Typically EBSD techniques like GOS, GAM, KAM are used to quantify the volume fraction recrystallisation of an annealed sample (i.e. static recrystallisation), based on the principle that a deformed grain has greater average local misorientation value, whereas a strain received grain (recrystallised ) has a low average disorientation value. However in DRX , recrystallisation and strain accumulation is a continuous process, how do we count for the recrystallised and then deformed grains? How to evaluate the rx fraction as a function of strain imposed?
Dear Sahithya Kandalam follow these two links, you may find them helpful
Article Estimation of recrystallized volume fraction from EBSD data
http://www.imim.pl/files/archiwum/Vol3_2005/abs3_16.pdf
The separation of post-DRX deformed grains from non DRX grains, and the combination of post-DRX deformed grains with freshly recrystallized grains is not trivial or certain. The most straightforward way to include the post-DRX deformed grains in your recrystallized fraction is to relax the recrystallization threshold slightly (eg. slightly increase the 'allowable' GOS/KAM angle).
For more careful analysis, the texture and grain growth pattern can help you distinguish such grains, though it may be difficult to automate. The retention of recrystallization texture in the post-DRX deformed grains was shown by Hadadzadeh et al in [1]. This is really nice if the material develops appreciable texture.
If not, you may need to look at the substructure and see if it shows signs of post-DRX grain growth, as we did in [2]. Grains with such indications are post-DRX grains. Beyond this, the distribution of misorientation axes & angles could help, since post-DRX deformed grains show mixed distributions [3].
[1] Article A New Grain Orientation Spread Approach to Analyze the Dynam...
[2] Article A micro-mechanism to explain the post-DRX grain growth at te...
[3] Article Flow Softening Index for Assessment of Dynamic Recrystalliza...
Hi Sahithya,
I agree with Mr Aashranth that partitioning of DRX grains in a post-hot deformed structure is not a trivial job through EBSD maps. I am not aware of any universal rule which can be applied across the materials with satisfactory results. Conditions should be determined based on the situation at hand. More often, it useful to combine more than one criteria to yield satisfactory results (for example, I prefer a combination of GOS max in combination with min grain size to get good approximations in Al-based alloys). The conditions must be determined based on microstructural features and, of course, experience in handling those features.
You can refer vast body of literature on the subject, and if you are lucky enough one of those reported methods might work for you. Otherwise, I'm afraid, you need to come up with your own system specific solution.
It is rather difficult to suggest any meaningful method without understanding ur research problem, system and microstructural characteristics that you are dealing with. I suggest you can discuss the issues with Prof Samajdar of ur institute in person. I am sure you will be benefited.
Best wishes.
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