Ceramic matrix composite

About: Ceramic matrix composite is a research topic. Over the lifetime, 7807 publications have been published within this topic receiving 117020 citations.

Microstructure and properties of spark plasma-sintered ZrO2-ZrB2 nanoceramic composites

Abstract: In a recent work,1 we have reported the optimization of the spark plasma sintering (SPS) parameters to obtain dense nanostructured 3Y-TZP ceramics. Following this, the present work attempts to answer some specific issues: (a) whether ZrO2-based composites with ZrB2 reinforcements can be densified under the optimal SPS conditions for TZP matrix densification (b) whether improved hardness can be obtained in the composites, when 30 vol% ZrB2 is incorporated and (c) whether the toughness can be tailored by varying the ZrO2–matrix stabilization as well as retaining finer ZrO2 grains. In the present contribution, the SPS experiments are carried out at 1200°C for 5 min under vacuum at a heating rate of 600 K/min. The SPS processing route enables retaining of the finer t-ZrO2 grains (100–300 nm) and the ZrO2–ZrB2 composite developed exhibits optimum hardness up to 14 GPa. Careful analysis of the indentation data provides a range of toughness values in the composites (up to 11 MPa·m1/2), based on Y2O3 stabilization in the ZrO2 matrix. The influence of varying yttria content, t-ZrO2 transformability, and microstructure on the properties obtained is discussed. In addition to active contribution from the transformation-toughening mechanism, crack deflection by hard second phase brings about appreciable increment in the toughness of the nanocomposites.

Modeling the Monotonic and Cyclic Tensile Stress-Strain Behavior of 2D and 2.5D Woven C/SiC Ceramic-Matrix Composites

Abstract: The deformation of 2D and 2.5 C/SiC woven ceramic-matrix composites (CMCs) in monotonic and cyclic loadings has been investigated. Statistical matrix multicracking and fiber failure models and the fracture mechanics interface debonding approach are used to determine the spacing of matrix cracks, the debonded length of interface, and the fraction of broken fibers. The effects of fiber volume fraction and fiber Weibull modulus on the damage evolution in the composites and on their tensile stress–strain curves are analyzed. When matrix multicracking and fiber/matrix interface debonding occur, the fiber slippage relative to the matrix in the debonded interface region of the 0° warp yarns is the main reason for the emergance of stress–strain hysteresis loops for 2D and 2.5D woven CMCs. A model of these loops is developed, and histeresis loops for the composites in cyclic loadings/unloadings are predicted.

Laminated ceramic structures from oxide systems

Abstract: In this paper we present the results recently obtained in the study of laminated ceramic composites The motivation for studying and producing laminated ceramic composites have been illustrated Theoretical model useful to guide the design of laminated structures have been discussed and a route to prepare layered structures in the system Al 2 O 3 -ZrO 2 have been suggested The residual stresses developed in the ceramic layers have been quantified by indentation technique and piezo-spectroscopic analysis With the latter technique also the stress distribution in the different layers has been assessed Higher wear resistance under sliding and abrasive conditions of layered ceramics have been demonstrated The improvement of fatigue contact damage resistance and an increase of Weibull modulus underlined

Embedding two-dimensional graphene array in ceramic matrix

Abstract: Dispersing two-dimensional (2D) graphene sheets in 3D material matrix becomes a promising route to access the exceptional mechanical and electrical properties of individual graphene sheets in bulk quantities for macroscopic applications. However, this is highly restricted by the uncontrolled distribution and orientation of the graphene sheets in 3D structures as well as the weak graphene-matrix bonding and poor load transfer. Here, we propose a previously unreported avenue to embed ordered 2D graphene array into ceramics matrix, where the catastrophic fracture failure mode of brittle ceramics was transformed into stable crack propagation behavior with 250 to 500% improvement in the mechanical toughness. An unprecedentedly low dry sliding friction coefficient of 0.06 in bulk ceramics was obtained mainly due to the inhibition of the microcrack propagation by the ordered 2D graphene array. These unique and low-cost 2D graphene array/ceramic composites may find applications in severe environments with superior structural and functional properties.

Method of manufacturing a ceramic matrix composite

Abstract: A method of manufacturing a ceramic matrix composite comprises forming a slurry comprising a ceramic sol, filler particles and a solvent and forming laminates of fibers (12). The laminates of fibers (12) are impregnated with the slurry and are stacked (14) on a mold (10). The stack (14) of laminates of fibers (12) is covered by a porous membrane (16), a breather fabric (18) and a vacuum bag (20). The vacuum bag (20) is evacuated and is heated to a temperature of 60° C. for 10 hours to produce a ceramic matrix composite. The ceramic matrix composite is then heated to a temperature of 1200° C. at atmospheric pressure to sinter the ceramic matrix composite.