Effect of graphene and SiC whisker on the mechanical properties of WC-TiC-TiN-Al2O3 nanocomposites

Abstract

In this study, dense binderless tungsten carbides (WC) were prepared through two-step sintering (TSS) employing TiC/TiN and MLG/SiCw as the reinforcements. Influences of the hybrid additives on the densification behavior, microstructure as well as mechanical performances of WC-based nano-composite were investigated. TiC/TiN hybrid incorporation resulted in an enhanced densification with inhibited coalescence of the binderless WC through improving the homogeneous distribution of Al2O3 in the WC matrix. The formation of solid-solution and minor liquid phase were the major densification mechanisms. Higher toughening effectiveness was obtained for MLG/SiCw hybrid doping in comparison with single MLG or SiCw addition. A hardness of 22.8 GPa, a flexural strength of 1174.3 MPa coupled with a fracture toughness of 12.7 MPa mm1/2 were achieved for the TiC/TiN and MLG/SiCw co-added WC-based samples. The dominated toughening mechanisms were determined as crack bridging and deflection, MLG/SiCw pullout as well as intragranular/ intergranular microstructure.