The Broadening of Crystallographic Orientation Distribution in Crept Ni-base Superalloys

2006 ◽  
Vol 980 ◽  
Author(s):  
Toru Inoue ◽  
Katsushi Tanaka ◽  
Hiroki Adachi ◽  
Kyosuke Kishida ◽  
Haruyuki Inui
Keyword(s):  
Slip System ◽  
Single Crystal ◽  
Creep Strain ◽  
Crystallographic Orientation ◽  
Orientation Distribution ◽  
Diffraction Peak ◽  
Rocking Curve ◽  
X Ray ◽  
Elastic Plastic ◽  
Creep Deformations

AbstractThe crystallographic orientation distribution, and its change accompanied with tilting γ/γ boundaries in Ni-based single crystal superalloys have been investigated by a theoretical elastic-plastic calculation, X-ray diffractometry and SEM-EBSD analysis. The distribution of the crystallographic orientation has significantly broadened by creep deformations. The broadening can be explained by an unbalance of the amount of creep dislocations of each slip system, which agrees with the result of elastic-plastic calculations. Creep strain of superalloys crept at a condition forming the raft structure can be estimated by the measurement of the width of rocking curve of a diffraction peak.

Effect of Creep Deformation on the Crystallographic Orientation Distribution in Ni Base Superalloy

2007 ◽  
Vol 26-28 ◽  
pp. 213-216 ◽  
Author(s):  
Toru Inoue ◽  
Katsushi Tanaka ◽  
Hiroki Adachi ◽  
Kyosuke Kishida ◽  
Haruyuki Inui
Keyword(s):  
Creep Deformation ◽  
Crystallographic Orientation ◽  
Orientation Distribution ◽  
Diffraction Peak ◽  
High Temperature Creep ◽  
Rocking Curve ◽  
Burgers Vector ◽  
X Ray ◽  
Creep Deformations ◽  
Base Superalloy

The crystallographic orientation distribution, and its change as a function of creep deformation in Ni-based single crystal superalloys have been investigated by X-ray diffractometry. The distribution of the crystallographic orientation has significantly broadened by creep deformations. Directional broadening of the distribution agrees with creep dislocations having the burgers vector of 1/2<101>. High temperature creep strain of superalloys can be estimated by a non-destractive test where the width of rocking curve of a diffraction peak is measured.

Crystallinity of YBa2Cu3O7−x single crystals grown by the pulling method

1996 ◽  
Vol 11 (4) ◽  
pp. 804-812 ◽  
Author(s):  
Y. Namikawa ◽  
M. Egami ◽  
S. Koyama ◽  
Y. Shiohara ◽  
H. Kutami
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Growth Direction ◽  
Annealed Sample ◽  
Seed Crystal ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
X Ray ◽  
Crystal Seed ◽  
Better Than

Large YBa2Cu3O7−x (Y123) single crystals (larger than 13 mm cubed) have been grown along the c-axis reproducibly by the modified pulling method. The crystallinity of Y123 single crystal was investigated by x-ray diffraction and x-ray topography. Crystals grown from an MgO single crystal seed had some low angle subgrain boundaries which tilted 0.1–0.8° from each other. These grain boundaries originated from the seed crystal, and the subgrains were extended along the growth direction from the seed crystal. Y123 single crystals with no marked subgrains in the whole area were obtained by using Y123 single subgrain crystal seeds. FWHM of the x-ray rocking curve for the crystal so produced was about 0.14°, which was much better than the spectrum consisting of several separated peaks obtained from the previous crystals. Tc onset of the annealed sample was about 93.6 K, and the transition width was about 0.9 K. The low angle subgrain boundaries did not seem to be effective pinning centers for the magnetic flux.

scholarly journals Preferred orientation of ettringite in concrete fractures

2009 ◽  
Vol 42 (3) ◽  
pp. 429-432 ◽  
Author(s):  
Hans-Rudolf Wenk ◽  
Paulo J. M. Monteiro ◽  
Martin Kunz ◽  
Kai Chen ◽  
Nobumichi Tamura ◽  
...  
Keyword(s):  
Single Crystal ◽  
Elastic Properties ◽  
Elastic Anisotropy ◽  
Rietveld Method ◽  
Orientation Distribution ◽  
Sulfate Attack ◽  
X Ray ◽  
Fracture Surfaces ◽  
Concrete Fractures ◽  
Loss Of Strength

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.

X-ray diffraction with a four-reflection monochromator

1987 ◽  
Vol 20 (6) ◽  
pp. 522-528 ◽  
Author(s):  
S. E. G. Slusky ◽  
A. T. Macrander
Keyword(s):  
Experimental Data ◽  
Indium Phosphide ◽  
Single Crystal ◽  
Simulated Data ◽  
Vertical Gradient ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
X Ray ◽  
Vertical Gradient Freeze

A formula is derived for simulating rocking-curve measurements made with an X-ray diffractometer fitted with a four-reflection monochromator. The derivation is carried out both graphically and algebraically. Results of a simulation using this formula are then compared with experimentally obtained rocking curves. The rocking curves were obtained using a diffractometer with a four-reflection monochromator that uses 440 reflections from two channel-cut germanium crystals. The experimental data comprise 200, 400, 600, 511, 711, 622, 422 and 444 reflections from thick single-crystal indium phosphide grown by the vertical-gradient freeze technique. The simulated data correlate well with the experimental data, although the simulations consistently show somewhat higher reflectivities and narrower linewidths than the experiment, indicating the existence of broadening mechanisms not included in the simulation that are affecting the experiment.

scholarly journals The Growth and Assessment of GaAs Epitaxial Layers Obtained From Ga-As-Bi Solutions

1987 ◽  
Vol 12 (4) ◽  
pp. 223-229 ◽  
Author(s):  
J. Kozlowski ◽  
M. Panek ◽  
M. Ratuszek ◽  
M. Tlaczala
Keyword(s):  
Single Crystal ◽  
Crystallographic Orientation ◽  
Epitaxial Layers ◽  
Solution Composition ◽  
Two Phase ◽  
X Ray ◽  
Low Sensitivity

X-Ray investigations of GaAs epitaxial layers obtained from Ga-As-Bi solutions with different amounts of bismuth are presented. An equilibrium cooling and two phase technique for the deposition of the GaAs epitaxial layers on semi-insulating GaAs:Cr(100) substrates has been used.It has been observed that independently of the growing solution composition, the epitaxial layers were single crystal of (100) crystallographic orientation. Bismuth and chromium were not identified as impurities in the investigated layers although this may be due to the low sensitivity (0.1 at . %) of the x-ray microprobe used.

Growth of Undoped GaAs Single Crystal by Pulling-Down Method

2010 ◽  
Vol 663-665 ◽  
pp. 1213-1216 ◽  
Author(s):  
Min Jin ◽  
Jia Yue Xu ◽  
Qing Bo He ◽  
Yong Zheng Fang ◽  
Hui Shen ◽  
...  
Keyword(s):  
Single Crystal ◽  
Melting Zone ◽  
Gaas Crystal ◽  
Rocking Curve ◽  
X Ray ◽  
Small Temperature Gradient ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Temperature Time ◽  
Undoped Gaas

Undoped GaAs single crystal has been grown in PBN crucibles by the pulling-down method. The temperature profile of the furnace was optimized with a narrow melting zone and a small temperature gradient at the solid-liquid interface. Quartz ampoules were used to protect the evaporation of As during the growth and the deformation of the ampoule was discussed as a function of temperature, time and pressure differential. A Ø56 mm×70 mm GaAs crystal with nearly 100 % single crystalline yield was obtained. X-ray rocking curve analysis revealed the excellent crystalline quality. The average EPD and electrical properties of the crystal were tested comparable to those of the crystal produced by the VGF method. Therefore, the pulling down method was a feasible approach for GaAs crystal production.

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