Grain boundary crystallography in polycrystalline yttria-stabilised cubic zirconia

Abstract

Properties of grain boundaries such as grain boundary energy, mobility and diffusion are reported to depend strongly on their crystallography. While studies on ceramic bicrystals with low Σ misorientations have shown highly ordered structures and low energies, studies on dense polycrystalline ceramics often show the significance of grain boundary planes. In the present study, grain boundary plane distributions were studied for yttria-stabilised cubic zirconia with varying grain sizes using Electron Back Scattered Diffraction technique combined with a stereological approach. Despite nearly isotropic grain boundary plane distributions, a highly anisotropic grain boundary character distribution is observed for specific misorientations. Certain low-energy symmetric tilts such as Σ3 and Σ11 are found to occur with high frequencies across the grain size range studied, leading to an inverse correlation between GB energy and frequency of occurrence, consistent with other ceramics studied in literature.

Keywords:

• Grain boundaries
• EBSD
• grain boundary character distribution
• symmetric tilts
• yttria-stabilised cubic zirconia

Acknowledgements

This work was initiated as CSL fractions in YCZ, under the guidance of Prof. Atul H. Chokshi and supported by the Department of Science and Technology. The author thanks Prof. A.H. Chokshi for the experimental facilities and discussions. The programmes on stereological analysis, developed by Prof. G.S. Rohrer and colleagues were introduced by Prof. A.D. Rollett during his visit to IISc, Bangalore; author sincerely thanks Prof. A.D. Rollett for the useful discussions. The author thanks Prof. Satyam Suwas for discussions and facilitating discussions with visiting researchers; Dr. K. S. Suresh, Prof. T. Watanabe and Dr. S. Zaefferer for inputs during various stages of the work.