Finding an orientation of a grain based on another grain

[danishTUE]

Hello Everyone,

I am new to MTex, so pardon if the query is very trivial.

I have a FCC grain (ley say g1) with a certain orientation (ley say with Bunge Euler Angle (in degrees): 21.46 156.22 245.5). I am interested in finding the orientation of another grain (ley say g2) such that the plane (111) of g1 is parallel to plane (-1-11) of g2 in a way that directions [ 0 1-1], [-1 0 1] and [1-1 0] of g1 are parallel to the directions [0 -1 -1] [1 0 1] [-1 1 0] of g2. I see from the documentation that probably rotation.map or rotation.fit should be used for this purpose. However, I am not very confident about it. Can you kindly suggest, how can I obtain the orientation of g2 using MTex?

Regards,

Danish

[ralfHielscher]

You are welcome

cs = crystalSymmetry('432');
g1 = orientation.byEuler([21.46 156.22 245.5]*degee,cs)
mori = orientation.map(Miller(1,1,1,cs),Miller(-1,-1,1,cs),Miller(0,1,-1,cs,'uvw'),Miller(0,-1,-1,cs,'uvw')))
g2 = g1 * inv(mori)

Ralf.

[danishTUE]

Many thanks Dr. Ralf. That worked well. I think in this way we can also calculate the orientation of a martensite variant (BCC) from parent austenite orientation (FCC). However, I do see that there is a dedicated MTex functionality for that.

[nyyssont]

Please see the examples in this section:
https://mtex-toolbox.github.io/MartensiteVariants.html

Modifying the command by Ralf:
KS = orientation.map(Miller(1,1,1,cs_aus),Miller(0,1,1,cs_bcc), Miller(-1,0,1,cs_aus),Miller(-1,-1,1,cs_bcc))

This produces the Kurdjumov-Sachs orientation relationship and is taken straight from the linked examples.