Effects of temperature and strain rate on the mechanical properties of T91 material tested in liquid lead bismuth eutectic

The effects of temperature and strain rate on the susceptibility of one of the most promising candidate materials for ADS, Ferritic/ Martensitic steel (T91), to liquid metal embrittlement have been investigated in the temperature interval 150 to 450°C, at strain rates between 1.10-3 s-1 and 1.10-6 s-1. The effect of the liquid lead bismuth eutectic has been evaluated by comparison between tests in the liquid metal and in Ar with 5% H2. Although the untreated T91 material did not undergo liquid metal embrittlement and there was no change in the tensile properties as function of temperature or strain rate due to the liquid metal, the pre-exposed T91, did show a decrease in total elongation. The total elongation of the untreated T91 specimens in liquid lead bismuth and in H2/Ar-gas mixture followed the same dependence on the temperature up to 245°C. At temperatures above 375°C no results are available from testing in controlled gas environment however reference data measured on the same batch of steel in air are used for comparison. The results are discussed in terms of self-healing mechanism and crack initiation processes.