| The development of a strain-tolerant superconducting Bi-2212 cable in conduit is described. Bi-2212, a high-temperature superconductor, shows great promise as a conductor for high-field superconducting magnets. However, because of its brittleness, it is susceptible to permanent mechanical degradation due to the accumulation of Lorentz stress through the winding of a superconducting magnet coil. This dissertation reports on the development and testing of a superconducting cable that redistributes stress internally so that performance is not degraded in superconducting magnet coils. The design concept and a finite element analysis of the cable are presented, and the testing of the structural material is described. The fabrication of the cable in conduit is detailed. The heat treatment of Bi-2212 is complicated by a narrow temperature window, outside of which the electrical properties of the superconductor quickly deteriorate. The development and calibration of the heat treatment is described. A number of samples were prepared: individual wires, short cable samples, and two test coils made of the cable. The experimental results for short samples and test coils made from the cable are presented. The dissertation concludes with a summary of the results and suggestions for further research. |
