Low cycle fatigue behavior of a 10% Cr martensitic steel at 600°C

Abstract

In this work, the low cycle fatigue (LCF) behavior of a 10% Cr martensitic steel was studied under fully reversed tension-compression loading at 600°C for constant strain amplitudes between ±0.20 to ±1.0%. The cyclic stress response exhibited a gradual softening regime until fracture after an initial short period of a nearly stable stress. The fatigue lifetime curve at 600°C was determined to be described by the Basquin-Manson-Coffin relationship. At constant strain amplitudes of ≥±0.35%, the cyclic strain resistance of the steel mostly depends on its plastic properties. The cyclic softening effect was attributed to the coarsening of the laths and subgrains, accompanied by a decrease in the dislocation density.