Graphene nanosheets were used as additives in the preparation of polycrystalline diamond compact (PDC) composites to overcome the low fracture toughness and heat resistance of PDC composites. The PDC composites were then sintered at a pressure of 5.8 GPa and a temperature of 1500 °C. Subsequently, the mechanical properties, microstructure, and toughness mechanism of PDC composites modified by graphene nanosheets were studied. The PDC sample prepared by adding 0.2 wt% graphene nanosheets had the best comprehensive performance. Compared with the sample without graphene nanosheets, the impact toughness of the sample with 0.2 wt% graphene nanosheets improved by 29.78%, while the heat-resistant temperature increased by 34.5 °C. The hardness and wear resistance of the sample did not show any significant decrease and were essentially the same as those of the unmodified PDC composite sample. Two factors were found to influence the toughening mechanism. On the one hand, the lubricating effect of graphene promoted particle rearrangement, pore filling, and mutual sliding between adjacent diamond particles, which resulted in a denser and more uniform PDC composite material. On the other hand, the graphene nanosheets at the triangular grain boundaries were interspersed in the cobalt binder and led to the formation of a unique structure of “cobalt-graphene nanosheets”. This unique structure acted as the skeletal structure and effectively prevented fracture crack propagation.

石墨烯纳米片被用作制备多晶金刚石复合材料 (PDC) 的添加剂，以克服 PDC 复合材料的低断裂韧性和耐热性。然后在 5.8 GPa 的压力和 1500 °C 的温度下烧结 PDC 复合材料。随后，研究了石墨烯纳米片改性的PDC复合材料的力学性能、微观结构和韧性机理。添加0.2 wt%石墨烯纳米片制备的PDC样品综合性能最好。与不含石墨烯纳米片的样品相比，含有0.2 wt%石墨烯纳米片的样品的冲击韧性提高了29.78%，耐热温度提高了34.5°C。样品的硬度和耐磨性没有表现出任何显着下降，与未改性 PDC 复合材料样品的硬度和耐磨性基本相同。发现有两个因素影响增韧机制。一方面，石墨烯的润滑作用促进了相邻金刚石颗粒之间的颗粒重排、孔隙填充和相互滑动，从而产生了更致密、更均匀的PDC复合材料。另一方面，三角形晶界处的石墨烯纳米片散布在钴粘合剂中，形成了独特的“钴-石墨烯纳米片”结构。这种独特的结构充当骨架结构，有效地阻止了断裂裂纹的扩展。一方面，石墨烯的润滑作用促进了相邻金刚石颗粒之间的颗粒重排、孔隙填充和相互滑动，从而产生了更致密、更均匀的PDC复合材料。另一方面，三角形晶界处的石墨烯纳米片散布在钴粘合剂中，形成了独特的“钴-石墨烯纳米片”结构。这种独特的结构充当骨架结构，有效地阻止了断裂裂纹的扩展。一方面，石墨烯的润滑作用促进了相邻金刚石颗粒之间的颗粒重排、孔隙填充和相互滑动，从而产生了更致密、更均匀的PDC复合材料。另一方面，三角形晶界处的石墨烯纳米片散布在钴粘合剂中，形成了独特的“钴-石墨烯纳米片”结构。这种独特的结构充当骨架结构，有效地阻止了断裂裂纹的扩展。三角形晶界处的石墨烯纳米片散布在钴粘合剂中，形成了独特的“钴-石墨烯纳米片”结构。这种独特的结构充当骨架结构，有效地阻止了断裂裂纹的扩展。三角形晶界处的石墨烯纳米片散布在钴粘合剂中，形成了独特的“钴-石墨烯纳米片”结构。这种独特的结构充当骨架结构，有效地阻止了断裂裂纹的扩展。