Effect of SiC whiskers on mechanical properties of thermally stable polycrystalline diamond prepared by HPHT sintering

In this study, polycrystalline diamond (PCD) with high thermal stability had been successfully synthesized at high pressure and high temperature. Studied PCD was found to be thermally stable in air up to ~968 °C. Meanwhile, maximum flexural strength of PCD was obtained to be 645 MPa. In order to improve fracture toughness of the thermally stable PCD, mass fraction of 1–20 wt% of SiC whiskers was introduced as reinforcements. Fracture toughness of PCD reinforced with 10 wt% SiC whiskers reached up to 7.3 MPa·m1/2, which was higher than that of PCD without SiC whiskers (4.5 MPa·m1/2). Multi-scale toughening mechanisms including crack deflection, whiskers bridging and pull-out were associated with such improvement. [Display omitted] •Thermally stable PCD was synthesized by high pressure and high temperature.•SiC whiskers as reinforcements were introduced into the PCD.•Fracture toughness of PCD reinforced with SiC whiskers was enhanced.•Toughening mechanism of SiC whiskers was investigated.