TY - JOUR
T1 - Relationships between conductor damage, quenching and electromechanical behavior in YBCO coated conductors
AU - Mbaruku, A. L.
AU - Trociewitz, U. P.
AU - Wang, X.
AU - Schwartz, J.
N1 - Funding Information:
Manuscript received August 29, 2006. This work was supported in part by the Air Force Office of Scientific Research, the National High Magnetic Field Laboratory (NHMFL), and the Center for Advanced Power Systems (CAPS).
PY - 2007/6
Y1 - 2007/6
N2 - The implementation of emerging superconducting materials into magnet systems with long service lifetimes requires a thorough understanding of their engineering properties, including their quench and electromechanical behaviors. Furthermore, it is essential to understand the role of defects in the conductor, whether they be pre-existing defects from the conductor manufacturing process that locally reduce J c, or local defects that result from a non-destructive quench (i.e., a quench that may reduce J c locally but does not significantly affect the end-to-end behavior). This paper reports results on both of these types of defects and the interplay between quenching and electromechanical behavior. Quench studies investigate the initiation and propagation of quenches in coated conductors. Disturbances in homogeneous conductors are initiated by a pulsed heater attached to the conductor. Disturbances in locally damaged conductors are initiated by increasing the transport current above the I c at the local defect but below the end-to-end I c. Samples are quenched to determine the minimum quench energy and the quench propagation velocity. Homogeneous samples are also quenched to the point of initiating local damage, thereby identifying the maximum allowable hot-spot temperature or hot-spot temperature gradient. Samples used in quench studies are subsequently used in I c -strain measurements to determine how quenching affects subsequent performance. Samples that exhibit reduced I c from quenching, and samples from regions adjacent to such damaged samples, are studied. It is found that quenching can reduce the electromechanical performance of conductors that do not initially show a reduction in their electrical performance.
AB - The implementation of emerging superconducting materials into magnet systems with long service lifetimes requires a thorough understanding of their engineering properties, including their quench and electromechanical behaviors. Furthermore, it is essential to understand the role of defects in the conductor, whether they be pre-existing defects from the conductor manufacturing process that locally reduce J c, or local defects that result from a non-destructive quench (i.e., a quench that may reduce J c locally but does not significantly affect the end-to-end behavior). This paper reports results on both of these types of defects and the interplay between quenching and electromechanical behavior. Quench studies investigate the initiation and propagation of quenches in coated conductors. Disturbances in homogeneous conductors are initiated by a pulsed heater attached to the conductor. Disturbances in locally damaged conductors are initiated by increasing the transport current above the I c at the local defect but below the end-to-end I c. Samples are quenched to determine the minimum quench energy and the quench propagation velocity. Homogeneous samples are also quenched to the point of initiating local damage, thereby identifying the maximum allowable hot-spot temperature or hot-spot temperature gradient. Samples used in quench studies are subsequently used in I c -strain measurements to determine how quenching affects subsequent performance. Samples that exhibit reduced I c from quenching, and samples from regions adjacent to such damaged samples, are studied. It is found that quenching can reduce the electromechanical performance of conductors that do not initially show a reduction in their electrical performance.
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U2 - 10.1109/TASC.2007.898874
DO - 10.1109/TASC.2007.898874
M3 - Article
AN - SCOPUS:34547410323
SN - 1051-8223
VL - 17
SP - 3044
EP - 3049
JO - IEEE Transactions on Applied Superconductivity
JF - IEEE Transactions on Applied Superconductivity
IS - 2
ER -