Effect of enforcement content on strength/toughness of laminated SiC_W/SiC ceramic composites

Laminated SiC whisker (SiC_W)/SiC ceramic composites were fabricated by tape casting and chemical vapor infiltration (TC-CVI) process and the effect of SiC_W content on the mechanical properties and microstructures of laminated ceramic composites was discussed. Strengthening/toughening mechanisms of laminated SiC_W/SiC ceramic composites were investigated. The results indicate that TC-CVI process can effectively increase the content of whiskers (40vol%) in composites and reduce the damage to whiskers during fabrication process. Moreover, the fabricated laminated SiC_W/SiC ceramic composites have appropriate interface bonding strength of interfacial and interlaminar. When SiC_W content increases, both of the density and mechanical properties of the laminated ceramic composites can be significantly improved. The density, flexural strength and fracture toughness of laminated SiC_W/SiC ceramic composites with 40vol% whisker are respectively 8.4%, 30.8% and 26.7% higher than those of laminated SiC_W/SiC ceramic composites with 25vol% whisker. Interfacial and interlaminar crack deflection, and interfacial crack bridging and whisker pull-out can be observed in the fracture morphologies, which are main toughening mechanisms. Large content of SiC_W and appropriate interface bonding strength between interfacial and interlaminar can obviously improve the strength and toughness of laminated SiC_W/SiC ceramic composites together.