Stressed Oxidation of C/SiC Composites

Stressed Oxidation of C/SiC Composites PDF

Author:

Publisher:

Published: 1997

Total Pages: 14

ISBN-13:

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Constant load, stressed oxidation testing was performed on T-300 C/SiC composites with a SiC seal coat. Test conditions included temperatures ranging from 350 to 1500 deg C at stresses of 69 MPa and 172 MPa (10 and 25 ksi). The coupon subjected to stressed oxidation at 550 deg C/69 MPa for 25 hours had a room temperature residual strength one-half that of the as-received coupons. The coupon tested at the higher stress and all coupons tested at higher temperatures failed in less than 25 hr. Microstructural analysis of the fracture surfaces, using SEM (scanning electron microscopy), revealed the formation of reduced cross-sectional fibers with pointed tips. Analysis of composite cross-sections show pathways for oxygen ingress. The discussion will focus on fiber/matrix interphase oxidation and debonding as well as the formation and implications of the fiber tip morphology.

Oxidation of Continuous Carbon Fibers Within a Silicon Carbide Matrix Under Stressed and Unstressed Conditions

Oxidation of Continuous Carbon Fibers Within a Silicon Carbide Matrix Under Stressed and Unstressed Conditions PDF

Author: Michael C. Halbig

Publisher:

Published: 2000

Total Pages: 18

ISBN-13:

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Carbon fiber reinforced silicon carbide matrix composites (C/SiC) are a ceramic matrix composite (CMC) material that offers benefits for use in a wide range of high temperature structural applications. However the susceptibility of the carbon fibers to degradation in oxidizing environments has hindered the material's use in certain applications requiring long lives under oxidizing conditions. The susceptibility of carbon fibers to oxidation will be discussed as well as the enhancement (improvement in oxidation resistance) of C/SiC materials. Thermogravimetric analysis of carbon fibers shows susceptibility to oxidation in two distinct kinetic regimes. However, in the thermogravimetric (wt. loss) analysis of unstressed, unenhanced, seal coated C/SiC coupons, the two regimes were not observed due to crack closure and matrix effects, which inhibited the oxidation process. Stressed oxidation (creep rupture) tests put the material under a stress, which is a more realistic condition for many applications. In stressed oxidation tests, the two oxidation kinetics regimes were observed. These tests can provide better insight into how the material will perform in applications involving stress. Stressed oxidation of enhanced materials containing oxidation inhibitors showed significantly improved lives at the specific test conditions considered, although there was susceptibility to oxidation at intermediate temperatures.

Stressed Oxidation of C/SiC Composites

Stressed Oxidation of C/SiC Composites PDF

Author: Michael C. Halbig

Publisher:

Published: 1997

Total Pages: 8

ISBN-13:

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Constant load, stressed oxidation testing was performed on T-300 C/SiC composites with a SiC seal coat. Test conditions included temperatures ranging from 350 to 1500 deg C at stresses of 69 MPa and 172 MPa (10 and 25 ksi). The coupon subjected to stressed oxidation at 550 deg C/69 MPa for 25 hours had a room temperature residual strength one-half that of the as-received coupons. The coupon tested at the higher stress and all coupons tested at higher temperatures failed in less than 25 hr. Microstructural analysis of the fracture surfaces, using SEM (scanning electron microscopy), revealed the formation of reduced cross-sectional fibers with pointed tips. Analysis of composite cross-sections show pathways for oxygen ingress. The discussion will focus on fiber/matrix interphase oxidation and debonding as well as the formation and implications of the fiber tip morphology.

Degradation of Continuous Fiber Ceramic Matrix Composites Under Constant-Load Conditions

Degradation of Continuous Fiber Ceramic Matrix Composites Under Constant-Load Conditions PDF

Author:

Publisher:

Published: 2000

Total Pages: 22

ISBN-13:

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Ten different ceramic matrix composite (CMC) materials were subjected to a constant load and temperature in an air environment. Tests conducted under these conditions are often referred to as stressed oxidation or creep rupture tests. The stressed oxidation tests were conducted at a temperature of 1454 deg C at stresses of 69 MPa, 172 MPa and 50% of each material's ultimate tensile strength. The ten materials included such CMCs as C/SiC, SiC/C, SiC/SiC, SiC/SiNC and C/C. The time to failure results of the stressed oxidation tests will be presented. Much of the discussion regarding material degradation under stressed oxidation conditions will focus on C/SiC composites. Thermogravimetric analysis of the oxidation of fully exposed carbon fiber (T300) and of C/SiC coupons will be presented as well as a model that predicts the oxidation patterns and kinetics of carbon fiber tows oxidizing in a nonreactive matrix.

Degradation of Continuous Fiber Ceramic Matrix Composites Under Constant Load Conditions

Degradation of Continuous Fiber Ceramic Matrix Composites Under Constant Load Conditions PDF

Author: MC. Halbig

Publisher:

Published: 2000

Total Pages: 16

ISBN-13:

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Ten different ceramic matrix composite (CMC) materials were subjected to a constant load and temperature in an air environment. Tests conducted under these conditions are often referred to as stressed oxidation or creep rupture tests. The stressed oxidation tests were conducted at a temperature of 1454°C at stresses of 69 MPa, 172 MPa and 50% of each material's ultimate tensile strength. The ten materials included such CMCs as C/SiC, SiC/C, SiC/SiC, SiC/SiNC and C/C. The time to failure results of the stressed oxidation tests will be presented. Much of the discussion regarding material degradation under stressed oxidation conditions will focus on C/SiC composites. Thermogravimetric analysis of the oxidation of fully exposed carbon fiber (T300) and of C/SiC coupons will be presented as well as a model that predicts the oxidation patterns and kinetics of carbon fiber tows oxidizing in a nonreactive matrix.

Durability of Ceramic-Matrix Composites

Durability of Ceramic-Matrix Composites PDF

Author: Li Longbiao

Publisher: Woodhead Publishing

Published: 2020-02-07

Total Pages: 478

ISBN-13: 0081030223

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Durability of Ceramic-Matrix Composites presents the latest information on these high-temperature structural materials and their outstanding advantages over more conventional materials, including their high specific strength, high specific modulus, high temperature resistance and good thermal stability. The critical nature of the application of these advanced materials makes it necessary to have a complete understanding of their characterization. This book focuses explicitly on the durability of CMCs and will be extremely valuable for materials scientists and engineers who are dealing with the simulation of durability response and fatigue of ceramic matrix composites. Provides the latest theoretical and applied research in the field of ceramic matrix composites, particularly as it relates to usage in aerospace propulsion systems Presents extensive information on the micromechanics of damage evolution, lifetime prediction and durability in ceramic matrix composites Details parameter studies that are valuable for materials development and lifetime durability studies

Factors Controlling Elevated Temperature Strength Degradation of Silicon Carbide Composites

Factors Controlling Elevated Temperature Strength Degradation of Silicon Carbide Composites PDF

Author: National Aeronautics and Space Administration (NASA)

Publisher: Createspace Independent Publishing Platform

Published: 2018-06-24

Total Pages: 26

ISBN-13: 9781721788200

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For 5 years, the cooperative agreement NCC3-763 has focused on the development and understanding of Sic-based composites. Most of the work was performed in the area of SiC fiber-reinforced composites for UEET and NGLT and in collaboration with Goodrich Corporation under a partially reimbursable Space Act Agreement. A smaller amount of work was performed on C fiber-reinforced SiC matrix composites for NGLT. Major accomplishments during this agreement included: Improvements to the interphase used in melt-infiltrated (MI) SiC/SiC composites which increases the life under stressed-oxidation at intermediate temperatures referred to as "outside-debonding". This concept is currently in the patent process and received a Space Act Award. Mechanistic-based models of intermediate temperature degradation for MI SiC/SiC Quantification and relatively robust relationships for matrix crack evolution under stress in SiC/SiC composites which serve as the basis for stress-strain and elevated temperature life models The furthering of acoustic emission as a useful tool in composite damage evolution and the extension of the technique to other composite systems Development of hybrid C-SiC fiber-reinforced SiC matrix composites Numerous presentations at conferences, industry partners, and government centers and publications in recognized proceedings and journals. Other recognition of the author's accomplishments by NASA with a TGIR award (2004), NASA's Medal for Public Service (2004), and The American Ceramic Society s Richard M. Fulrath Award (2005). The following will briefly describe the work of the past five years in the three areas of interest: SiC/SiC composite development, mechanistic understanding and modeling of SiC/SiC composites, and environmental durability of C/SiC composites. More detail can be found in the publications cited at the end of this report. Glenn Research Center

Ceramic Matrix Composites

Ceramic Matrix Composites PDF

Author: Narottam P. Bansal

Publisher: John Wiley & Sons

Published: 2014-11-24

Total Pages: 725

ISBN-13: 1118231163

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This book is a comprehensive source of information on various aspects of ceramic matrix composites (CMC). It covers ceramic and carbon fibers; the fiber-matrix interface; processing, properties and industrial applications of various CMC systems; architecture, mechanical behavior at room and elevated temperatures, environmental effects and protective coatings, foreign object damage, modeling, life prediction, integration and joining. Each chapter in the book is written by specialists and internationally renowned researchers in the field. This book will provide state-of-the-art information on different aspects of CMCs. The book will be directed to researchers working in industry, academia, and national laboratories with interest and professional competence on CMCs. The book will also be useful to senior year and graduate students pursuing degrees in ceramic science and engineering, materials science and engineering, aeronautical, mechanical, and civil or aerospace engineering. Presents recent advances, new approaches and discusses new issues in the field, such as foreign object damage, life predictions, multiscale modeling based on probabilistic approaches, etc. Caters to the increasing interest in the application of ceramic matrix composites (CMC) materials in areas as diverse as aerospace, transport, energy, nuclear, and environment. CMCs are considered ans enabling technology for advanced aeropropulsion, space propulsion, space power, aerospace vehicles, space structures, as well as nuclear and chemical industries. Offers detailed descriptions of ceramic and carbon fibers; fiber-matrix interface; processing, properties and industrial applications of various CMC systems; architecture, mechanical behavior at room and elevated temperatures, environmental effects and protective coatings, foreign object damage, modeling, life prediction, integration/joining.

26th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - A, Volume 23, Issue 3

26th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - A, Volume 23, Issue 3 PDF

Author: Hua-Tay Lin

Publisher: John Wiley & Sons

Published: 2009-09-28

Total Pages: 872

ISBN-13: 0470295198

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This volume is part of the Ceramic Engineering and Science Proceeding (CESP) series. This series contains a collection of papers dealing with issues in both traditional ceramics (i.e., glass, whitewares, refractories, and porcelain enamel) and advanced ceramics. Topics covered in the area of advanced ceramic include bioceramics, nanomaterials, composites, solid oxide fuel cells, mechanical properties and structural design, advanced ceramic coatings, ceramic armor, porous ceramics, and more.

21st Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - A, Volume 18, Issue 3

21st Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - A, Volume 18, Issue 3 PDF

Author: J. P. Singh

Publisher: John Wiley & Sons

Published: 2009-09-28

Total Pages: 812

ISBN-13: 0470294922

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This volume is part of the Ceramic Engineering and Science Proceeding (CESP) series. This series contains a collection of papers dealing with issues in both traditional ceramics (i.e., glass, whitewares, refractories, and porcelain enamel) and advanced ceramics. Topics covered in the area of advanced ceramic include bioceramics, nanomaterials, composites, solid oxide fuel cells, mechanical properties and structural design, advanced ceramic coatings, ceramic armor, porous ceramics, and more.