Irradiation-induced hardening and softening of CLAM steel under Fe ion irradiation

摘要

The irradiation-induced hardening and softening of CLAM steel irradiated with 3.5 MeV Fe13+ ions at temperatures of 300 A degrees C and 550 A degrees C were investigated by nanoindentation tests in combination with microstructures. Irradiation- induced hardening occurred in the steel irradiated at 300 A degrees C to doses of 0.46 dpa, 0.94 dpa, and 2.79 dpa. The hardening occurred at 300 A degrees C is mainly attributed to the formation of irradiation-produced dislocation loops and a network of tangled dislocations in the irradiated steel samples. Significant hardening was found in the steel irradiated at 550 A degrees C to 0.38 dpa. On the contrary, irradiation-induced softening occurred in the steel irradiated at 550 A degrees C to both 0.76 dpa and 2.75 dpa. Irradiation-produced dislocation loops are not dominant effect on the irradiation hardening of the steel samples irradiated at 550 A degrees C. The hardening and softening of the irradiated steel were explained in terms of the irradiation-produced defects and recovery process occurred during the irradiation.