Effects of Finely Dispersed B_4C on the Strength and Toughness of Si_3N_4 Ceramics

The effects of B_4C transformation on the strength and toughness of Si_3N_4 ceramics were studied based on the mechanical properties and microstructure of Si_3N_4 ceramics containing 0-30wt% of B_4C.The strengthening and toughening mechanisms were also discussed by means of several strengthening and toughening models,and toughness of energy-balance theory.Results show that the bending strength and toughness of Si_3N_4 ceramics can be effectively increased by the aid of B_4C transformation.