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.

Angel of the North

640px-Fly-Angel

The Angel of the North: Image from Wikipedia

At 200 tonnes excluding the concrete piles used to support it, the total cost of The Angel Of The North was said to be £800,000. That means the installed cost for the 200,000 kg was £4 / kg.

The Angel Of The North owes it’s appearance to the weathering steel it is constructed from, these steels are designed to form a stable oxide layer, with a low corrosion rate across the entire surface. This strategy means that it’s possible to have a reasonable service lifetime with a minimum of maintenance, even an initial layer of paint is unnecessary.

Example weathering steel compositions / wt%

Grade C Si Mn P S Cr Cu V Ni
ASTM A242 0.12 0.25–0.75 0.20–0.50 0.01–0.20 0.030 0.50–1.25 0.25–0.55 0.65
ASTM A588 0.16 0.30–0.50 0.80–1.25 0.030 0.030 0.40–0.65 0.25–0.40 0.02–0.10 0.40

Somewhat uniquely for steels, the initial rust layer protects the steel underneath from further deterioration, eliminating the need for paint. This depends on environmental conditions, too much humidity too often mean that the rust layer never reaches a stable point. This can lead to corrosion and loss of integrity.

edX

edX.org is a really fun site. I tried this course: CS50 introduction to computer science. It seems like a really good course, I attempted to study it a couple of times and registered for the certificate so I would have some skin in the game, but I still didn’t manage to finish, although this course has a very engaging presentation and it very well made. I think trying to do the course along with the regular teaching schedule is probably a better idea than going self-paced for me.

Screenshot at 2018-02-27 11-48-03

https://online-learning.harvard.edu/course/cs50-introduction-computer-science

I had fun pretending to learn about steel on the course “introduction to steel which is presented by Mark Miodownik. This is a short course, if you want a basic introduction to steel, or to look at some of the mechanics of an edx course this course can be completed quickly.

Screenshot at 2018-02-27 11-47-02

https://www.edx.org/course/introduction-steel-tenarisuniversity-steel101x-2

Finally I followed this course from MIT which teaches computer science and programming using the python language, https://www.edx.org/course/introduction-computer-science-mitx-6-00-1x-11. It’s really a good course if you found you are programming already but have never studied programming formally (or even if you intend to program in future!). It took me a whole bunch of time each week to work through the problem sets, maybe try not having too much spare time for it to gobble up. Problem sets and exam questions are completed in python, I think they recommend the spyder ide, and then loaded for automatic marking.

Screenshot at 2018-02-27 11-55-57

Now I should be learning biochemistry, so I have this to learn from (and Alberts’ The Cell).

Screenshot at 2018-02-27 11-56-41

https://www.edx.org/course/introduction-biology-secret-life-mitx-7-00x-7

Elon Musk launches Tesla – Falcon Heavy test flight

Elon Musk launched his Tesla, but this was a launch was different, it was the launch of his own Cherry Red Roadster in to space.

Some people in NASA criticised the plan of NASA to use corporate suppliers to design and launch rockets needed for them to replace the space shuttle — enabling manned missions to the international space station (strange because I think previous rocket engines were built commercially?).

The Falcon Heavy maiden flight was intended to accomplish several objectives:

  • survive launch
  • separate the side booster cores
  • return the two side boosters to Cape Canaveral
  • separate the core and the upper stage to light engines for orbit insertion
  • land the central first stage booster core on an autonomous drone ship
  • relight the upper stage to orbit in the van Allen belts for several hours
  • relight the upper stage again to put the payload into its heliocentric orbit

 

It was reported that after a successful launch, the two booster rockets successfully (simultaneously) landed back at the Cape Canaveral launch site. The core engine impacted 100 meters from the drone ship at 500 kilometres per hour, after 2 of 3 engines failed to reignite.The final upper stage transfer burn to solar orbit produced an orbit that will be beyond the orbit of Mars at its furthest point from the sun.

Amazon health care?

Amazon has started a new company with JP Morgan and Berkshire Hathaway to provide health care to its employees.

Atom positions in steel

I was able to make some data sets available this year from work published in 2004 and in 2017 showing how atoms arrange themselves in nanostructured steel (Super Bainite).

There are a couple of motivations for making the data sets available. Firstly it is good practice and makes it possible for others to analyse the data to check reproducibility of my work, and there is also possibility to extract further information. It also serves as a back-up for the data sets by putting them on internet, one of the best back-ups available… 🙂

Another is that, at the time of conducting these experiments a frustration of mine was that there was no [simple] way to view the positions without access to commercial software, for me, that was once I had left the facility I visited to undertake part of the work. Hopefully the sharing of atom position data will become more standard procedure in future, with the increasing sophistication of high-level computing languages and expansion of open software. This may allow new developments in reconstruction of volumes, analysis of the atom positions, and education of users; benefiting the atom probe field.

The data were collected by using a pulsed electric field concentrated on the tip of a needle made by electropolishing the steel sample. By pulsing the voltage both the time-of-flight and the position the projected atom hits a detector screen can be recorded. This can then be mapped back to the sample volume, allowing measurement of the composition of the steel with better than nanometre resolution. The technique is called 3D atom probe (3DAP) tomographic atom probe (TAP) or atom probe tomography (APT). This technique is related to field ion microscopy.

The volume studied include volumes from various crystal structures (BCC bainitic ferrite, FCC thin-film austenite, carbides such as Fe3C cementite) in the particular steel I was studying (nanostructured carbide-free bainite — see papers for details).

Data can be found here:
https://www.repository.cam.ac.uk/handle/1810/265717
https://www.repository.cam.ac.uk/handle/1810/265720

The papers describing the data can be found here:

https://www.phase-trans.msm.cam.ac.uk/2004/atom.probe.bainite.html

https://www.repository.cam.ac.uk/handle/1810/263230

I’m glad to make these data sets available, and hope they will continue to be available in the future from the Cambridge repository website.

At the time I did the experiments, only commercial software was available to view the atom probe data such as IVAS ivas, but today I believe it should be possible to view the atom positions using software such as 3depict 3d epict.