High-Temperature Low-Cycle Fatigue Tests on Hastelloy X

Tensile and low cycle fatigue tests were conducted on Hastelloy X in vacuum at several temperatures from room temperature to 900°C. The mid-range ductility minimum generally observed in nickel-base superalloys did not show itself in the material containing yttrium and which was solution heat treated at a higher temperature. The fatigue crack growth rate was calculated from the measured intervals of fatigue striation observed by scanning electron microscopy. The specimen that was fractured at 900°C did not present the typical fatigue surface, and instead the rupture was characterized by marked reduction in area and a large cavity in the center of the fracture.