Mechanical Extremes Thrust: Severe Plastic Deformation Team
Cu 10 nm nanocrystalline sample being uni-axial compressed to strain of 20% (video first half) and then stress released (video second half). Blue: atoms that were not displaced; green: atoms displaced by the Burgers vector of a Shockley partial; orange: atoms displaced by the Burgers vector of a perfect dislocation; red: atoms displaced by more than the Burger vector of a perfect dislocation. It shows that partial and perfect dislocations nucleate from grain boundaries and be absorbed to the neighbor grain boundaries.
When the sample being stress released, partial dislocations retract themselves, but perfect dislocations do not. It shows the reversible process of partial dislocations. This video is a part of the work in ref. [*]
[*] N. Q. Vo, R. S. Averback, P. Bellon, S. Odunuga, and A. Caro, Phys. Rev. B 77, 134108 (2008)