SiC/SiC Composites for 1200°C and Above

DiCarlo, James A.; Yun, H. M.; Morscher, Gregory N.; Bhatt, Ramesh S.

doi:10.1007/0-387-23986-3_4

Cited by 110 publications

(85 citation statements)

References 12 publications

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“…In specific, CMCs could be applied to hot section components of gas turbines [1], aerojet engines [2], thermal protection systems [3], and hot control surfaces [4]. The benefits of implementing these materials include reduced cooling air requirements, lower weight, simpler component design, longer service life, and higher thrust [5]. It has been identified in NASA High Speed Research (HSR) program that the SiC/SiC CMC has the most promise for high temperature, high oxidation applications [6].…”

Section: Introductionmentioning

confidence: 99%

Monitoring damage accumulation in ceramic matrix composites using electrical resistivity

2008

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The electric resistance of woven SiC fiber reinforced SiC matrix composites were measured under tensile loading conditions. The results show that the electrical resistance is closely related to damage and that real-time information about the damage state can be obtained through monitoring of the resistance. Such self-sensing capability provides the possibility of on-board/in-situ damage detection and accurate life prediction for hightemperature ceramic matrix composites.Woven silicon carbide fiber-reinforced silicon carbide (SiC/SiC) ceramic matrix composites (CMC) possess unique properties such as high thermal conductivity, excellent creep resistance, improved toughness, and good environmental stability (oxidation resistance), making them particularly suitable for hot structure applications. In specific, CMCs could be applied to hot section components of gas turbines [1], aerojet engines [2], thermal protection systems [3], and hot control surfaces [4]. The benefits of implementing these materials include reduced cooling air requirements, lower weight, simpler component design, longer service life, and higher thrust [5]. It has been identified in NASA High Speed Research (HSR) program that the SiC/SiC CMC has the most promise for high temperature, high oxidation applications [6].One of the critical issues in the successful application of CMCs is on-board or insitu assessment of the damage state and an accurate prediction of the remaining service life of a particular component. This is of great concern, since most CMC components envisioned for aerospace applications will be exposed to harsh environments and play a key role in the vehicle's safety. On-line health monitoring can enable prediction of remaining life; thus resulting in improved safety and reliability of structural components. Monitoring can also allow for appropriate corrections to be made in real time, therefore leading to the prevention of catastrophic failures. Most conventional nondestructive evaluation (NDE) techniques such as ultrasonic C-scan, x-ray, thermography, and eddy current are limited since they require structural components of complex geometry to be taken out of service for a substantial length of time for post-damage inspection and assessment. Furthermore, the typical NDE techniques are useful for identifying large interlaminar flaws, but insensitive to CMC materials flaws developed perpendicular to the surface under tensile creep conditions. There are techniques such as piezoelectric sensor [7,8], and optical fiber [9,10] that could be used for on-line health monitoring of CMC structures. However, these systems involve attaching an external sensor or putting special fibers in CMC composites, which would be problematic at high temperature applications.https://ntrs.nasa.gov/search.jsp?R=20080047468 2018-05-11T18:03:58+00:00Z Most composite materials are multifunctional materials in which the damage is coupled with the material electrical resistance, providing the possibility of real-time information about the damage state thro...

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Section: Introductionmentioning

confidence: 99%

Monitoring damage accumulation in ceramic matrix composites using electrical resistivity

2008

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“…A 3 He cryostat is configured to allow simultaneous conductance measurement near dc and noise measurement near 2 MHz [25]. For dc measurements, the three reservoirs are each connected to a voltage amplifier, a current source, and a resistor to ground (r = 5 kΩ).…”

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confidence: 99%

“…Power spectral densities S V1,2 and cross-spectral density S V12 of these voltage fluctuations [25] are averaged over 20 s, except where noted. Following the calibration of amplifier gains and electron temperature T e using noise thermometry [25], the dot's intrinsic current noise power spectral densities S 1,2 and cross spectral density S 12 are extracted by taking into account the feedback [7] and thermal noise from the finite-impedance external circuit [26].…”

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confidence: 99%

Noise Correlations in a Coulomb-Blockaded Quantum Dot

et al. 2007

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We report measurements of current noise auto-and cross-correlation in a tunable quantum dot with two or three leads. As the Coulomb blockade is lifted at finite source-drain bias, the autocorrelation evolves from super-Poissonian to sub-Poissonian in the two-lead case, and the crosscorrelation evolves from positive to negative in the three-lead case, consistent with transport through multiple levels. Cross-correlations in the three-lead dot are found to be proportional to the noise in excess of the Poissonian value in the limit of weak output tunneling.Considered individually, Coulomb repulsion and Fermi statistics both tend to smooth electron flow, thereby reducing shot noise below the uncorrelated Poissonian limit [1,2]. For similar reasons, Fermi statistics without interactions also induces a negative noise crosscorrelation in multiterminal devices [1,2,3,4]. It is therefore surprising that under certain conditions, the interplay between Fermi statistics and Coulomb interaction can lead to electron bunching, i.e., super-Poissonian auto-correlation and positive cross-correlation of electronic noise.The specific conditions under which such positive noise correlations can arise has been the subject of numerous theoretical [5,6,7,8,9,10,11,12,13,14] and experimental [14,15,16,17,18,19,20,21,22,23] [10,15,24] occurring naturally in these devices. In more controlled geometries, super-Poissonian noise has been associated with inelastic cotunneling [9] in a nanotube quantum dot [20], and with dynamical channel blockade [11,12] in GaAs/AlGaAs quantum dots in the weak-tunneling [21] and quantum Hall regimes [22]. Positive noise cross-correlation has been observed in a capacitively-coupled double dot [23] as well as in electronic beam-splitters following either an inelastic voltage probe [5,6,7,8,19] or a super-Poissonian noise source [18]. The predicted positive noise cross-correlation in a three-lead quantum dot [12] has not been reported experimentally to our knowledge.This Letter describes measurement of current noise auto-and cross-correlation in a Coulomb-blockaded quantum dot configured to have either two or three leads. As a function of gate voltage and bias, regions of superand sub-Poissonian noise, as well as positive and negative noise cross-correlation, are identified. Results are in good agreement with a multi-level sequential-tunneling model in which electron bunching arises from dynamical chan-

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“…This is especially true of the more recent third generation fibers, whose near-stoichiometric composition has increased their chemical and environmental stability. Since SiC fiber-reinforced CMCs are being developed for hot-section components of gas-based turbine engines that require long life cycles in a combustion gas environment [71,94], it is critical to understand environmental effects on SiC fibers. That understanding rests on a foundational understanding of topics such as fracture toughness, subcritical crack growth, and environmentally assisted crack growth (or stress corrosion cracking).…”

Section: Environmental Effects On the Durability Of Sic Fibers And Simentioning

confidence: 99%

Creep of Hi-Nicalon S Ceramic Fiber Tows at 800 deg C in Air and in Silicic Acid-Saturated Steam

Robertson¹

2015

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SiC/SiC Composites for 1200°C and Above

Cited by 110 publications

References 12 publications

Monitoring damage accumulation in ceramic matrix composites using electrical resistivity

Monitoring damage accumulation in ceramic matrix composites using electrical resistivity

Noise Correlations in a Coulomb-Blockaded Quantum Dot

Creep of Hi-Nicalon S Ceramic Fiber Tows at 800 deg C in Air and in Silicic Acid-Saturated Steam

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