Dislocation generation in diamond under extreme loading

AC Li and BY Li and RE Rudd and MA Meyers, MATTER, 6 (2023).

DOI: 10.1016/j.matt.2023.06.044

Diamond is, by virtue of its high bonding forces and Peierls-Nabarro barrier stresses, among the hardest materials on earth due to the difficulty of generating and moving dislocations. We demonstrate, using molecular dynamics and analytical calculations, that the generation of defects is dependent on loading orientation. Shock loading single- crystal diamond along 001 and 011 to a stress of 137 GPa did not reveal dislocations, whereas loading along 111 generated profuse dislocations. The introduction of a void at the latter orientation generated dislocations at 72.6 GPa. Two slip systems were identified: <011>100 and <112>111. The threshold for plastic deformation in diamond is orientation dependent and significantly lower than reported in previous studies: 0.14 G (shear modulus). The void collapse generated localized amorphization for 001. These results on the anisotropy of plasticity and void effects have relevance for the improvement of symmetry in the collapse of diamond capsules in inertial fusion experiments.

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