【摘要】 在MgB2/Fe超导带材中,Fe包套与MgB2超导芯的交界处有很薄的反应层,其主要成分为Fe2B和FeB,其电阻率很高,导致当电流在基材和超导芯间转移时存在一个转移长度,在这一长度上会产生电压分布并伴随有焦耳热产生,从而影响到带材的临界电流测量和热稳定性.本文使用分布电阻模型分析了MgB2/Fe超导带材中的电流转移特点,推导出电流转移长度的公式及由于电流转移产生的焦耳热.并把电流转移产生的焦耳热加入到MgB2/Fe超导带材在绝热条件下失超传播的一维分析当中,推导出失超传播速度的公式,对超导带材失超传播速度的传统计算公式进行了改进.本文对研究MgB2/Fe复合超导带材的热稳定性分析及MgB2超导带材的实用化具有参考价值.更多还原

【Abstract】 In MgB2/Fe tape,a reaction layer (Fe2B and FeB) is formed between Fe sheath and MgB2 core during heat treatment. This layer has relatively high electrical resistivity and also low thermal conductivity. The current transfer exists between Fe sheath and MgB2 core because of the reaction layer. An equivalent circuit model was established in order to study the current transfer processes in MgB2/Fe tape. The current transfer processes brings more Joule heating when a segment of MgB2 filament transform from superconducting to normal state. So the current transfer can affect the stability of MgB2/Fe tape. The traditional calculation formula for the quench propagation velocities was improved. The numerical model is useful in studying the stability of MgB2/Fe tape.更多还原