Author Topic: How ger the disorientation angle of every BCC atoms?  (Read 319 times)

Qriver

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How ger the disorientation angle of every BCC atoms?
« on: August 03, 2018, 05:01:33 PM »
Hi everyone,
For the cluster analysis, if the distance between two two atoms is less than cutoff radius, the two atoms will belong to one cluster. But one cluster may have several grains, I want to get the disorientation angle of every BCC atoms to identify different grains in one cluster.
But how can I do?
Thank you!
Shuai

Alexander Stukowski

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Re: How ger the disorientation angle of every BCC atoms?
« Reply #1 on: August 06, 2018, 12:11:14 PM »
Dear Shuai,

There is no easy answer to this problem. You may know already that the Polyhedral Template Matching function in OVITO allows calculating a per-atom lattice orientation from the arrangement of the nearest neighbor atoms.

Correctly assigning atoms to different grains based on this local lattice orientation information is, however, a difficult task and we are actively working on possible solutions. It's a challenging and long-term research project, because, for example, the local lattice orientations typically fluctuate heavily due to thermal vibrations of atoms, elastic strain variations and stress fields induced by surrounding defects. Developing a robust algorithm that correctly identifies grain boundaries, in particular low-angle ones, in the presence of such fluctuations is difficult.

A collaborator of mine, Peter Larsen, has developed an experimental grain segmentation algorithm for OVITO over the past months. But we are still in an early phase and this feature is not yet publicly available. We need to do more testing and research before it can be shared with others.

-Alexander

Qriver

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Re: How ger the disorientation angle of every BCC atoms?
« Reply #2 on: August 06, 2018, 04:09:52 PM »
Hi Alexander,

Thank you very much!

Shuai