Effect of temperature on low cycle fatigue behavior of T91 steel in liquid lead-bismuth eutectic environment at 150–550 °C

The low cycle fatigue behavior of T91 steel in a lead–bismuth eutectic and an air environment was investigated at 150–550 °C. The temperature dependent “fatigue endurance peak and trough” was found in liquid LBE. Quasi-cleavage cracking was observed on the fracture surface at 150 °C and 350 °C, which indicates the occurrence of liquid metal embrittlement (LME). The plasticity recovery reduced LME susceptibility of T91 steel at 250 °C and 550 °C. The effects of LME, liquid LBE corrosion and dynamic strain aging on the mechanisms of fatigue crack initiation and propagation are discussed.