Study on the Structural Characteristics of Bi-Sr-Ca-Cu-O Single Crystals Using the Method of Crystal Rotation

AbstractThe role of grain boundary constraint in strain localization, slip system activation, slip transmission, and the concomitant constitutive response was examined performing a series of uniaxial compression tests on tantalum bicrystals. Tantalum single crystals were diffusion bonded to form a (011) twist boundary and compressed along the [011] direction. The resulting threedimensional deformation was analyzed via volume reconstruction. With this technique, both the effective states of stress and strain over the cross-sectional area could be measured as a function of distance from the twist boundary, revealing a highly constrained grain boundary region. Post-test metallurgical characterization was performed using Electron Back-Scattered-Diffraction (EBSD) maps. The results, a spatial distribution of slip patterning and mapping of crystal rotation around the twist-boundary, were analyzed and compared to the known behavior of the individual single crystals. A rather large area near the grain boundary revealed no crystal rotation. Instead, patterns of alternating crystal rotation similar to single crystal experiments were found to be some distance away (~1mm) from the immediate grain boundary region, indicating the large length scale of the rotation free region.

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Influence of crucible and crystal rotation on oxygen-concentration distribution in large-diameter silicon single crystals

Journal of Crystal Growth ◽

10.1016/0022-0248(95)00494-7 ◽

1996 ◽

Vol 166 (1-4) ◽

pp. 669-674 ◽

Cited By ~ 7

Author(s):

Isao Kanda ◽

Takefumi Suzuki ◽

Kiyoshi Kojima

Keyword(s):

Single Crystals ◽

Oxygen Concentration ◽

Concentration Distribution ◽

Large Diameter ◽

Crystal Rotation

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Local and Global Effects in Texture and Microstructure Observed after Channel-Die Compression of Copper Single Crystals and after Cross-Rolling of Copper Sheets

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.105.321 ◽

2005 ◽

Vol 105 ◽

pp. 321-326

Author(s):

Jan Pospiech ◽

Zdzislaw Jasieński ◽

M. Ostafin ◽

Robert A. Schwarzer

Keyword(s):

Single Crystals ◽

Deformation Process ◽

Structural Characteristics ◽

Rolling Direction ◽

Local Analysis ◽

Orientation Measurement ◽

Individual Crystal ◽

Copper Single Crystals ◽

High Dynamics ◽

Deformation Step

The change of the deformation path leads to destabilization of the substructure and affects the texture of the deformed metal. The observed changes of texture and microstructure are, as a rule, significant and their characteristics depend on the geometry of the deformation process. Previous investigations on copper (and copper alloy) samples after deformation by rolling and channel-die compression were based on X-ray pole figure measurements and on observations in the light microscope. Hereby only global texture and structural characteristics have been obtained. The present study is mainly based on measurements of individual crystal orientations performed by ACOM (Automated Crystal Orientation Measurement, “Automated EBSD”) in the SEM which enables a precise local analysis of the investigated phenomena. For the channel-die experiments, (1 1 2)[1 1 -1] and (1 1 2)[1 -1 0] oriented copper single crystals have been used. After pre-deformation, a second deformation step has been carried out in transverse direction. The {1 1 2}<1 1 0> orientations are destabilized by channel-die compression, and clusters of layers develop which are composed of complementary {1 1 0}<1 1 2> components. The deformation process in polycrystalline sheets after rotating the rolling direction leads again to a distinct disintegration of the microstructure and destabilization of the b fiber. This process of microstructure reorganization after pre-deformation is fast and of high dynamics.

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Active Slip Systems Evaluated by a Crystal Rotation Axis Method in Cold-Rolled Cube-Oriented Aluminum Single Crystals

MATERIALS TRANSACTIONS ◽

10.2320/matertrans.l-m2009820 ◽

2009 ◽

Vol 50 (9) ◽

pp. 2192-2200 ◽

Cited By ~ 9

Author(s):

K. Kashihara ◽

T. Shibayanagi

Keyword(s):

Single Crystals ◽

Rotation Axis ◽

Slip Systems ◽

Crystal Rotation ◽

Cold Rolled ◽

Active Slip

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YBa2Cu3O7−x single-crystal growth by the pulling method with crystal rotation effect control

Journal of Materials Research ◽

10.1557/jmr.1995.1593 ◽

1995 ◽

Vol 10 (7) ◽

pp. 1593-1600 ◽

Cited By ~ 18

Author(s):

Y. Namikawa ◽

M. Egami ◽

Y. Yamada ◽

Y. Shiohara

Keyword(s):

Crystal Growth ◽

Single Crystal ◽

Single Crystals ◽

Forced Convection ◽

Rotation Rate ◽

Growth Interface ◽

Crystal Rotation ◽

Crystal Diameter ◽

Rich Liquid ◽

Floating Particles

YBa2Cu3C7−x (Y123) single crystals have been grown by the modified pulling method (Solute Rich Liquid Crystal Pulling method, SRL-CP). For further superconductor device application, it is important to establish a technique that enables us to produce larger Y123 single crystals consistently. We have investigated the relationship among the crystal size, the crystal rotation rate, the flow pattern in the melt, and the temperature at the crystal growth interface experimentally. Increase of the crystal diameter and/or the crystal rotation rate increased the strength of the forced convection in the melt, and as a result, the temperature at the crystal growth interface increased. This resulted in a reduction of the crystal growth rate. On the other hand, the forced convection should be kept high enough to prevent floating particles attaching to the growing crystal. Therefore, in order to grow a larger single crystal, it was necessary to control the crystal rotation rate according to the change of the crystal diameter with time. We succeeded in crystal pulling along the c-axis of a relatively large Y123 single crystal which was 17 mm × 17 mm and 8 mm in length.

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