Comparative study of the behavior of different highly alloyed steels in liquid sodium

Investigation of crack propagation resistance of 304L, 316L and 316L(N) austenitic steels in liquid sodium

“…Our study shows that the 304 L, the 316 L and, contrary to prior results of reference [13], the 316 L(N) austenitic steels have a lower crack propagation resistance in oxygenated liquid sodium. This difference in LME response for 316 L(N) could be attributed to the higher triaxiality of the axisymmetric notched geometry compared with the SPT test used by Serre et al [13]. More critically, the absence of LME could also be explained by an incomplete or absence of wetting since it is possible that an insufficient wetting was reached before SPT tests.…”

“…Still, this study may have missed the range or the conditions where LME can be maximum, even though a broad range of mechanical test parameters such as temperature and strain rate was investigated [17]. Our study shows that the 304 L, the 316 L and, contrary to prior results of reference [13], the 316 L(N) austenitic steels have a lower crack propagation resistance in oxygenated liquid sodium. This difference in LME response for 316 L(N) could be attributed to the higher triaxiality of the axisymmetric notched geometry compared with the SPT test used by Serre et al [13].…”

“…It is not sufficient to carry out in-situ experiments, one has also to make sure that LME prerequisites are fulfilled. Indeed, in a recent study of LME sensitivity on austenitic steels (15-15Ti and 316 L(N)) by in-situ small punch tests (SPT), a small effect of sodium on mechanical resistance was found for these steels, associated mainly with a ductile fracture mode [13]. Some scatter as a function of strain rate and temperature was also observed in these data.…”

“…Serre et al [13] reported that, in their conditions, liquid metal embrittlement has not to be considered for the 316 L(N) austenitic steel in the temperature range [473e823 K]. These authors observed a slight reduction in the mechanical properties for the specimens tested by small punch test in liquid sodium but the fracture mode remains fully ductile in their conditions.…”