Effect of Irradiation fluence on Tensile Properties in High Cr FMS Steel

High Cr steels are widely used as high temperature materials in the power plants and chemical industries due to their high strength and thermal conductivity, low thermal expansion, and good resistance to corrosion. Owing to the better irradiation characteristics (e.g. excellent irradiation swelling resistance) of these steels than austenitic alloys, they have been receiving attention for an application to the fuel cladding of Sodium Cooled Fast Reactor in Europe, USA and Japan. Irradiation damage caused by high energy particles occurs when the particles displace atoms from their normal lattice position. This irradiation induced microstructural changes lead to lattice hardening, which causes an increase in the yield strength and ultimate tensile strength and a decrease in the elongation. Below 400 .deg. C, the interstitials are mobile relative to vacancies, and the interstitials combine to form dislocation loops that increase strength and decrease ductility. The magnitude of the hardening changed with irradiation temperature, irradiation fluence and materials. In the present study, we performed irradiation tests to know the effect of irradiation fluence on tensile properties in high Cr FMS steel