X-ray challenge

Spot what is the problem with my experiment shown in this image:

X-ray diffractometer


Introducing Crystallographic Hangman

Introducing the great new game Crystallographic Hangman.

Sodium Chloride Unit Cell
Picture courtesy of Wikipedia

New Podcasts

I made three new podcasts with Prof. Harry Bhadeshia on his latest papers on transformation texture, the new delta-Trip steels and on prediction of Hot Strength of ferritic steels.

The work on transformation texture is from Saurabh Kundu’s thesis were Patel and Cohen’s model has been shown to correctly predict the orientation relationship between ferrite and austenite after martensitic transformation. It’s shown that variants are selected by free energy differences that can be calculated depending on the orientation.

The delta-Trip steels were developed as a result of the prediction of neural networks, were after the neural network was made computer optimisation was used to try and maximise the mechanical properties. This work was done with Saurabh Chatterjee in collaboration with Murugananth Marimuthu. Both Saurabh Kundu and Saurabh Chatterjee completed their PhD’s at Cambridge while visiting from Tata Steel, Murugananth Marimuthu is a previous member of the phase transformations group, and has now also joined Tata Steel’s research and development section.

The work on Hot Strength of ferritic steels is the part of Radu Dmitriu’s topic of research. A neural network model of the hot-strength of ferritic steels. It was observed from the neural network that the strength is expected to suddenly start to decrease at 800 Kelvin, which can has been explained to be due to changes in the mobility of dislocations.


According to wordpress documentation these links should get added to the rss feed of this bainite blog as enclosures.

Podcast: Hot Strength

Podcast: Delta Ferrite

Podcast: Transformation Texture

Subcribing to RSS Feed of this webpage should get you all the podcasts, or for Podcasts Only
Subscibe to RSS Feed for posts I remember to add to Podcasts category



It’s reported in the press that the diamond facility has made it’s first observation of synchrotron light, they achieved this on 30th May, after first getting electrons around the storage ring for the first time on 5th May.

See the BBC news coverage here (including video).

Diamond can host up to forty beamlines from it’s 3 GeV storage ring. Seven beamlines will be available on the first day of operation sometime in 2007 (Phase I), and 22 will be built by 2011.

See the planned beam lines

The seven beamlines constructed in phase I will be:

  • Extreme conditions beamline (I15) for studying materials under intense temperatures and pressures.
  • Materials and magnetism beamline (I16) to probe the electronic and magnetic properties of materials at the atomic level.
  • Three macromolecular crystallography beamlines (I02, I03 & I04) for understanding the structure of complex biological samples, including proteins.
  • Microfocus spectroscopy beamline (I18) able to map the chemical composition of complex materials, such as moon rocks and geological samples.
  • Nanoscience beamline (I06) capable of imaging structures and devices at a few millionths of a millimetre.

Details of how to get beamtime should be here.


I’ve found a solution to a problem i’ve been having with the map program XRDCALC. It seemed to me that is had suddenly stopped working, everything would run fine but the volume fraction was reported as “error %”. I had made a lot of changes to the version which I use, maybe I had introduced an error, or maybe changing the version of linux had caused the problem (change in C library or some such thing). I downloaded the original version again and got the same error using the downloaded binary.

Inputs that don’t work (from hidden file ‘.a_inputs’):

1 1 1
2 0 0
2 2 0
1 1 3
1 1 0
2 0 0
1 1 2
2 2 0

results in the error:

--------------  RESULT --------------------

preT:0.003651 Aus:0.107513 fer:0.033961

Percentage of austenite :       nan %    Error : 0.3638 %
Percentage of ferrite : nan %    Error : 0.3638 %

Look into the filename a_XRD_result for your results

                         Thank you for using xrdcalc- Ananth

Checking the files I generated with my first use of this program I was surprised to see that the order matters for the peak indexes. The end of the file should be like this;

1 1 1
0 0 2
0 2 2
1 1 3
0 1 1
0 0 2
1 1 2
0 2 2

Hoorah it works now. It wasn’t that the program suddenly stopped working but I had changed how I was giving the inputs. This strange error needs investigation but the program is still usable and work can proceed on several fronts that had been held up because of this.