Tensile properties of ODS-14%Cr ferritic alloy irradiated in a spallation environment

The tensile properties of mechanically-alloyed oxide dispersion strengthened MA957 steel were measured at room temperature following irradiation in the SINQ spallation target up to almost 20 dpa corresponding to an accumulated helium content of about 1750 appm, with an average irradiation temperature range of 100–360 °C. In contrast to the behaviour of 9Cr–1Mo martensitic steel samples subjected to identical irradiation conditions and which were drastically embrittled at high dose, all tested MA957 specimens displayed a ductile fracture mode as shown by the measured values of uniform and total elongations and by the results of fracture surface examinations. This good mechanical behaviour is a new evidence that this type of material may be able to sustain high displacement damage and helium levels and is thus particularly well suited for fusion applications.