Critical Current Under Uniaxial Strain on High-Pressure Heat Treatment Bi-2212 Round Wire

China Fusion Engineering Test Reactor project (CFETR), the next generation of Tokamak, has been incorporated into the important development of nuclear fusion in the future. Compared to the low temperature superconducting materials, Bi2212 is one of the most promising superconducting materials due to the high irreversible field and outstanding current-carrying capacity. In particular, its critical properties can be improved dramatically by high-pressure heat treatment, which could enlarge its application range. The critical current performance of Bi-2212 round wire (RW) with high-pressure heat treatment under uniaxial strain are studied at 4.2 K in 12 T background field at Institute of Plasma Physics, Chinese Academy of Science (ASIPP). All samples are provided by Northwest Institute for Non-ferrous Metal Research (NIN) in China with new techniques. The results showed that samples with 1 bar pressure heat treatment presented a more drastic degradation under compressive and tensile stress than that the samples heat-treated with 30 and 50 bar pressure. In order to study the influence of different thermal contraction coefficient between the substrate and sample, two springs with different materials were used for the experiment. According to the results, it was found that Cu-Be alloy spring is more compatible for Bi-2212 RW than Ti-6Al-4V alloy spring.