mtex examples with data

I have been doing a bit of play using mtex to look at some EBSD data which I previous exported to .ctf format. mtex is an open source (GPL) software, which written for the commercial matlab software. The mtex package comes along with several examples and tutorials which can be read within matlab or over the http-internet-web.

Example scripts for using mtex are also available to download from the recently published paper “On Three-Dimensional Misorientation Spaces” by Krakow etal. published in Proceedings of the Royal Society A, 473, 2017.

Scripts and EBSD data for the case studies in the paper are available here:

https://www.repository.cam.ac.uk/handle/1810/263510

Scripts for producing other figures in the paper (explaining orientation relations etc.) are available from the mtex website here (along with other examples):

https://mtex-toolbox.github.io/publications.html

Screenshot from 2018-06-11 19-56-55

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Control of texture in materials using mtex /matlab at Sandvik

Dr Claes Olsson from Sandvik AB’s Materials Technology division explained at the Matlab expo 2016 how Sandvik has used the MTEX toolbox for analyzing and modeling crystallographic textures by means of pole figure and EBSD data. The software has been integrated into the work of the Materials Technology division allowing an auditable methodology for quality control, meeting standards to supply to their nuclear customers (e.g. in case of rolling zircalloy with controlled texture). Initial example of use was with pole figure data collected with a diffractometer, but they have also used the software to analyse EBSD data.
Screenshot from 2018-06-07 19-42-12
A video of the presentation can be seen here:
Screenshot from 2018-06-07 19-39-32
Slides can be found here:
Mtex is a free toolbox released under the GNU GPL 2, which works inside the commercially available matlab environment.

Crystallographic Centenary Celebration

It’s a 100 years since something to do with the Bragg’s discovery of X-rays. The Royal Society have made a cartoon about it.

Shear Relief

I’m very happy that my paper was accepted for publication in Metallurgical and Materials Transactions A. It took a long time from performing the experiment to presenting the results, mainly because I needed to repeat the analysis which was something I wasn’t able to make time for until I had to submit the thesis.

Surface relief caused by shear transformation of bainite

Surface relief caused by shear transformation of bainite

In the paper atomic force microscopy is used to measure the shear component of extremely thin plates of bainitic ferrite in superbainite. The shear component is surprisingly large compared to the value we expected of 0.23–0.28 based on previous experiments carried out after transformation at higher temperatures (such as the results by Swallow and Bhadeshia).

It seems like the higher strain may help to explain why the bainitic ferrite plates are so thin and slender. It would now be really interesting to test if that is true or not, which is something I couldn’t really do by looking at the TEM and SEM images I have already.

More details on my web-page at Mathew Peet| Papers| Surface Relief Due to Bainite Transformation at 200°C

Article is currently available electronically by using DOI

Ferrite crystal structure in cmd format for jmol


<?xml version="1.0"?>
<molecule xmlns="http://www.xml-cml.org/schema">
<crystal>
<scalar title="a">2.882</scalar>
<scalar title="b">2.882</scalar>
<scalar title="c">2.882</scalar>
<scalar title="alpha">90.00</scalar>
<scalar title="beta">90.00</scalar>
<scalar title="gamma">90.00</scalar>
</crystal>
<atomArray>
<atom id="Fe1" xFract="0.0" yFract="0.0" zFract="0.0" elementType="Fe"/>
<atom id="Fe2" xFract="0.5" yFract="0.5" zFract="0.5" elementType="Fe"/>
</atomArray>
</molecule>

After viewing cmlexplained.
Jmol is a an open-source Java viewer for chemical structures

Density of Iron Carbide (Fe3C)

There are 4 molecules of Fe3C per unit cell. The cell is orthorombic, typical lattice parameters at room temperature are given below from Mehl etal, Trans AIMME, 1933.

Mass
——-

m = mass of 1 mole of unit cells
= 12 x FeRAM + 4 x CRAM
= 12 x 55.845 + 4 x 12.011 = 670.14 + 48.044
= 718.184 g/mol

Fe3C unit cell is 718.184 g/mol

Volume
——-
v = volume of 1 mole of unit cells
= AV x a x b x c
= 6.0221415 × 1023 x 4.518 x 5.069 x 6.736 x 10-30
= 9.2901×10-5 m3

Density
——-
d = density
= m/v
= 0.71814 kg / 9.2901 x 10-5 m3
= 7730.14 kg/m3

View FCC Austenite in three dimensions

Channel 4 seem to be showing some 3d programs on t.v. the consequence is you can get 3d glasses for free in sainsburys, and you can use them with the Jmol sorfware to view molecular models in three dimensions.

3 dimensional model of 2 FCC unit cells

2 FCC unit cells (click image to enlarge)