Abstract
Ultrasonic and rotating bending fatigue tests were carried out for Inconel 718 in order to investigate the effect of elevated temperature on fatigue properties. In ultrasonic, fatigue strength at 500℃ was larger than that at room temperature, and many intergranular facets were observed on the fracture surface at 500℃ in addition to striations and transgranular facets which observed at room temperature. This means that there are two factors which oppose each other to fatigue strength at which elevated temperature.
