Home About us Contact
|
Home About us Contact | ||
|
|
||
Deformed Crystals (deformed + crystal)
Selected AbstractsInterbranch transient beating of X-ray intensities in deformed crystalsACTA CRYSTALLOGRAPHICA SECTION A, Issue 4 2010M. Shevchenko X-ray dynamical diffraction in a deformed crystal is studied using the interbranch resonance concept. It is shown that appreciable beating of the X-ray intensities may be induced by a lattice distortion that produces interbranch transformations of the local dispersion surface. In X-ray plane-wave topography, this effect may be observed as interference fringes arising around the kinematical image of a defect. It is predicted that such interbranch fringes can be induced by edge dislocations. [source] Phase modulation effects in X-ray diffraction from a highly deformed crystal with variable strain gradientACTA CRYSTALLOGRAPHICA SECTION A, Issue 5 2009M. Shevchenko The X-ray interbranch scattering by lattice distortions is studied for a thin crystal whose thickness is appreciably less than the conventional X-ray extinction length. The concept of interbranch phase modulation of the X-ray wavefield is extended to the case of a large gradient which depends on depth inside the crystal. The prominent interbranch features of the diffracted intensity are also established within this concept. Numerical calculations of the diffracted intensity are presented for an exponential strain gradient model to illustrate this. Diffraction (extinction) contrast is discussed for a strongly deformed specimen containing a single dislocation. It is predicted that for large values of the X-ray extinction length the extinction contrast may arise even in the case of a very thin crystal. This effect, owing to the interbranch phase changes of the waves scattered in the deformed matrix, is observed in experiments with protein crystals. [source] Rotation axis analysis of deformed crystals by X-rays and electronsJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 4 2008András Borbély X-ray and electron backscatter diffraction (EBSD) have been applied to investigate misorientation distributions in copper single crystals plastically deformed in single and multiple slip. The misorientation distributions are represented by `rocking curves' about specific rotation axes. Very good agreement for the rocking curves established by the two methods was obtained, despite the large difference between their resolution depths. Following this agreement, a new rotation axis imaging scheme, based on the EBSD data, is proposed in order to visualize the crystallite blocks and characterize the nature of their dislocation boundaries. [source] Interbranch transient beating of X-ray intensities in deformed crystalsACTA CRYSTALLOGRAPHICA SECTION A, Issue 4 2010M. Shevchenko X-ray dynamical diffraction in a deformed crystal is studied using the interbranch resonance concept. It is shown that appreciable beating of the X-ray intensities may be induced by a lattice distortion that produces interbranch transformations of the local dispersion surface. In X-ray plane-wave topography, this effect may be observed as interference fringes arising around the kinematical image of a defect. It is predicted that such interbranch fringes can be induced by edge dislocations. [source] A Fourier optics approach to the dynamical theory of X-ray diffraction , continuously deformed crystalsACTA CRYSTALLOGRAPHICA SECTION A, Issue 4 2004Giovanni Mana X-ray diffraction in continuously deformed crystals is considered by application of Fourier optics and from the viewpoint of the analogy between X-ray dynamics and the motion of two-level systems in quantum mechanics. Different forms of Takagi's equations are traced back to a common framework and it is shown that they are different ways to represent the same propagation equation. A novel way to solve Takagi's equations in the presence of a constant strain gradient is presented and approximation methods derived from quantum mechanics are considered. Crystal deformation in X-ray interferometry and two-crystal spectrometry are discussed and it is demonstrated that Si lattice-parameter measurements depend on the diffracting plane spacing on the crystal surface. [source] | ||||||||||