Enhanced mechanical properties of cBN-Al-Si3N4 composites by introducing diamond

Cubic boron nitride (cBN) matrix composites were fabricated by introducing submicron diamond under high pressure and high temperature (5.5 GPa, 1500 degrees C). A systematic evaluation of the effects of diamond content on phase composition, microstructure, and mechanical properties of the composites was conducted. We found that diamond has a significant effect on improving the mechanical properties of the composite. The introduction of a small amount of submicron diamond is beneficial to obtain a dense microstructure. The hardness of the composite increased monotonously with increasing diamond content, and the maximum value reached 54.92 GPa. With diamond content of 4 wt%, flexural strength, relative density, and fracture toughness of the composite all reached the maximum value, which was 726.27 MPa, 99.21%, and 7.46 MPa.m(1/2), respectively.

Automated summary

Cubic boron nitride (cBN) matrix composites with submicron diamond exhibit improved mechanical properties. The introduction of a small amount of diamond enhances the density and hardness of the composites. At a diamond content of 4 wt%, the composite achieves the highest values of flexural strength, relative density, and fracture toughness.