Misorientation Characteristics Research Articles

An investigation on high-angle grain boundaries in melt-textured YBa 2Cu 3O 6+ x superconductors

Six high-angle (range between 17° and 77°) grain boundaries in melt-textured YBa 2Cu 3O 6+ x superconducting materials, namely GB1, GB2, GB3, GB4, GB5 and GB6, have been investigated. Three of them GB1, GB2 and GB3 have high values of critical current, while the other three GB4, GB5 and GB6 possess low values of critical current. From TEM studies, GB1, GB2 and GB6 are found to be related to fully oxygenated CCSL boundary, while GB4 and GB5 are related to oxygen-deficient constraint coincidence site lattice (CCSL) boundary. GB3 is found to be a random grain boundary where its misorientation characteristics do not match any CCSL within the limitation of Σ<100. The analyses of the TEM studies along with the critical current measurements obtained on GB1, GB2, GB4 and GB5 indicate that oxygen distribution at the grain boundary plays an important role in the coupling of grain boundaries in YBa 2Cu 3O 6+ x superconductor. However, the behaviors of GB3 and GB6 suggest that the CCSL theory is not general in predicting the superconducting behavior of high-angle grain boundaries in YBa 2Cu 3O 6+ x superconductors.

Orientation and misorientation characteristics of annealed, rolled and recrystallized copper

The texture and microstructure of annealed, rolled and recrystallized copper (99.99%) were investigated using conventional X-ray diffraction and single-crystal electron backscattering diffraction (EBSP) in a scanning electron microscope. From the EBSP data, misorientation distribution functions for next neighbor orientation relationships were derived, which show that the undeformed (annealed) starting material and the recrystallized sample have primary and secondary twin correlations, whereas in the deformed sample no preferred misorientations are observed. The microtexture of a single grain with twin lamellae in the deformed sample was analyzed in detail using automated analysis of electron backscattering diffraction patterns. The twin relationship is transformed continuously into a high angle grain boundary during deformation. Orientation gradients within one grain increase steadily up to 20°.

Analysis of Misorientation Characteristics in Annealed and Deformed Copper

Analysis of Misorientation Characteristics in Annealed and Deformed Copper