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Title: Texture and Anisotropy of Polycrystalline Piezoelectics

Abstract

Piezoelectricity is manifested in ferroelectric ceramics by inducing a preferred volume fraction of one ferroelectric domain variant orientation at the expense of degenerate orientations. The piezoelectric effect is therefore largely controlled by the effectiveness of the electrical poling in producing a bias in ferroelectric (180{sup o}) and ferroelastic (non-180{sup o}) domain orientations. Further enhancement of the piezoelectric effect in bulk ceramics can be accomplished by inducing preferred orientation through grain-orientation processes such as hot forging or tape casting that precede the electrical-poling process. Coupled crystal orientation and domain orientation processing yields ceramics with an even greater piezoelectric response. In this paper, preferred orientations of domains and grains in polycrystalline piezoelectric ceramics generated through both domain- and grain-orientation processing are characterized through pole figures and orientation distribution functions obtained using data from a variety of diffraction techniques. The processing methods used to produce these materials and the methods used to evaluate preferred orientation and texture are described and discussed in the context of prior research. Different sample and crystal symmetries are explored across a range of commercial and laboratory-prepared materials. Some of the variables presented in this work include the effects of in situ thermal depoling and the detailed processing parametersmore » used in tape casting of materials with preferred crystallite orientations. Preferred orientation is also correlated with anisotropic properties, demonstrating a clear influence of both grain and domain orientations on piezoelectricity.« less

Authors:
; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
930004
Report Number(s):
BNL-80617-2008-JA
Journal ID: ISSN 0002-7820; JACTAW; TRN: US200822%%1157
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of the American Ceramic Society; Journal Volume: 90; Journal Issue: 8
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANISOTROPY; CASTING; CERAMICS; CRYSTALS; DIFFRACTION; DISTRIBUTION FUNCTIONS; FORGING; GRAIN ORIENTATION; MATERIALS; ORIENTATION; PIEZOELECTRICITY; PROCESSING; TEXTURE; VOLUME; national synchrotron light source

Citation Formats

Jones,J., Iverson, B., and Bowman, K. Texture and Anisotropy of Polycrystalline Piezoelectics. United States: N. p., 2007. Web. doi:10.1111/j.1551-2916.2007.01820.x.
Jones,J., Iverson, B., & Bowman, K. Texture and Anisotropy of Polycrystalline Piezoelectics. United States. doi:10.1111/j.1551-2916.2007.01820.x.
Jones,J., Iverson, B., and Bowman, K. Mon . "Texture and Anisotropy of Polycrystalline Piezoelectics". United States. doi:10.1111/j.1551-2916.2007.01820.x.
@article{osti_930004,
title = {Texture and Anisotropy of Polycrystalline Piezoelectics},
author = {Jones,J. and Iverson, B. and Bowman, K.},
abstractNote = {Piezoelectricity is manifested in ferroelectric ceramics by inducing a preferred volume fraction of one ferroelectric domain variant orientation at the expense of degenerate orientations. The piezoelectric effect is therefore largely controlled by the effectiveness of the electrical poling in producing a bias in ferroelectric (180{sup o}) and ferroelastic (non-180{sup o}) domain orientations. Further enhancement of the piezoelectric effect in bulk ceramics can be accomplished by inducing preferred orientation through grain-orientation processes such as hot forging or tape casting that precede the electrical-poling process. Coupled crystal orientation and domain orientation processing yields ceramics with an even greater piezoelectric response. In this paper, preferred orientations of domains and grains in polycrystalline piezoelectric ceramics generated through both domain- and grain-orientation processing are characterized through pole figures and orientation distribution functions obtained using data from a variety of diffraction techniques. The processing methods used to produce these materials and the methods used to evaluate preferred orientation and texture are described and discussed in the context of prior research. Different sample and crystal symmetries are explored across a range of commercial and laboratory-prepared materials. Some of the variables presented in this work include the effects of in situ thermal depoling and the detailed processing parameters used in tape casting of materials with preferred crystallite orientations. Preferred orientation is also correlated with anisotropic properties, demonstrating a clear influence of both grain and domain orientations on piezoelectricity.},
doi = {10.1111/j.1551-2916.2007.01820.x},
journal = {Journal of the American Ceramic Society},
number = 8,
volume = 90,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • The spatial model of a polycrystal was used to prove the existence of exact (quantitative) relationship between texture and distribution of CSL boundaries for < hkl > type if textures and also to determine features of spatial distribution of CSL boundaries: number CSL boundaries per grain and number CSL boundaries in triple-line. The main conclusion is that the texture strongly affects the grain boundary misorientation distribution and distribution of CSL boundaries and each type of texture generates characteristic types of CSL boundaries.
  • The monotonic and cyclic behavior of polycrystalline copper can be greatly affected by the crystallographic texture. Samples with strong textures related to multiple slip directions show higher values of the saturation stress than those samples with weak multiple slip textures or random textures related to single slip orientations. The effect of texture on cyclic behavior is complex, and seems to be controlled by several factors related to enhanced or suppressed hardening for multiple and single slip orientations respectively, the influence of texture on elastic stresses at twin boundaries, and the behavior of the grain boundaries in general, the nature andmore » properties of which can be partially determined by the presence of texture. Grain size has a much smaller effect than texture in the cyclic behavior of polycrystalline copper for grain sizes ranging from 700 to 100 {mu}m. At low plastic strains the effect of these parameters seems to be very small as well, and the hardening appears to be related only to the dislocation structure for single slip that is characteristic of that level of strain. It can also be concluded that it is possible to study the effects of texture and grain size separately, by appropriate control of microstructure and without recourse to special manufacturing techniques.« less
  • Polycrystalline material of various grain sizes of AlSi-alloy containing second-phase particles have been deformed at room temperature in axisymmetric compression. The variation in crystallographic orientation in the as-deformed material was obtained by the Electron Back Scattered Pattern (EBSP) technique in SEM. ``Random`` and cumulative long range misorientation gradients have been quantified within the matrix (M) and at heterogeneities such as the grain boundary (GB), the triple line region (TL) and in the vicinity of large second phase particles (P) in material compressed to equivalent plastic strains of 0.2 and 0.4. It is shown that the misorientation gradient increases differently inmore » different regions with increasing strain. Maximum values were found in regions expected to be more strained than average in order to accommodate imposed constraint from neighboring grains or front the presence of large second phase particles. An important feature of the deformed structure seems to be the cumulative rotation of the lattice about an axis close to the {l_angle}111{r_angle}-axis in regions with large misorientations.« less
  • Computer simulations were performed to determine the most probable grain boundary misorientation distribution (GBMD) in model polycrystalline superconductors. GBMDs in polycrystalline superconductors can be expected to dictate the macroscopic transport critical current density, {ital J}{sub {ital c}}. Calculations were performed by simulating model polycrystals and then determining the GBMD. Such distributions were calculated for random materials having cubic, tetragonal, and orthorhombic crystal symmetry. In addition, since most high temperature superconductors are tetragonal or pseudotetragonal, the effect of macroscopic uniaxial and biaxial grain orientation texture on the GBMD was determined for tetragonal materials. It is found that macroscopic texture drastically altersmore » the grain boundary misorientation distribution. The fraction of low angle boundaries increases significantly with uniaxial and biaxial texture. The results of this study are important in correlating the macroscopic transport {ital J}{sub {ital c}} with the measured grain orientation texture as determined by x-ray diffraction {copyright} {ital 1996 American Institute of Physics.}« less
  • Resonant ultrasound spectroscopy was used to measure the orthorhombic elastic constants of rolled, polycrystalline plates of Cu, Cu{endash}5{percent} Zn, and Cu{endash}15{percent} Zn. The experimental results were fit to theoretical expressions to determine the orientation-distribution coefficients W{sub 400}, W{sub 420}, and W{sub 440}. These coefficients are related to texture (the nonrandom orientation of crystallites). The experimental results were in good agreement with theory for the Cu and the Cu{endash}15{percent} Zn materials. The agreement was not as good for the more anisotropic Cu{endash}5{percent} Zn material, especially for the in-plane compressional constants C{sub 11} and C{sub 22}. The ultrasonically derived {ital W}{close_quote}s weremore » compared to those obtained from neutron measurements for the Cu{endash}Zn alloys. Pole plots based on the two types of measurements, using W{sub 400}, W{sub 420}, and W{sub 440}, were in excellent agreement for the 15{percent} Zn material, and in qualitative agreement for the 5{percent} Zn material. The results support the idea that acoustic methods can be used to measure the low-order {ital W}{close_quote}s in polycrystalline materials. {copyright} {ital 1999 Acoustical Society of America.}« less