MICROTEXTURE AND MESOTEXTURE IN HIGH-J(C) BI-2223

The microstructure of high-J(c) Bi-2223 powder-in-tube tapes was studi ed using x-ray and electron diffraction. Although the c-axis is nomina lly aligned perpendicular to the tape surface (FWHM similar to 20 degr ees), x-ray phi scans and pole figures show no evidence of any in-plan e texture, either macroscopically or locally. Electron backscatter dif fraction patterns acquired in a scanning electron miscroscope (SEM) we re used to measure individual grain orientations. Grain boundary misor ientation between adjacent grains was described by rotation angles and axes (i.e. the disorientation) and compared with theoretical values o f ideal coincidence site lattices (CSLs). Data collected from over 113 spatially correlated grains resulting in 227 grain boundaries, show t hat over 40% of the boundaries are small angle. In addition, 8% of the boundaries were found to be within the Brandon criterion for CSLs (la rger than Sigma 1 and less than Sigma 50). Grain boundary ''texture ma ps'' derived from the SEM image and orientation data reveal the presen ce of percolative paths between low energy boundaries.