Molecular dynamics simulations for responses of nano twinned diamond films under nanoindentation
C Huang and XH Peng and B Yang and YB Zhao and HG Xiang and X Chen and QB Li and T Fu, CERAMICS INTERNATIONAL, 43, 16888-16894 (2017).
We performed molecular dynamics (MD) simulations for the responses of single crystal (SC) and nanotwinned (nt) diamond films under nanoindentation, respectively, aimed to uncover the effects of twin boundary (TB) and twin thickness (delta) on hardness (H) and the corresponding deformation mechanisms. We found the Hall-Petch type relationship between H and delta. We also found that the inelastic deformation of SC-diamond under indentation could mainly be attributed to the nucleation and propagation of <110>111 dislocation loops. It showed that dislocation blockage and pile up at the TBs may induce additional hardening of the nt-diamond, while the softening of the material could be attributed to: (i) the formation and movement of the dislocation loops parallel with the surface, and (ii) the breakage of TBs, which may serve as new sites for dislocations nucleation.
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