Understanding number of varients for shoji nishiyama and discussion on OR fitting

[natan12134]

Hello all,

I am working with a pure cobalt dataset with both parent and child phases. The misorientation of the phase boundaries corresponds well with the shoji nishiyama OR which is expected. However, there are a couple of inconsistencies I was wondering if I could gain some insight on. First, when displaying the unique variants for the S-N OR, it gives 24 unique variants I am expecting 12 unique ways a FCC grain can transform to and HCP one. I was wondering if someone can explain if there is something wrong going on with the variant calculation or if there something I am missing.

I also see some inconsistencies when defining the same OR different ways. Using the OR in the orientation function (1,1,1)//(0,0,0,1) & <1,0,-1>//<2,-1,-1,0> I get the follow error when defining the same OR manually "Inconsistent pairs of vectors! The angle between u1, u2 and v1, v2 needs to be the same, but differs by 45°". If I switch the OR form in the orientation function (1,1,1)//(0,0,0,1) & <1,-1,0>//<1,1,-2,0> I get the same result as before but if I manually define this new form, I now get either 4 or 6 unique variants randomly each time I run the procedure. Using peak fitting gives the same parent-child and child-child disorientations as manually defining the OR but with 24 unique variants.

The parent-child and child-child plots show that the dataset does not fit the S-N OR which I am skeptical of.

Thank you for any insight,
Nathan