The scanning electron microscopy was adopted to identify the fracture features of specimen in FGH97

which had been tested under the conditions of stress-ratio of 0.05

750℃ and various dwell times. It was found that

for dwell time of 90s

the fatigue striation feature gradually disappeared with the increment of the stress intensity factor range values

and the turning point of neglecting fatigue loads located at the medium stress intensity factor range evel. But the corresponding stress intensity factor range values located at the lower levels for 450s and 1500s dwell time. Based on the trinomial model including fatigue item

creep item and creep-fatigue interaction item

the time-dependent and cycle-dependent components were employed to describe the test data of creep-fatigue crack growth in FGH97. The proportions of contribution to crack growth rate (CGR) of the two components are significantly influenced by stress intensity factor range values at different dwell times. The model for describing the time-dependent crack growth rate is proposed according to the analysis results. Furthermore

the stress intensity factor range values

which could affect the predominant factor of time-dependent component or time-dependent and cycle-dependent component on CGR

are obtained at various dwell times.