Susumu Horibe

Fatigue behaviour of sintered SiC; temperature dependence and effect of doping with aluminium

Cyclic and static fatigue behaviours were investigated using sintered β-SiC materials with indentation-induced precracks, focusing especially on the temperature dependence and the effect of doping with aluminium. No effects of cyclic loading were observed in the crack growth of materials both with and without aluminium, tested for the whole temperature range of room temperature to 1500° C, suggesting that cyclic fatigue might be insignificant in SiC. However, there is static fatigue damage in the material, the causes of which seem to be different depending upon the temperature and the aluminium doping. The static fatigue observed at room temperature is environmentally assisted cracking, whereas the fatigue at high temperature (1500° C) seems to be controlled by the creep properties. In the high-temperature behaviour, doping SiC with aluminium makes its strength decrease for the case where the material is loaded to failure in a short time, but makes the resistance to cracking rather increase for the case where the sample is statically loaded at lower stresses for a relatively long time.

Corrosion fatigue in simulated aggressive marine environment

Etude des proprietes de fatigue en milieu corrosif sur un acier haute resistance. Analyse de la fissuration