Radiation effects on the mechanical properties of stainless steels

Abstract Stainless steels irradiated by electrons at 77 K were deformed at 77 and 290 K in order to investigate the isochronal annealing effects on their yield strengths in the temperature range 77 to 900 K. The austenitic stainless steel (JPCA-2) showed large irradiation hardening both for the 77 and 290 K. test. Furthermore, it was found from the test at 290 K that this hardening remained up to 900 K. On the contrary, for the ferritic/martensitic or martensitic stainless steel (JFMS or HT-9) irradiation softening was observed. In particular, both the isochronal annealing curves for the HT-9 with a single tempered martensite phase indicated that a large reduction of the yield stress amounted to 20–30% and this softening did not change during annealing up to 900 K. Furthermore, the characteristic feature of the ferritic/martensitic stainless steels was examined using pure Fe-Cr and Fe-Cr-C alloys as controls.