THE EFFECT OF THE MICROSTRUCTURE ON THE STATIC FATIGUE BEHAVIOR OF SI3N4

The effect of the microstructure on the static fatigue behaviour of tw o Si3N4 samples containing different sintering aids has been studied. The results show that the static fatigue behaviours of the two samples are consistent with each other in various media, i.e. the rate of cra ck growth of both materials is greatest in water, followed by air, and then kerosene. A distinctive microstructure endows one of the samples with a higher fracture toughness. In turn this results in a higher cr ack propagation resistance and a longer service life at the same stres s level.