Role of interfacial debonding and matrix cracking in the effective thermal diffusivity of SiC fibre-reinforced chemical vapour deposited SiC matrix composites

Hasselman, D. P. H.; Venkateswaran, A.; Yu, Min; Tawil, H.

doi:10.1007/bf00721838

Cited by 27 publications

(11 citation statements)

References 13 publications

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“…However, such cracks also impede heat flow in the plane that contains the fibers, thereby reducing the thermal conductivity. [1][2][3] Under out-of-plane loading, failure occurs via delamination through the matrix, with relatively little resistance coming from the fibers. Delamination cracks present a particularly large impediment to heat flow in the through-thickness direction, 4 because of the relatively small amounts of fiber bridging and, hence, the large crack opening displacements (␦).…”

Section: Introductionmentioning

confidence: 99%

Thermal Conductance of Delamination Cracks in a Fiber‐Reinforced Ceramic Composite

McDonald

Dryden

Majumdar

et al. 2000

Journal of the American Ceramic Society

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The thermal conductance of delamination cracks in a unidirectionally reinforced ceramic composite is investigated. A phase-sensitive photothermal technique is used to measure the crack conductance in situ under load. Special emphasis is given to the effects of the local crack opening displacement (␦). A crack conductance model that considers the contributions from both the air and the fibers within the crack is developed and compared with the measurements. Despite considerable scatter in the experimental data, the model adequately predicts the increased conductance that is associated with fiber bridging, as well as the overall trend that is observed with ␦.

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Section: Introductionmentioning

confidence: 99%

Thermal Conductance of Delamination Cracks in a Fiber‐Reinforced Ceramic Composite

McDonald

Dryden

Majumdar

et al. 2000

Journal of the American Ceramic Society

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“…However, these mechanisms are detrimental to other properties pertinent to thermostructural performance, especially the thermal diffusivity. 2,3 The latter property is important in determining the magnitude of thermal stresses when the material is subjected to temperature gradients and is therefore relevant to its thermal shock resistance.…”

Section: Introductionmentioning

confidence: 99%

Effects of Matrix Cracks on the Thermal Diffusivity of a Fiber‐Reinforced Ceramic Composite

McDonald

Dryden

Zok

2001

Journal of the American Ceramic Society

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Effects of matrix cracks and the attendant interface debonding and sliding on both the longitudinal and the transverse thermal diffusivities of a unidirectional Nicalon/MAS composite are investigated. The diffusivity measurements are made in situ during tensile testing using a phase-sensitive photothermal technique. The contribution to the longitudinal thermal resistance from each of the cracks is determined from the longitudinal diffusivity along with measurements of crack density. By combining the transverse measurements with the predictions of an effective medium model, the thermal conductance of the interface (characterized by a Biot number) is determined and found to decrease with increasing crack opening displacement, from an initial value of Ϸ1 to Ϸ0.3. This degradation is attributed to the deleterious effects of interface sliding on the thermal conductance. Corroborating evidence of degradation in the interface conductance is obtained from the inferred crack conductances coupled with a unit cell model for a fiber composite containing a periodic array of matrix cracks. Additional notable features of the material behavior include: (i) reductions of Ϸ20% in both the longitudinal and the transverse diffusivities at stresses near the ultimate strength, (ii) almost complete recovery of the longitudinal diffusivity following unloading, and (iii) essentially no change in the transverse diffusivity following unloading. The recovery of the longitudinal diffusivity is attributed to closure of the matrix cracks. By contrast, the degradation in the interface conductance is permanent, as manifest in the lack of recovery of the transverse diffusivity.

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“…The greatest effect in reducing thermal diffusivity can be for heat flow perpendicular to the fibre matrix interface. 26 The experimental observations in this study strongly indicated that the interface structure plays significant role, and makes a significant contribution to the heat transport behaviour across the composite. Therefore, it has a great influence on the thermal diffusivity values of the SiC fibre reinforced glass ceramic matrix composite.…”

Section: Resultsmentioning

confidence: 89%

“…[23][24][25][26] The resistance can arise from thermal expansion mismatch between composite constituents that resulted in an interfacial gap that is one of the reasons for low thermal diffusivity values. The coefficient of the SiC fibre is higher than that of the matrix with the values 1.8 × 10 −6 K −1 for barium osumilite and 3.30 × 10 −6 K −1 for SiC fibre.…”

Section: Resultsmentioning

confidence: 99%

Thermal diffusivity measurement of SiC fibre reinforced BMAS glass ceramic composites exposed mechanical damage

Yilmaz

2007

Journal of the European Ceramic Society

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Role of interfacial debonding and matrix cracking in the effective thermal diffusivity of SiC fibre-reinforced chemical vapour deposited SiC matrix composites

Cited by 27 publications

References 13 publications

Thermal Conductance of Delamination Cracks in a Fiber‐Reinforced Ceramic Composite

Thermal Conductance of Delamination Cracks in a Fiber‐Reinforced Ceramic Composite

Effects of Matrix Cracks on the Thermal Diffusivity of a Fiber‐Reinforced Ceramic Composite

Thermal diffusivity measurement of SiC fibre reinforced BMAS glass ceramic composites exposed mechanical damage

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