Transverse stress and fatigue effects in Y-Ba-Cu-O coated IBAD tapes
Transverse stress and fatigue effects in Y-Ba-Cu-O coated IBAD tapes
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DOI：
10.1109/77.919790
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发表时间：
2001-03-01
影响因子：
1.8
通讯作者：
McCowan, CN
中科院分区：
文献类型：
--
作者：
Ekin, JW;Bray, SL;McCowan, CN
本文报道了在76 K自磁场中，静态和循环（疲劳）横向应力对离子束辅助沉积（IBAD）Ya-Ba-Cu-O涂层带材临界电流的影响。具有IBAD缓冲层的Inconel衬底（100 μ m厚）上的Ya-Ba-Cu-O膜（类似于1 μ m厚）具有超过1 MA/cm（2）的临界电流密度J（c）和约50的n值（其中n是超导体到正常转变的锐度的指数）。在100 MPa的静态载荷下，J（c）的降解小于5%（120 MPa时为7%）。当经受循环载荷时，2000次疲劳循环后J（c）的额外退化小于2%。样品的显微镜检查表明，这种有限的J（c）退化可能是由于在经受这些高横向压力后，样品边缘附近形成的纵向裂纹引起的。这种断裂模式表明，来自高屈服基底的纵向侧支撑或磁体结构的环氧树脂浸渍可以提供额外的耐受性，以防止J（c）因横向应力而退化。
Measurements of the effects of static and cyclic (fatigue) transverse stress on the critical current of Ya-Ba-Cu-O coated tapes made by ion-beam-assisted deposition (IBAD) are reported at 76 K in self magnetic field. Ya-Ba-Cu-O films (similar to1 mum thick) on Inconel substrates (100 mum thick) with IBAD buffer layers had critical-current densities J(c) exceeding 1 MA/cm(2) and n values of about 50 (where n is an index of the sharpness of the superconductor-to-normal transition). Under static loads of 100 MPa, the degradation in J(c) was less than 5% (7% at 120 MPa). When subjected to cyclic loading, there was less than 2% additional degradation in J(c) after 2000 fatigue cycles. Microscopic examination of the samples indicates that this limited J(c) degradation may have arisen from longitudinal cracks forming near the edges of the sample after being subjected to these high transverse pressures. This fracture mode would indicate that longitudinal side support from high-yield substrates or epoxy impregnation of magnet structures may provide additional tolerance against degradation in J(c) from transverse stress.