Grain Boundaries in Materials (Low Angle Boundaries, Coincidence Site Lattices)

Most engineering materials are polycrystalline where the individual grains are separated by grain boundaries. Because of the mutual rotation of individual grains, the periodicity of the atoms at the grain boundary is disrupted and they have higher energies compared to a perfect single crystal. However, for low angle rotations the boundaries can minimize the disruption by forming periodic arrays of dislocations; at higher angles of rotation the destabilization of the grain boundary can also be reduced through the formation of Coincidence Site Lattices with so-called “Sigma” values. This video, presented at a level accessible to a materials science undergraduate, provides a brief overview of the formation and description of these special types of grain boundaries.

[@Ashish-299]

Can’t be explained better than this. Thanks a lot.

[@peterdavies6179]

Thank you!

[@jiachengwang1755]

I am a beginner at learning grain boundaries. Best video I have ever found!!!

[@peterdavies6179]

Thank you, glad you found it helpful

[@ankitroy9283]

Hard to find such a clear explanation even at university lectures.

[@peterdavies6179]

Thank you

[@alekseiegorov9857]

Clear (and funny!) explanation of the topic! Thank you Prof. Davies!

[@kritikakhanal3658]

Thank you so much ,i needed this ❤

[@wenwu-xu]

Thanks a lot for sharing. This is the best video I have ever seen teaching CSL!!!

[@peterdavies6179]

Glad it was helpful!

[@sarialzarey3508]

Thanks for such valuable information in the video. Keep going

[@swahid9343]

Thank you professor.

[@yuan_tu]

Hi Peter, thanks to your introduction. It really helps me understand CSL GBs...No animals are harmed, except for the duck...

[@rshi579]

may i have a pdf copy of your slides?

[@rshi579]

Thanks!

[@Pedritox0953]

Very nice models!

[@peterdavies6179]

Thank you!

[@keremcandizdar9975]

Hi, You said that low angle boundaries orientation is below 5degree however in the next slides there is an example that shows it as 10 degree in SrTiO3

[@peterdavies6179]

Yes the 5 degree quote was an approximation, you can go a little higher.

[@balaacharya3941]

sir rotation axis 111, 001, 110 ? what doe it means

[@peterdavies6179]

This is the direction perpendicular to the view on the slide; the grain is rotated around that direction (axis)