Effect of transverse compressive stress on transport critical current density of Y-Ba-Cu-O coated Ni and Ni-W RABiTS tapes

Published

January 1, 2003

Author(s)

Najib Cheggour, John (Jack) W. Ekin, Cameron C. Clickner, Ron Feenstra, P Goyal, D F. Paranthaman, Noel Rutter

Abstract

Transport properties of yttrium-barium-copper-oxide (YBCO) coatings on both pure-nickel and nickel-3at%tungsten rolling-assisted-biaxially-textured substrates (RABiTS) were tested under transverse compressive stress up to 180 MPa. Transport critical-current densities (J_c) were measured on samples having an initial J_c in the range of 1 MA/cm² at 76 K and self magnetic field. Transverse compressive stress can cause significant degradation of J_c in YBCO deposited on pure-nickel RABiTS unless appropriate work-hardening treatment or a sufficient frictional support are provided to the sample. Preliminary results obtained for YBCO on nickel-3at%tungsten alloy RABiTS suggest that the electromechanical properties of these conductors may be improved if such material is used for the substrate. Stress-strain characteristics were measured on nickel and nickel-3at%tungsten RABiTS substrate materials at 76 K. The tensile yield strength, Young's modulus, and proportional limit of elasticity of both materials were determined. Scanning electron microscopy was used to also investigate the microstructure of the coated-conductor samples after electromechanical testing. Mechanical cracks with multi-patterned orientations were observed in the ceramic layers. The data indicate that the formation of cracks in the ceramic layers initiated by the yielding of the substrate material, the primary cause for the degradation of J_c in the samples investigated.

Citation

Ceramic Transactions

Volume

140

Pub Type

Journals

Keywords

ceramic, coated conductors, critcal current density, mechanical cracks, mechanical properties, microstructure, strain

Citation

Cheggour, N. , Ekin, J. , Clickner, C. , Feenstra, R. , Goyal, P. , Paranthaman, D. and Rutter, N. (2003), Effect of transverse compressive stress on transport critical current density of Y-Ba-Cu-O coated Ni and Ni-W RABiTS tapes, Ceramic Transactions (Accessed December 10, 2024)