|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Refractory Metals 2016
||Introduction of Precisely Controlled Microstructural Defects into SRF Cavity Nb Sheet and Their Impact on Local Superconducting Properties
||Mingmin Wang, Di Kang, Zuhawn Sung, Peter J. Lee, Anatolii A Polyanskii, Christopher C. Compton, Thomas R. Bieler
|On-Site Speaker (Planned)
Formation of a SRF cavity from Nb sheets introduces microstructural defects such as dislocations and low-angle grain boundaries that can become favorable sites for pinning centers for magnetic flux, which degrades cavity performance. Therefore, effects of grain boundaries on magnetic flux behavior in strained bicrystal Nb samples were investigated. Laue X-ray and electron backscattered diffraction (EBSD) mapping were used to characterize microstructural defects and to assess which grain boundaries and orientations will produce model defects after tensile deformation similar to that expected in forming cavities made from large grain material. Grain boundaries and orientations were chosen to favor specific slip systems, which generate dislocations with special angles with respect to the grain boundaries of the bicrystal Nb samples. The generated defect structures were characterized using EBSD and electron channeling contrast imaging. Cryogenic magneto-optical imaging was used to directly observe the penetration of magnetic flux into the deformed Nb.
||Planned: A print-only volume