Liquid metal embrittlement of an austenitic 316L type and a ferritic–martensitic T91 type steel by mercury

The susceptibility to liquid metal embrittlement (LME) of 316L and T91 steels by mercury has been studied at room temperature. A dedicated experimental device using center crack tension (CCT) specimens was built. We developed a specimen preparation procedure that must be rigorously applied in order to investigate the embrittling effect of Hg. The high strength ferritic–martensitic steel of type T91 is embrittled by Hg at room temperature over a large range of crosshead speeds, between 6.67 × 10−7 and 6.67 × 10−3 m s−1. More surprisingly, the austenitic steel of type 316L is also embrittled by Hg between 1.67 × 10−8 and 2.5 × 10−4 m s−1. The fracture of the T91 and 316L CCT specimens in contact with Hg occurs by shear band decohesion over the above-mentioned range of crosshead speeds.