Microstructure and J/sub c/-B performance of DRHQ processed Nb/sub 3/Al tape with Ag stabilizer
Microstructure and J/sub c/-B performance of DRHQ processed Nb/sub 3/Al tape with Ag stabilizer
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带Ag稳定剂的DRHQ加工Nb/sub 3/Al带材的显微组织和J/sub c/-B性能
DOI：
10.1109/tasc.2004.830368
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发表时间：
2004
影响因子：
1.8
通讯作者：
M. Yuyama
中科院分区：
文献类型：
--
作者：
A. Kikuchi;Y. Iijima;N. Banno;T. Takeuchi;K. Inoue;S. Nimori;M. Kosuge;M. Yuyama
DRHQ 工艺适用于具有内部 Ag 稳定剂的果冻卷 Nb/sub 3/Al 前驱体。 Ag内部稳定剂可有效提高DRHQ处理导体的超导稳定性，Ag稳定剂/非Ag稳定剂的比率为0.32。 DRHQ 工艺需要减少前体（例如带状样品）的弯曲应变。经过 DRHQ 处理且带有 Ag 稳定剂的磁带的最大 T/sub c/ 和 B/sub c2/(4.2 K) 分别为 18.4 K 和 29.7 T。在25 T的高磁场下获得了210 A/mm/sup 2/的大型传输核心-J/sub c/(4.2 K)，这比典型的RHQT处理的线材大20倍。另一方面，在低于 20 T 的场中，J/sub c/ 随着第二 RHQ 期间峰值加热温度的增加而明显下降。根据TEM观察，DRHQ处理的Nb/sub 3/Al中仍然形成堆垛层错，但与RHQT处理的Nb/sub 3/Al相比，堆垛层错的密度变得非常小。此外，随着峰值加热温度的升高，堆垛层错逐渐消失。 DRHQNb/sub 3/Al 的几百纳米晶粒尺寸仍然相当小。因此，这些结果支持堆垛层错应作为 RHQT 和 DRHQ 处理的 Nb/sub 3/Al 导体的有效钉扎中心占主导地位。
The DRHQ process was applied to the jelly-rolled Nb/sub 3/Al precursors having internal Ag stabilizers. The Ag internal stabilizer is effective to improve the superconducting stability of the DRHQ processed conductor with the Ag-stabilizer/non-Ag ratio of 0.32. The DRHQ process needs a reduction of a bending strain of the precursors, such as tape-formed specimen. The maximum T/sub c/ and B/sub c2/(4.2 K) of the DRHQ-processed tape with Ag stabilizer are 18.4 K and 29.7 T, respectively. Large transport core-J/sub c/(4.2 K) of 210 A/mm/sup 2/ was obtained at high magnetic field of 25 T, which is 20 times larger than that of the typical RHQT-processed wires. On the other hand, J/sub c/ in fields below 20 T apparently decreased with increasing the peak heating temperature during the second-RHQ. According to the TEM observation, the stacking faults were still formed in the DRHQ-processed Nb/sub 3/Al, but their density becomes very small compared with that of the RHQT-processed Nb/sub 3/Al. In addition, the stacking faults gradually vanished with increasing the peak heating temperature. The grain size of several hundred nanometers for the DRHQNb/sub 3/Al is still rather small. Thus, these results support that the stacking faults should be dominant as the effective pinning center for the both of RHQT- and DRHQ-processed Nb/sub 3/Al conductors.