Reduced-order Models for Microstructure-Sensitive Effective Thermal Conductivity of Woven Ceramic Matrix Composites with Residual Porosity

2021 ◽  
pp. 114399
Author(s):  
Adam P. Generale ◽  
Surya R. Kalidindi
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Residual Porosity ◽  
Reduced Order Models ◽  
Matrix Composites ◽  
Reduced Order

Ceramic Matrix Composite with Increased Thermal Conductivity

2006 ◽  
Vol 45 ◽  
pp. 1405-1410 ◽  
Author(s):  
J.C. Ichard ◽  
R. Pailler ◽  
Jacques Lamon
Keyword(s):  
Thermal Conductivity ◽  
Sol Gel ◽  
Ceramic Matrix Composite ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Gas Production ◽  
Matrix Composites ◽  
Porous Network ◽  
Infiltration Process ◽  
Melt Infiltration

The purpose of the study was to increase the thermal conductivity of multilayered and self-sealing ceramic matrix composites via the silicon melt infiltration process. The first step of the process consisted in filling porosity using various organic xerogels by the sol-gel route. Carbon xerogels obtained by subsequent pyrolysis may reduce and homogenize the porous network within the composite. Cracking of the xerogels due to volumic shrinkage occurring during air drying may be decreased by controlling the initial parameters as concerns the gel solution and/or by operating a second impregnation/pyrolysis step. Filling of such composites by liquid silicon revealed that a specific route and particular conditions are necessary to eliminate porosity by controlling gas production species from pore surface at high temperature. This may be achieved through a directional flow and using highly viscous silicon (thanks to a localized wick), and by keeping the sides of the materials permeable to gas. This led to composite materials with a thermal conductivity which was four times as high as that of those materials densified via CVI. An increase in mechanical properties was also observed.

Uni-axial stress–strain response and thermal conductivity degradation of ceramic matrix composite fibre tows

2009 ◽  
Vol 465 (2109) ◽  
pp. 2849-2876 ◽  
Author(s):  
C. Tang ◽  
M. Blacklock ◽  
D. R. Hayhurst
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Axial Stress ◽  
Ceramic Matrix Composite ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Strain Response ◽  
Matrix Composites ◽  
Stress Strain ◽  
Fibre Failure

A physical model, previously developed by one of the authors, has been extended to cover thermal conductivity degradation owing to the uni-axial stress–strain response of aligned groups of fibres or tows found in ceramic matrix composites. Both the stress–strain and thermal models, together with their coupling, have been shown to predict known composite behaviour qualitatively. The degradation of longitudinal thermal properties is shown to be driven by strain-controlled fibre failure; while the degradation of transverse thermal properties is because of the growth of fibre–matrix interface wake-debonded cracks, coupled with strain-driven fibre failure.

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