Fatigue crack growth behavior of GH3230 alloy at high temperature by direct current potential drop method

The fatigue crack growth test of GH3230 alloy at high temperature was carried out by direct current potential drop method. The effects of temperature and stress intensity factor on the fatigue crack growth rate of GH3230 alloy were analyzed, and the fracture surface was analyzed by scanning electron microscope. The results show that under the same stress intensity factor, the crack growth rate of the alloy increased with the increase of temperature. When the temperature rose from 750 ℃ to 850 ℃, the crack growth rate increased obviously. When the temperature rose from 850 ℃ to 950 ℃, the difference of crack growth rate under small stress intensity factor was not big. With the increase of stress intensity factor and temperature, the difference of crack growth rate increased. It could be seen from the observation of the fracture surface that in the crack propagation zone and the transient fracture zone, the fracture surface presented typical fatigue striation and dimple characteristics. With the increase of temperature, the oxide particles on the fracture surface increased, and the fatigue striation in the crack propagation zone was less obvious.