Radiation defects and hydrogen in austenitic and austenitic-martensitic steels under low-temperature neutron irradiation

The experimental data concerning the effect of hydrogen (300 appm), radiogenic helium, and low-temperature neutron irradiation (77 K) on the properties of the promising austenitic 16Cr15Ni3Mo1Ti and austenitic-martensitic 16Cr9Ni3Mo steels have been reported. It has been found that hydrogen saturation causes an increase in the yield stress, with this increase being larger in the martensitic than in the austenitic phase. The yield stress of both steels increases substantially after exposure to fast neutrons. The variation of the yield stress of the two-phase steel and its phase components under low-temperature neutron irradiation has been estimated. The displacement cascades begin overlapping under irradiation at a fluence larger than 1.5 × 10 18 cm −2 .