A Preliminary Study on Helium and Sulfur Ion-Irradiated BCC Iron: In Situ Tensile Testing Using a Push-To-Pull Device

Under energetic radiation exposure, significant changes in material behavior occur because of the substantial increase in the point defect population and other higher order defects. Here, we report preliminary results of a study in which an in situ transmission electron microscopy (TEM)-based push-to-pull (PTP) tensile test technique was utilized to understand the microstructure and its impact on mechanical and fracture behavior in irradiated BCC iron. Density functional theory-based calculations predict a strong segregation tendency of helium and sulfur to grain boundaries. Pure iron specimens were separately implanted with energetic helium and sulfur ions at 550°C to examine the effect of ion irradiation on the microstructure using TEM, and the mechanical response in terms of strength and embrittlement behavior using the PTP technique.