibers and the matrix in the fiber/matrix interface oxidation and interface wear region, the interface debonded length, interface counter-slip length and interface new-slip length are determined using the fracture mechanics approach. The fatigue hysteresis loops models are developed considering the synergistic effects of hold time and cyclic loading. The relationships between the fatigue hysteresis loops models and internal multiple fatigue damage mechanisms are established. The effects of fiber volume fraction, matrix crack spacing, fatigue stress levels, hold time and oxidation temperature on the fatigue hysteresis loops shape, location and area, fatigue hysteresis modulus and the fiber/matrix interface slip lengths are investigated. The experimental fatigue hysteresis loops, fatigue hysteresis dissipated energy, fatigue hysteresis modulus and the fiber/matrix interface slip lengths of cross-ply SiC/MAS and 2D SiC/SiC composites under cyclic loading for different hold time at elevated temperatures in air condition are predicted.

Damage development and lifetime prediction of fiber-reinforced ceramic-matrix composites subjected to dwell-fatigue loading at elevated temperatures in oxidizing atmosphere

Damage development and lifetime prediction of fiber-reinforced ceramic-matrix composites subjected to dwell-fatigue loading at elevated temperatures in oxidizing atmosphere

Synergistic effects of fiber/matrix interface wear and fibers fracture on matrix multiple cracking in fiber-reinforced ceramic-matrix composites

ABSTRACTIn this paper, the synergistic effects of fiber/matrix interface wear and fibers fracture on matrix multiple cracking in fiber-reinforced ceramic-matrix composites (CMCs) are investigated using the critical matrix strain energy (CMSE) criterion. The shear-lag model combined with the fiber/matrix interface wear model, fibers fracture model and the fiber/matrix interface fracture mechanics debonding criterion is adopted to analyze the fiber and matrix axial stress distribution inside of the damaged composite. The relationships between the matrix multiple cracking, fatigue peak stress, applied cyclic number, fiber/matrix interface wear and debonding and fibers failure are established. The effects of fiber volume fraction, fiber/matrix interface shear stress, fiber/matrix interface debonded energy, cycle number, fatigue peak stress and fibers strength on matrix multiple cracking evolution are discussed. Comparisons of matrix multiple cracking with/without cyclic fatigue loading are analyzed. The experimental multiple matrix cracking of unidirectional SiC/CAS, SiC/CAS-II, SiC/Borosilicate and mini-SiC/SiC composites with/without cyclic fatigue loading are predicted.

Fatigue life prediction of ceramic-matrix composites

PurposeThis paper aims to predict fatigue life and fatigue limit of fiber-reinforced ceramic-matrix composites (CMCs) with different fiber preforms, i.e. unidirectional, cross-ply, 2D-, 2.5D- and 3D-woven, at room and elevated temperatures.Design/methodology/approachUnder cyclic loading, matrix multicracking and interface debonding occur upon first loading to fatigue peak stress, and the interface wear appears with increasing cycle number, leading to degradation of the interface shear stress and fibers strength. The relationships between fibers fracture, cycle number, fatigue peak stress and interface wear damage mechanism have been established based on the global load sharing (GLS) criterion. The evolution of fibers broken fraction versus cycle number curves of fiber-reinforced CMCs at room and elevated temperatures have been obtained.FindingsThe predicted fatigue life S–N curve can be divided into two regions, i.e. the Region I controlled by the degradation of interface shear stress and fibers strength and the Region II controlled by the degradation of fibers strength.Practical/implicationsThe proposed approach can be used to predict the fatigue life and fatigue limit of unidirectional, cross-ply, 2D-, 2.5D- and 3D-woven CMCs under cyclic loading.Originality/valueThe fatigue damage mechanisms and fibers failure model were combined together to predict the fatigue life and fatigue limit of fiber-reinforced CMCs with different fiber preforms.

Comparisons of thermomechanical fatigue hysteresis loops of fiber-reinforced ceramic-matrix composites subjected to different phase angles

In this paper, comparisons of thermomechanical fatigue hysteresis loops of fiber-reinforced ceramic-matrix composites (CMCs) subjected to different phase angles of θ = 0, π/3, π/2, and π have been investigated. The shape, location, and area of fatigue hysteresis loops are affected by the phase angle under the thermomechanical cyclic loading. The effects of fiber volume fraction, fatigue peak stress, matrix crack spacing, interface frictional coefficient, and interface debonded energy on the thermomechanical fatigue hysteresis loops and fiber/matrix interface slip of different phase angles are discussed. The fatigue hysteresis loops of cross-ply CMCs under the phase angles of θ = 0 and π are predicted for different fatigue peak stresses and cycle numbers.

Modeling of the Thermomechanical Fatigue Behavior of Fiber-Reinforced Ceramic-Matrix Composites Subjected to Different Phase Angles

AbstractUnder thermomechanical fatigue (TMF) loading, the thermal cyclic temperature may change with decreasing or increasing applied stress upon unloading or reloading. The damage inside of fiber-...

Modeling out-of-phase thermomechanical fatigue hysteresis of long fiber-reinforced ceramic-matrix composites subjected to different loading sequence

Modeling out-of-phase thermomechanical fatigue hysteresis of long fiber-reinforced ceramic-matrix composites subjected to different loading sequence

A thermomechanical fatigue hysteresis-based damage evolution model for fiber-reinforced ceramic–matrix composites

In this paper, a thermomechanical fatigue hysteresis-based damage evolution model for fiber-reinforced ceramic–matrix composites has been developed. Upon unloading and reloading, the fiber/matrix interface debonded length, interface counter-slip length, and interface new-slip length change with increasing or decreasing applied stress, which affects the stress–strain fatigue hysteresis loops and fatigue hysteresis-based damage parameters. The reloading/unloading stress–strain relationships when fiber/matrix interface partially or completely debonding are determined as a function of interface debonding/sliding, peak stress, applied cycle number, and thermal cycle temperature. The relationships between thermomechanical fatigue loading parameters (i.e. peak stress, applied cycle number, and thermal cyclic temperature), fiber/matrix interface debonding/sliding lengths, and fatigue hysteresis-based damage parameters (i.e. fatigue hysteresis dissipated energy, fatigue hysteresis modulus, and fatigue peak strain) have been established. The effects of fiber volume fraction, peak stress, matrix cracking space, and thermal cyclic temperature range on damage evolution under the out-of-phase thermomechanical cyclic loading have been discussed. The differences in damage evolution between in-phase/out-of-phase thermomechanical fatigue and isothermal fatigue loading at the same peak stress have been analyzed. The damage evolution of cross-ply SiC/magnesium aluminosilicate composite under the out-of-phase thermomechanical and isothermal fatigue loading has been predicted.

In-phase thermomechanical fatigue damage evolution of long fiber-reinforced ceramic-matrix composites using fatigue hysteresis-based damage parameters

Under in-phase (IP) thermomechanical fatigue (TMF) loading, the thermal cyclic temperature changes with decreasing or increasing applied stress upon unloading or loading, and the fiber/matrix interface shear stress in the long fiber-reinforced ceramic-matrix composites (CMCs) changes with applied cycles. In this paper, the in-phase TMF damage evolution of CMCs has been investigated, considering the coupling effects of TMF loading stress level, thermal cyclic temperature and applied cycles. The interface debonding and sliding lengths are determined based the thermomechanical micromechanical stress field and the fracture mechanics approach. The relationships between the TMF hysteresis parameters, interface damage, thermal cyclic temperature and applied cycles have been developed. The damage accumulation processes subjected to in-phase TMF for different fibers volume fraction, peak stress, matrix crack spacing, interface properties and thermal cyclic temperature range have been analyzed. The distinction of the damage evolution between the in-phase TMF and isothermal fatigue (IF) loading at the same applied stress has been analyzed. The damage evolution of cross-ply CMCs subjected to the in-phase TMF and IF loading have been predicted.

Hysteresis loops of fiber-reinforced ceramic-matrix composites under in-phase/out-of-phase thermomechanical and isothermal cyclic loading

In this paper, the stress−strain hysteresis loops of fiber-reinforced ceramic-matrix composites (CMCs) under in-phase/out-of-phase thermomechanical and isothermal cyclic loading have been investigated. The thermomechanical hysteresis loops models have been developed considering synergistic effects of thermal temperature cycling, stress levels and fiber/matrix interface debonding. The relationships between thermal cyclic temperatures, peak stress, fiber/matrix interface shear stress and stress−strain hysteresis loops under in-phase/out-of-phase thermomechanical and isothermal cyclic loading have been established. The effects of fiber volume fraction, peak stress, matrix crack spacing, interface frictional coefficient, interface debonded energy and temperature range on the stress−strain hysteresis loops under in-phase/out-of-phase thermomechanical and isothermal cyclic loading have been analyzed. The hysteresis loops of cross-ply SiC/magnesium aluminosilicate (MAS) composite under in-phase/out-of-phase thermomechanical and isothermal fatigue loading have been predicted.

Damage monitor and life prediction of carbon fiber-reinforced ceramic-matrix composites at room and elevated temperatures using hysteresis dissipated energy-based damage parameter

In this paper, the damage monitor and life prediction of carbon fiber-reinforced ceramic-matrix composites (C/SiC CMCs) have been investigated using the hysteresis dissipated energy-based damage parameter. The evolution of the interface shear stress, hysteresis dissipated energy, hysteresis dissipated energy-based damage parameter and the broken fibers fraction vs. cycle number, the fatigue life S‒N curves of unidirectional, cross-ply and 2.5D C/SiC composites at room temperature and 800 °C in air atmosphere have been analyzed. For unidirectional C/SiC, the hysteresis dissipated energy and hysteresis dissipated energy-based damage parameter first increase and then decrease with cycle number, and the fatigue limit stress decreases from 88% tensile strength at room temperature to 20% of the tensile strength at 800 °C in air atmosphere; for cross-ply C/SiC, the hysteresis dissipated energy and hysteresis dissipated energy-based damage parameter decrease with increasing applied cycles, and the fatigue limit stress decreases from 85% tensile strength at room temperature to 22% tensile strength at 800 °C in air; and for 2.5D C/SiC, the hysteresis dissipated energy and hysteresis dissipated energy-based damage parameter increases with cycle number, and the fatigue limit stress decreases from 70% tensile strength at room temperature to 25% tensile strength at 800 °C in air.