Microstructure, composition and critical current density of superconducting Nb3Sn wires

被引:95
作者
Fluekiger, R. [1 ,2 ]
Uglietti, D. [3 ]
Senatore, C. [1 ,2 ]
Buta, F. [3 ]
机构
[1] Univ Geneva, Dept Condensed Matter Phys, CH-1211 Geneva, Switzerland
[2] Univ Geneva, MANEP NCCR, CH-1211 Geneva, Switzerland
[3] Univ Geneva, Appl Phys Grp, CH-1211 Geneva, Switzerland
关键词
D O I
10.1016/j.cryogenics.2008.05.005
中图分类号
O414.1 [热力学];
学科分类号
摘要
The production of superconducting Nb3Sn multifilamentary wires with optimized critical currents requires a detailed knowledge of various processes, involving both the mechanical deformation and the reaction kinetics. The physical properties of the Nb3Sn phase are briefly reviewed, the precise knowledge of their variation as a function of the Sn content being essential for the optimization of the critical current density,J(c). The variation of the transition temperature T-c, the upper critical field, B-c2(0), and the normal state electric resistivity rho(o), as a function of the Sn content, beta, in the binary system Nb1-beta Sn beta is carefully analyzed. The effect of Ta, Ti and Ta + Ti additives to Nb3Sn on the physical properties is discussed in detail. Low temperature specific heat measurements are introduced for determining the Tc distribution inside Nb3Sn filaments while avoiding shielding effects. The microstructure of the superconducting phase in Bronze Route and Internal Sn Diffusion processed wires is studied, taking into account the unique microstructure of Bronze Route filaments, comprising an equiaxed and a columnar grain region, their areas being comparable. The Sn content increases gradually, from 18 to 22 at.% in columnar and from 22 to 25 at.% in equiaxed grains. Taking into account the equiaxed grains only in Bronze Route wires, it is found that the pinning force density FGB is essentially the same as in the superconducting part of Internal Sn and PIT wires. The lower values of the overall F-GB in Bronze Route wires is due to the presence of columnar grains, with lower Tc and B-c2. The presence of columnar grains also explains the deviation from linearity of the Kramer rule in Bronze Route wires. The mechanism leading to the variation of J(c), vs. epsilon, where c is the uniaxial applied strain, is correlated to the elastic tetragonal distortion of the A15 phase in the filaments, caused by the matrix precompression or by Lorentz forces. The behavior of J(c), (epsilon) is found to show systematic differences between Bronze Route and Internal Sn processed wires. Possible reasons for the stronger variation of J(c) (epsilon) up to 21 T in Internal Sn wires are discussed. (c) 2008 Elsevier Ltd. All rights reserved.
引用
收藏
页码:293 / 307
页数:15
相关论文
共 94 条
  • [81] The strain dependence of the critical properties of Nb3Sn conductors
    ten Haken, B
    Godeke, A
    ten Kate, HHJ
    [J]. JOURNAL OF APPLIED PHYSICS, 1999, 85 (06) : 3247 - 3253
  • [82] INTERFERENCE BETWEEN SUPERCONDUCTIVITY AND MARTENSITIC TRANSITION IN A15-COMPOUNDS
    TOYOTA, N
    KOBAYASHI, T
    KATAOKA, M
    WATANABE, HFJ
    FUKASE, T
    MUTO, Y
    TAKEI, F
    [J]. JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, 1988, 57 (09) : 3089 - 3101
  • [83] Uglietti D, 2006, AIP CONF PROC, V824, P528
  • [84] The effect of Ti addition on critical parameters and transport properties of quaternary (Nb, Ta, Ti)3Sn wires
    Uglietti, D.
    Abaecherli, V.
    Buta, F.
    Seeber, B.
    Fluekiger, R.
    [J]. SUPERCONDUCTOR SCIENCE & TECHNOLOGY, 2006, 19 (11) : 1185 - 1190
  • [85] A device for critical current versus strain measurements up to 1000 A and 17 T on 80 cm long HTS and LTS technical superconductors
    Uglietti, D
    Seeber, B
    Abächerli, V
    Pollini, A
    Eckert, D
    Flükiger, R
    [J]. SUPERCONDUCTOR SCIENCE & TECHNOLOGY, 2003, 16 (09) : 1000 - 1004
  • [86] UGLIETTI D, 2006, THESIS U GENEVA GENE
  • [87] ATOMIC ORDERING IN BINARY A15-TYPE PHASES
    VANREUTH, EC
    WATERSTRAT, RM
    [J]. ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL CRYSTALLOGRAPHY AND CRYSTAL CHEMISTRY, 1968, B 24 : 186 - +
  • [88] STRUCTURE AND PROPERTIES OF NB3SNHX
    VIELAND, LJ
    WICKLUND, AW
    WHITE, JG
    [J]. PHYSICAL REVIEW B, 1975, 11 (09): : 3311 - 3316
  • [89] SPECIFIC HEAT OF NIOBIUM-TIN
    VIELAND, LJ
    WICKLUND, AW
    [J]. PHYSICAL REVIEW, 1968, 166 (02): : 424 - &
  • [90] VIELAND LJ, 1968, PHYS LETT, V34, pA43