Asymmetric behaviour of Jc(ε) in Nb3Sn wires and correlation with the stress induced elastic tetragonal distortion
Asymmetric behaviour of Jc(ε) in Nb3Sn wires and correlation with the stress induced elastic tetragonal distortion
复制标题
Nb3Sn 丝中 Jc(ε) 的不对称行为及其与应力引起的弹性四方变形的相关性
DOI：
10.1088/0953-2048/18/12/032
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发表时间：
2005
影响因子：
3.6
通讯作者：
B. Seeber
中科院分区：
文献类型：
--
作者：
R. Flükiger;D. Uglietti;V. Abächerli;B. Seeber
采用改进的沃尔特斯弹簧（WASP）研究了单轴应变对0.8 m长Nb3Sn导线在21 T以下临界电流的影响。对于采用青铜路径和Sn内部扩散工艺制备的Nb3Sn线，在应变εm两侧的临界电流密度与单轴应变ε的函数表现出不对称行为，其中Jc达到最大值。回顾之前对10至600 K之间的青铜路线加工导线的x射线和中子衍射测量，结果表明，应变值εm两侧的Jc（ε）的不对称行为与应力诱导的四方晶格参数a和c的个别变化有关。目前对Nb3Sn丝的Jc与应变的测量表明，相对于用青铜方法得到的丝，用Sn内部扩散方法制备的丝具有更强的应变依赖性。造成这种差异的原因是由于两种类型的电线中灯丝结构的个别细节，例如灯丝内部的不同Sn分布以及灯丝尺寸（分别为4和80 μ m）的非常不同。
The effect of uniaxial strain on the critical current of 0.8 m long Nb3Sn wires up to 21 T is studied by the modified Walters spring (WASP). For Nb3Sn wires, prepared by both the bronze route and the internal Sn diffusion process, the critical current density as a function of the uniaxial strain ε is found to exhibit an asymmetric behaviour on both sides of the strain εm, where Jc reaches its maximum. Revisiting earlier x-ray and neutron diffraction measurements on bronze route processed wires between 10 and 600 K, it is shown that the asymmetric behaviour of Jc(ε) on both sides of the strain value εm is connected to individual variations of the stress-induced tetragonal lattice parameters a and c. The present measurements of Jc versus strain for Nb3Sn wires show stronger strain dependence for wires prepared by the internal Sn diffusion method with respect to those obtained by the bronze route. The reasons for this difference are attributed to the individual details of the filament configuration in both types of wire, for example the different Sn distributions inside the filaments and the very different filament sizes, 4 and 80 µm, respectively.