2008 Volume 3 Pages 017
The manufacturing process of creep specimens and an irradiation technique in a liquid metal environment for in-pile and creep measurements of irradiated samples are established for highly purified V-4Cr-4Ti, NIFS-HEAT alloys. Irradiation experiments with sodium-enclosed irradiation capsules in JOYO and lithiumenclosed irradiation capsules in HFIR-17J were conducted using pressurized creep tubes. From thermal creep experiments, the activation energy of creep deformation using pressurized creep tubes was determined to be 210 kJ/mol·K, the creep stress factor was 4.9 for an 800°C creep test, and its mechanism was determined to be a climb-assisted glide of dislocation motion. It was found that the creep strain rate exhibited a linear relationship with effective stress up to 150 MPa from 425 to 600°C under JOYO and HFIR irradiation. The activation energy of irradiation creep was estimated to be 46 kJ/mol·K. No significant difference in irradiation creep behavior between the liquid sodium and liquid lithium environments was observed. A set of essential physical data of irradiation creep properties was obtained for V-4Cr-4Ti alloys.
