Properties of superconducting CU-rich composites containing V_3SI or V_3GA

[摘要] Superconducting Cu-rich composites containing the A-15 compoundsV₃Si or V₃Ga have been made by the "Tsuei" process, whichconsists of melting the constituent elements into ingots followed bysubsequent cold working and heat treatment. The superconductingtransition temperatures of the resulting composites have been measured.X-ray diffraction analyses have been performed to identifythe phases in the alloys. The microstructures have been studied usingboth the optical metallograph and the scanning electron-microscope.For some composites containing V₃Ga, the critical current densitiesas functions of transverse magnetic field up to 60 kG, and as functionsof temperature from 4.2°K to 12°K have been measured. It wasfound that the Tsuei process does not work for the composites containingV₃Si, but works satisfactorily for the composites containingV₃Ga. The reasons are discussed based on the results of microstructurestudies, electrical resistivity measurements, and also therelevant binary phase diagrams. The relations between the measuredproperties and the various metallurgical factors such as the alloycompositions, the cross-section reduction ratios of the materials,and the heat treatment are discussed. The basic mechanism for theobserved superconductivity in the materials is also discussed. In addition,it was found that the Tsuei composites are expected to havehigh inherent magneto-thermal stability based on the stability theoryof superconducting composites.

[发布机构] University:California Institute of Technology;Department:Engineering and Applied Science

[关键词] Applied Physics