The Effect of Texture and Microstructure on the Macroscopic Properties of Polycrystalline Piezoelectrics: Application to Barium Titanate and PZN–PT |
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Authors: | R. Edwin Garcí a,W. Craig Carter, Stephen A. Langer |
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Affiliation: | Center for Theoretical and Computational Materials Science, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8500; Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 01239-4307; Information Technology Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8910 |
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Abstract: | The effects of crystallographic texture and microstructure are analyzed for polycrystalline tetragonal BaTiO3, pseudotetragonal PZN–PT, and cubic BaTiO3. For tetragonal BaTiO3 and pseudotetragonal PZN–PT, we demonstrate that a high anisotropy of the single-crystal properties induces an apparent enhancement in the macroscopic piezoelectric response. For tetragonal BaTiO3, the predicted macroscopic piezoelectric constants d 31 and d 33 are enhanced with respect to its single-crystal value at the expense of the spatial contributions from d 15. For samples possessing fiber texture, an optimal response is predicted for samples that are not perfectly textured. Similarly, an apparent enhancement of the macroscopic value of d 15 is predicted for PZN–PT. For cubic BaTiO3, the low anisotropy of the underlying crystal properties induces a uniform decrease of the macroscopic electrostrictive constant, Q 11, with decreasing texture. A completely random polycrystal provides 0.85±0.05 times its single-crystal response. |
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