Longitudinal Component Resistivities of Multifilamentary Composite Strands — Influences of Size Effect and Filament/Matrix Interdiffusion

  • D. S. Pyun
  • E. W. Collings
Part of the An International Cryogenic Materials Conference Publication book series (ACRE, volume 40)


Longitudinal resistivity measurements were performed on the electrolytically separated components (shell, interfilamentary matrix, and filaments) of two pairs of un-heat-treated Nb-46.5 wt. %Ti multifilamentary strands (matrices Cu and Cu-0.5 wt. % Mn, respectively) at 295 and 12 K. The measurements were also repeated on the Cu-matrix pair after annealing at 150, 245, and 415°C. It was observed that: (1) The residual resistivity ratio and ρ 12K of the Cu shell of the annealed NbTi/Cu strands ( ≈170 and ≈ 10 nΩcm, respectively) agreed with typical bulk values of OFHC Cu. (2) The Cu-shell resistivities of as-received strands (un-heat-treated) had been enhanced by drawing-induced deformation microstructure. (3) The residual resistivity of the Cu matrix was 4 to 6 times larger than that of the corresponding Cu shell — an enhancement attributable to size effect. (4) Size effect makes a negligible contribution to the resistivity of the Cu-Mn matrix. (5) Annealing at moderate temperatures reduces the shell resistivity; conversely, that of the matrix increases as the annealing temperature is raised above 300°C, presumably as a result of filament/matrix interdiffusion.


Matrix Resistivity Filament Diameter Electrolytic Etching Longitudinal Resistivity Residual Resistivity Ratio 
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Copyright information

© Springer Science+Business Media New York 1994

Authors and Affiliations

  • D. S. Pyun
    • 1
  • E. W. Collings
    • 1
  1. 1.Battelle Memorial InstituteColumbusUSA

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