Hi Cathal: Neither Tango nor Mabmbo will solve your problem. You may need use a technique called reconstruction where the prior austenite grains could be recovered. There are several softwares could do this. You may search Cyril Cayron, Goro Miyamoto...in RG, and get help from them.

Hi Cathal: Please read this paper from Dr Fengwei in UL "Microscale modelling of the deformation of a martensitic steel using the Voronoi Tessellation method". I remember he used MTEX Software which combines with Matlab to identify PAG. Furthermore, I suggest that you need to know the inherent relationship of block before you start to identify PAG. You can contact Dr. FengWei and discuss with him.

do you have access to a TEM?

Hi Cathal, It is difficult to do, but if you know the details on lattice parameters for phases (austenite, cementite, pearlite etc.), that you have in the structure, you could try to detect a multiphase map. And then you could tell something about grains. Now it is not clear. You can think it is subgrain but it can also be a phase boundary. How do you prove that? Subgrains definition is rather complicated as you can change the value of what you decide to be a subgrain by yourself. There is no distinct criterion on that. But if you detect in a big grain some low-angle GB structure and the color between them will be almost the same on the orientation map - this could be a good sign for subgrains detection.

I also propose you to try another software for EBSD mapping. May be it has some unique features that could help you more or some predefined database of well-known phases.

Good luck,

Anton