![Temperature Dependence of Crack Wake Bridging Stresses in Silicon Carbide-reinforced Alumina Composites [microform] PDF](https://books.google.com/books/content/images/frontcover/pdebtgAACAAJ?fife=w150-h200)
Author: G. Reza (Gholam Reza) Sarrafi-NourPublisher: National Library of Canada = Bibliothèque nationale du Canada
ISBN: 9780612413061
Category :
Languages : en
Pages : 262
Book Description
Temperature Dependence of Crack Wake Bridging Stresses in Silicon Carbide-reinforced Alumina Composites [microform]
![Temperature Dependence of Crack Wake Bridging Stresses in Silicon Carbide-reinforced Alumina Composites [microform] PDF](https://books.google.com/books/content/images/frontcover/pdebtgAACAAJ?fife=w80-h100)
Author: G. Reza (Gholam Reza) Sarrafi-NourPublisher: National Library of Canada = Bibliothèque nationale du Canada
ISBN: 9780612413061
Category :
Languages : en
Pages : 262
Book Description
Temperature Dependence of Crack Wake Bridging Stresses in Silicon Carbide-reinforced Alumina Composites
Author: Temperature Dependence of Crack Wake Bridging Stresses in Silicon Carbide-reinforced Alumina Composites
Author: G. Reza Sarrafi-NourPublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
R-curves for a SiC-platelet-reinforeed alumina and a SiC-whisker-reinforced alumina were obtained between room temperature and 1400°C from chevron-notched flexure specimens. In response to evidence that R-curves alone provide inadequate characterization of the crack wake bridging processes due to their strong geometry dependence, a procedure based on a fracture mechanics weight function was developed to characterize the bridging stresses imposed on the crack surfaces by the bridging elements as a function of crack surface displacement. Finite element analysis was used to obtain the required weight function for crack surface tractions in specific chevron-notched flexure specimen geometries, and to find the crack opening displacement due to the applied load. An iterative scheme was devised to extract the bridging relation from the measured R-curves. The temperature dependence of the bridging stresses could then be studied through analysis of the R-curves measured for the composites. Similar levels of bridging stresses were found in both of the composites. The bridging stresses in the SiCpl-Al2O3 were found to be limited to a smaller crack surface displacement range, almost half of the value for the SiCw-Al2O3 material. These stresses were found to decay linearly with temperature in the whisker-reinforced material, while the limited non-linearity observed in the case of the platelet-reinforcement was attributed to the presence of an interfacial amorphous phase found in this composite. The unexpected similarity in the magnitude of the bridging stresses in the two composites is discussed in terms of the micromechanics of pullout bridging. The crack tip toughness is found to increase with temperature in the whisker-reinforced material. In agreement with some previous studies of the composite, this toughening effect is associated with a microcrack zone formed ahead of the crack tip by the coalescence of diffusional cavities at the SiC w/Al2O3 interface. However, the results do not indicate any crack length dependence in this behavior or any influence from the microcrack zone on the bridging stresses.
Ambient and Elevated Temperature Fracture and Cyclic-fatigue Properties in a Series of Al-containing Silicon Carbide Ceramics
Author: Rong Yuan (M.S.)Elevated Temperature Crack Growth Resistance of Alumina-silicon-carbide Composite Under Static and Cyclic Loads
Author: Xiaohua HanEnvironmental Effects on Elevated Temperature Subcritical Crack Growth of SiC
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 10
Book Description
Time-dependent crack growth measurements of ceramic composites in varying environments were conducted on materials consisting of chemical vapor infiltrated SiC reinforced with Nicalon fibers having C-interfaces. Crack velocities are determined as a function of applied stress intensity and time for varying O2 levels. Results are presented for crack velocity/stress intensity relationships in pure Ar and in Ar plus 2000-, 5000-, 10,000-, and 20,000-ppM O2 atmospheres at 1100C. A 2D micromechanics model is used to represent the time-dependence of observed crack bridging events and to rationalize the observed phenomena.
Tensile Creep of Silicon Carbide Whisker-reinforced Alumina Composites [microform]
![Tensile Creep of Silicon Carbide Whisker-reinforced Alumina Composites [microform] PDF](https://books.google.com/books/content/images/frontcover/JaSttAEACAAJ?fife=w80-h100)
Author: Guang-Chun QuanPublisher: Library and Archives Canada = Bibliothèque et Archives Canada
ISBN: 9780612977914
Category : Aluminum oxide
Languages : en
Pages : 340
Book Description
Alumina composites with 10, 20 and 30 volume % SiC whiskers were fabricated using colloidal processing methods followed by uniaxial hot pressing. The tensile creep properties of these materials have been studied between 1200°C and 1400°C.
Physics Briefs
Author: Report of the Presidential Commission on the Space Shuttle Challenger Accident
Author: DIANE Publishing CompanyPublisher: DIANE Publishing
ISBN: 0788119125
Category :
Languages : en
Pages : 267
Book Description
Classic and Advanced Ceramics
Author: Robert B. HeimannPublisher: John Wiley & Sons
ISBN: 352763018X
Category : Technology & Engineering
Languages : en
Pages : 573
Book Description
Based on the author's lectures to graduate students of geosciences, physics, chemistry and materials science, this didactic handbook covers basic aspects of ceramics such as composition and structure as well as such advanced topics as achieving specific functionalities by choosing the right materials. The focus lies on the thermal transformation processes of natural raw materials to arrive at traditional structural ceramics and on the general physical principles of advanced functional ceramics. The book thus provides practice-oriented information to readers in research, development and engineering on how to understand, make and improve ceramics and derived products, while also serving as a rapid reference for the practitioner. The choice of topics and style of presentation make it equally useful for chemists, materials scientists, engineers and mineralogists.