轴向拉伸应变对YBCO涂层导体V-I特性曲线的影响研究

Effect of axial tension strain on the V-I characteristic curves of YBa_2Cu_3O_7- xcoated conductors

文中实验测试了YBCO涂层导体在77K(液氮)、自场环境、不同轴向拉伸应变情况下的V-I特性曲线,并获得相应的n值。接着,通过对实验数据的拟合建立了一种理论模型,对不同应变下的V-I特性曲线进行了修正,模型修正的结果很好的反映了在实际不同应变情况下的V-I特性曲线变化特征。在此基础上,建立了这种材料n值和应变之间的理论模型,计算结果与实验数据吻合较好。最后,考虑到YBCO涂层导体的n值在材料的弹性区受轴向拉伸应变的影响很小,给出了YBCO涂层导体临界电流与轴向拉伸应变的理论预测模型。通过与实验数据的对比,该理论模型可准确预测任意应变状态下YBCO涂层导体的V-I特性曲线和所对应的n值及其在弹性区的临界电流。

The V- I characteristic curves, n value and critical current are very important parameters for many industrial applications of high temperature superconductors. So, to study a behavior of them as a function of axial tension strain is quite necessary. In this paper, The V-I characteristic curves and the n value of YBa2Cu3O7-xCoated Conductor （YBCO CC） with difterent axial tension strain at 77K （ liquid nitrogen）, self - field were measured. A theoretical model was firstly given to correct the V - 1 characteristic curves of YBa/Cu3O7-x coated conductor by fitting of the experimental data. In addition, the n value of YBa2Cu3O7-xcoated conductor as a function of axial tension strain was given through the theoretical model. Considering that the axial tension strain has little influence on the n value of the YBa2 Cu3O7-x coated conductor when the material was in the elastic region, we further give the theoretical model on the critical current of the YBCO coated conductor with the axial tension strain. By comparison with experimental data, the V - I characteristic curves and the n value of YBa2 Cu3 O7-x coated conductor with arbitrary axial tension strain at 77K（ liquid nitrogen）, self- field could be given by our model, also the critical current of YBa2Cu3O7-x coated conductor with reversible strain. It has very important practical significance for the research of the theory of YBCO coated conductors and the design of the important parameters in engineering application.