Crack-growth behavior of alloy 230 under creep-fatigue conditions

The effect of temperature and hold time on cracking susceptibility of Alloy 230 has been studied using precracked compact-tension specimens. The complex creep-fatigue loading interactions have been evaluated by imposing different hold times on a triangular waveform associated with cyclic loading under a constant stress-intensity-factor-range. The results indicate that the crack-growth-rate was significantly enhanced at higher temperatures even at very short hold times. The fracture morphology was changed from transgranular to predominantly intergranular due to the introduction of longer hold times and/or increasing temperature.