Interactions between shuffle-set (001) dislocation and (111) twin boundary in nanotwinned diamond

Recent studies have revealed unprecedented fracture toughness in synthesized nanotwinned diamond (nt-diamond) due to the obstruction of dislocations by twin boundary. However, the atomic-scale interactions between dislocations and twin boundary in diamond remain elusive and unclear. In this work, we take advantage of the recently published interatomic potential for diamond's dislocation activity to study the interactions between (001) dislocation and (111) twin boundary in molecular dynamics (MD) simulations. The twin boundaries show obvious hindrance for (001) dislocation. In the penetrations, the shuffle-set dislocation will climb to the upper gliding plane and leave a vacancy tube behind. With the gradual increase of applied shear stress, the vacancy left on the twin boundary could launch another shuffle-set dislocation in the opposite direction in matrix. The mechanism revealed in this work show obvious difference between the interaction between twinning and dislocation in metals. This study will provide a fundamental understanding of the dislocation behaviors and their strengthening and toughing mechanisms in nt-diamond materials and the related materials.