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Influence of Manganese on the Upper Critical Field of Two Series of β-Quenched- and Precipitation-Heat-Treated NbTi Alloys

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

Abstract

The superconducting transition temperature, Tc, and the 4.2-K upper critical field, Hc2, of a series of NbTi alloys both without and with the addition of about 0.5 at. % Mn has been measured resistively and inductively. The samples were in the form of: (1) β-quenched starting ingots and (2) precipitation heat treated (PHT) Cu-matrix mono-filamentary strands. It was noted that: (1) Although the addition of about 0.5 wt. % Mn produced no significant change in the Hc2 and Tc of the homogeneous β-quenched single-phase NbTi series it significantly modified those of the PHT set. The latter result is interpreted in terms of the α-phase-suppressing (i.e. β-stabilizing) propensity of Mn which turns out to be six times stronger than that of Nb. (2) The inductively measured superconducting-transition widths, ΔTc, of the PHT specimens were considerably larger than those of the β-quenched (single-phase) samples as a result of PHT-induced compositional inhomogeneity. (3) An anomalous composition dependence of Tc and ΔTc exhibited by the higher concentration PHT ternary alloys was interpreted in terms of proximity effect associated with a Mn-induced refinement of α-phase particle size.

Keywords

Ternary Alloy Critical Field Superconducting Transition Temperature Niobium Concentration Electronic Specific Heat Coefficient 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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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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