Notes from NRC-M Workshop in Microstructural Engineering

June 1, 2009

Here are some interesting things that I learnt from the participants of Micro-09.

  • Dr. Chandan Srivatsava, a Centenary post-doc at the Department of Materials Engineering, IISc spoke about compositional characterization of nanoparticles using TEM. Apparently, one of the problems that one encoutners while doing the experiments is the drift in TEM. While discussing several ways of minimizing it, he explained how if you set the equipment as if you are going to take the readings the next moment, and then leave the room for a cup of coffee and come back after 20-30 minutes, the drift problem is minimized. So, I guess, while mathematicians are busy converting coffee into theorems, the microscopists are busy concerting coffee into compositions — which, by the way,  reminds me why the closure of coffee board at IISc is such a regrettable decision 😦
  • Most materials are most brittle in Mode I. (Vikram)
  • The image formation mechanisms in microscopes are three: optical, scanning and projection. The image formation mechanism in TEM is optical.TEM images are not only diffration but also aberration limited. And, the equivalent of SANS and SAXS exists for electrons also — fluctuation microscopy is the SAES. (G K Dey, Head, Division of Materials Science, BARC)
  • Indian electrical power production has increased by a factor of 100 since independnece. Of the power generated, 40% if lost, of which 60% of the losses are technical. (I Samajdar)
  • Using EBSD, you can obtain whatever grain size you want to!Severe plastic deformation (SPD) are those deformation in which there are large amount of high angle grain boundaries (where, high angle grain boundaries are defined as those with a misorientation exceeding 15 degrees); quantitatively, in SPD, there is a higih angle boundary from any point in the microstructure in any direction within 1 microns, and the ratio of high angle grain boundary to total grin boundaries is more than 70%.

    Further, SPD materials are lean in dislocations since they are absorbed in low angle grain boundaries. This results in better ductility and more uniform corrosion.

    High cycle fatigue, which is related to elastic strain, improves because of improved fracture strength in SPD materials, while low cycle fatigue which is related to plastic strain degrades.Al, Cu, and Ag belong to three different stacking fault energy regimes and hence are important for texture studies. (Satyam)

  • The talks of Aloke Paul and his student Kiran as well as those of Santonu Ghosh and Prasad were very interesting too, and some of them raised some very interesting, unresolved issues which made the workshop very exciting.

I had fun time interacting with the participants as well as chatting with old friends. On the whole, it was a wonderful experience. I hope Abi keeps up the tradition and run one Micro conference once in a year — and invites me! 🙂

PS: The slides of my presentation titled Modelling elastic stress induced morphological instabilities is available for download in my googlepages homepage (in PDF format).

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2 Responses to “Notes from NRC-M Workshop in Microstructural Engineering”

  1. Phaniraj Says:

    Apparently, the drift in a SuperSTEM-2 is 2000 times slower than the continental drift.

  2. Phaniraj Says:

    But even that seems to be not enough. This website(http://openlearn.open.ac.uk/mod/resource/view.php?id=172175) gives the rate at which the indian plate is pushing the himalayas as 50 mm/year. Thats large if we are into lattice imaging.


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