Mechanics of Nb-Ti superconducting composites Public Deposited

http://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/0p096b30f

Descriptions

Attribute NameValues
Creator
Abstract or Summary
  • Mechanical behavior of Nb-Ti superconducting composites with copper matrices have been studied experimentally and theoretically. Experimental work includes extensive measurements of Cu/Nb-Ti composite system. Techniques for fine fiber testing and composite wire measurement have been developed. Experimental parameters examined in this research include geometry, hardness, Young's modulus, Poisson's ratio, yield strength and ultimate strength. Three theoretical models have been developed to study the mechanics of the Cu/Nb-Ti composite system. The influence of several design parameters on the mechanics of the Nb-Ti composites was studied and provides some insight on superconducting composite design for improvements in processing and performance. The mechanical behavior of the Cu/Nb-Ti composite system are found to be functions of geometry, composition and processing. Geometry of Nb-Ti superconducting composites is different from most engineering composites and there are two factors affecting sample geometry: the variability of fiber geometry and the placement of fibers within the composite. The strength distribution of Nb-Ti fibers is closely related to the distribution of fiber geometry and the composite strength increases as the scatter of fiber strength decreases. Heat treatment reduces the hardness of the bulk copper dramatically. The first heat treatment increases the strength and hardness of the Nb-Ti fibers, further heat treatments reduce the strength and hardness while increasing Young's modulus of the fibers. As the extent of cold work increases, the strength of Nb-Ti fibers and that of the composite wires increases. Cold work effects on the Young's modulus of the composites and the Nb-Ti fibers are not significant. For a constant global Cu/SC ratio, the lower the local Cu/SC ratio, the lower the micro-in-plane stresses. From this point of view, the fibers should be packed as close as possible to one another. For a constant local Cu/SC ratio, when the inner radius of the Nb-Ti assembly increases (the fibers are packed further from center), the macro-in-plane stresses increase. From this point of view, the fibers should be packed as close to the center of the wire as possible. For a constant geometry, the higher the difference between E[subscript f] and E[subscript m], the lower the in-plane stresses, and the higher the difference of the Poisson's ratio between the components, the higher the in-plane stresses.
Resource Type
Date Available
Date Copyright
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Committee Member
Academic Affiliation
Non-Academic Affiliation
Subject
Rights Statement
Peer Reviewed
Language
Digitization Specifications
  • File scanned at 300 ppi (Monochrome, 8-bit Grayscale) using ScandAll PRO 1.8.1 on a Fi-6770A in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR.
Replaces
Additional Information
  • description.provenance : Made available in DSpace on 2012-11-08T19:44:30Z (GMT). No. of bitstreams: 1 GuoZhiqiang1995.pdf: 5143714 bytes, checksum: 12688943eaa0e462a4614131614f3745 (MD5) Previous issue date: 1994-06-23
  • description.provenance : Submitted by Sergio Trujillo (jstscanner@gmail.com) on 2012-11-07T22:02:01Z No. of bitstreams: 1 GuoZhiqiang1995.pdf: 5143714 bytes, checksum: 12688943eaa0e462a4614131614f3745 (MD5)
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2012-11-07T23:09:53Z (GMT) No. of bitstreams: 1 GuoZhiqiang1995.pdf: 5143714 bytes, checksum: 12688943eaa0e462a4614131614f3745 (MD5)
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2012-11-08T19:44:30Z (GMT) No. of bitstreams: 1 GuoZhiqiang1995.pdf: 5143714 bytes, checksum: 12688943eaa0e462a4614131614f3745 (MD5)

Relationships

In Administrative Set:
Last modified: 08/20/2017

Downloadable Content

Download PDF
Citations:

EndNote | Zotero | Mendeley

Items