Quantification of fatigue crack propagation of an austenitic stainless steel in mercury embrittlement

Naoe, Takashi   ; Yamaguchi, Yoshihito ; Futakawa, Masatoshi  

Liquid metals are expected to be used as the nuclear materials because of its good thermal conductivity. However, in specific combinations of the liquid and solid metals, liquid metals have possibility to decrease lifetime of the structural material due to the LME. In this study, the LME in combination between the mercury and an austenitic stainless steel as a target and structural material for the pulsed spallation neutron source was investigated through the fatigue tests with the notched specimen under mercury immersion. The FRASTA method combined with the measurement of the notch opening distance was performed to estimate the fatigue crack growth rate in mercury. The results showed that the fatigue crack growth rate in mercury was slightly higher than that of in air at low cycle fatigue region. It was suggested that the crack propagation accelerated by the mercury immersion.