Fine grained tantalum for composite Nb3Sn superconductor diffusion barrier sheet Conference Paper

abstract

• Poor deformation behavior of commercial polycrystalline Ta sheet used for Sn diffusion barriers in Nb3Sn composite superconductors leads to the use of more Ta than may be necessary in these conductors, and to strand fracture during wire drawing. These problems arise because of nonuniform deformation of the Ta layer when co-drawn with Cu. The origin of the problem resides in the microstructure of the Ta and the code formation mechanics of relatively strong BCC Ta with weaker and more ductile adjacent FCC Cu. In an attempt to remedy this problem, we have processed 25 mm square bars of Ta by multi-axis severe plastic deformation (SPD) via equal channel angular extrusion, then rolled the bars to sheet and annealed the as-worked sheet. The processing is done to refine the microstructure and reduce nonuniformities in grain size and texture. Measurements of hardness, microstructure and mechanical properties are reported for bulk and sheet Ta. The results of SPD processing are encouraging.

authors

• Hartwig, Karl

published proceedings

• IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY

author list (cited authors)

• Mathaudhu, S. N., Hartwig, K. T., & Barber, R. E.

citation count

• 3

complete list of authors

• Mathaudhu, Suveen N||Hartwig, K Ted||Barber, Robert E

publication date

• June 2007

publisher

• Institute of Electrical and Electronics Engineers (IEEE)  Publisher

published in

• IEEE Transactions on Applied Superconductivity  Journal

keywords

• Diffusion Barrier
• ECAE
• ECAP
• Mechanical Properties
• Microstructure
• Nb3Sn Superconductors
• Recrystallization
• Severe Plastic Deformation
• Tantalum

Digital Object Identifier (DOI)

• 10.1109/TASC.2007.899413

start page

• 2660

end page

• 2663

volume

• 17

issue

• 2

URL

• http%3A%2F%2Fdx.doi.org%2F10.1109%2Ftasc.2007.899413