Abstract
R-curve and fatigue crack growth behavior of partially stabilized zirconia were studied using indentation-strength-in-bending (ISB) method and static and cyclic fatigue tests. The indentation-strength measurements in ISB method indicated that there is no increasing crack extension resistance, that is, a flat R-curve behavior. On the other hand, the relation between crack growth rate and stress intensity factor in subcritical crack growth obtained from lifetime measurements in the static and cyclic fatigue tests indicated that the cyclic loading accelerated the subcritical crack growth rate. X-ray diffraction patterns of fracture surfaces showed that stress induced phase transformation from tetragonal to monoclinic occurred by the loading. As the results, it is considered that the R-curve appeared to be rising fast but saturated at high toughness value, and the micro cracks induced by cyclic loading facilitated the subcritical crack growth.
