Fabrication and mechanical properties of TiN whisker toughening TiB2 based ceramic cutting tool composite

A TiB2 based ceramic cutting tool composite toughened by TiN whisker was developed. The results show that when the content of TiN whisker powder is 30 vol%, the flexural strength, Vickers hardness and fracture toughness of the composite are 862 MPa, 22.5 GPa, and 8.1 MPa m1/2, respectively. Compared with the composite reinforced by 30 vol% TiN particle, the fracture toughness of the composite toughened by 30 vol% TiN whisker only increases by 11.0 %. Improvement in the fracture toughness of the TiN particle reinforcing composite can be mainly due to the contribution of the mechanisms such as crack deflection and ductile metal phase toughening. These toughening mechanisms almost disappear in the TiN whisker toughening composite because of the high proportion of transgranular fracture. At the same time, the TiN whisker toughening composite also faces the problem of difficulty in whisker pullout. These problems mean that there is still a possibility of further improvement in the fracture toughness of the TiN whisker toughening TiB2 based ceramic cutting tool composite.