Microstructure evolution during cyclic tests on EUROFER 97 at room temperature. TEM observation and modelling

► Low cycle fatigue test are carried out on EUROFER 97 at room temperature. ► EUROFER 97 shows a pronounced cyclic softening accompanied by microstructural changes. ► Cycling induces a decrement in dislocation density and subgrain growth. ► A simple mean-field model based on crystalline plasticity is proposed. ► The mean subgrain size evolution is predicted by modelling.