Evaluation of notched fatigue strength at elevated temperature by linear notch mechanics

The notched fatigue strength of nickel-base superalloy Inconel 718 has been investigated under rotating bending loading at room temperature and 500 de grees C in air. The applicability of linear notch mechanics to the evaluati on of notched fatigue strength at elevated temperature was assessed in term s of the fatigue limit for crack initiation and that for crack growth. The effect of temperature on the fatigue strength and notch sensitivity of Inco nel 718 was examined. The results were discussed from the viewpoints of the softening of matrix and surface oxidation at elevated temperature. (C) 199 9 Elsevier Science Ltd. All rights reserved.