Hybrid multilayer graphene and SiC whisker reinforced TiB2 based nano-composites by two-step sintering

Abstract

Advances in the TiB2 nano-composites reinforced with hybrid of SiC whisker (SiCw) and multilayer graphene (MLG) have been thoroughly investigated. Hybrid reinforcements, combining the advantages of SiCw as well as MLG, resulted in further enhanced mechanical properties in TiB2-based ceramic nano-composites. Excellent mechanical properties were achieved for hybrid MLG/SiCw reinforced TiB2–TiN–MgO samples with 2.0 wt% SiCw and 0.4 wt% MLG through two-step sintering with a hardness of 21.2 GPa, a flexural strength of 1006.3 MPa and a fracture toughness of 8.8 MPa mm1/2. Hybrid addition of MLG and SiCw performed effectively on improving the densification and inhibiting grain growth of TiB2-based ceramics. Furthermore, hybrid addition of MLG/SiCw could significantly improve the dispersion of MgO nano-particulates in TiB2 matrix. The synergistic effect of crack deflection, branching and bridging as well as MLG/SiCw pullout dramatically enhanced the toughness of TiB2–TiN–MgO ceramic nano-composites.