Measurement of the single crystal elasticity matrix of polycrystalline materials

An analytic continuation method for obtaining rigorous bounds on the effective complex permittivity ε * of polycrystalline composite materials is developed. It is assumed that the composite consists of many identical anisotropic crystals, each with a unique orientation. The key step in obtaining the bounds involves deriving an integral representation for ε *, which separates parameter information from geometrical information. Forward bounds are then found using knowledge of the single crystal permittivity tensor and mean crystal orientation. Inverse bounds are also developed, which recover information about the mean crystal orientation from ε *. We apply the polycrystalline bounds to sea ice, a critical component of the climate system. Different ice types, which result from different growth conditions, have different crystal orientation and size statistics. These characteristics significantly influence the fluid transport properties of sea ice, which control many geophysical and biogeochemical processes important to the climate and polar ecosystems. Using a two-scale homogenization scheme, where the single crystal tensor is numerically computed, forward bounds for sea ice are obtained and are in excellent agreement with columnar sea ice data. Furthermore, the inverse bounds are also applied to sea ice, helping to lay the groundwork for determining ice type using remote sensing techniques.

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Use of Imaging Plates in X-Ray Analysis

Textures and Microstructures ◽

10.1155/tsm.29.89 ◽

1997 ◽

Vol 29 (1-2) ◽

pp. 89-101 ◽

Cited By ~ 6

Author(s):

M. Ermrich ◽

F. Hahn ◽

E. R. Wölfel

Keyword(s):

Single Crystal ◽

Single Crystals ◽

Powder Diffraction ◽

Polycrystalline Materials ◽

Imaging Plate ◽

Two Dimensional ◽

X Ray ◽

Working Principle ◽

Imaging Plates

Two-dimensional detectors have opened a new area for the investigation of both single crystals and polycrystalline materials. The working principle of Imaging Plates is described. Some characteristics and the advantages of an Imaging Plate are discussed using the STOE Imaging Plate Diffraction System for different kinds of X-ray analysis: (i) single crystal diffractometry, (ii) powder diffraction and (iii) stress and texture investigations.

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Synthesis of polycrystalline materials of SrWO4 and growth of its single crystal

Frontiers of Chemistry in China ◽

10.1007/s11458-006-0023-z ◽

2006 ◽

Vol 1 (3) ◽

pp. 264-267 ◽

Cited By ~ 1

Author(s):

Jiandong Fan ◽

Huaijin Zhang ◽

Zhengping Wang ◽

Wenwei Ge ◽

Jiyang Wang

Keyword(s):

Single Crystal ◽

Polycrystalline Materials

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Electrical Transport Properties of the Pentatelluride Materials Hfte5 and Zrte5

MRS Proceedings ◽

10.1557/proc-478-249 ◽

1997 ◽

Vol 478 ◽

Cited By ~ 6

Author(s):

T. M. Tritt ◽

M. L. Wilson ◽

R. L. Littleton ◽

C. Feger ◽

J. Kolis ◽

...

Keyword(s):

Single Crystal ◽

Single Crystals ◽

Electrical Transport ◽

Entire Range ◽

Room Temperature ◽

Polycrystalline Material ◽

Polycrystalline Materials ◽

Electrical Transport Properties ◽

Low Dimensional ◽

P Type

AbstractWe have measured the resistivity and thermopower of single crystals as well as polycrystalline pressed powders of the low-dimensional pentatelluride materials: HfTe5 and ZrTe5. We have performed these measurements as a function of temperature between 5K and 320K. In the single crystals there is a peak in the resistivity for both materials at a peak temperature, Tp where Tp ≈ 80K for HfTe5 and Tp ≈ 145K for ZrTe5. Both materials exhibit a large p-type thermopower around room temperature which undergoes a change to n-type below the peak. This data is similar to behavior observed previously in these materials. We have also synthesized pressed powders of polycrystalline pentatelluride materials, HfTe5 and ZrTe5. We have measured the resistivity and thermopower of these polycrystalline materials as a function of temperature between 5K and 320K. For the polycrystalline material, the room temperature thermopower for each of these materials is relatively high, +95 μV/K and +65 μV/K for HfTe5 and ZrTe5 respectively. These values compare closely to thermopower values for single crystals of these materials. At 77 K, the thermopower is +55 μV/K for HfTe5 and +35 μV/K for ZrTe5. In fact, the thermopower for the polycrystals decreases monotonically with temperature to T ≈ 5K, thus exhibiting p-type behavior over the entire range of temperature. As expected, the resistivity for the polycrystals is higher than the single crystal material, with values of 430 mΩ-cm and 24 mΩ-cm for Hfre5 and ZrTe5 respectively, compared to single crystal values of 0.35 mΩ-cm (HfTe5) and 1.0 mΩ-cm (ZrTe5). We have found that the peak in the resistivity evident in both single crystal materials is absent in these polycrystalline materials. We will discuss these materials in relation to their potential as candidates for thermoelectric applications.

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Plasticity-Damage Couplings: From Single Crystal to Polycrystalline Materials

10.1007/978-3-319-92922-4 ◽

2019 ◽

Cited By ~ 5

Author(s):

Oana Cazacu ◽

Benoit Revil-Baudard ◽

Nitin Chandola

Keyword(s):

Single Crystal ◽

Polycrystalline Materials

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Residual Stress Measurement of Silicon Nitride and Silicon Carbide by X-Ray Diffraction Using Gaussian Curve Method

Advances in X-ray Analysis ◽

10.1154/s0376030800020784 ◽

1988 ◽

Vol 32 ◽

pp. 459-469 ◽

Cited By ~ 4

Author(s):

Masanori Kurita ◽

Ikuo Ihara ◽

Nobuyuki Ono

Keyword(s):

Residual Stress ◽

Single Crystal ◽

Elastic Constants ◽

Stress Measurement ◽

Polycrystalline Materials ◽

X Ray Diffraction ◽

X Ray ◽

Small Areas ◽

Curve Method ◽

The Continuum

The residual stress induced by grinding or some thermal treatment has a large effect on the strength of ceramics. The X-ray technique can be used to nondestructively measure the residual stress in small areas on the surface of polycrystalline materials. The X-ray stress measurement is based on. the continuum mechanics for macroscopically isotropic polycrystalline materials. In this method, the stress value is calculated selectively from strains of a particular diffraction plane in the grains which are favorably oriented for the diffraction. In general, however, the elastic constants of a single crystal depend on the plane of the lattice, since a single crystal is anisotropic, The behavior of the deformation of individual crystals in the aggregate of polycrystalline materials under applied stress has not yet been solved successfully. Therefore, the stress constant and elastic constants for a particular diffracting plane should be determined experimentally in order to determine the residual stress accurately by X-ray diffraction.

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