Effects of Ti(C,N) Nanoparticles on Mechanical Properties of the Si3N4 Ceramics
Si3N4-Ti(C,N) nanocomposites fabricated by vacuum hot pressing with Al2O3 and Y2O3 as additives were investigated. The results showed that the α-Si3N4 phase converted completely into whisker-shaped β-Si3N4 grains after vacuum sintering at 1700°C. Suitable addition and well dispersion of the Ti(C,N) particles can restrained the lateral growth of the β-Si3N4 grains, increasing aspect ratio of the β-Si3N4 grains and improving bending strength of the composites. Fracture toughness of the composites is higher than that of the β-Si3N4 ceramics, and the main toughening mechanism is crack bridging due to the higher aspect ratio of the β-Si3N4 grains.With the addition of 1vol% of Ti(C,N), the composite has a relative density of 99.31%, Vicker’s hardness of 15.9 GPa, bending strength of 993 MPa, and fracture toughness of 9.9 MPa·m1/2.
Linli Xu, Wenya Tian and Elwin Mao
Q. Li et al., "Effects of Ti(C,N) Nanoparticles on Mechanical Properties of the Si3N4 Ceramics", Applied Mechanics and Materials, Vols. 80-81, pp. 119-122, 2011