Compressive pre-strain in high-niobium-fraction Nb3Sn superconductors
Compressive pre-strain in high-niobium-fraction Nb3Sn superconductors
复制标题
DOI：
10.1109/tasc.2005.849360
复制
发表时间：
2005-06-01
影响因子：
1.8
通讯作者：
Zhang, YZ
中科院分区：
文献类型：
--
作者：
Ekin, JW;Cheggour, N;Zhang, YZ
用高铌分数制备的多丝Nb3Sn超导股具有极高的临界电流密度，但在测试过程中有时会略微稳定。我们报告了一种确定此类导体预应变的技术，其中将额外的稳定铜电镀到导体上，并通过外推到制备的铌分数来确定预应变。该技术用于测量高铌含量为20% ~ 30%的导体的预应变。这些导体的预应变epsilon（max）值降至0.1% ~ 0.2%，明显低于传统青铜工艺Nb3Sn导体（铌含量通常为10% ~ 15%）的0.2% ~ 0.4%的epsilon（max）值。然而，在导体基体中加入约20%的分散强化铜，可将epsilon（max）恢复到0.25%至0.35%的范围，从而为高铌分数股的磁体设计提供实用的epsilon（max）水平。
Multifilamentary Nb3Sn superconducting strands fabricated with high niobium fractions have exceptionally high critical-current densities but are sometimes marginally stable during testing. We report a technique for determining the pre-strain in such conductors, in which additional stabilizing copper is electroplated onto the conductor and the pre-strain is determined by extrapolation to the as-fabricated niobium fraction. This technique is used to measure the pre-strain in conductors with high niobium fractions of 20% to 30%. Values of the pre-strain epsilon(max) in these conductors are reduced to the range 0.1% to 0.2%, which is significantly less than the epsilon(max) values of 0.2% to 0.4% in traditional bronze-process Nb3Sn conductors (where niobium fractions are typically about 10% to 15%). However, including about 20% dispersion-strengthened copper into the conductor matrix restores epsilon(max) to the range 0.25% to 0.35%, thus providing practical levels of epsilon(max) for magnet design in high-niobium-fraction strands.