Influence of void density on dislocation mechanisms of void shrinkage in nickel single crystal based on molecular dynamics simulation

Highlights: • Influence of void density on the void shrinkage in nickel single crystal is studied. • Dislocation evolution and reactions during void shrinkage is analyzed by DXA. • The higher void density can accelerate the yield of the nickel single crystal. • The void size decreases with the increase in the void density at a constant stain. Molecular dynamics (MD) simulations were performed to investigate influence of void density on dislocation mechanism of void shrinkage in nickel single crystal. The simulation results show that the higher void density can accelerate the yield of nickel single crystal. During the compression, all the dislocations are emitted toward the other side of the voids, which causes the atoms on the void surface to move into the voids and finally leads to the shrinkage of the voids. There exist six types of dislocations during void shrinkage of nickel single crystal, and the densities of all the six types of dislocations increase with the increase in the void density. The increase of Shockley partial dislocations enhances the slip ability of nickel single crystal, so the void size decreases with the increase in the void density at a constant stain.