Tensile properties and critical current strain limits of reinforced Bi-2212 conductors for high field magnets

[摘要] We study here the effect of axial strain on the degradation of the critical current Icfor bare and reinforced, overpressure processed Bi-2212 conductors. We show that reinforcement markedly improves the conductor's stress limit, doubling it from ~150 MPa in the bare conductor to ~300 MPa when reinforced. We find also that certain processes used to reinforce the conductor slightly reduce the Icdegradation strain limit from ~0.6% to ~0.4%. Stress vs strain data taken from the samples studied here has been used to create a finite element model to explore the feasibility of using a reinforced Bi-2212 strand (produced by Solid Material Solutions) in a small test coil. The model predicts an IC limited coil with a maximum hoop strain of 0.31%, well below the experimentally verified strain limit, and is designed to lead to Bi-2212 coils that are not strain limited, but Iclimited.

[发布机构] Applied Superconductivity Center, National High Magnetic Field Laboratory, Florida State University, Tallahassee; FL; 32310, United States^1;Magnet Science and Technology Division, National High Magnetic Field Laboratory, Florida State University, Tallahassee; FL; 32310, United States^2;Solid Material Solutions, Chelmsford; MA; 01863, United States^3

[关键词] Axial strain;High field magnets;Ic degradation;Overpressure;Solid material;Strain data;Strain limit;Stress limits