Critical current of dense Bi-2212 round wires as a function of axial strain
Critical current of dense Bi-2212 round wires as a function of axial strain
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DOI：
10.1088/0953-2048/28/3/032001
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发表时间：
2015-03-01
影响因子：
3.6
通讯作者：
Larbalestier, D. C.
中科院分区：
文献类型：
--
作者：
Godeke, A.;Hartman, M. H. C.;Larbalestier, D. C.
测量了具有Ag合金基体的致密Bi 2Sr 2CaCu 2 O 8 +x（Bi-2212）圆线的临界电流（I-c）作为轴向施加应变（α）的函数，以确定与Bi-2212细丝中具有大（30-50%）空隙率的线相比，I-c（α）行为是否得到改善。在约890 ℃下，在100巴压力下，在Ar气体混合物中的1%O-2下使线反应，以在部分熔融反应期间使Bi-2212部分致密化。在佛罗里达州立大学测量了4.2 K和5 T下的I-c后，将金属丝部分送到劳伦斯伯克利国家实验室，在那里使用U形弯曲弹簧测量了4.2 K和5 T下的I-c（ε（a））。我们发现，I-c（ε（a））具有0.3%宽的线性可逆应变范围。一个意想不到的结果是，该可逆范围的宽度似乎与仅在1巴下反应的多孔样品的宽度相当，显然否定了较早的合理假设，即密度更大的样品将更具弹性。
The critical current (I-c) of dense Bi2Sr2CaCu2O8+x (Bi-2212) round wires with Ag-alloy matrices was measured as a function of axial applied strain (epsilon(a)), to determine whether the I-c(epsilon(a)) behavior is improved in comparison to wires with a large (30-50%) void fraction in the Bi-2212 filaments. Wires were reacted at approximately 890 degrees C under a 1% O-2 in Ar gas mixture at 100 bar pressure to densify the Bi-2212 fraction during the partial melt reaction. After measurement of the I-c at 4.2 K and 5 T at Florida State University, wire sections were sent to Lawrence Berkeley National Laboratory where I-c(epsilon(a)) was measured at 4.2 K at 5 and 15 T using a U-shaped bending spring. We found that I-c(epsilon(a)) has a 0.3% wide linear reversible strain range. An unexpected result is that the width of this reversible range seems comparable to that found for porous samples reacted at only 1 bar, apparently negating an earlier plausible supposition that fuller density samples would be more resilient.