Strengthening and toughening of CNTs-reinforced B4C-SiC ceramic composite material via spark plasma sintering

For addressing the issue of low relative density, poor fracture toughness of boron carbide ceramics, carbon nanotubes (CNTs)-reinforced B4C-SiC ceramic composite material was prepared via spark plasma sintering (SPS), and the impact of CNTs on the strengthening and toughening of the composite was studied. The evidence revealed that an appropriate amount of CNTs can enhance the discharge effect and improve the compactness. As the CNTs content increased, the flexural strength and fracture toughness took on a tendency to first rise and then drop. After mixing .5 wt.% CNTs, the flexural strength and fracture toughness were 499 MPa and 5.38 MPa & BULL;m(1/2), which increased by 59.4% and 28.4%, respectively. The transformation of fracture mode, grain refinement, bridging and pulling-out of CNTs efficiently enhance the mechanical properties.