Kinetics of thermal and radiation-stimulated ageing of EhP838 stainless steel

Method of electric resistance measurement has been used to study phase stability of EhP 838 austenitic stainless steel under thermal and radiation conditions. The EhP 838 has been irradiated with 2 MeV electrons up to approximately 1019 cm-2 doses in the temperature range of 100-400 deg C. Low temperature annealing of the EhP 838 austenized samples is conducted at 100 deg and 400 deg C with duration up to approximately 13 hr. It is shown that phase transformations accompanied by considerable change of specific electric resistance under conditions of the thermal annealing as well as at irradiation. Activation energies of the thermal and radiation ageing processes equal correspondingly to 0.53 and 0.30 eV are determined. On the base of the analysis the conclusion is made that the most probable processes, proceeding during the low temperature annealing or under irradiation are the formation of nitride and carbide nuclei (especially under conditions of irradiation)