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Why is the grain boundary normal information needed? #1

Open RecryMagnet opened 1 year ago

RecryMagnet commented 1 year ago

Please tell me why the first row of the two rotation matrices must be specified as the grain boundary normal, why the grain boundary normal will affect the grain boundary energy, for example, the same CSL3 coincidence lattice grain boundary, if it has different grain boundary normals, then the grain boundary energy is different. Is it different? It’s strange. Translate to English: If this information is necessary, then 2D ebsd data can only obtain two-dimensional grain boundary normal data, and rotate the two-dimensional grain boundary normal data to the direction of the x-axis by the rotation matrix and then left multiply by the rotation matrix P and Q obtained by the Euler angle. Get a new rotation matrix and then calculate the grain boundary energy. Is this correct? Thank you so much.

sutatch commented 7 months ago

Thank you so much for the questions. You are right that the energies are different when the grain boundary normals are different, please see the distributions of grain boundary energies at a fixed misorientation (i.e. Σ3, Σ5, Σ9, in Acta Materialia 88, 346–354, 2015). Knowing that is quite strange, but these differences in the grain boundary energies play a major role in governing the grain boundary character distributions (GBCDs) or the development of the grain boundary engineering concept. While the 2D EBSD can be used to define the misorientation or adjoined grains, the grain boundary normal could not be characterized by the EBSD measurements. In such cases, the 3D EBSD or statistical analysis [Z. Metallk. 95:197–214, 2004, Metall Mater Trans A 35:1981–1989, 2004]. of the EBSD must be used.
To compare the grain boundary energy from the P and Q matrix with the traditional method of defining the crystallographic structures of grain boundary, the rotation axis and angle (CSL) should be determined first and the grain boundary normal data are then simply given by the first line of the P and Q matrix in the direction of the x-axis as you mentioned.

I am sorry for the late reply.

Merry X mas and happy new year.

Sutatch :- )