Project

# MTEX - free crystallographic texture analysis software

Goal: MTEX http://mtex-toolbox.github.io/ is a very general crystallographic texture analysis software that aims at providing the fundamentals for any kind of computation in the field of EBSD, XRD, elasticity, plasticity, etc. The project is to make MTEX more mature and versatile with every new release.

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## Project log

Dear MTEX community,
we are very proud to announce MTEX 5.8. This release greatly improves parent grain reconstruction by implementing and including many small tools for making the reconstruction process more reliable.
A summary of the changes can be found at https://mtex-toolbox.github.io/changelog.html.

• 24.01
• Swerim
I recommend anyone struggling with the reconstruction of lath martensite check out the new features. The variant graph approach is a good step towards universally robust, self-guiding, fast and low-effort reconstruction algorithms!

The variant graph is a new, hybrid algorithm that combines the strengths of established global grain graph and local neighbor level voting approaches, while alleviating their shortcomings, to reconstruct parent grains from orientation maps of partially or fully phase-transformed microstructures. The variant graph algorithm is versatile and is capable of reconstructing transformation microstructures from any parent-child combination by clustering together child grains based on a common parent orientation variant. The main advantage of the variant graph over the grain graph is its inherent ability to more accurately detect prior austenite grain boundaries. A critical examination of Markovian clustering and neighbor level voting as methods to reconstruct prior austenite orientations is first conducted. Following this, the performance of the variant graph algorithm is showcased by reconstructing the prior austenite grains and boundaries from an example low-carbon lath martensite steel microstructure. Programmatic extensions to the variant graph algorithm for specific morphological conditions and the merging of variants with small mutual disorientation angles are also proposed. The accuracy of the reconstruction and the computational performance of the variant graph algorithm is either on-par or outperforms alternate methods for parent grain reconstruction. The variant graph algorithm is implemented as a new addition to the functionalities for phase transformation analysis in MTEX 5.8 and is freely available for download by the community.
Dear MTEX community,
we are very happy to announce the MTEX workshop 2022 (https://mtex-toolbox.github.io/workshops) which will be organized as an online workshop from March 21st to March 30th 2020.
The purpose of the workshop is twofold. The first week is an MTEX training course with focus on data cleaning, interpretation and visualization. Participants can send in their data, that will analyzed during the exercises. The course also provides basic knowledge on crystallography and texture analysis, as we believe that MTEX significantly helps understanding these subjects. After successfully attending this course you will get a certificate which counts for 5 ETCS points.
The second week it planed as an MTEX user meeting. All current and future MTEX users are invited to share specific use cases, tips and tricks and discuss recent and upcoming developments in MTEX. The schedule includes introductory presentations of invited speakers to general use cases of MTEX as well as 20 minutes talks by the participants on specific applications.
I would be very happy to have nice online workshop with as many discussions as we had in the last years. Hope to see you soon.
Ralf Hielscher, Rüdiger Kilian, Luiz Morales and Frank Niessen.

This manual is aimed at quickly teaching new MTEX users how to correctly do EBSD texture analysis to produce EBSD maps and pole figures. It will also provide a reference for intermediate users, and advice on verifying the accuracy of your EBSD maps. It is intended to be simple, direct, and accessible to users of all backgrounds with many examples and images.
A versatile generic framework for parent grain reconstruction from fully or partially transformed child microstructures was integrated into the open-source crystallographic toolbox MTEX. The framework extends traditional parent grain reconstruction, phase transformation and variant analysis to all parent-child crystal symmetry combinations. The inherent versatility of the universally applicable parent grain reconstruction methods, and the ability to conduct in-depth variant analysis are showcased via example workflows that can be programmatically modified by users to suit their specific applications. This is highlighted by three applications namely, $\alpha$-to-$\gamma$ reconstruction in a lath martensitic steel, $\alpha$-to-$\beta$ reconstruction in a Ti alloy, and a two-step reconstruction from $\alpha$-to-$\varepsilon$-to-$\gamma$ in a twinning and transformation -induced plasticity steel. Advanced orientation relationship discovery and analysis options, including variant analysis, is demonstrated via the add-on function library, ORTools.
Dear MTEX community,
we are very proud to announce MTEX 5.7. This release comes together with the and bundles our efforts to make parent grain reconstruction in MTEX more powerful and user friendly with every release.
A summary of the changes can be found at https://mtex-toolbox.github.io/changelog.html.

The analysis of manifold valued data using embedding based methods is linked to the problem of finding suitable embeddings. In this paper we are interested in embeddings of quotient manifolds SO(3)/S of the rotation group modulo finite symmetry groups. Data on such quotient manifolds naturally occur in crystallography, material science and biochemistry. We provide a generic framework for the construction of such embeddings which generalizes the embeddings constructed in arXiv:1701.01579. The central advantage of our larger class of embeddings is that it comprises isometric embeddings for all crystallographic symmetry groups.
We are happy to announce MTEX 5.6.1 (https://github.com/mtex-toolbox/mtex/releases/download/mtex-5.6.1/mtex-5.6.1.zip) which does not contain any big new feature but a list of small bug fixes.
We hope you like it,

Dear MTEX community,
we are very proud to announce MTEX 5.6 which features a major revision of the parent grain reconstruction functionality. Most importantly, it is now much more easier and user friendly to reconstruct parent grain structures in various setting. See https://mtex-toolbox.github.io/MaParentGrainReconstruction.html and https://mtex-toolbox.github.io/TiBetaReconstruction.html for examples and have a look at the changelog (https://mtex-toolbox.github.io/changelog.html).
We also greatly improved the compatibility of MTEX with older Matlab versions.
We hope you enjoy MTEX and would be happy to welcome you at the MTEX workshop 2021 (https://www-user.tu-chemnitz.de/~rahi/mtexWorkshop21/index.php).

Dear MTEX community,
we are very happy to announce the MTEX workshop 2021 (https://www-user.tu-chemnitz.de/~rahi/mtexWorkshop21/index.php) which will be organized as an online workshop from March 8th to March 17th 2021.
The purpose of the workshop is twofold. The first week is an MTEX training course that also provides basic knowledge on crystallography and texture analysis. We believe that MTEX provides an efficient way to grain better understanding on these subjects. After successfully attending this course you will get a certificate which counts for 4 ETCS points.
The second week it planed as MTEX user meeting. All current and future MTEX users are invited to share specific use cases, tips and tricks and discuss recent and upcoming developments in MTEX. The schedule includes introductory presentations of invited speakers to general use cases of MTEX as well as 20 minutes talks by the participants on specific applications.
I would be very happy to have nice online workshop with as many discussions as we had in the last years. Hope to see you soon.
Ralf Hielscher and Rüdiger Kilian.

Dear MTEX community,
we are very proud to announce MTEX 5.5. which includes major bug fixes in the volume computation function and many other small improvements. As new features it offers a much more comfortable way to analyze low angle grain boundaries and introduces orientational embeddings which allows to work with orientation data as with ordinary tensors without the need to take care about symmetry.
Please check https://mtex-toolbox.github.io/changelog.html for more details.
We hope you enjoy MTEX,
The MTEX team.

We have just powered up a new MTEX forum https://github.com/mtex-toolbox/mtex/discussions directly on Github to discuss and answer questions around MTEX.
You may want to check out the new wish-list https://github.com/mtex-toolbox/mtex/discussions/518 where you can suggest and vote for new MTEX features.
All the best,
Ralf.

Dear MTEX community,
a prerelease of the upcoming MTEX version 5.5. has been made available at https://mtex-toolbox.github.io/ New features are listed in the changelog at https://mtex-toolbox.github.io/changelog.html
I would be happy about any feedback about the new features and naming schemata.
All the best,
Ralf.

Dear MTEX community,
we are very proud to announce MTEX 5.4.0 which introduces phase transition analysis and parent grain reconstruction to the very core of MTEX. In particular, the code of Gerrit Ter Haar for Titanium beta phase reconstruction and the code by Tuomo Nyyssönen for parent Austenite reconstruction have been lifted to a unified framework for parent phase reconstruction of any phase transition. Have a look at the documentation: Austenite reconstruction, beta phase reconstruction, variant analysis.
For more details please check out the changelog at https://mtex-toolbox.github.io/changelog.html
We hope you enjoy MTEX,
The MTEX team.

This paper compares several well known sliding-window methods for denoising crystal orientation data with variational methods adapted from mathematical image analysis. The variational methods turn out to be much more powerful in terms of preserving low-angle grain boundaries and filling holes of non-indexed orientations. The effect of denoising on the determination of the kernel average misorientation and the geometrically necessary dislocation density is also discussed. Synthetic as well as experimental data are considered for this comparison. The examples demonstrate that variational denoising techniques are capable of significantly improving the accuracy of properties derived from electron backscatter diffraction maps.
We present spherical analysis of electron backscatter diffraction (EBSD) patterns with two new algorithms: (1) band localisation and band profile analysis using the spherical Radon transform; (2) orientation determination using spherical cross correlation. These new approaches are formally introduced and their accuracies are determined using dynamically simulated patterns. We demonstrate their utility with an experimental dataset obtained from ferritic iron. Our results indicate that the analysis of EBSD patterns on the sphere provides an elegant method of revealing information from these rich sources of crystallographic data.
Note: Version 3.3 replaced due to waitbar bug. MTEX lets you do EBSD data analysis in MATLAB. This app is a GUI to make it easier. This app was designed to provide the most common EBSD map utilities (and a few for pole figures) to help a new user quickly plot maps, annotate them for presentation, and investigate their data. While you do this, you can also generate the corresponding command line instructions for these actions, allowing you to learn, save a copy, and expand on them This app does not have anywhere near the functionality of MTEX- it's much more basic. Some MTEX functions not included in this app are IPF maps, ODF maps, Twin calculations, data smoothing, and rotation operations. For more information about MTEX capabilities, take a look at http://mtex-toolbox.github.io/documentation.html
To have a nice start into the year 2020 we have updated MTEX to version 5.2.8. Which improves the halfQuadraticFilter for denoising EBSD data. It is now much faster and allows also for denoising of EBSD maps on hexagonal grids.
A happy new year 2020!

Dear MTEX community,
its a big pleasure for us to announce the next MTEX workshop 2020.
In contrast to the previous workshops the next MTEX workshop extends over two weeks. The first week with the title Learning Crystallographic Texture Analysis with MTEX from 02.03.2020 to 06.03.2020 is mainly devoted to beginners in MTEX and/or texture analysis and do not require any preliminary knowledge in programming. The idea is to use MTEX as tool to illustrate and understand the basic concepts of crystallographic texture analysis by applying them to toy problem. Therefore, each day of the first week consists of two morning lectures and two afternoon exercises.
The second week from 09.03.2020 to 13.03.2020 continues the lectures of the first week but stands in the tradition of the previous MTEX workshops to focus on recent developments and applications of MTEX. There will be invited lectures on practical applications of MTEX, contributed talks and a round table discussion about further development in MTEX.
Participating in both week is equivalent to 4 ETCS points.
We would be very happy to welcome you in Chemnitz,
Rüdiger Kilian and Ralf Hielscher.

Dear MTEX users,
alongside with the new documentation we made it more simple for you to help improving it. There are two starting points for improvements:
• The documentation page (https://mtex-toolbox.github.io/Documentation.html) which explains you in detail how to contribute spelling fixes, additional comments, theoretical discussions to the documentation. Sections in documentation we find need most urgent improvement are marked as TODO.
• The examples page (https://mtex-toolbox.github.io/examples) where we aim at collecting MTEX examples scripts from real applications. Hence, if you have published research and you want to share the way you used MTEX to analyse your data please send us your script. As a bonus, those scripts will be maintained to keep them running with upcoming MTEX version.
Everybody, who contributes to MTEX will be automatically mentioned on the MTEX contributors page (https://github.com/mtex-toolbox/mtex/graphs/contributors).
Thank you very much,

Dear MTEX users,
we are very proud to announce MTEX 5.2 which introduces the following new features:
• new homepage with much improved documentation
• more colornames like orange, gold, ...
• improved import wizard
• support for hexagonal EBSD grids
• spherical Bingham distribution: fitting and random sampling
• several speed improvements
• many minor improvements and bug fixes
Please check the changelog for more details.
We hope you enjoy MTEX,
The MTEX team.

This is a revision of the algorithm for prior austenite reconstruction written for Matlab R2017X and MTEX 5.1.1. It allows the calculation of prior austenite orientation for individual misorientations and triple points.
The university of Chemnitz just announced an open W2 professorship on electron microscopy and micro structure analysis.
More details can be found at
Ralf.

Progressive deformation of upper mantle rocks via dislocation creep causes their constituent crystals to take on a non-random orientation distribution (crystal preferred orientation or CPO). The resulting anisotropy of the rock’s elastic properties can be observed by seismic techniques, and provides a means to constrain mantle convective flow patterns. Existing methods for calculating the evolution of CPO in deforming olivine-dominated rocks rely on unwieldy discrete representations of the crystal orientation distribution in terms of a large number (10^3–10^4) of individual grains. Here we propose a more efficient method in which CPO is represented using three continuous analytical functions (structured basis functions or SBFs), each of which represents a virtual CPO produced by the action of just one of the three dominant slip systems of olivine. The SBFs are then combined using an appropriate weighting scheme to represent a realistic CPO that results from the simultaneous activity of all three slip systems. We assume that olivine CPO is a unique function of the finite strain experienced by the aggregate, which implies that the weights of the SBFs depend only on the two ratios of the lengths of the axes of the finite strain ellipsoid (FSE) and the two ratios of the strengths (critical resolved shear stresses) of the slip systems. Our preferred set of weighting coefficients is obtained by least-squares fitting of the SBF expansion to the predictions of a kinematic model (solved by the method of characteristics) in which the amplitudes of the crystallographic spins do not increase with strain. Calculation of CPO using this model is ≈107 times faster than full homogenization approaches such as the second-order self-consistent model, and the result fits the characteristics-based solution with a variance reduction ≥88.6 percent ≥88.6 percent for equivalent strains up to 0.9. Finally, we propose a simple modification of the FSE that prevents the CPO from becoming singular at large strains.
Dear MTEX users,
I'm glad to announce the Chemnitz MTEX Workshop 2019.
The workshop is thought as MTEX introductory course and an MTEX user meeting to share ideas and learn from each other about how to adapt and apply MTEX to specific applications and to inform about recent developments. Thus the participants are encouraged to present their applications and customization of MTEX in 15 minute talks.
The workshop will be divided into four parts
1. An comprehensive introduction into MTEX.
2. What is new in MTEX 5.1 and 5.2 with focus on texture evolution and the estimation of geometrically necessary disclocation densities.
3. Session talks by the participants.
4. Introductory talks and guided exercises by the invited speakers
• Ben Britton, Imperial College London, UK
• David Mainprice, Universite Montpellier, France
• Rüdiger Kilian, Universität Basel, Switzerland
• to be announced
Time: Monday, 04th of March to Friday, 8th of March 2019
Location: Chemnitz University of Technology, Germany
I would be very happy to welcome you to Chemnitz.
Ralf Hielscher

We present spherical analysis of electron backscatter diffraction (EBSD) patterns with two new algorithms: (1) pattern indexing utilising a spherical Radon transform and band localisation; (2) pattern indexing with direct spherical cross correlation on the surface of the sphere, with refinement. These new approaches are formally introduced and their accuracies are determined using dynamically simulated patterns. We demonstrate their utility with an experimental dataset obtained from ferritic iron. Our results indicate that analysis of EBSD patterns on the surface of a sphere provides a valuable method of unlocking information from these rich sources of crystallographic data. Highlights 1. We present a method to approximate Kikuchi patterns on the surface of a sphere. 2. Our approximations enable spherical Radon transformations for pattern indexing. 3. Cross correlation is performed on the sphere for precise orientation determination. 4. All methods are speed optimized using fast Fourier algorithms on the sphere and the orientation space.
MTEX is a free command-line driven crystallographic software developed by Ralf Hielscher to run on Matlab. This GUI was written by Jessica Hiscocks to simplify use of MTEX for casual users, and make free crystallographic analysis more accessible to everyone. If you would like individual help, I offer personal tutoring sessions and can write custom scripts to automate your data analysis. Email me at grandriverjh@gmail.com for further details. This version of the app (2.4) requires MTEX version 5 or later, and was written for Matlab 2016b. In Version 2.4, a script recording button has been added, allowing you to see the MTEX code for yourself, generate a personalised script, adapt it, and learn how to write it. Several bugfixes have also been made, most notably to the histogram export function and annotation of cubic and HCP shapes. To install: download the .zip file and extract it. Take the GUI (extension .mlapp), and put it in your matlab working directory (where your EBSD data is located). Rename it to AnnotateR2p4.mlapp if necessary. You should see it listed the 'current folder' area of matlab at the left. Double click on it to run. When the app opens, click the 'getting started' button for more help. If you get stuck, just send me a message.
This paper compares several well-known methods for denoising orientation data with methods adapted from mathematical image analysis. The latter ones turn out to be much more powerful in terms of preserving low angle grain boundaries and filling holes of non-indexed orientations. We also discuss the effect of denoising to the determination of the kernel average misorientation and the geometrically necessary dislocation density. Synthetic as well as experimental data are considered for this comparison. The examples demonstrate that variational denoising techniques are capable of significantly improving the accuracy of properties derived from EBSD maps.
The crystallography and morphology of the intercritical austenite phase in two high-aluminum steels annealed at 850 °C were examined on the basis of electron backscattered diffraction analysis, in concert with a novel orientation relationship determination and prior austenite reconstruction algorithm. The formed intercritical austenite predominantly shared a Kurdjumov–Sachs-type semicoherent boundary with at least one of the neighboring intercritical ferrite grains. If the austenite had nucleated at high-energy sites (such as a grain corner or edge), no orientation relationship was usually observed. The growth rate of the austenite grains was observed to be slow, causing phase inequilibrium even after extended annealing times. The small austenite grain size and phase fraction were consequently shown to affect martensite start temperature. Both steels had distinct variant pairing tendencies under the intercritically annealed condition.
MTEX is a free command-line driven crystallographic software developed by Ralf Hielscher to run on Matlab. This GUI was written by Jessica Hiscocks to simplify use of MTEX for casual users, and make free crystallographic analysis more accessible to everyone. If you would like individual help, I offer personal tutoring sessions and can write custom scripts to automate your data analysis. Email me at grandriverjh@gmail.com for further details. This version of the app (2.2) requires MTEX version 5 or later, and was written for Matlab 2016b.
Major improvments in MTEX 5.1. are GND computation and Birefringence
computing geometrically necessary dislocations with MTEX, the geometry of misorientations, clustering algorithms
Comparison of EBSD denoising techniques, computation of geometrically necessary dislocations using MTEX
WHAT’S NEW?
New splash page, allowing for loading of selected tabs to simplify workflow, and help with getting started. New, extensive help sections and tutorials.
New Histogram page, allowing for creation and customization of grain and EBSD histograms, and exporting of histogram data.
New Live Observer tab, allowing for manual inspection of point orientations in terms of parameters, pole figures, and the crystal shape.
New Annotation option using automatically generated crystal shape.
Previously separate unit cell and annotation files are now integrated in the app, as are help files.
The pole figure default settings now cover more options.
New grains data export option, simplifying offline statistical analysis.
Grain boundary phase indexing bug fixed.