Strengthening effects of penetrating twin boundary and phase boundary in polycrystalline diamond
B Yang and K Tong and C Huang and ZP Qi and DQ Yin and Q Wei and ZS Zhao and XH Peng and N Hu, DIAMOND AND RELATED MATERIALS, 117, 108436 (2021).
The hardness and toughness of polycrystalline diamond have been improved simultaneously in recent years by introducing high-density twin boundaries (TBs) and phase boundaries (PBs), which challenges the existing strengthening and toughening trade-off mechanisms. In this article, we studied the mechanical behavior of polycrystalline diamond rich in high-density penetrating TBs or PBs using first-principles calculations and molecular dynamics simulations. The results showed that TBs can significantly inhibit the nucleation and propagation of dislocations, while PBs has a weak inhibitory effect. Therefore, the polycrystalline diamond rich in TBs possesses relatively superior mechanical properties. The obvious difference of the effects of TBs and PBs on the mechanical properties of polycrystalline diamond is due to the better structural and thermal stability of the former. These results will enrich the existing strengthening and toughening mechanisms in the field of superhard carbon materials.
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