Mechanical Properties of Superconducting Nb-Ti Composites
Mechanical Properties of Superconducting Nb-Ti Composites
复制标题
超导铌钛复合材料的力学性能
DOI：
10.1007/978-1-4613-9850-9_55
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发表时间：
1977
期刊：
影响因子：
--
通讯作者：
C. Koch
中科院分区：
文献类型：
--
作者：
D. Easton;C. Koch
近年来，大型超导磁体在受控热核反应堆等离子体安全壳中的应用受到越来越多的关注。小半径达6米、大半径达12米的环形磁铁正处于概念设计阶段。这种尺寸的磁体使通常与超导磁体有关的问题更加复杂。在过去，大型线圈被设计成在比短样品测试中测量的值低得多的电流密度下工作。然而，托卡马克约束系统将需要接近短样本性能的磁场，并且必须防止有时在大线圈中观察到的“训练”效应。当可以通过导体的初始电流低于短样本测试中发现的值，但在几次超导到正常状态的转变后增加时，就会发生训练。大多数参与大型设备建造的工人都认为，为了尽量减少训练，应该避免导体的任何移动，但这种效果的确切机制仍然不清楚，埃文斯认为铌钛合金的锯齿状屈服与训练有关，而爱德华塞特等人发现应变显然起着主要作用。
Recently, the use of large superconducting magnets for plasma containment in controlled thermonuclear reactors has gained increased attention. Toroidal magnets up to 6 m minor radius and 12 m major radius are in the conceptual design stage. Magnets of this size compound the problems normally associated with superconducting solenoids. In the past, large coils were designed to operate at current densities much lower than the values measured in short-sample tests. However, the Tokamak confinement system will require magnetic fields approaching short-sample performance, and the “training”[1] effect sometimes observed in large coils must be prevented. Training occurs when the initial current that can be passed through a conductor is below that value found in a short-sample test but increases after several superconducting to normal state transitions. Most workers involved in the construction of large devices agree that any movement of the conductor should be avoided in order to minimize training, but the exact mechanism of the effect is still unclear Evans suggests that serrated yielding of the Nb-Ti is related to training, while Edwardset al. found that strain apparently plays a major role.