Processing and Properties of Oriented SiC Whisker-Reinforced Si_3N_4 Ceramic Matrix Composites

摘要

Whisker orientation is one of key factors affecting whisker toughening mechanisms. By extrusion, SiC(w)/Si_3N_4 composites with nearly 1-dimensional oriented alignment of whiskers were prepared. The results showed that whisker orientation had a dramatic influence on strength and toughness of the composites. Especially, along the direction of whisker oriented alignment, as great as 200MPa and 3MPa·m~(1/2) improvements in bending strength and fracture toughness of SiC(w)/Si_3N_4 composites were obtained respectively. Through analyzing the fractographs in the different whisker orientation of the composites, the effects of whisker orientation on toughening mechanisms were discussed. The results showed that effects of whisker reinforcing and loughening could be improved simultaneously through whisker oriented alignment.