高临界电流密度、低损耗Cu5Ni基NbTi线材制备技术研究

重离子装置中的加速器磁体均服役在±2.25T/s的高速脉冲条件下,因此要求该种磁体所用的超导线材具有较高的临界电流和较低的损耗。针对项目需求,本文设计及制备了两种新型结构的NbTi/Cu5Ni超导线材,芯数分别为12960芯和10800芯、铜比2.0、芯丝直径均小于5 μm。系统研究了两种新型结构超导线的芯丝截面形貌、芯丝表面形貌、磁滞损耗及不同时效热处理下的临界电流密度和n值。通过优化工艺后获得了Jc(5 T、4.2 K)为2902 A/mm_²,Qh(4.2 K,± 3T)为34.2 mJ/cm_³ 的千米级NbTi/Cu5Ni超导长线,并可实现批量化生产,为重离子装置的研制提供材料基础。

Fabrication of High Critical Current Density and Low AC loss NbTi Superconducting Wire with matrix of Cu5Ni alloy

Working with fast pulse current, low loss NbTi superconducting wires are required to reduce energy losses in High Intensity Heavy-Ion Accelerator Facility (HIAF) magnets. The new type of NbTi superconducting wires with high critical current and low loss are needed to develop. NbTi/Cu5Ni superconducting wire with filament number of 12960 and 10080 and Cu/Sc ratio of 2.0 were designed and fabricated by double stacking method. The microstructure and influence of aging heat treatment on the critical current density and break times of NbTi/Cu5Ni superconducting wire are presented in this paper. After the process optimization, NbTi/Cu0.5Mn superconducting wire with the critical current density (Jc) of 2902A/mm_² at 5T 4.2K, with the hysteresis of 34.2 J/cm_³ at ± 3T was achieved in mass production.