TENSILE PROPERTIES OF REDUCED-ACTIVATION FE-9CR-2W STEELS AFTER FFTF IRRADIATION

In order to develop radiation resistant steels with reduced activation for fusion reactor applications, the effect of fast neutron irradiati on was investigated on the tensile properties of five types of Fe-9Cr- 2W martensitic steel with and without small additions of boron, yttriu m and aluminum. Miniature tensile specimens of the steels were irradia ted to 28 dpa at 663 K and 33-35 dpa at 703, 793 and 873 K in the Fast Flux Test Facility (FFTF) and were deformed at temperatures between 3 00 and 873 K. The yield and ultimate tensile stresses were not signifi cantly affected by the irradiations, but the total elongation was cons iderably decreased by the irradiation at 663 K. The reduction in elong ation depended strongly on the test temperature with a maximum at arou nd 673 K. The addition of yttrium alone tended to increase the high te mperature strength, while the simultaneous addition of yttrium and alu minum tended to decrease the total elongation.