|About this Abstract
||Materials Science & Technology 2020
||Advanced Characterization of Materials for Nuclear, Radiation, and Extreme Environments
||STEM Characterization of Dislocation Loops for an Irradiated Model FCC Alloy
||Pengyuan Xiu, Lumin Wang, Kevin G. Field
|On-Site Speaker (Planned)
In this study, we systematically developed the on-zone scanning transmission electron microscopy (STEM) methodology for imaging perfect and faulted dislocation loops in irradiated FCC materials, demonstrated on a model NiFe-20Cr alloy. Three major zone axes , ,  were studied using on-zone STEM imaging. Simulated dislocation loop morphology maps were developed to aid in loop type identification. Other imaging techniques using S/TEM were conducted to compare with STEM bright-field and annular-dark-field imaging, including on-zone, two-beam conditions bright-field and Rel-Rod dark-field imaging in conventional TEM (CTEM). On-zone  STEM-BF imaging was identified as the preferred method to robustly detect and identify both types of loops in irradiated FCC alloys. Factors affecting imaging resolution and signal-to-noise-ratio including camera length and collection angle were also investigated. The developed on-zone STEM methodology is shown to be a marked improvement for loop characterization over the common Rel-Rod imaging techniques used in the nuclear materials field.
||Planned: Publication outside of MS&T