Abstract
Single edge notched specimens of a unidirectional SiC long fiber reinforced titanium alloy were fatigued under four point bending. Propagation behavior of fatigue cracks was observed on the basis of the effect of the fiber bridging. The branched fatigue cracks were initiated from the notch root. The crack propagation rate decreased with crack extension due to the crack bridging by reinforced fibers. The longitudinal stress in the reinforced fiber was measured by using high spatial resolution synchrotron radiation. The interfacial frictional stress between the matrix and the fiber could be directly determined by X-ray method. The bridging stress was also measured as a function of a distance from a crack-tip. The stress intensity factor range corrected on the basis of the shielding effect agreed well with that for the monolithic titanium alloy, when compared at the same crack propagation rate.
