2000 Volume 64 Issue 12 Pages 1269-1274
Life of Nuclear Reactor Pressure Vessel Steels (RPVS) is restricted by reduction of toughness resulting from radiation hardening. Radiation hardening of RPVS is mainly due to interactions of irradiation defects and impurities, especially copper, included in the steels. It is very important for the RPVS life assessment to clarify the mechanism of radiation hardening and toughness recovery by annealing.
Fe, Cu ions and neutrons were used to irradiate high purity Fe-Cu model alloys, and the correlation between microstructure and mechanical property was examined. The results are summarized as follows.
(1) After ion irradiation copper precipitates, which have FCC structure and size of 4-12 nm in diameter, were observed. (2) The degree of radiation hardening depended on copper concentration. The more copper content, the higher yield strength. (3) After annealing above 873 K, yield strength of the neutron-irradiated specimens recovered to the pre-irradiation value.
