|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Thermo-mechanical Response of Materials with Special Emphasis on In-situ Techniques
||In-situ ECCI Characterization of Microstructural Defects and their Effect on Superconducting Properties of SRF Cavity Niobium
||Mingmin Wang, Shreyas Balachandran, Santosh Chetri, Anatolii A Polyanskii, Peter J Lee, Christopher C Compton, Thomas R Bieler
|On-Site Speaker (Planned)
Microstructural defects such as dislocations and grain boundaries in high purity niobium can degrade superconducting cavity performance by trapping magnetic flux, degrading thermal conductivity, and perturbing superconducting currents. Understanding the relationship between microstructural defects and their influence on magnetic flux behavior in niobium is necessary to reduce performance variability. In this study, seven bi-crystal tensile samples were extracted on strategically chosen grain boundaries from two niobium slices. Electron Channeling Contract Imaging (ECCI) was performed to evaluate dislocation structure evolution in samples deformed to 5% strain in-situ in a SEM. Samples for Magneto-Optical Imaging (MOI) extracted from the tensile samples enabled visualization of magnetic flux penetration with a magnetic field applied below the critical temperature, such that the effect of grain boundaries and dislocations on the superconducting properties can be evaluated. Research supported by DOE/OHEP contracts DE-SC0009962, DE-SC0009960, NSF- DMR-1157490, and the state of Florida.
||Planned: Supplemental Proceedings volume