New insight into fatigue life of modified 9Cr-1Mo steel in liquid lead–bismuth environment and life prediction considering environmental factors.

• New insights in fatigue life of T91 steel in LBE are obtained using existing data. • A plastic LME factor is proposed to quantitatively evaluate the effect of LME and oxide film. • The LME effect is related to temperature instead of the plastic strain amplitude. • A fatigue life prediction model considering different factors is proposed with high accuracy regardless of data from different sources. The fatigue life of modified 9Cr-1Mo steel in liquid lead bismuth eutectic (LBE) at different strain amplitudes, temperatures and oxygen concentrations are analyzed. A liquid metal embrittlement (LME) factor of plastic strain is proposed to account for the reduced fatigue life induced by LME effect, which is also found to correlate well with tensile elongation in LBE. In low oxygen content LBE, the LME effect is influenced by temperature instead of plastic strain amplitude. While in high oxygen content LBE, the plastic LME factor is found to decrease exponentially with increasing plastic strain amplitude. Based on these findings, a fatigue life prediction model is proposed taking into account of different environmental influencing factors. In total, 86 data points are used with 70 % data points for independent validation only. Regardless of the discrepancy in fatigue life from different sources, good prediction results are still achieved with 98 % data points fall within ± 3 error band and 75 % data points fall within ± 2 error band. [ABSTRACT FROM AUTHOR]