Microstructure and Texture in Copper Sheets after Reverse and Cross Rolling

2005 ◽  
Vol 105 ◽  
pp. 309-314 ◽  
Author(s):  
M. Ostafin ◽  
Jan Pospiech ◽  
Robert A. Schwarzer
Keyword(s):  
Grain Boundaries ◽  
Crystal Orientation ◽  
High Spatial Resolution ◽  
Rolling Direction ◽  
Orientation Measurement ◽  
Orientation Data ◽  
Cross Rolling ◽  
X Ray ◽  
Orientation Mapping ◽  
The Individual

The objectives of this investigation are structural effects in electrolytic copper sheets which are caused by the change of the direction of rolling. Unidirectional, reverse as well as cross-rolling at 90° respectively at 45° to the precedent rolling direction have been applied down to final deformations as low as 80% reduction in thickness. Texture has been determined by ACOM (Automated Crystal Orientation Measurement, “Automated EBSD”) in the SEM and by X-ray pole figure measurement. The main benefits of ACOM are a high spatial resolution which enables the investigation of texture gradients from the mid plane to the surface of the sheet, and the visualization of the microstructure by crystal orientation mapping. In addition to local texture, statistical distributions of misorientations across grain boundaries and of S grain boundaries have been derived from the individual grain orientation data. The change of the path of plastic deformation induces a destabilization of the substructure which is formed during the primary step of unidirectional rolling. A distinct change of texture is found depending on the deformation process. In cross rolling, the b fiber changes into the unstable b90 fiber which almost disappears with progressive deformation along the new rolling direction.

scholarly journals Microscopic Stress and Strain Evolved in a Twinning-Induced Plasticity Fe-Mn-C Steel

2014 ◽  
Vol 996 ◽  
pp. 135-140
Author(s):  
Shigeru Suzuki ◽  
Shigeo Sato ◽  
Koji Hotta ◽  
Eui Pyo Kwon ◽  
Shun Fujieda ◽  
...  
Keyword(s):  
Strain Distribution ◽  
Crystal Orientation ◽  
Fem Simulation ◽  
Tensile Loading ◽  
Stress And Strain ◽  
X Ray Diffraction ◽  
Principal Stresses ◽  
Orientation Data ◽  
Tensile Direction ◽  
X Ray

White X-ray diffraction with micro-beam synchrotron radiation was used to analyze microscopic stress evolved in coarse grains of a twinning-induced plasticity Fe-Mn-C steel under tensile loading. In addition, electron backscatter diffraction (EBSD) was used to determine the crystal orientation of grains in the polycrystalline Fe-Mn-C steel. Based on these orientation data, the stress and strain distribution in the microstructure of the steel under tensile loading was estimated using FEM simulation where the elastic anisotropy or the crystal orientation dependence of the elasticity was taken into account. The FEM simulation showed that the strain distribution in the microstructure depends on the crystal orientation of each grain. The stress analysis by the white X-ray diffraction indicated that the direction of the maximum principal stresses at measured points in the steel under tensile loading are mostly oriented toward the tensile direction. This is qualitatively consistent with the results of by the FEM simulation, although absolute values of the principal stresses may contain the effect of heterogeneous plastic deformation on the stress distribution.

scholarly journals Microtexture Characterization by EBSP in Iron and Titanium Alloys

1993 ◽  
Vol 20 (1-4) ◽  
pp. 165-177 ◽  
Author(s):  
R. Penelle ◽  
T. Baudin
Keyword(s):  
Titanium Alloy ◽  
Distribution Function ◽  
Good Accuracy ◽  
Orientation Distribution ◽  
Orientation Measurement ◽  
X Ray ◽  
Pole Figures ◽  
Main Components ◽  
The Individual ◽  
The Right

The Orientation Distribution Function (O.D.F.) calculation is usually performed using pole figures measured by X-ray or neutron diffraction. However, this kind of experimental technique does not allow to determine a total ODF since the odd terms of the series expansion are not directly accessible from pole figures. The individual orientation measurement technique can be used but it is necessary to estimate the right orientation number necessary to calculate a statistically reliable ODF. For samples at the surface, at the fifth of the thickness from the surface and at the centre of a Fe 3% Si sheet, the present study shows that only 100 orientations are sufficient to find the main components of the texture but this number must be increased by a factor 10 to evaluate with a rather good accuracy the height of the peaks. In the case of a titanium alloy so called TA6V 350 orientations appear to be sufficient.

A Comparison of Stem-EDX and Auger Analysis of Segregation: The Plaudits and the Pitfalls.

1997 ◽  
Vol 3 (S2) ◽  
pp. 539-540
Author(s):  
G.J. Tatlock
Keyword(s):  
Grain Boundaries ◽  
Potential Problem ◽  
High Spatial Resolution ◽  
Boundary Segregation ◽  
Line Profiles ◽  
Auger Analysis ◽  
X Ray ◽  
Counting Statistics ◽  
Electron Energy Loss ◽  
Equilibrium Segregation

Equilibrium segregation to grain boundaries has been studied for many years, but only recently have the techniques to quantify such segregation at high spatial resolution become widely available. These include, for example, the Auger surface analysis of fractured samples, or the study of boundaries edge-on in a field emission gun STEM equipped with energy dispersive X-ray analysis or electron energy loss spectroscopy. The key question, however, is whether these different techniques yield the same results when applied to a specific set of samples, and this paper reviews some of the successes and problems associated with such studies.For STEM analysis of grain boundary segregation, several instruments now routinely give probe sizes of ∼1nm. Hence line profiles across grain boundaries at this level of resolution are quite feasible. However a larger probe with greater probe current and better X-ray counting statistics is often more useful, especially if sample drift is a potential problem.

Effects of dislocations and sub-grain boundaries on X-ray response maps of CdZnTe radiation detectors

2011 ◽  
Vol 1341 ◽  
Author(s):  
A. Hossain ◽  
A. E. Bolotnikov ◽  
G. S. Camarda ◽  
Y. Cui ◽  
R. Gul ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
High Spatial Resolution ◽  
Radiation Detectors ◽  
National Synchrotron Light Source ◽  
X Ray ◽  
Response Mapping ◽  
Mapping System ◽  
Te Inclusions ◽  
Synchrotron Light

ABSTRACTThe imperfect quality of CdZnTe (CZT) crystals for radiation detectors seriously diminishes their suitability for different applications. Dislocations and other dislocation-related defects, such as sub-grain boundaries and dislocation fields around Te inclusions, engender significant charge losses and, consequently, cause fluctuations in the detector’s output signals, thereby hindering their spectroscopic responses. In this paper, we discuss our results from characterizing CZT material by using a high-spatial-resolution X-ray response mapping system at BNL’s National Synchrotron Light Source. In this paper, we emphasize the roles of these dislocation-related defects and their contributions in degrading the detector’s performance. Specifically, we compare the effects of the sub-grain- and coherent twin-boundaries on the X-ray response maps.

Automated Crystal Orientation Mapping (ACOM) of Thin Metallization Layers and Interconnects

1997 ◽  
Vol 472 ◽  
Author(s):  
R.A. Schwarzer
Keyword(s):  
Electron Microscope ◽  
Grain Orientation ◽  
Crystal Orientation ◽  
Silicon Substrates ◽  
Orientation Measurement ◽  
Orientation Mapping ◽  
Grain Orientations ◽  
Aluminum Metallization ◽  
Crystal Orientation Mapping

ABSTRACTA system for acquisition and interpretation of Kikuchi patterns with computer-controlled electron microscopes is presented. It enables interactive as well as fully automated determination of individual grain orientations. Special features for automated crystal orientation mapping (ACOM) with the scanning electron microscope (SEM) are digital beam scan, autocalibration and dynamic focus controlled by the computer. With the present setup about three orientations per second can be measured unattendedly. In the transmission electron microscope (TEM) the on-line determination of Burgers vectors and identification of deformation systems are based on crystal orientation measurement. The characterization of dislocations is facilitated by the simulation of diffraction patterns on the computer as a function of specimen tilt.Crystal orientation maps are obtained by assigning to the raster points in the image a color specific for the grain orientation, the misorientation or character of the grain boundary. The dala set of grain orientations is used to calculate the Schmid factors grain by grain, the orientation distribution function (ODF) and the correlated as well as the uncorrelated misorientation distribution functions (MODF) which characterize crystallographic texture in a statistical sense.Applications of individual grain orientation measurement are:. Thermomechanical hillocks in aluminum metallization layers on silicon substrates. Stress-induced grain growth in aluminum metallization layers on silicon substrates. Electromigration voids and hillocks in aluminum interconnectsA working hypothesis for electromigration failure, based on experimental findings, is discussed

scholarly journals The Preparation of Mg, Cd and Zn Samples for Crystal Orientation Mapping with BKD in an SEM

2007 ◽  
Vol 15 (2) ◽  
pp. 40-43
Author(s):  
R.A. Schwarzer
Keyword(s):  
Crystal Orientation ◽  
High Performance ◽  
Materials Science ◽  
Orientation Measurement ◽  
Beam Spot ◽  
Kikuchi Pattern ◽  
Orientation Mapping ◽  
Invaluable Tool ◽  
User Intervention ◽  
Better Than

Backscatter Kikuchi Diffraction (BKD) from crystalline solids has been known since 1928. But only during the last decade, when sufficiently sensitive cameras, fast PCs and high-performance SEMs have been available, has this technique been developed into an invaluable tool for materials' science and geology. BKD is also known as “Backscatter Electron Diffraction” (EBSD) if referred to the commercial trademarked systems OXFORD/HKL “Channel” or EDAX-TSL “OIM”. Crystal Orientation Measurement/ Mapping (COM), without user intervention, is performed in an SEM by digitally scanning the beam spot across the specimen, acquiring and transferring one Backscatter Kikuchi Pattern (BKP) after another into the computer, indexing it, and calculating the crystal orientation of the grain under the beam spot. The sample is typically tilted by 70° towards a phosphor screen for pattern collection. Spatial resolution is in the range of <0.05 μm and accuracy is better than 0.5°.

scholarly journals Crystal orientation measurements using SEM–EBSD under unconventional conditions

2015 ◽  
Vol 30 (2) ◽  
pp. 104-108 ◽  
Author(s):  
Karsten Kunze
Keyword(s):  
Crystal Orientation ◽  
Electron Backscatter Diffraction ◽  
Bulk Specimen ◽  
X Ray ◽  
Analytical Technique ◽  
Orientation Mapping ◽  
Electron Backscatter ◽  
Backscatter Diffraction ◽  
Element Mapping ◽  
Scanning Electron

Electron backscatter diffraction (EBSD) is a micro-analytical technique typically attached to a scanning electron microscope (SEM). The vast majority of EBSD measurements is applied to planar and polished surfaces of polycrystalline bulk specimen. In this paper, we present examples of using EBSD and energy-dispersive X-ray spectroscopy (EDX) to analyze specimens that are not flat, not planar, or not bulk – but pillars, needles, and rods. The benefits of low vacuum SEM operation to reduced drift problems are displayed. It is further demonstrated that small and thin specimens enhance the attainable spatial resolution for orientation mapping (by EBSD or transmission Kikuchi diffraction) as well as for element mapping (by EDX).

scholarly journals Density-based clustering of crystal (mis)orientations and the orix Python library

2020 ◽  
Vol 53 (5) ◽  
pp. 1293-1298
Author(s):  
Duncan N. Johnstone ◽  
Ben H. Martineau ◽  
Phillip Crout ◽  
Paul A. Midgley ◽  
Alexander S. Eggeman
Keyword(s):  
Grain Boundaries ◽  
Clustering Algorithm ◽  
Three Dimensional ◽  
Orientation Relationships ◽  
Orientation Data ◽  
Orientation Space ◽  
Density Based Clustering ◽  
Orientation Mapping ◽  
Special Orientation ◽  
Clustering Approach

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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