scholarly journals Microstructural Characterization by Automated Crystal Orientation and Phase Mapping by Precession Electron Diffraction in TEM: Application to Hot Deformation of a γ-TiAl-based Alloy

2019 ◽  
Vol 25 (6) ◽  
pp. 1457-1465
Author(s):  
Vajinder Singh ◽  
Chandan Mondal ◽  
P. P. Bhattacharjee ◽  
P. Ghosal
Keyword(s):  
Electron Diffraction ◽  
Hot Deformation ◽  
Crystal Orientation ◽  
Microstructural Characterization ◽  
Advanced Characterization ◽  
Precession Electron Diffraction ◽  
Phase Mapping ◽  
Diffraction Patterns ◽  
Symmetry Effect ◽  
Structure Evaluation

AbstractMicrostructural evolution of a hot deformed γ-TiAl-based Ti–45Al–8Nb–2Cr–0.2B (at.%) alloy has been studied using an advanced characterization technique called automated crystal orientation and phase mapping by precession electron diffraction carried out in a transmission electron microscope (with a NanoMEGAS attachment). It has been observed that the technique, having a capability to recognize diffraction patterns with improved accuracy and reliability, is particularly suitable for characterization of complex microstructural features evolved during hot deformation of multiphase (α2 + γ + β)-based TiAl alloys. Examples of coupled orientations and phase maps of the present alloy demonstrate that the accurate reproduction of the very fine lamellar structure (α2 + γ + γ) is feasible due to its inherent high-spatial resolution and absence of a pseudo-symmetry effect. It enables identification of salient features of γ-TiAl deformation behavior in terms of misorientation analyses (GAM, GOS, and KAM) and transformation characteristics of very fine lamellar constituent phases. Apart from conventional strain analyses from the orientation database, an attempt has been made to image the dislocation sub-structure of γ-phases, which supplements the deformation structure evaluation using this new technique.

scholarly journals Crystallographic characterization of polycrystalline materials: High resolution automated crystallite orientation & phase mapping and Precession electron diffraction ring patterns

2010 ◽  
Vol 16 (S2) ◽  
pp. 768-769 ◽  
Author(s):  
S Rouvimov ◽  
P Moeck ◽  
E Rauch ◽  
Y Maniette ◽  
D Bultreys
Keyword(s):  
High Resolution ◽  
Electron Diffraction ◽  
Polycrystalline Materials ◽  
Crystallite Orientation ◽  
Diffraction Ring ◽  
Precession Electron Diffraction ◽  
Phase Mapping

Extended abstract of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010.

The symmetry of precession electron diffraction patterns

2010 ◽  
Vol 237 (3) ◽  
pp. 511-515 ◽  
Author(s):  
J.-P. MORNIROLI ◽  
P. STADELMANN ◽  
G. JI ◽  
S. NICOLOPOULOS
Keyword(s):  
Electron Diffraction ◽  
Precession Electron Diffraction ◽  
Diffraction Patterns

Reconstruction of the Projected Potential from a through Voltage Series of Dynamical Electron Diffraction Patterns Including Absorption

2001 ◽  
Vol 7 (S2) ◽  
pp. 914-915
Author(s):  
C. Koch ◽  
J.C.H. Spence
Keyword(s):  
Electron Diffraction ◽  
Crystal Orientation ◽  
Specimen Thickness ◽  
Experimental Realization ◽  
Crystal Potential ◽  
Scattering Effects ◽  
Electron Microscopes ◽  
Diffraction Patterns ◽  
Multiple Scattering Effects ◽  
Better Than

Recently several different methods have been proposed to reconstruct the projected crystal potential from electron diffraction patterns. These methods envolve either diffraction patterns at many different orientations (as many orientations as beams in the pattern) and/or images, which makes their experimental realization difficult. We propose an entirely new method for reconstructing the projected crystal potential from fully dynamical [including absorption and multiple scattering effects to all orders] diffraction patterns from only a single crystal orientation and no image at all. Knowledge of the specimen thickness is not necessary. However, it requires diffraction patterns at many different accelarating voltages, which is a parameter that can easily be varied (within a certain range) in most modern electron microscopes. Since the intensities in the electron diffraction pattern are not affected by lens abberations this method is capable of reconstructing the projected potential with a resolution far better than that of any method using HRTEM images.

scholarly journals Phase mapping of 2xxx-series aluminium alloys by scanning precession electron diffraction

2016 ◽  
pp. 255-256
Author(s):  
Jonas Kristoffer Sunde ◽  
Sigurd Wenner ◽  
Antonius T.J. van Helvoort ◽  
Duncan N. Johnstone ◽  
Paul A. Midgley ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Aluminium Alloys ◽  
Precession Electron Diffraction ◽  
Phase Mapping

Automatic Crystallographic Characterization in a Transmission Electron Microscope: Applications to Twinning Induced Plasticity Steels and Al Thin Films

2013 ◽  
Vol 19 (3) ◽  
pp. 693-697 ◽  
Author(s):  
M. Galceran ◽  
A. Albou ◽  
K. Renard ◽  
M. Coulombier ◽  
P.J. Jacques ◽  
...  
Keyword(s):  
Thin Films ◽  
Electron Microscope ◽  
Electron Diffraction ◽  
Transmission Electron Microscope ◽  
Microstructural Characterization ◽  
Fine Grained ◽  
Mapping Tool ◽  
Transmission Electron ◽  
Kikuchi Lines ◽  
Diffraction Patterns

AbstractA new automated crystallographic orientation mapping tool in a transmission electron microscope technique, which is based on pattern matching between every acquired electron diffraction pattern and precalculated templates, has been used for the microstructural characterization of nondeformed and deformed aluminum thin films and twinning-induced plasticity steels. The increased spatial resolution and the use of electron diffraction patterns rather than Kikuchi lines make this tool very appropriate to characterize fine grained and deformed microstructures.

scholarly journals Crystal Orientation Mapping via STEM/NBD: Improved Quality with Precession Electron Diffraction and Energy Filtering

2011 ◽  
Vol 17 (S2) ◽  
pp. 1074-1075 ◽  
Author(s):  
G Pavia ◽  
G Benner ◽  
H Niebel ◽  
E Rauch ◽  
M Véron
Keyword(s):  
Electron Diffraction ◽  
Crystal Orientation ◽  
Energy Filtering ◽  
Orientation Mapping ◽  
Precession Electron Diffraction ◽  
Crystal Orientation Mapping

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.

Precession electron diffraction-assisted crystal phase mapping of metastable c-GaN films grown on (001) GaAs

2014 ◽  
Vol 77 (12) ◽  
pp. 980-985 ◽  
Author(s):  
Francisco Ruiz-Zepeda ◽  
Yenny L. Casallas-Moreno ◽  
Jesus Cantu-Valle ◽  
Diego Alducin ◽  
Ulises Santiago ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Crystal Phase ◽  
Precession Electron Diffraction ◽  
Phase Mapping

Specifics of the data processing of precession electron diffraction tomography data and their implementation in the program PETS2.0

2019 ◽  
Vol 75 (4) ◽  
pp. 512-522 ◽  
Author(s):  
Lukáš Palatinus ◽  
Petr Brázda ◽  
Martin Jelínek ◽  
Jaromíra Hrdá ◽  
Gwladys Steciuk ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Data Processing ◽  
Diffraction Data ◽  
Crystal Orientation ◽  
Diffraction Method ◽  
Specific Aspect ◽  
Electron Diffraction Data ◽  
Diffraction Tomography ◽  
Profile Fitting ◽  
Precession Electron Diffraction

Electron diffraction tomography (EDT) data are in many ways similar to X-ray diffraction data. However, they also present certain specifics. One of the most noteworthy is the specific rocking curve observed for EDT data collected using the precession electron diffraction method. This double-peaked curve (dubbed `the camel') may be described with an approximation based on a circular integral of a pseudo-Voigt function and used for intensity extraction by profile fitting. Another specific aspect of electron diffraction data is the high likelihood of errors in the estimation of the crystal orientation, which may arise from the inaccuracies of the goniometer reading, crystal deformations or crystal movement during the data collection. A method for the refinement of crystal orientation for each frame individually is proposed based on the least-squares optimization of simulated diffraction patterns. This method provides typical angular accuracy of the frame orientations of less than 0.05°. These features were implemented in the computer program PETS 2.0. The implementation of the complete data processing workflow in the program PETS and the incorporation of the features specific for electron diffraction data is also described.

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