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A single crystal nickel-base superalloy with < 001 > orientation was subjected to high cycle fatigue loading at temperature of 700 degrees C and 870 degrees C. The tests were performed in ambient atmosphere under load control at a stress ratio R=sigma(min)/sigma(max)=0.1 and a frequency of 83.3 Hz on smooth specimens. In this paper, the premature initiation and rapid propagation of cracks to failure due to high frequency cyclic loading were explored. The dislocation characteristics and fracture surface observation were evaluated through scanning electron microscopy and transmission electron microscopy, respectively. The results showed that the fatigue strength at 700 degrees C was higher than that at 870 degrees C. At 700 degrees C the interaction of cyclic stress with high temperature induced the precipitation of homogeneous hyperfine secondary gamma' particles, that is beneficial to fatigue strength. At 870 degrees C, the cyclic stress led to the formation of persistent slip bands moving through the gamma matrix channels and the gamma' precipitates. The morphology change of gamma' phase was not notable during the deformation at high frequency cyclic loading.