Effect of grain size on cyclic fatigue and static fatigue behaviour sintered Al_2O_3

摘要

The fatigue behaviour of ceramics is an important factor for their application, particularly for struc-tural components. The behaviour has already been examined for some ceramics under various types of loading, but basic data for plain specimens looks insufficient. More information on factors affecting the fatigue strength seems necessary to clarify the fracture mechanism of ceramics and their reliability as structural materials. The effect of grain size on the fatigue strength of sintered A12O3 plain specimens has not been studied much in comparison with the effect on the static strength. In previous studies [1,2] the effect of grain size on the cyclic fatigue beha-viour was studied under rotary bending. According to the results, the fatigue strength, both static and cyclic, seems to be dependent on grain size. How-ever, elementary data on this problem are of limited availability. Therefore, both rotary bending and static fatigue tests were performed on the two kinds of plain specimens with different grain sizes at room temperature. The static fatigue test was performed by a non-rotating fatigue machine. The two fatigue tests were performed for a fairly long period to examine the existence of a knee, and the difference in the effects of grain size on the two fatigue types was studied.