Fracture modes of HAYNES® 230® alloy during fatigue-crack-growth at room and elevated temperatures

Fatigue-crack-growth tests with different hold times were conducted on HAYNES 230 alloy at room and elevated temperatures in air. Temperature and hold time effects on the fatigue and overload fractography were evaluated. The influence of the stress intensity factor range was also assessed. The role of carbides in the fracture process was discussed. An oxide-removal technique was applied on the high-temperature fracture surfaces when dark oxide layer precluded the identification of fracture features. The fracture mechanism was found to change from a transgranular mode to an intergranular one as the hold time increased.