<p>Carbon/Carbon (C/C) composites are currently the material of choice for use on advanced thermal protection systems for high speed flight vehicles due to their excellent thermophysical properties, high specific stiffness and strength in hypersonic flight operational environments. Understanding the ultra-high thermophysical properties of C/C is essential for design purposes, especially where limited data exists for the temperature range of interest. To address this need, the thermophysical and spectroscopic properties of a nominated high density C/C composite material were characterized. Properties such as specific heat, thermal diffusivity, thermal expansion and thermal conductivity for the material in all three material orientations (x, y, z) were investigated between ambient temperature to 2600 <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$^\circ $</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mo>∘</mo> </mmultiscripts> </math></EquationSource> </InlineEquation>C. X-ray diffraction (XRD) and Raman spectroscopy were conducted to inform the chemical structure of the C/C composite material and thus provide rationale for the measured thermophysical behaviour. The thermophysical assessment of the C/C composite is provided in two parts, the first set of thermal properties were determined for the material in its untreated state (no heat treatment), and the second set demonstrates the effect of heat treatment on the chemical structure and resulting thermal properties. The coefficient of thermal expansion (CTE), diffusivity and conductivity of the composite exhibit a distinctive shift in the material properties for the temperature range of 1300 <InlineEquation ID="IEq2"> <EquationSource Format="TEX">$^\circ $</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mo>∘</mo> </mmultiscripts> </math></EquationSource> </InlineEquation>C to 1500 <InlineEquation ID="IEq3"> <EquationSource Format="TEX">$^\circ $</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mo>∘</mo> </mmultiscripts> </math></EquationSource> </InlineEquation>C. Subsequent thermal analyses beyond that temperature range are markedly different and indicative of the thermophysical properties expected of a composite subjected to heat treatment. Analyses of the same specimens (pre- and post-heating) were also conducted using XRD and Raman microscopy in order to investigate the resultant variation in thermophysical properties as a result of repeated heat treatments. The findings were useful to assess the performances of the C/C composite in extremely high temperature conditions for the potential applications of hypersonic vehicle structure and components.</p>

Thermophysical Properties of a High Density Carbon/Carbon Composite from Ambient to Ultra-high Temperatures

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发表日期：

2026年5月23日

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Marco Attia,
Wyman Zhuang,
Kilahney Murphy

摘要

Carbon/Carbon (C/C) composites are currently the material of choice for use on advanced thermal protection systems for high speed flight vehicles due to their excellent thermophysical properties, high specific stiffness and strength in hypersonic flight operational environments. Understanding the ultra-high thermophysical properties of C/C is essential for design purposes, especially where limited data exists for the temperature range of interest. To address this need, the thermophysical and spectroscopic properties of a nominated high density C/C composite material were characterized. Properties such as specific heat, thermal diffusivity, thermal expansion and thermal conductivity for the material in all three material orientations (x, y, z) were investigated between ambient temperature to 2600 $^\circ $ $^{\circ}$ C. X-ray diffraction (XRD) and Raman spectroscopy were conducted to inform the chemical structure of the C/C composite material and thus provide rationale for the measured thermophysical behaviour. The thermophysical assessment of the C/C composite is provided in two parts, the first set of thermal properties were determined for the material in its untreated state (no heat treatment), and the second set demonstrates the effect of heat treatment on the chemical structure and resulting thermal properties. The coefficient of thermal expansion (CTE), diffusivity and conductivity of the composite exhibit a distinctive shift in the material properties for the temperature range of 1300 $^\circ $ $^{\circ}$ C to 1500 $^\circ $ $^{\circ}$ C. Subsequent thermal analyses beyond that temperature range are markedly different and indicative of the thermophysical properties expected of a composite subjected to heat treatment. Analyses of the same specimens (pre- and post-heating) were also conducted using XRD and Raman microscopy in order to investigate the resultant variation in thermophysical properties as a result of repeated heat treatments. The findings were useful to assess the performances of the C/C composite in extremely high temperature conditions for the potential applications of hypersonic vehicle structure and components.