Proton irradiation for radiation-induced changes in microstructures and mechanical properties of austenitic stainless steel

• Published in: Journal of nuclear materials 2019-01, Vol.513, p.271-281
• Main Authors: Jin, Hyung-Ha, Hwang, Seong Sik, Choi, Min Jae, Lee, Gyeong-Geun, Kwon, Junhyun
• Format: Article
• Language: English
• Subjects: Austenitic stainless steel; Austenitic stainless steels; Chemical composition; Crystal defects; Dartrose; Dosage; Electron microscopy; Electrons; Focused ion beam; Grain boundaries; Indentation; Irradiation; Mechanical properties; Microstructure; Nano-indentation; Neutron irradiation; Neutron radiation; Organic chemistry; Proton damage; Proton irradiation; Radiation; Radiation damage; Radiation effects; Radiation hardening; Stainless steel; Transition points; Transmission electron microscopy
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2018.11.017

We report on microstructural and mechanical property changes as a function of radiation damage value in proton-irradiated austenitic stainless steel by means of advanced characterization techniques. The microstructural changes in proton-irradiated austenitic stainless steel were analyzed by transmission electron microscopy for observation of radiation-induced defects as well as the measurement of the chemical composition at grain boundaries. The radiation hardening after the proton irradiation was characterized by nano indentation for changes in hardness profiles with radiation damage. Various transition points for microstructural and mechanical property changes under proton irradiation are analyzed via material characterization of proton-irradiated austenitic stainless steels. The saturation is expected to occur at approximately 10 displacements per atom (dpa) for the radiation-induced segregation of Cr, Ni, and P and approximately 2.5 dpa for radiation hardening. The cavity formation is observed to occur at hydrogen concentration levels greater than 5E5 atomic parts per million (appm) H. It is also found that the transition from black dot to Frank loop happened above approximately 1 dpa. Profiles of radiation-induced segregation and radiation hardening as a function of dpa can be extended to the high irradiation condition, and can be compared with experimental data for neutron irradiation-induced segregation and radiation hardening. The radiation-induced segregation after the proton irradiation at 360 °C are in good agreement with that after neutron irradiation. On the other hand, it is observed that the evolution of radiation-induced defects and the corresponding radiation hardening exhibit sooner, that appears to be because of the dose rate effect.