|About this Abstract
||MS&T21: Materials Science & Technology
||Probing Defect Properties and Behavior under Mechanical Deformation and Extreme Conditions
||Measuring Elemental Segregation and Vacancy Migration Using Atom Probe Tomography
||Xing Wang, Jonathan Poplawsky, Yanwen Zhang, Karren L. More
|On-Site Speaker (Planned)
Cavity is an important defect structure in irradiated materials. Cavity growth is often controlled by the clustering of vacancies. Due to different element diffusivities mediated by vacancies, the vacancy flux to cavities will lead to local elemental segregations, providing a unique probe to quantify vacancy migration and its effects on cavity growth. Here, atom probe tomography (APT) was used to accurately measure segregations near nanoscale cavities in concentrated solid solution alloys (CSAs). We show that Cr is depleted more than other elements, indicating faster vacancy migration via this element and explaining the larger cavity growth rate in CSAs containing Cr. Segregation analyses also find Pd repels other oversized elements such as Fe and Cr, adding extra migration paths for vacancies and suppressing cavity growth. This work was supported by EDDE, an EFRC funded by U.S. DOE-BES. APT was conducted at ORNL’s CNMS, a U.S. DOE Office of Science User Facility.