Implication of Time Dependent and Environmental Response of Structural Ceramics in Life Estimating Procedures

1983 ◽  
pp. 435-455 ◽  
Author(s):  
E. M. Lenoe ◽  
J. R. Peters
Keyword(s):  
Time Dependent ◽  
Environmental Response ◽  
Structural Ceramics

Critical Conditions for Crack-Healing of Structural Ceramics under Constant or Cyclic Stress

2006 ◽  
Vol 317-318 ◽  
pp. 461-464
Author(s):  
Masato Ono ◽  
Wataru Nakao ◽  
Koji Takahashi ◽  
Kotoji Ando
Keyword(s):  
Threshold Stress ◽  
Bending Strength ◽  
Cyclic Stress ◽  
Static Stress ◽  
Time Dependent ◽  
Critical Conditions ◽  
Crack Healing ◽  
Structural Ceramics ◽  
Cyclic Stresses ◽  
Sic Whiskers

Mullite reinforced by SiC whiskers, Mullite(W), was developed with the aim of improving fracture toughness and to add crack-healing ability. For determining the threshold stress during crack-healing, a composite having a semi-elliptical surface crack of 100 μm was crack-healed at 1473 K for 8 h in air under elevated static and cyclic stresses and the bending strength at 1473 K of the crack-healed composite under stress were also investigated. Mullite(W) crack-healed under static stress below 100 MPa were never fractured during crack-healing and had the same bending strength as the specimens crack-healed under no-stress. Therefore, the threshold static stress during crack-healing of Mullite(W) has been determined to be 100 MPa. The threshold cyclic stress has also been determined to be 150 MPa. Considering that the crack growth is time-dependent, the threshold stress for all conditions during crack-healing of Mullite(W) has been concluded to be 100 MPa.

The Ceramic Technology Project: Ten Years of Progress

1993 ◽  
Author(s):  
D. Ray Johnson ◽  
Robert B. Schulz
Keyword(s):  
Gas Turbines ◽  
Life Prediction ◽  
High Reliability ◽  
Ceramic Technology ◽  
Time Dependent ◽  
Structural Ceramics ◽  
Technology Project ◽  
Heat Engines ◽  
Heavy Duty Diesel

The Ceramic Technology Project was initiated in 1983 for the purpose of developing highly reliable structural ceramics for applications in advanced heat engines, such as the automotive gas turbines and advanced heavy duty diesel engines. The reliability problem was determined to be a result of uncontrolled populations of processing flaws in the brittle, flaw-sensitive materials, along with microstructural features, such as grain boundary phases, that contribute to time dependent strength reduction in service at high temperatures. The approach taken to develop high reliability ceramics included the development of tougher materials with greater tolerance to microstructural flaws, the development of advanced processing technology to minimize the size and number of flaws, and the development of mechanical testing methodology and the characterization of time dependent mechanical behavior, leading to a life prediction methodology for structural ceramics.

TIME-DEPENDENT PHENOMENA CAUSED BY THE EC DECAY IN Co2+ [Fe(CN)6]3-

1980 ◽  
Vol 41 (C1) ◽  
pp. C1-239-C1-240 ◽  
Author(s):  
Takayuki Kobayashi ◽  
Tetsuo Kitahara
Keyword(s):  
Time Dependent
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