EFFECT OF CARBON ON IRRADIATION HARDENING OF REDUCED-ACTIVATION 10CR-30MN AUSTENITIC STEELS

Tensile properties of reduced-activation 10Cr-30Mn austenitic steels w ith carbon levels from 0.003 to 0.55% were investigated over the tempe rature range from room temperature to 873 K after neutron irradiation in the Japan Materials Testing Reactor at 573 K to 8.5 x 10(22) n/m(2) . Irradiation-induced increase in yield stress increased significantly with carbon concentration up to about 0.1% and it was constant above 0.1% carbon. A high density of dislocation loops with small (below 10 nm) and large (20-30 nm) sizes formed during irradiation. The high den sity, small loops caused a large irradiation hardening, while the larg e loops contributed only slightly to irradiation hardening. It was con sidered that carbon atoms formed the small loops together with irradia tion defects. The deformation channeling was observed in the irradiate d high carbon steels, 0.11 and 0.55% carbon, but not in the very low c arbon steel, 0.003% carbon, after deformation near room temperature.