Microstructure and mechanical properties of neutron-irradiated ultra-fine-grained SUS316L stainless steels and electrodeposited nanocrystalline Ni and Ni–W alloys

In order to overcome the irradiation embrittlement in metallic materials, ultra-fine grained SUS316L steels with their grain sizes between 0.1 and 1 μm have been developed by mechanical alloying, and nanocrystalline Ni and Ni–W alloys with their grain sizes between about 6 nm and 20 μm have been developed by electrodeposition. In order to clarify the effects of the neutron irradiation on mechanical properties of the nanocrystalline materials, Vickers microhardness measurements and transmission electron microscopy (TEM) were performed before and after the irradiation of 1.14 × 10 23 and 1.14 × 10 24 n/m 2 . When the grain sizes were less than about 0.3 μm in the SUS316L and the Ni–W alloys, Vickers hardness was almost unchanged, and the irradiation defects could not observed by TEM.