Effect of Silicon on Electron Irradiation Behavior in China Low Activation Martensitic Steels

The irradiation damage behavior of two China low activation martensitic （CLAM） steels with different composition was studied by high voltage electron microscope. The results indicate that a lot of voids form in CLAM steel without silicon addition during electron irradiation. When irradiated to 14 dpa at 450 ℃, the number density of voids is about 8.7×10²¹ m^－3, and the irradiation swelling is approximately 0.26%. The irradiation swelling of CLAM steel without silicon addition at 450 ℃ is larger than that of at 500 ℃. When the irradiation damage rate is 2×10－3 dpa/s, no voids can be found in CLAM steel with silicon addition, so silicon is a good alloying element for irradiation swelling resistance in CLAM steels. When irradiated at 450 ℃, a kind of coherent precipitates form in silicon added CLAM steel.