High Compressive Axial Strain Effect on the Critical Current and Field of Nb3Sn Superconductor Wire

  • J. W. Ekin
  • S. L. Bray
Part of the Advances in Cryogenic Engineering Materials book series (ACRE, volume 42)


The axial strain dependence of the critical current Ic and effective upper critical field Bc2* have been measured on a series of Nb3Sn wire superconductors having initial compressive strain as large as -0.95% arising from thermal contraction of the conductor matrix. Results include data for binary Nb3Sn and ternary Nb3Sn with Ti additions. The effective upper critical field Bc2* is obtained using a general form of the pinning expression, since the data show that the Kramer method is not generally applicable to ternary Nb3Sn superconductors. The Ic and Bc2* data fit the strain scaling law well. The results are also consistent with earlier-published Tc vs. strain data for Nb3Sn at compressive strain as large as -0.85% and with Ic vs. strain data for stainless-steel reinforced Nb3Sn superconductors at compressive strain as large as -0.65%. The data contradict, however, recently reported Bc2* data obtained on multifilamentary Nb3Sn wires where high compressive strain was applied by soldering the wires to a bending beam and then flexing the beam.


Axial Strain Compressive Strain Critical Current Critical Field Uniaxial Strain 
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  1. 1.
    J. W. Ekin, Strain scaling law for flux pinning in practical superconductors. Part 1: Basic relationship and application to Nb3Sn conductors, Cryogenics 20:611 (1980).CrossRefGoogle Scholar
  2. 2.
    J. W. Ekin, Strain scaling law for flux pinning in NbTi, Nb3Sn, Nb-Hf/Cu-Sn-Ga, V3Ga and Nb3Ge, IEEE Trans. on Magn. 17:658 (1981).CrossRefGoogle Scholar
  3. 3.
    J. W. Ekin, R. Flukiger, and W. Specking, Effect of stainless steel reinforcement on the critical current versus strain characteristic of multifilamentary Nb3Sn superconductors, J. Appl. Phys. 54:2869 (1983).CrossRefGoogle Scholar
  4. 4.
    B. ten Haken, A. Godeke, and H. H. J. ten Kate, The influence of compressive and tensile axial strain on the critical properties of Nb3Sn conductors, IEEE Trans. Appl. Superconductivity, 5:1909 (1995).CrossRefGoogle Scholar
  5. 5.
    The dependence of Bc2* on strain for ternary (Nb-Ti)3Sn has been shown earlier to be steeper than for binary Nb3Sn. This is readily represented by the strain scaling law using a larger value of “a” in Eqn. 2.Google Scholar
  6. 6.
    E. J. Kramer, Scaling laws for flux pinning in hard superconductors, J. Appl. Phys. 44:1360 (1973).CrossRefGoogle Scholar
  7. 7.
    M. Dunn, Dept. of Mech. Eng., Univ. of Colo., Boulder, CO, private communication.Google Scholar
  8. 8.
    T. Luhman, M. Suenaga, and C. J. Klamut, Influence of tensile stresses on the superconducting temperature of multifilamentary Nb3Sn composite conductors, Adv. Cryog. Eng. 24:325 (1978).CrossRefGoogle Scholar
  9. 9.
    J. W. Ekin, Strain scaling law and the prediction of uniaxial and bending strain effects in multifilamentary superconductors, in: Filamentary A15 Superconductors, M. Suenaga and A. F. Clark eds., Plenum Press, New York (1980), p. 187.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1996

Authors and Affiliations

  • J. W. Ekin
    • 1
  • S. L. Bray
    • 1
  1. 1.Electromagnetic Technology DivisionNational Institute of Standards and TechnologyBoulderUSA

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