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STUDY OF STRENGTH
AND FATIGUE BEHAVIOR
OF SOME CERAMIC MATERIALS*
Qiao Guanjun Jin Zhihao
School of Materials Science and Engineering, Xi'an Jiaotong University,
Xi'an 710049, China |
Abstract:
The fatigue behavior is systematically investigated with three typical ceramic materials, including Y2O3-ZrO2, Si3N4 and a machinable glass-ceramic. Cyclic, static and dynamic fatigue tests are conducted in three environments, I.e., moist air, distilled water and kerosene. The effects of environment and loading condition on fatigue behavior are analyzed. The difference between materials is discussed. Experiment results show that, for all the three materials, fatigue life under cyclic load is the shortest and a small n value (fatigue exponent) is obtained. Compared with the other materials, Si3N4 ceramic has a very large n value under static load. Therefore the static fatigue for Si3N4 ceramics may be neglected. Cyclic load decreases the fatigue life of transformation-toughening ceramics (Y-TZP)
more seriously, while no remarkable difference is observed
between cyclic and static fatigue for original glass of the
glass-ceramic. A new idea about the physical meaning of n value
and the concept of intrinsic stress-corrosion exponent n0
is introduced. The n value could be divided into two terms,
i.e., n=n0 + nμ, where nμ
describes the contribution of microstructure toughening and is
very sensitive to environment and loading conditions. This theory could be used to describe and explain the experiment results successfully.
Key words:
Strength Fatigue Ceramics Stress corrosion exponent
* This project is supported by
National Natural Science Foundation of China (No.50072017).
Selected from Proceedings of 2000 the First International Conference on
Mechanical Engineering. revised manuscript July 26, 2001
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