Journal articles: 'Crystal preferred orientation'

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Wenk, Hans-Rudolf, Paulo J. M. Monteiro, Martin Kunz, Kai Chen, Nobumichi Tamura, Luca Lutterotti, and John Del Arroz. "Preferred orientation of ettringite in concrete fractures." Journal of Applied Crystallography 42, no. 3 (May 15, 2009): 429–32. http://dx.doi.org/10.1107/s0021889809015349.

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Sulfate attack and the accompanying crystallization of fibrous ettringite [Ca6Al2(OH)12(SO4)3·26H2O] cause cracking and loss of strength in concrete structures. Hard synchrotron X-ray microdiffraction is used to quantify the orientation distribution of ettringite crystals. Diffraction images are analyzed using the Rietveld method to obtain information on textures. The analysis reveals that thecaxes of the trigonal crystallites are preferentially oriented perpendicular to the fracture surfaces. By averaging single-crystal elastic properties over the orientation distribution, it is possible to estimate the elastic anisotropy of ettringite aggregates.

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Müller-Stoffels, Marc, Pat J. Langhorne, Chris Petrich, and Edward W. Kempema. "Preferred crystal orientation in fresh water ice." Cold Regions Science and Technology 56, no. 1 (April 2009): 1–9. http://dx.doi.org/10.1016/j.coldregions.2008.11.003.

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Schwarzer, Robert A., and Hasso Weiland. "Electron Microscopy for the determination of preferred crystal orientations: A concise review." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 4 (August 1990): 434–35. http://dx.doi.org/10.1017/s0424820100175302.

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The distribution of grain orientations (“crystal texture”, “preferred orientations”) is a distinctive feature of microstructure, since important material properties are anisotropic, and changes of crystal texture may be found in workpieces which are typical for fabrication processes and use. Two complementary computerized techniques /1/ are available for the study of preferred crystal orientations on a microscale using electron microscopy:the measurement of individual grain orientations (TEM, SEM)polefigure measurements (TEM).The standard methods of orientation determination grain by grain using a TEM are the interpretation of SAD spot and of microbeam diffraction Kikuchi patterns. Thin samples, however, are required which are transparent for high-energy electrons.

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Yoshioka, S., H. Fujita, S. Kinoshita, and B. Matsuhana. "Alignment of crystal orientations of the multi-domain photonic crystals in Parides sesostris wing scales." Journal of The Royal Society Interface 11, no. 92 (March 6, 2014): 20131029. http://dx.doi.org/10.1098/rsif.2013.1029.

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It is known that the wing scales of the emerald-patched cattleheart butterfly, Parides sesostris , contain gyroid-type photonic crystals, which produce a green structural colour. However, the photonic crystal is not a single crystal that spreads over the entire scale, but it is separated into many small domains with different crystal orientations. As a photonic crystal generally has band gaps at different frequencies depending on the direction of light propagation, it seems mysterious that the scale is observed to be uniformly green under an optical microscope despite the multi-domain structure. In this study, we have carefully investigated the structure of the wing scale and discovered that the crystal orientations of different domains are not perfectly random, but there is a preferred crystal orientation that is aligned along the surface normal of the scale. This finding suggests that there is an additional factor during the developmental process of the microstructure that regulates the crystal orientation.

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Telang, A. A., T. T. Bieler, S. Choi, and K. K. Subramanian. "Orientation imaging studies of Sn-based electronic solder joints." Journal of Materials Research 17, no. 9 (September 2002): 2294–306. http://dx.doi.org/10.1557/jmr.2002.0337.

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Single shear lap specimens were subjected to creep, isothermal aging, and thermomechanical fatigue (TMF). Scanning electron microscopy micrographs of previously polished specimens revealed changes in surface morphology. Orientation imaging microscopy was carried out on the same specimens to study the microstructural evolution and crystal orientation changes. As-fabricated joints consistently show a preferred crystal orientation with a few minority orientations with highly preferred misorientations. Alloy additions caused an increase in the number of statistically significant crystal orientations and misorientations. The solidification microstructure was unchanged due to room-temperature creep. Aging caused development and motion of well-defined subgrain boundaries and removal of most minority orientations. TMF causes heterogeneous refinement of the microstructure that accounts for the localized grain boundary sliding in regions of high strain concentration. This study implies that the lead-free solder joints are not polycrystals, but multicrystals, so that deformation is very heterogeneous and sensitive to strain and temperature history.

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Wu, Yin, Jun Wang, Xinba Yaer, Lei Miao, Boyu Zhang, Feng Guo, and Shuai Zhang. "Effects of preferred orientation and crystal size on thermoelectric properties of sodium cobalt oxide." Functional Materials Letters 09, no. 01 (February 2016): 1650010. http://dx.doi.org/10.1142/s1793604716500107.

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To examine the effect of crystal size and orientation effect on ZT, polycrystalline NaxCo2O4 materials were prepared by pressing layered crystals obtained in sol–gel (SG) synthesis, molten salt synthesis (MSS) with and without additional ball milling (BM) treatment and 1:1 molar ratio mixture (Mixture) of BM powder and MSS powders. We found that the orientation effect and crystal size for four samples follow Mixture < SG < BM < MSS and BM < Mixture < SG < MSS, respectively. Electrical conductivity was obviously enhanced in the highly orientated BM and MSS samples when compared with SG and Mixture. It appears that the crystal size plays a dominant role in thermal conductivity rather than Seebeck coefficient by controlling the phonon scattering at grain boundaries. Thermal conductivity for BM was significantly decreased in comparison to MSS, although both BM and MSS show comparable orientation effect. The maximum ZT value is developed to near 0.51 at 814[Formula: see text]K upon increasing the electrical resistivity and decreasing the thermal conductivity, which are mainly governed by the condition of crystal size and orientation effect.

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Wenk, Hans-Rudolf, Waruntorn Kanitpanyacharoen, and Yang Ren. "Slate – A new record for crystal preferred orientation." Journal of Structural Geology 125 (August 2019): 319–24. http://dx.doi.org/10.1016/j.jsg.2017.12.009.

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Lonardelli, Ivan, Hans-Rudolf Wenk, and Y. Ren. "Preferred orientation and elastic anisotropy in shales." GEOPHYSICS 72, no. 2 (March 2007): D33—D40. http://dx.doi.org/10.1190/1.2435966.

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Anisotropy in shales is becoming an important issue in exploration and reservoir geophysics. In this study, the crystallographic preferred orientation of clay platelets that contributes to elastic anisotropy was determined quantitatively by hard monochromatic X-ray synchrotron diffraction in two different shales from drillholes off the coast of Nigeria. To analyze complicated diffraction images with five different phases (illite/smectite, kaolinite, quartz, siderite, feldspar) and many overlapping peaks, we applied a methodology based on the crystallographic Rietveld method. The goal was to describe the intrinsic physical properties of the sample (phase composition, crystallographic preferred orientation, crystal structure, and microstructure) and compute macroscopic elastic properties by averaging single crystal properties over the orientation distribution for each phase. Our results show that elastic anisotropy resulting from crystallographic preferred orientation of the clay particles can be determined quantitatively. This provides a possible way to compare measured seismic anisotropy and texture-derived anisotropy and to estimate the contribution of the low-aspect ratio pores aligned with bedding.

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Johnstone, Duncan N., Ben H. Martineau, Phillip Crout, Paul A. Midgley, and Alexander S. Eggeman. "Density-based clustering of crystal (mis)orientations and the orix Python library." Journal of Applied Crystallography 53, no. 5 (September 23, 2020): 1293–98. http://dx.doi.org/10.1107/s1600576720011103.

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Crystal orientation mapping experiments typically measure orientations that are similar within grains and misorientations that are similar along grain boundaries. Such (mis)orientation data cluster in (mis)orientation space, and clusters are more pronounced if preferred orientations or special orientation relationships are present. Here, cluster analysis of (mis)orientation data is described and demonstrated using distance metrics incorporating crystal symmetry and the density-based clustering algorithm DBSCAN. Frequently measured (mis)orientations are identified as corresponding to similarly (mis)oriented grains or grain boundaries, which are visualized both spatially and in three-dimensional (mis)orientation spaces. An example is presented identifying deformation twinning modes in titanium, highlighting a key application of the clustering approach in identifying crystallographic orientation relationships and similarly oriented grains resulting from specific transformation pathways. A new open-source Python library, orix, that enabled this work is also reported.

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Vochten, R., R. Huysmans, N. Blaton, and O. M. Peeters. "Simple device for mounting crystals for single-crystal diffractometry." Journal of Applied Crystallography 30, no. 4 (August 1, 1997): 513. http://dx.doi.org/10.1107/s0021889896015865.

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Yoshikawa, Noboru, Takanori Endo, Shoji Taniguchi, Satoshi Awaji, Kazuo Watanabe, and Eiji Aoyagi. "Microstructure and orientation of iron crystals by thermal chemical vapor deposition with imposition of magnetic field." Journal of Materials Research 17, no. 11 (November 2002): 2865–74. http://dx.doi.org/10.1557/jmr.2002.0416.

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Iron crystals were deposited by thermally activated chemical vapor deposition with imposition of magnetic field. In this study, the deposition was conducted by imposing a magnetic field up to 3.5 T in a temperature range between 0.48 and 0.51 of TmFe (melting point of iron), which is below the Curie point of iron (0.58 TmFe). The microstructures and crystal orientations of the deposits were investigated. In the deposition process, island-shaped crystals were formed on a scale of several microns; then a film was grown by their coalescence. As the magnetic field magnitude increased, population of the island-shaped crystals having a cubic shape increased. Simultaneously, their ω-scanned (200) profile became sharper. Their degree of (100) preferred orientation was dependent on the magnetic field up to 3.5 T, which is usually high enough for the saturated magnetization of iron crystals. However, when the substrate was placed parallel to the magnetic field, (100) preferred orientation was not observed for the island-shaped crystals. A large and bimodal ω-scanned (110) profile having sharp peaks was obtained when the substrate was inclined 45° to the field. Preferred (100) orientation was not obtained from the iron films, for which two reasons were pointed out. The first is the secondary grown crystals on the island-shaped crystals having different orientations, and the second is the observed zone III grain structure of the films, where grain boundary migration occurred.

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Judson, E. A., D. N. Hill, R. A. Young, J. R. Cagle, W. J. Lackey, W. B. Carter, and E. K. Barefield. "An analysis of preferred orientation in YBa2Cu3O7–x superconducting films deposited by CVD on single-crystal and polycrystalline substrates." Powder Diffraction 9, no. 4 (December 1994): 250–59. http://dx.doi.org/10.1017/s0885715600018960.

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YBa2Cu3O7–x films were deposited by chemical vapor deposition (CVD) onto single-crystal MgO, single-crystal Al2O3, and polycrystalline Al2O3 substrates, characterized before and after annealing, and tested for their superconducting properties. The preferred orientation in the films was analyzed (i) with pole figures and (ii) by comparison of experimental x-ray powder diffraction patterns with those calculated for the material using the March–Dollase function to model the degree of preferred orientation. Preferred orientation was significant in as-deposited films, with March coefficients ranging from 0.1–0.5 (random orientation would have a coefficient of 1.0). The (006) pole figures of the films on single crystal substrates exhibited uniquely symmetric patterns. On single-crystal MgO before annealing, a minor secondary orientation of (006) poles in the film was observed in a pattern consistent with the symmetry of major crystallographic directions of MgO. On single-crystal Al2O3 after annealing, a “dual orientation” phenomenon was observed. The high-temperature anneal destroyed the orientation and superconducting properties of the CVD films deposited at high temperatures.

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Rehman, Hafiz Ur, David Mainprice, Fabrice Barou, Hiroshi Yamamoto, and Kazuaki Okamoto. "EBSD-measured crystal preferred orientation of eclogites from the Sanbagawa metamorphic belt, central Shikoku, SW Japan." European Journal of Mineralogy 28, no. 6 (March 7, 2016): 1155–68. http://dx.doi.org/10.1127/ejm/2016/0028-2574.

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Pan, Hui, Han Sun, Cheekok Poh, Yuanping Feng, and Jianyi Lin. "Single-crystal growth of metallic nanowires with preferred orientation." Nanotechnology 16, no. 9 (June 29, 2005): 1559–64. http://dx.doi.org/10.1088/0957-4484/16/9/025.

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Pabich, Stephanie, Christian Vollmer, and Nikolaus Gussone. "Investigating crystal orientation patterns of foraminiferal tests by electron backscatter diffraction analysis." European Journal of Mineralogy 32, no. 6 (November 13, 2020): 613–22. http://dx.doi.org/10.5194/ejm-32-613-2020.

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Abstract. We studied the crystallographic orientation of calcite crystals in benthic foraminifers by electron backscatter diffraction (EBSD). Individuals of two species, Gyroidinoides soldanii and Cibicidoides grimsdalei, featuring different test structures, were investigated for a time span covering 43 Myr. The aims of this study are to visualize test structure differences in foraminifers and to reveal potential changes in crystal orientation and grain size over time caused by diagenetic reactions such as recrystallization. Such recrystallization effects over time may aid in the interpretation of time-resolved geochemical data obtained on foraminiferal samples for paleo-environmental reconstructions. The EBSD patterns clearly resolve the different test structures of the two species. Cibicidoides grimsdalei has the c axes perpendicular to the test surface. An apparent shift in the preferred crystal orientation can most likely be attributed to a mismatch between the equatorial plane and cutting plane of the foraminiferal test, highlighting the importance of reproducible preparation techniques. In Gyroidinoides soldanii, the c axes of the calcite crystals show a broader distribution of the crystals with no preferred orientation. The specimens show no change in crystal sizes over time, with a frequency maximum corresponding to the spot size of the electron beam. Overall, the differences between the two species demonstrate that EBSD is a powerful tool to visualize and differentiate between foraminiferal test structures.

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Li, Ling, Carl Goodrich, Haizhao Yang, Katherine R. Phillips, Zian Jia, Hongshun Chen, Lifeng Wang, et al. "Microscopic origins of the crystallographically preferred growth in evaporation-induced colloidal crystals." Proceedings of the National Academy of Sciences 118, no. 32 (August 2, 2021): e2107588118. http://dx.doi.org/10.1073/pnas.2107588118.

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Unlike crystalline atomic and ionic solids, texture development due to crystallographically preferred growth in colloidal crystals is less studied. Here we investigate the underlying mechanisms of the texture evolution in an evaporation-induced colloidal assembly process through experiments, modeling, and theoretical analysis. In this widely used approach to obtain large-area colloidal crystals, the colloidal particles are driven to the meniscus via the evaporation of a solvent or matrix precursor solution where they close-pack to form a face-centered cubic colloidal assembly. Via two-dimensional large-area crystallographic mapping, we show that the initial crystal orientation is dominated by the interaction of particles with the meniscus, resulting in the expected coalignment of the close-packed direction with the local meniscus geometry. By combining with crystal structure analysis at a single-particle level, we further reveal that, at the later stage of self-assembly, however, the colloidal crystal undergoes a gradual rotation facilitated by geometrically necessary dislocations (GNDs) and achieves a large-area uniform crystallographic orientation with the close-packed direction perpendicular to the meniscus and parallel to the growth direction. Classical slip analysis, finite element-based mechanical simulation, computational colloidal assembly modeling, and continuum theory unequivocally show that these GNDs result from the tensile stress field along the meniscus direction due to the constrained shrinkage of the colloidal crystal during drying. The generation of GNDs with specific slip systems within individual grains leads to crystallographic rotation to accommodate the mechanical stress. The mechanistic understanding reported here can be utilized to control crystallographic features of colloidal assemblies, and may provide further insights into crystallographically preferred growth in synthetic, biological, and geological crystals.

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Wenk, Hans-Rudolf, Ivan Lonardelli, Hermann Franz, Kurt Nihei, and Seiji Nakagawa. "Preferred orientation and elastic anisotropy of illite-rich shale." GEOPHYSICS 72, no. 2 (March 2007): E69—E75. http://dx.doi.org/10.1190/1.2432263.

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Shales display significant seismic anisotropy that is attributed in part to preferred orientation of constituent minerals. This orientation pattern has been difficult to quantify because of the poor crystallinity and small grain size of clay minerals. A new method is introduced that uses high-energy synchrotron X-rays to obtain diffraction images in transmission geometry and applies it to an illite-rich shale. The images are analyzed with the crystallographic Rietveld method to obtain quantitative information about phase proportions, crystal structure, grain size, and preferred orientation (texture) that is the focus of the study. Textures for illite are extremely strong, with a maximum of 10 multiples of a random distribution for (001) pole figures. From the three-dimensional orientation distribution of crystallites, and single-crystal elastic properties, the intrinsic anisotropic elastic constants of the illite aggregate (excluding contribution from aligned micropores) can be calculated by appropriate medium averaging. The illitic shale displays roughly transverse isotropy with [Formula: see text] close to [Formula: see text] and more than twice as strong as [Formula: see text]. This method will lend itself to investigate complex polymineralic shales and quantify the contribution of preferred orientation to macroscopic anisotropy.

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Sitepu, Husin, Brian H. O'Connor, and Deyu Li. "Comparative evaluation of the March and generalized spherical harmonic preferred orientation models using X-ray diffraction data for molybdite and calcite powders." Journal of Applied Crystallography 38, no. 1 (January 19, 2005): 158–67. http://dx.doi.org/10.1107/s0021889804031231.

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Preferred crystallographic orientation,i.e.texture in crystalline materials powder diffraction data, can cause serious systematic errors in phase composition analysis and also in crystal structure determination. The March model [Dollase (1986).J. Appl. Cryst.19, 267–272] has been used widely in Rietveld refinement for correcting powder diffraction intensities with respect to the effects of preferred orientation. In the present study, a comparative evaluation of the March model and the generalized spherical harmonic [Von Dreele (1997).J. Appl. Cryst.30, 517–525] description for preferred orientation was performed with X-ray powder diffraction data for molybdite (MoO3) and calcite (CaCO3) powders uniaxially pressed at five different pressures. Additional molybdite and calcite powders, to which 50% by weight silica gel had been added, were prepared to extend the range of preferred orientations considered. The patterns were analyzed initially assuming random orientation of the crystallites and subsequently the March model was used to correct the preferred orientation. The refinement results were compared with parallel refinements conducted with the generalized spherical harmonic [Sitepu (2002).J. Appl. Cryst.35,274–277]. The results obtained show that the generalized spherical harmonic description generally provided superior figures-of-merit compared with the March model results.

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Dorner, Dorothée, and Stefan Zaefferer. "Microstructure and Texture of Shear Bands in Cold Rolled Silicon Steel Single Crystals of Goss Orientation." Solid State Phenomena 105 (July 2005): 239–44. http://dx.doi.org/10.4028/www.scientific.net/ssp.105.239.

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An initially Goss-oriented ({110}<001> preferred crystal orientation) FeSi single crystal was cold rolled up to 89 % reduction in thickness. The microstructure and texture of shear bands, which develop at strains higher than 70 %, were investigated by the EBSD (electron backscatter diffraction) technique. The texture components within and ouside of the shear bands are the two symmetrical {111}<112> orientations and the {110}<001> orientation. We conclude that crystallographic slip is the deformation mechanism that is active both within and outside of the shear bands.

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Raymer, D. G., and J. M. Kendall. "Seismic Anisotropy in Salt Structures Due to Preferred Crystal Orientation." Revue de l'Institut Français du Pétrole 53, no. 5 (September 1998): 585–94. http://dx.doi.org/10.2516/ogst:1998053.

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Yang, Chia-Ming, Po-Wei Chen, Jui-Chao Kou, Pavel Diko, In-Gann Chen, and Maw-Kuen Wu. "Low Porosity FeSe Preferred Orientation Crystal Growth by Bridgman Method." IEEE Transactions on Applied Superconductivity 21, no. 3 (June 2011): 2845–48. http://dx.doi.org/10.1109/tasc.2010.2086414.

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Goto, Masahiro, Akira Kasahara, Tetsuo Oishi, Youko Konishi, and Masahiro Tosa. "Low Frictional Coating of Copper Oxide with Preferred Crystal Orientation." Tribology Letters 17, no. 1 (July 2004): 51–54. http://dx.doi.org/10.1023/b:tril.0000017418.50533.b6.

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Corkery, Robert W., and Eric C. Tyrode. "On the colour of wing scales in butterflies: iridescence and preferred orientation of single gyroid photonic crystals." Interface Focus 7, no. 4 (June 16, 2017): 20160154. http://dx.doi.org/10.1098/rsfs.2016.0154.

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Lycaenid butterflies from the genera Callophrys , Cyanophrys and Thecla have evolved remarkable biophotonic gyroid nanostructures within their wing scales that have only recently been replicated by nanoscale additive manufacturing. These nanostructures selectively reflect parts of the visible spectrum to give their characteristic non-iridescent, matte-green appearance, despite a distinct blue–green–yellow iridescence predicted for individual crystals from theory. It has been hypothesized that the organism must achieve its uniform appearance by growing crystals with some restrictions on the possible distribution of orientations, yet preferential orientation observed in Callophrys rubi confirms that this distribution need not be uniform. By analysing scanning electron microscope and optical images of 912 crystals in three wing scales, we find no preference for their rotational alignment in the plane of the scales. However, crystal orientation normal to the scale was highly correlated to their colour at low (conical) angles of view and illumination. This correlation enabled the use of optical images, each containing up to 10 4 –10 5 crystals, for concluding the preferential alignment seen along the at the level of single scales, appears ubiquitous. By contrast, orientations were found to occur at no greater rate than that expected by chance. Above a critical cone angle, all crystals reflected bright green light indicating the dominant light scattering is due to the predicted band gap along the direction, independent of the domain orientation. Together with the natural variation in scale and wing shapes, we can readily understand the detailed mechanism of uniform colour production and iridescence suppression in these butterflies. It appears that the combination of preferential alignment normal to the wing scale, and uniform distribution within the plane is a near optimal solution for homogenizing the angular distribution of the band gap relative to the wings. Finally, the distributions of orientations, shapes, sizes and degree of order of crystals within single scales provide useful insights for understanding the mechanisms at play in the formation of these biophotonic nanostructures.

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Zou, H. F., H. J. Yang, J. Tan, and Z. F. Zhang. "Preferential growth and orientation relationship of Ag3Sn grains formed between molten Sn and (001) Ag single crystal." Journal of Materials Research 24, no. 6 (June 2009): 2141–44. http://dx.doi.org/10.1557/jmr.2009.0237.

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The current study shows that there is a preferred orientation relationship between Ag3Sn and Ag in reaction between molten Sn and Ag. Due to the preferred orientation relationship, the morphology of Ag3Sn grains formed on (001) Ag single crystal is different from those formed on (011), (358) single crystal Ag, and polycrystalline Ag Facet scallop-type Ag3Sn grains formed irregularly on (011), (358) single crystal Ag, and polycrystalline Ag; whereas the regular Ag3Sn grains with parallel edges grew on (001) Ag single crystal, and they were elongated along two perpendicular directions. The orientation relationship between Ag3Sn grains and (001) Ag single crystal was determined using electron backscattered diffraction. The preferential growth of regular Ag3Sn grains with parallel edges formed on (001) Ag single crystal can be attributed to their minimum misfit.

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Chen, Di Chun, Hong Tao Li, Hui Gong, Xiao Ping Wang, and Jing Hua Yao. "Influence of Doping Element Crystal Structure on the Microstructure of Cr Films by Magnetron Sputtering." Key Engineering Materials 723 (December 2016): 464–69. http://dx.doi.org/10.4028/www.scientific.net/kem.723.464.

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Cr films with different doping elements were deposited onto silicon wafer by magnetron sputtering. The microstructure and preferred orientation of Cr films were analyzed by TEM and XRD. The results show that the doping element W with bcc structure can strongly inhibit preferred orientation growth trend along (110) crystal plane of Cr film. A nano-multilayer structure is easily formed in the film, which is composed of Cr and W single layer. The doping element Al with fcc structure can strongly inhibit preferred orientation growth trend along all crystal planes of Cr film. The average grain size of Al (Ce) doped Cr film decreased significantly and the crystallization degree improved with the rare earth element Ce added. Both the doping element Zn with hcp structure and the doping element C with hexagonal structure can inhibit preferred orientation growth trend along (110) crystal plane of Cr film. The mechanism is to form the replacement solid solution and interstitial solid solution with Cr atoms, respectively. Nano-multilayer structure composed of Cr and Zn (or C) single layer formed in the films.

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Sitepu, Husin. "Texture and structural refinement using neutron diffraction data from molybdite (MoO3) and calcite (CaCO3) powders and a Ni-rich Ni50.7Ti49.30 alloy." Powder Diffraction 24, no. 4 (December 2009): 315–26. http://dx.doi.org/10.1154/1.3257906.

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Preferred orientation or texture is a common feature of experimental powder patterns. The mathematics of two commonly used models for preferred orientation—the March-Dollase and the generalized spherical-harmonic models—is reviewed. Both models were applied individually to neutron powder data from uniaxially pressed molybdite (MoO3) and calcite (CaCO3) powders in Rietveld analyses, as well as the as-received powders. The structural refinement results are compared to single-crystal structures. The results indicate that reasonable refinement of crystal structures can be obtained using either the March model or generalized spherical-harmonic description. However, the generalized spherical-harmonic description provided better Rietveld fits than the March model for the molybdite and calcite. Therefore, the generalized spherical-harmonic description is recommended for correction of preferred orientation in neutron diffraction analysis for both crystal structure refinement and phase composition analysis. Subsequently, the generalized spherical-harmonic description is extended to crystal structure refinement of annealed and the aged polycrystalline Ni-rich Ni50.7Ti49.30 shape memory alloys.

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Vachon, Rémi, Mohsen Bazargan, Christoph F. Hieronymus, Erika Ronchin, and Bjarne Almqvist. "Crystal rotations and alignment in spatially varying magma flows: 2-D examples of common subvolcanic flow geometries." Geophysical Journal International 226, no. 1 (March 31, 2021): 709–27. http://dx.doi.org/10.1093/gji/ggab127.

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Summary Elongate inclusions immersed in a viscous fluid generally rotate at a rate that is different from the local angular velocity of the flow. Often, a net alignment of the inclusions develops, and the resulting shape preferred orientation of the particle ensemble can then be used as a strain marker that allows reconstruction of the fluid’s velocity field. Much of the previous work on the dynamics of flow-induced particle rotations has focused on spatially homogeneous flows with large-scale tectonic deformations as the main application. Recently, the theory has been extended to spatially varying flows, such as magma with embedded crystals moving through a volcanic plumbing system. Additionally, an evolution equation has been introduced for the probability density function of crystal orientations. Here, we apply this new theory to a number of simple, 2-D flow geometries commonly encountered in magmatic intrusions, such as flow from a dyke into a reservoir or from a reservoir into a dyke, flow inside an inflating or deflating reservoir, flow in a dyke with a sharp bend, and thermal convection in a magma chamber. The main purpose is to provide a guide for interpreting field observations and for setting up more complex flow models with embedded crystals. As a general rule, we find that a larger aspect ratio of the embedded crystals causes a more coherent alignment of the crystals, while it has only a minor effect on the geometry of the alignment pattern. Due to various perturbations in the crystal rotation equations that are expected in natural systems, we show that the time-periodic behaviour found in idealized systems is probably short-lived in nature, and the crystal alignment is well described by the time-averaged solution. We also confirm some earlier findings. For example, near channel walls, fluid flow often follows the bounding surface and the resulting simple shear flow causes preferred crystal orientations that are approximately parallel to the boundary. Where pure shear deformation dominates, there is a tendency for crystals to orient themselves in the direction of the greatest tensile strain rate. Where flow impinges on a boundary, for example in an inflating magma chamber or as part of a thermal convection pattern, the stretching component of pure shear aligns with the boundary, and the crystals orient themselves in that direction. In the field, this local pattern may be difficult to distinguish from a boundary-parallel simple shear flow. Pure shear also dominates along the walls of a deflating magma chamber and in places where the flow turns away from the reservoir walls, but in these locations, the preferred crystal orientation is perpendicular to the wall. Overall, we find that our calculated patterns of crystal orientations agree well with results from analogue experiments where similar geometries are available.

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Karel, Miloslav, and Jaroslav Nývlt. "Measurement of growth rates for single crystals and pressed tablets of CuSO4.5 H2O on a rotating disc." Collection of Czechoslovak Chemical Communications 54, no. 11 (1989): 2951–61. http://dx.doi.org/10.1135/cccc19892951.

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Measured growth and dissolution rates of single crystals and tablets were used to calculate the overall linear rates of growth and dissolution of CuSO4.5 H2O crystals. The growth rate for the tablet is by 20% higher than that calculated for the single crystal. It has been concluded that this difference is due to a preferred orientation of crystal faces on the tablet surface. Calculated diffusion coefficients and thicknesses of the diffusion and hydrodynamic layers in the vicinity of the growing or dissolving crystal are in good agreement with published values.

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Choi, Se Weon, Young Chan Kim, Cheol Woo Kim, Jae Ik Cho, and Chang Seog Kang. "Corrosion and Soldering Behaviour of STD61 Coated by Arc Ion Plating Coatings." Advanced Materials Research 813 (September 2013): 39–42. http://dx.doi.org/10.4028/www.scientific.net/amr.813.39.

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In order to investigate corrosion and soldering behaviour of STD61, TiN and TiAlN were coated on the surface of STD61 by using Arc Ion Plating. The structure of the coatings was examined as a function of deposition conditions by X-ray diffraction, and the crystallographic orientation was determined by use of a texture coefficient. TiN coating was grown with a strong (111) preferred orientation of a typical NaCl-type crystal structure. This strong (111) preferred orientation had been commonly observed from the TiN coatings deposited by physical vapour deposition techniques. TiAlN coatings, however, showed relatively multiple orientations mainly of (111) and (200). Furthermore, TiAlN film demonstrated superior corrosion resistance in a molten aluminum alloy at 680°C. This paper described in detail the corrosion and mass loss phenomena related to this steel-cast metal interaction.

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30

Nasello, Olga B., Laura Levi, and Franco Prodi. "Crystal Structure of Ice Accreted on an Ice Substrate." Journal of Glaciology 33, no. 113 (1987): 120–22. http://dx.doi.org/10.1017/s0022143000005426.

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Abstract Thin ice deposits, grown on a prismatic ice substrate and the first layers of large deposits grown about a cylindrical ice collector, are studied. Experiments were performed at 30 m s–1 wind speed and T a near –20° C. Progressive structural changes in thin accretions with time of water-injection were observed, when the substrate temperature was Ts > –5°C. After 60s injection, which determined a deposit ~1 mm thick, the preferred orientation was established and the mean grain area was ~0.01 mm2. Such structural changes did not appear along the initial layers of thick deposits. These differed mainly from the subsequent zone because of the larger value of the preferred angle between the c-axis and the growth direction. These effects are discussed by considering the nucleation and orientation selection processes which occurred during droplet freezing and the annealing effects that occurred below the growth front. The different c-axis orientations in the initial and main zones are related to the different Ts values during their formation.

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31

Nasello, Olga B., Laura Levi, and Franco Prodi. "Crystal Structure of Ice Accreted on an Ice Substrate." Journal of Glaciology 33, no. 113 (1987): 120–22. http://dx.doi.org/10.3189/s0022143000005426.

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AbstractThin ice deposits, grown on a prismatic ice substrate and the first layers of large deposits grown about a cylindrical ice collector, are studied. Experiments were performed at 30 m s–1 wind speed and Ta near –20° C. Progressive structural changes in thin accretions with time of water-injection were observed, when the substrate temperature was Ts > –5°C. After 60s injection, which determined a deposit ~1 mm thick, the preferred orientation was established and the mean grain area was ~0.01 mm2. Such structural changes did not appear along the initial layers of thick deposits. These differed mainly from the subsequent zone because of the larger value of the preferred angle between the c-axis and the growth direction. These effects are discussed by considering the nucleation and orientation selection processes which occurred during droplet freezing and the annealing effects that occurred below the growth front. The different c-axis orientations in the initial and main zones are related to the different Ts values during their formation.

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32

Hu Hai-Ning, Chen Jing-Lan, and Wu Guang-Heng. "Control of the preferred orientation in electrodeposited single-crystal Fe nanowires." Acta Physica Sinica 54, no. 1 (2005): 389. http://dx.doi.org/10.7498/aps.54.389.

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Kim, Junha, and Haemyeong Jung. "New Crystal Preferred Orientation of Amphibole Experimentally Found in Simple Shear." Geophysical Research Letters 46, no. 22 (November 28, 2019): 12996–3005. http://dx.doi.org/10.1029/2019gl085189.

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34

Kiuchi, Masato, Masato Tomita, Kanenaga Fujii, Mamoru Satou, and Ryuichi Shimizu. "Titanium Nitride Crystal Growth with Preferred Orientation by Dynamic Mixing Method." Japanese Journal of Applied Physics 26, Part 2, No. 6 (June 20, 1987): L938—L940. http://dx.doi.org/10.1143/jjap.26.l938.

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35

Borradaile, Graham J. "Paleomagnetism carried by crystal inclusions: The effect of preferred crystallographic orientation." Earth and Planetary Science Letters 126, no. 1-3 (August 1994): 171–82. http://dx.doi.org/10.1016/0012-821x(94)90249-6.

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36

Xu, Y., D. S. Xue, D. Q. Gao, J. L. Fu, X. L. Fan, D. W. Guo, B. Gao, and W. B. Sui. "Ordered CoFe2O4 nanowire arrays with preferred crystal orientation and magnetic anisotropy." Electrochimica Acta 54, no. 24 (October 2009): 5684–87. http://dx.doi.org/10.1016/j.electacta.2009.05.012.

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37

Gautam, Jai, Roumen H. Petrov, Elke Leunis, and Leo Kestens. "Strain Induced Inward Grain Growth during Recrystallisation in Steel Sheets with BCC Crystal Structure." Materials Science Forum 715-716 (April 2012): 303–8. http://dx.doi.org/10.4028/www.scientific.net/msf.715-716.303.

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The present paper investigates the potential application of Strain Induced Boundary Migration mechanism on the two different types of surface textures developed after α-γ-α phase transformation annealing, one with preferred cube and Goss orientation at the surface and the other with random surface texture without preferred orientations. It has been demonstrated that these surface texture components grow in across the thickness of the sheet after an appropriate combinations of a critical amount of rolling reductions and an annealing treatment at the recrystallisation temperature.

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38

Voltolini, Marco, Hans-Rudolf Wenk, Nazmul Haque Mondol, Knut Bjørlykke, and Jens Jahren. "Anisotropy of experimentally compressed kaolinite-illite-quartz mixtures." GEOPHYSICS 74, no. 1 (January 2009): D13—D23. http://dx.doi.org/10.1190/1.3002557.

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The anisotropy of physical properties is a well-known characteristic of many clay-bearing rocks. This anisotropy has important implications for elastic properties of rocks and must be considered in seismic modeling. Preferred orientation of clay minerals is an important factor causing anisotropy in clay-bearing rocks such as shales and mudstones that are the main cap rocks of oil reservoirs. The preferred orientation of clays depends mostly on the amount of clays and the degree of compaction. To study the effect of these parameters, we prepared several samples compressing (at two effective vertical stresses) a mixture of clays (illite and kaolinite) and quartz (silt) with different clay/quartz ratios. The preferred orientation of the phases was quantified with Rietveld analysis on synchrotron hard X-ray images. Pole figures for kaolinite and illite display a preferred orientationof clay platelets perpendicular to the compaction direction, increasing in strength with clay content and compaction pressure. Quartz particles have a random orientation distribution. Aggregate elastic properties can be estimated by averaging the single-crystal properties over the orientation distribution obtained from the diffraction data analysis. Calculated P-wave velocity anisotropy ranges from 0% (pure quartz sample) to 44% (pure clay sample, highly compacted), but calculated velocities are much higher than measured velocities. This is attributed to uncertainties about single-crystal elastic properties and oriented micropores and limited grain contacts that are not accounted for in the model. In this work, we present an effective method to obtain quantitative data, helping to evaluate the role of clay percentage and compaction pressure on the anisotropy of elastic properties of clay-bearing rocks.

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Hu, YuHao, Jiajun Zhu, Chao Zhang, Wulin Yang, Licai Fu, Deyi Li, and Lingping Zhou. "Understanding the Preferred Crystal Orientation of Sputtered Silver in Ar/N2 Atmosphere: A Microstructure Investigation." Advances in Materials Science and Engineering 2019 (November 6, 2019): 1–8. http://dx.doi.org/10.1155/2019/3079393.

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Silver thin films were prepared by direct current (DC) magnetron sputtering technique in Ar/N2 atmosphere with various N2 volumetric ratios on Si substrates. Silver thin films prepared in pure Ar atmosphere show highly (111) preferred orientation. However, as the N2 content increases, Ag (111) preferred orientation evolves into (100) preferred orientation gradually. When N2 content is more than 12.5 vol.%, silver thin films exhibit highly (100) preferred orientation. Moreover, the average grain size decreases with increasing N2 content. Silver thin films with low relative density are prepared at high N2 content, which results in higher resistivity of films. By analyzing the resistivity and microstructures of silver thin films, the optimum range of N2 content to get compact silver thin films is found to be not more than 33.3 vol.%. Finally, the mechanism of N2 addition on microstructure evolution of silver thin films was proposed.

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Rodriguez-Navarro, Alejandro B. "Registering pole figures using an X-ray single-crystal diffractometer equipped with an area detector." Journal of Applied Crystallography 40, no. 3 (May 15, 2007): 631–34. http://dx.doi.org/10.1107/s0021889807014574.

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The orientation of crystals in a polycrystalline sample is adequately described using pole figures, displaying the three-dimensional distribution of specific crystallographic directions or poles. Registration of pole figures is necessary to characterize the preferred orientation of crystals and its influence on the anisotropy of properties in textured materials. It is also useful to understand the development of highly organized microstructures in polycrystalline materials. Pole figures can be registered efficiently using an area detector, available at most modern single-crystal diffractometers. This paper describes in detail the procedure of data collection and processing of pole figures using a single-crystal diffractometer equipped with an area detector. Specifically, a Bruker SMART APEX diffractometer was used, but this methodology can be readily adapted to other diffractometers.

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Andreev, G. N., B. Jordanov, E. H. Korte, and B. Schrader. "FT-Raman Polarization Spectroscopy of Nonmesogenic Guest Molecules Oriented in Nematic Liquid Crystal Solvents." Applied Spectroscopy 51, no. 11 (November 1997): 1753–56. http://dx.doi.org/10.1366/0003702971939479.

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The experimental technique for Raman spectroscopic measurements of aligned liquid crystals was adopted for studying the orientation of nonmesogenic guest molecules dissolved in nematic liquid crystal hosts. Polarization FT-Raman spectra of diphenylacetylene (tolane) dissolved in nematic liquid crystals of 4-alkyl-4'-cyanobicyclohexyl type (ZLI-1695) have been recorded. The intensity ratios, R = IYY /IZZ, of the bands polarized perpendicular ( IYY) to the preferred molecular orientation, and parallel ( IZZ) to it, are rediscussed. A clear polarization equivalent to that of the host was found for the guest molecule tolane. The obtained data serve for determining the symmetry properties of the observed vibrations of the dissolved molecule.

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Matthies, Siegfried, and Hans-Rudolf Wenk. "Transformations for monoclinic crystal symmetry in texture analysis." Journal of Applied Crystallography 42, no. 4 (June 13, 2009): 564–71. http://dx.doi.org/10.1107/s0021889809018172.

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Monoclinic crystals can be described in two settings: in the first setting theC2rotation axis is parallel to thezaxis and in the second setting it is parallel to theyaxis. Transformations of lattice parameters, Miller and zone indices, and atomic coordinates is straightforward; the situation is far more complex for texture analysis with orientation distributions and corresponding representations. This article gives explicit transformations that need to be applied, not only for texture analysis but also for calculations of physical properties of materials with preferred orientation. In texture research the relationship between the Cartesian crystal coordinate system and the unit cell must be unambiguously defined and a uniform convention is desirable.

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WONGPAN, PAT, DAVID J. PRIOR, PATRICIA J. LANGHORNE, KATHERINE LILLY, and INGA J. SMITH. "Using electron backscatter diffraction to measure full crystallographic orientation in Antarctic land-fast sea ice." Journal of Glaciology 64, no. 247 (September 12, 2018): 771–80. http://dx.doi.org/10.1017/jog.2018.67.

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ABSTRACTWe have mapped the full crystallographic orientation of sea ice using electron backscatter diffraction (EBSD). This is the first time EBSD has been used to study sea ice. Platelet ice is a feature of sea ice near ice shelves. Ice crystals accumulate as an unconsolidated sub-ice platelet layer beneath the columnar ice (CI), where they are subsumed by the advancing sea–ice interface to form incorporated platelet ice (PI). As is well known, in CI the crystal preferred orientation comprises dominantly horizontal c-axes, while PI has c-axes varying between horizontal and vertical. For the first time, this study shows the a-axes of CI and PI are not random. Misorientation analysis has been used to illuminate the possible drivers of these alignments. In CI the misorientation angle distribution from random pairs and neighbour pairs of grains are indistinguishable, indicating the distributions are a consequence of crystal preferred orientation. Geometric selection during growth will develop the a-axis alignment in CI if ice growth in water is fastest parallel to the a-axis, as has previously been hypothesised. In contrast, in PI random-pair and neighbour-pair misorientation distributions are significantly different, suggesting mechanical rotation of crystals at grain boundaries as the most likely explanation.

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Kejzlar, Pavel, Zuzana Andršová, Martin Švec, Lukáš Voleský, and Michal Tregler. "Possibilities of Usage of EBSD for Study of DC06 Steel Deformation." Materials Science Forum 891 (March 2017): 101–5. http://dx.doi.org/10.4028/www.scientific.net/msf.891.101.

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EBSD is an analytical technique, which uses diffraction of backscattered electrons on the sample’s crystal lattice to determine the crystal structure and orientation. Point-by-point mapping of crystal orientation and misorientation, calculation of sub-grain boundaries angles and statistical processing of grain data allow identifying and displaying elastically and plastically deformed zones, textures. Orientation mapping and pole-and inverse pole figures allow to identify preferred slip planes and texture, however misorientation reveals areas where higher stress concentration appears, dislocation arrays and internal defects.

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Sun, Xueying, Mingyue He, and Jinlin Wu. "Study of the Preferred Orientation of Hydroxyapatite in Ivory from Zimbabwe and Mammoth Ivory from Siberia." Crystals 11, no. 5 (May 20, 2021): 572. http://dx.doi.org/10.3390/cryst11050572.

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In this paper, the pole figures plotted from X-ray diffraction data are employed to analyze the orientation of hydroxyapatite in ivory and mammoth ivory for the first time. The results present evidence of the lamellar structure and the hydroxyapatite appeared as tabular. A preferred orientation of hydroxyapatite was revealed in terms of the calculated orientation factor and the characteristics found in the pole figures. The c-axes of hydroxyapatite are mainly oriented along the growth direction. Both a-axes are on the left of the angle bisector of Retzius. Approximately 25–30° separates the a-axes and the angle bisector of Retzius in ivory, whereas the figure is approximately 10–15° in mammoth ivory. Our work is significant in providing more accurate knowledge of the shapes and organizational state of bio-mineral crystals and providing insight into crystal formation and development in bio-mineralization.

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Shyu, Jiin-Jyh, and Jenn-Ming Wu. "Surface characteristics of high-strength MgO–CaO–SiO2−P2O5 glass-ceramics." Journal of Materials Research 9, no. 3 (March 1994): 717–22. http://dx.doi.org/10.1557/jmr.1994.0717.

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Surface-related characteristics (growth of surface layer and crystal preferred orientation) and the resulting mechanical strength of apatite-containing glass-ceramics in the system MgO–CaO–SiO2−P2O5 were investigated. The variations of surface-layer thickness and crystal preferred orientation were explained by a criterion considering both the surface and bulk nucleation of apatite phase. Glass-ceramics with a fairly high strength of 250–410 MPa could be obtained by an appropriate two-step heat treatment. The high strength in the present study is closely related to the growth of the surface layer, which might result in surface compressive-stress.

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47

Gnesin, B. A., and M. Yu Starostin. "Textures of Phases in Al2O3 - ZrO2 (Y2O3) Eutectic Composites." Textures and Microstructures 25, no. 1 (January 1, 1995): 25–32. http://dx.doi.org/10.1155/tsm.25.25.

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Crystallograhic textures of phases in eutectics Al2O3 + ZrO2 (Y2O3) were investigated by means of X-ray diffraction. In all studied eutectic polycrystalls (grown from the melt by EFG technique) a preferred orientation [0001] of Al2O3 along the growth direction in all the samples was revealed for both initial orientations of Al2O3 seeding crystal: <0001> and <1011>. For a cubic ZrO2 there were two types of a preferred orientations: sharp ones, close to <123> with a 6-fold symmetry and more spread <110>. Such a 6-fold symmetry for a cubic phase appears in eutectic due to a joint crystallization.

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Kang, Liping, Lingli Wang, Haiyan Wang, Xiaodong Zhang, and Yongqiang Wang. "Preparation and Performance of Gallium Nitride Powders with Preferred Orientation." MATEC Web of Conferences 142 (2018): 01009. http://dx.doi.org/10.1051/matecconf/201814201009.

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The paper prepared the III-V semiconductor, hexagonal wurtzite Gallium nitride powders by calcining a gallium oxide in flowing ammonia above 900 °C (1173K). Because of the solid-state reaction process that the gallium oxide transformed to GaN through solid-state gallium oxynitrides (GaOxNy) as inter-mediates, the Gallium nitride powders which are agglomerates of tens nanometers flake crystallites retain the rod shape and grain size of raw gallium oxide and have slight (002) plane preferred orientation. The near-edge emission of Gallium nitride at 346 nm has a blue shift of 187 meV attributed to a decrease in disorder of the material that is decided by the (002) plane preferred orientation. The preferred orientation and a blue shift have some kind of reference significance to single crystal growth.

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Akimoto, Koichi, Melania Lijadi, Shingo Ito, and Ayahiko Ichimiya. "Interface Structure and Preferred Orientation of Ag/Si(111) Revealed by X-Ray Diffraction." Surface Review and Letters 05, no. 03n04 (June 1998): 719–22. http://dx.doi.org/10.1142/s0218625x98001080.

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We studied buried interface structures of [Formula: see text] and Ag/Si(111)-(7 × 7) samples using grazing incidence X-ray diffraction with synchrotron radiation. We also measured the crystal orientation of the Ag overlayers of the samples. Of the numerous [Formula: see text] structures, only boron-induced [Formula: see text] structure has been detected in buried interfaces. We studied the buried interface superstructure of Ag(26 nm thick)/[Formula: see text], and detected a [Formula: see text] fractional order reflection peak. This means that the [Formula: see text] structure remained at the interface. Our results for the crystal orientation of the Ag overlayers of [Formula: see text] showed that Ag{110}, Ag{100} and Ag{111} planes were grown on the surface. By measuring several samples prepared at various substrate temperatures, (290–370 K), we found a strong correlation between the appearance of interface [Formula: see text] structure and the growth of the Ag{110} plane. In contrast, our results for the crystal orientation of the Ag overlayers of Ag(26 nm thick)/Si(111)-(7 × 7) showed that only the Ag{111} plane was grown on the surface.

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Lagoeiro, Leonardo, Paola Ferreira, and Cristiane Castro. "Crystallographic Control on the Development of Texture in Precipitated Quartz Grains." Materials Science Forum 495-497 (September 2005): 57–62. http://dx.doi.org/10.4028/www.scientific.net/msf.495-497.57.

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In this study we analysed microstructures and determined [c]-axis textures of quartz crystals in veins formed parallel to composition banding in naturally deformed iron oxide-quartz rocks. Only veins of few millimeters thick were sampled. These veins were formed in a regime of non-coaxial deformation under temperature of ~300°C. We made thin sections from rock slabs cut perpendicular to shear plane and parallel to shear direction. In thin sections veins are composed of large single quartz crystals of lens or rhomb-shaped blocks similar to s-porphyroclast systems. Lattice distortion (i.e. undulose extinction, gradual lattice banding and subgrain boundaries) occurs in single crystals as revealed by optical microscopy. Distortion was caused by slip of dislocations preferentially on basal planes. These are also planes along which microcracks developed. Distinct types of microcracks are individualized based on size, orientation and distribution of voids. Microcracrack voids are filled by polycrystalline quartz aggregates. In contrast to single crystals, these aggregates do not have any optical microstructure that might be related to crystal plastic process. Moreover grain size distribution are quite different from those related to dynamic recrystallized aggregates. Despite of that, polycrystalline quartz aggregates have strong [c]-axis preferred orientations. These orientations are similar to those of single crystals close to the microfracture walls. In large spaced voids c-axes orientation of quartz in polycrystalline aggregate have significant misorientation angles with respect to the single crystal [c]-axis orientation, reaching values up to 45° to the foliation plane (XY section of the finite strain). Based on microstructural and textural data we propose a mode for quartz [c]-axis texture development in both single crystals and polycrystalline aggregates that fill microcrack voids.

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Journal articles on the topic 'Crystal preferred orientation'

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