Please use this identifier to cite or link to this item: http://elar.rsvpu.ru/handle/123456789/15303
Title: Gas and RRR distribution in high purity niobium EB welded in ultra-high vacuum.
Authors: Anakhov, S.
Singer, X.
Singer, W.
Wen, H
Issue Date: 2006
Publisher: AMER INST PHYSICS, 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA
Abstract: Electron beam (EB) welding in UHV (ultra-high vacuum, 10(-5) divided by 10(-8) mbar) is applied in the standard fabrication of high gradient niobium superconducting radio frequency (SRF) cavities of TESLA design. The quality of EB welding is critical for cavity performance. Experimental data of gas content (H-2, O-2, N-2) and RRR (residual resistivity ratio) measurements in niobium (Nb) welding seams are presented. EB welding in UHV conditions allow to preserve low gas content (1 divided by 3 wt. ppm hydrogen and 5 divided by 7 ppm. oxygen and nitrogen), essential for high values of RRR - 350 divided by 400 units. Gas content redistribution in the electron beam welded and heat affected region take place in the welding process. Correlation between gas solubility parameters, RRR and thermal conductivity are presented. Mechanisms of gas solubility in EB welding process are discussed.
Keywords: ELECTRON BEAM WELDING
GAS CONTENT
RESIDUAL RESISTIVITY RATIO
Conference name: 2nd International Symposium on Hydrogen in Matter
Conference date: JUN 13-17, 2005
ISBN: 0-7354-0329-5
ISSN: 0094-243X
Appears in Collections:Научные публикации, проиндексированные в SCOPUS и WoS

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