Application of the 3D X-Ray Crystal Microscope to Study Mesoscale Structure of Materials

2003 ◽  
Vol 779 ◽  
Author(s):  
Gene E. Ice ◽  
Wenjun Liu ◽  
Bennett C. Larson ◽  
Fredrick J. Walker
Keyword(s):  
Plastic Deformation ◽  
Plastic Strain ◽  
Three Dimensions ◽  
Polycrystalline Materials ◽  
Crystalline Orientation ◽  
Materials Properties ◽  
X Ray ◽  
Mesoscale Structure ◽  
Elastic And Plastic Deformation ◽  
Strain Tensors

AbstractThe 3D x-ray crystal microscope is an emerging tool for the study of mesoscale structure in polycrystalline materials. With this nondestructive device, local crystalline orientation, phase, elastic and plastic strain tensors can be measured with submicron spatial resolution in three dimensions. A key step in analyzing the Laue patterns from the 3D microscope is indexing the reflections, which determines the orientation of the sub-grain. With current algorithms, the angles between pairs, triplets and quadruplets of reflections are compared to theoretical angles to make guesses as to the reflection indices. The ability to index a pattern can however be compromised by both elastic and plastic deformation of a grain; elastic deformation changes the angles between reflections and plastic deformation increases the uncertainty in the centroid of each reflection. Here we report on the use of an indexing algorithm that simultaneously fits all peaks from a subgrain. This algorithm is more robust than previous methods and allows for indexing of deformed or strained grains. Some applications to studies of mesoscale materials properties are described.

scholarly journals Elastic and Plastic Deformation Behavior Studied by In-Situ Synchrotron X-ray Diffraction in Nanocrystalline Nickel

2016 ◽  
Vol 57 (9) ◽  
pp. 1447-1453 ◽  
Author(s):  
Hiroki Adachi ◽  
Yui Karamatsu ◽  
Shota Nakayama ◽  
Tomotaka Miyazawa ◽  
Masugu Sato ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Deformation Behavior ◽  
X Ray Diffraction ◽  
Nanocrystalline Nickel ◽  
X Ray ◽  
Plastic Deformation Behavior ◽  
Elastic And Plastic Deformation

Modeling and Numerical Simulations of Microdiffraction from Deformed Crystals

2002 ◽  
Vol 731 ◽  
Author(s):  
R.I. Barabash ◽  
G.E. Ice ◽  
F.J. Walker
Keyword(s):  
Plastic Deformation ◽  
Three Dimensions ◽  
Alternative Methods ◽  
Deformation Tensor ◽  
Polycrystalline Materials ◽  
Laue Pattern ◽  
Stress Strain ◽  
Crystalline Materials ◽  
Comparable Method ◽  
Tensor Distributions

AbstractBrilliant synchrotron microprobes offer new opportunities for the analysis of stress/strain and deformation distributions in crystalline materials. Polychromatic x-ray microdiffraction is emerging as a particularly important tool because it allows for local crystal-structure measurements in highly deformed or polycrystalline materials where sample rotations complicate alternative methods; a complete Laue pattern is generated in each volume element intercepted by the probe beam. Although a straightforward approach to the measurement of stress/strain fields through white-beam Laue microdiffraction has been demonstrated, a comparable method for determining the plastic-deformation tensor has not been established. Here we report on modeling efforts that can guide automated fitting of plastic-deformation-tensor distributions in three dimensions.

Use of Image-Processing Tools for Texture Analysis of High-Energy X-ray Synchrotron Data

1998 ◽  
Vol 31 (5) ◽  
pp. 647-653 ◽  
Author(s):  
R. Fisker ◽  
H. F. Poulsen ◽  
J. Schou ◽  
J. M. Carstensen ◽  
S. Garbe
Keyword(s):  
Image Processing ◽  
Nonlinear Least Squares ◽  
High Energy ◽  
Three Dimensions ◽  
Polycrystalline Materials ◽  
Data Sets ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray

The introduction of synchrotron beamlines for high-energy X-ray diffraction raises new possibilities for texture determination of polycrystalline materials. The local texture can be mapped out in three dimensions and texture developments can be studiedin situin complicated environments. However, it is found that a full alignment of the two-dimensional detector used in many cases is impractical and that data-sets are often partially subject to geometric restrictions. Estimating the parameters of the traces of the Debye–Scherrer cones on the detector therefore becomes a concern. Moreover, the background may vary substantially on a local scale as a result of inhomogeneities in the sample environmentetc. A set of image-processing tools has been employed to overcome these complications. An automatic procedure for estimating the parameters of the traces (taken as ellipses) is described, based on a combination of a circular Hough transform and nonlinear least-squares fitting. Using the estimated ellipses the background is subtracted and the intensity along the Debye–Scherrer cones is integrated by a combined fit of the local diffraction pattern. The corresponding algorithms are presented together with the necessary coordinate transform for pole-figure determination. The image-processing tools may be useful for the analysis of noisy or partial powder diffraction data-sets in general, provided flat two-dimensional detectors are used.

High pressure deformation study of zirconium

2007 ◽  
Vol 22 (2) ◽  
pp. 113-117 ◽  
Author(s):  
Sven C. Vogel ◽  
Helmut Reiche ◽  
Donald W. Brown
Keyword(s):  
Plastic Deformation ◽  
Hydrostatic Pressure ◽  
High Pressures ◽  
Texture Evolution ◽  
Compressive Load ◽  
Vertical Direction ◽  
Tensile Load ◽  
Polycrystalline Materials ◽  
Active Deformation ◽  
Elastic And Plastic Deformation

In situ deformation studies of polycrystalline materials using diffraction are an established method to understand elastic and plastic deformation of materials. Studies of active deformation mechanisms, the interplay of deformation with texture, and ultimately the development of predictive capabilities for deformation modeling are an active field of research. Parameters studied by diffraction are typically lattice strains and texture evolution, which coupled with the macroscopic flow curve allow for improved understanding of the micro-mechanics of deformation. We performed a study of the uniaxial deformation of Zircaloy-2 at 2 GPa at the 13-BM-D beamline at the Advanced Photon Source. The deformation-DIA apparatus generates a confining hydrostatic pressure using a cubic anvil setup. Two differential rams allow an increase (compressive load) or decrease (tensile load) of the uniaxial straining in the vertical direction, allowing studies of plastic deformation at high pressures. In this paper, we describe how macroscopic strains, hydrostatic pressure, and uniaxial strains are derived and present some brief results.

Energy-Tunable X-Ray Diffraction in Polycrystalline Materials: a Look at Microstructure in Seashells

2001 ◽  
Vol 678 ◽  
Author(s):  
Emil Zolotoyabko ◽  
John P. Quintana
Keyword(s):  
Structural Characteristics ◽  
Depth Resolution ◽  
Three Dimensions ◽  
Polycrystalline Materials ◽  
X Ray Diffraction ◽  
Penetration Length ◽  
X Ray ◽  
Strain Components ◽  
Laminated Structures ◽  
Non Destructive

AbstractWe developed a depth-sensitive x-ray diffraction technique in which diffraction profiles are measured at x-ray energies that are varied by small steps. The method is intended for synchrotron beam lines and provides non-destructive mapping of structural characteristics in inhomogeneous polycrystalline materials. Depth resolution is achieved due to an energy dependence of the x-ray penetration length. Application of this technique to seashells allowed us to extract spatial distributions of preferred orientation and strain components, which revealed pronounced variations of the shell microstructure in three dimensions. The results shed light on “engineering solutions” by mollusk. The developed technique can be used to characterize various laminated structures and composite materials.

Three-Dimensional X-Ray Structural Microscopy Using Polychromatic Microbeams

MRS Bulletin ◽  
2004 ◽  
Vol 29 (3) ◽  
pp. 170-176 ◽  
Author(s):  
Gene E. Ice ◽  
Bennett C. Larson
Keyword(s):  
Crystal Structure ◽  
Three Dimensional ◽  
X Rays ◽  
Actual Structure ◽  
X Ray ◽  
Elastic And Plastic Deformation ◽  
Strain Tensors ◽  
Microprobe Technique

AbstractIn this article, the authors describe the principle and application of differential-aperture x-ray microscopy (DAXM). This recently developed scanning x-ray microprobe technique uses a confocal or traveling pinhole camera approach to determine the crystal structure, crystallographic orientation, and elastic and plastic strain tensors within bulk materials. The penetrating properties of x-rays make the technique applicable to optically opaque as well as transparent materials, and it is nondestructive; this provides for in situ, submicrometer-resolution characterization of local crystal structure and for measurements of microstructure evolution on mesoscopic length scales from tenths to hundreds of micrometers. Examples are presented that illustrate the use of DAXM to study grain and subgrain morphology, grain-boundary types and networks, and local intra- and intergranular elastic and plastic deformation. Information of this type now provides a direct link between the actual structure and evolution in materials and increasingly powerful computer simulations and multiscale modeling of materials microstructure and evolution.

Plastic Deformation in Microtomed Sections

1971 ◽  
Vol 29 ◽  
pp. 458-459
Author(s):  
J. Temple Black
Keyword(s):  
Plastic Deformation ◽  
Plastic Strain ◽  
Applied Stress ◽  
Elastic Strain ◽  
High Strain ◽  
Tool Material ◽  
Cutting Edge ◽  
Material Structure ◽  
Geometrical Constraints

The output of the ultramicrotomy process with its high strain levels is dependent upon the input, ie., the nature of the material being machined. Apart from the geometrical constraints offered by the rake and clearance faces of the tool, each material is free to deform in whatever manner necessary to satisfy its material structure and interatomic constraints. Noncrystalline materials appear to survive the process undamaged when observed in the TEM. As has been demonstrated however microtomed plastics do in fact suffer damage to the top and bottom surfaces of the section regardless of the sharpness of the cutting edge or the tool material. The energy required to seperate the section from the block is not easily propogated through the section because the material is amorphous in nature and has no preferred crystalline planes upon which defects can move large distances to relieve the applied stress. Thus, the cutting stresses are supported elastically in the internal or bulk and plastically in the surfaces. The elastic strain can be recovered while the plastic strain is not reversible and will remain in the section after cutting is complete.

The structure of amorphous and polycrystalline materials using energy-filtered RDF analysis

1992 ◽  
Vol 50 (2) ◽  
pp. 1190-1191
Author(s):  
David Cockayne ◽  
David McKenzie
Keyword(s):  
Electron Diffraction ◽  
Diffraction Pattern ◽  
Density Function ◽  
Electron Diffraction Pattern ◽  
Polycrystalline Materials ◽  
Nearest Neighbour ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Reduced Density ◽  
System F

The technique of Electron Reduced Density Function (RDF) analysis has ben developed into a rapid analytical tool for the analysis of small volumes of amorphous or polycrystalline materials. The energy filtered electron diffraction pattern is collected to high scattering angles (currendy to s = 2 sinθ/λ = 6.5 Å-1) by scanning the selected area electron diffraction pattern across the entrance aperture to a GATAN parallel energy loss spectrometer. The diffraction pattern is then converted to a reduced density function, G(r), using mathematical procedures equivalent to those used in X-ray and neutron diffraction studies.Nearest neighbour distances accurate to 0.01 Å are obtained routinely, and bond distortions of molecules can be determined from the ratio of first to second nearest neighbour distances. The accuracy of coordination number determinations from polycrystalline monatomic materials (eg Pt) is high (5%). In amorphous systems (eg carbon, silicon) it is reasonable (10%), but in multi-element systems there are a number of problems to be overcome; to reduce the diffraction pattern to G(r), the approximation must be made that for all elements i,j in the system, fj(s) = Kji fi,(s) where Kji is independent of s.

Sign in / Sign up

Export Citation Format

Share Document