EFFECT OF TEXTURE ON GRAIN-BOUNDARY MISORIENTATION DISTRIBUTIONS IN POLYCRYSTALLINE HIGH-TEMPERATURE SUPERCONDUCTORS

Computer simulations were performed to determine the most probable gra in boundary misorientation distribution (GBMD) in model polycrystallin e superconductors. GBMDs in polycrystalline superconductors can be exp ected to dictate the macroscopic transport critical current density, J (c). Calculations were performed by simulating model polycrystals and then determining the GBMD. Such distributions were calculated for rand om materials having cubic, tetragonal, and orthorhombic crystal symmet ry. In addition, since most high temperature superconductors are tetra gonal or pseudotetragonal, the effect of macroscopic uniaxial and biax ial grain orientation texture on the GBMD was determined for tetragona l materials. It is found that macroscopic texture drastically alters t he grain boundary misorientation distribution. The fraction of low ang le boundaries increases significantly with uniaxial and biaxial textur e. The results of this study are important in correlating the macrosco pic transport J(c) with the measured grain orientation texture as dete rmined by x-ray diffraction (C) 1996 American Institute of Physics.