Mechanical Properties of Textured Bi2Sr2CaCu2O8+d High-Temperature Superconductors

Authors: Jose Ygnacio Pastor, Pedro Poza, and Javier Llorca, Polytechnic University of Madrid, J. Am. Ceram. Soc., 82 [11] 3139-44 (1999)

Abstract

The mechanical properties of Bi2Sr2CaCu2O8+d fibers produced via laser-induced directional solidification at different growth rates were determined through longitudinal and transverse tension tests, as well as flexure tests. In addition, polished sections of as-received fibers and the fracture surfaces of the broken samples were examined using scanning electron microscopy to elucidate the relationship between the microstructure and the mechanical properties. The fibers were anisotropic, and the transverse fiber strength was very low, because of early failure via cleavage of the grains perpendicular to the c-axis. The longitudinal strength and the degree of anisotropy increased as the fiber growth rate decreased, whereas the transverse strength followed the opposite trend. This behavior was due to changes in the porosity and the alignment of the crystals along the fiber axis.