MRI用低铜比NbTi超导线材组织和性能  

MICROSTRUCTURE AND PROPERTY OF MRI NbTi SUPERCONDUCTING WIRE

作　　者：郭强[1,2] 李建峰[1,2] 王庆相[1,2] 闫凯娟 朱燕敏[1,2] 刘建伟[1,2] 刘向宏[1,2] 冯勇[1,2] 张平祥[1,2,3] 

机构地区：[1]西部超导材料科技股份有限公司,西安710018 [2]超导材料制备国家工程实验室,西安710018 [3]西北有色金属研究院,西安710016

出　　处：《低温物理学报》2014年第5期346-349,共4页Low Temperature Physical Letters

基　　金：国家863专项(批准号:2014AA032701)资助课题~~

摘　　要：本文以高均匀性Nb47Ti合金锭和高纯无氧铜为原材料,制备了铜比为1.0,Φ0.846mm的MRI（Magnetic Resonance Imaging）用低铜比NbTi/Cu超导线.研究了最终应变和间隔应变对MRI用NbTi/Cu超导线微观组织和临界电流密度的影响.测试结果表明：时效3次时,最终应变在3.0~4.4之间,随最终应变增大,临界电流密度呈先增大而后降低,最终趋于稳定的变化规律;最终应变相同的条件下,增大间隔应变会导致临界电流密度的降低.经过工艺优化后,临界电流密度最高为3208A/mm2（4.2K,5T,判据0.1μV/cm）.微观组织观察表明：临界电流密度最高时,α-Ti沉淀相呈褶皱弯曲状,并弥散的分布在β-NbTi基体之上.In present paper, NbTi/Cu wire with the copper-to-superconductor ratio of 1.0 was prepared using high homogenous Nb47Ti alloy bar and oxygen-free copper firstly. The effect of final strain and interval strain on the microstructure and critical current density of NbTi superconducting wire was investigated. It can be drawn from a lot of experiments that for 3 times heat treatments, critical current density raised firstly, and then descended to a stable value as the final drawing strain varies from 3.0 to 4. 4. In addition, improving the interval strain between heat treatments resulted in the decline of critical current density while the final strain is fixed. Measurement results show that the acquired maximum critical current density can reach 3208A/mm2 at 4. 2 K and 5 T（criterion： 0. 1μV/ cm）. TEM observations showed that α-Ti precipitates dispersed within the superconducting β-NbTi matrix with strong fold and curl for the NbTi wire with highest critical current density at 4. 2 K.

关 键 词：NbTi/Cu超导线 临界电流密度 α-Ti沉淀相 最终应变 间隔应变 

分 类 号：TM26[一般工业技术—材料科学与工程]