Author(s)

Z. Knesl, L. Kunz, V. Sklenicka & D. Vilimek

Abstract

A notch effect under creep/high-cycle-fatigue loading conditions was studied both theoretically and experimentally in notched specimens of an advanced 9%Cr steel of the type P91 at 600°C. Experiments were performed under condition of the constant maximum net stress. The stress ratio R, i.e., the cyclic stress component of creep/fatigue loading was varied. The dependence of time to fracture on R exhibits nonmonotonous behaviour with a pronounced maximum coinciding with the fracture mode transition from pure creep to fatigue. The notched specimens show increased rupture strength when compared with smooth bars. The strengthening due to the notch depends on the notch geometry. It is shown that the notch tip stress triaxiality pa

Keywords