Low cycle fatigue behavior of cast nickel base superalloy K52

Low cycle fatigue (LCF) behaviors of cast nickel-base superalloy K52 at different temperatures were investigated, and the fatigue parameters were given by analyzing its cyclic stress-strain curves and strain-life curves. Cyclic stress response curves show that the alloy exhibited cyclic hardening and softening behaviors at room temperature and 900 degrees C, respectively. OM and SEM observations indicated that LCF cracks initiated predominantly on the surface of specimen or at the near-surface defects. Once initiated, cracks would propagate perpendicularly to the loading direction and the specimens exhibited transgranular fracture.