X-Ray Diffraction line profile analysis of defects and precipitates in high displacement damage neutron-irradiated austenitic stainless steels

Abstract

Irradiation-induced defects and the precipitates in the wrapper material of the Indian Fast Breeder Test Reactor (FBTR), SS 316 are analyzed using the synchrotron source-based Angle Dispersive X-Ray Diffraction (ADXRD) technique with X-rays of energy 17.185 keV (wavelength ∼0.72146 Å). The differences and similarities in the high displacement damage samples as a function of dpa (displacement per atom) and dpa rate in the range of 2.9 × 10−7- 9 × 10−7 dpa/s are studied. Ferrite and M23C6 are commonly observed in the present set of high displacement damage 40–74 dpa SS 316 samples irradiated at temperatures in the range of 400–483 °C. Also, the dislocation density has increased as a function of the irradiation dose. The X-ray diffraction peak profile parameters quantified such as peak shift and asymmetry show that the irradiation-induced defects are sensitive to the dpa rate-irradiation temperature combinations. The increase in yield strength as a function of displacement damage is also correlated to the dislocation density.

Keywords

• Neutron irradiation
• Irradiation-induced defects
• Austenitic stainless steels
• X-ray diffraction
• Irradiation-induced phases
• M23C6 variation