抄録
LCF tests were carried out at 565°C on a ferrite-bainite 241Cr1Mo steel that has been taken from a power plant component after a 160000 h service time. Before fatigue, a detailed preliminary analysis of the microstructure was first performed not only in terms of precipitates but also in terms of dislocation cell subboundaries present in the bainitic grains. Strain cycling globally led to a softening of the alloy which can be preceded by a hardening period depending on the strain amplitude. A fatigue cellular structure developed in the ferritic grains whatever the strain level. In the bainite, it was possible by CBED to show a rotation of the preexisting cells as indicated by the orientation measurements. The mechanisms of cyclic plasticity of the 241Cr1Mo steel is thus explained by considering the individual behavior of each phase.
