At present, when I study the microscopic evolution mechanism of Ti6Al4V alloy during superplastic forming, EBSD observation can be carried out for grain size. At present, we intend to further study the phenomena of dynamic recrystallization and dislocation motion. Excuse me, is there any effective means to observe the location of dynamic recrystallization nucleation and the distribution of dislocations during deformation on a smaller scale?
Hi Junzhou,
If your grain size/step size allows it, you can totally track the processes of dynamic rex via EBSD. As you know, dynamically recrystallized grains are characterized by a relatively low strain stored energy (dislocation density). To identify these grains, you may want to plot EBSD maps colored according to the Grain Orientation Spread (GOS) and/or Grain Average Misorientation (GAM) parameters. Rex grains will be those of lowest GOS and GAM. Note that the GOS is grain size sensitive, so small grains will likely have a low GOS...which doesn't mean they are necessarily dynamically rex. Personally, I like to use both GOS and GAM maps to find the dynamically rex grains. The GAM is step size sensitive. So if you plan to track the evolution of dynamic rex processes in a variety of microstructures using a collection of EBSD maps, you will want to be consistent with the step size. I believe these are the simplest and more straightforward ways to find the dynamically rex grains. There are also more advanced methods which consist in estimating the GND density from EBSD maps.
Hi Junzhou,
If your grain size/step size allows it, you can totally track the processes of dynamic rex via EBSD. As you know, dynamically recrystallized grains are characterized by a relatively low strain stored energy (dislocation density). To identify these grains, you may want to plot EBSD maps colored according to the Grain Orientation Spread (GOS) and/or Grain Average Misorientation (GAM) parameters. Rex grains will be those of lowest GOS and GAM. Note that the GOS is grain size sensitive, so small grains will likely have a low GOS...which doesn't mean they are necessarily dynamically rex. Personally, I like to use both GOS and GAM maps to find the dynamically rex grains. The GAM is step size sensitive. So if you plan to track the evolution of dynamic rex processes in a variety of microstructures using a collection of EBSD maps, you will want to be consistent with the step size. I believe these are the simplest and more straightforward ways to find the dynamically rex grains. There are also more advanced methods which consist in estimating the GND density from EBSD maps.
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