Microstructure and Mechanical Properties of Hot-Pressed Silicon Carbide Fiber-Reinforced Silicon Carbide Composite

摘要

Continuous 2D woven SiC fiber-reinforced SiC composites were fabricated by hot-pressing at 1650-1750℃ under a pressure of 40 MPa using Al_2O_3-Y_2O_3-CaO system as sintering additives. Bulk density of the composites with non-coated Hi-Nicalon decreased with lowering sintering temperature, whereas that of the composites with BN-coated Hi-Nicalon did not show much difference. The fracture behavior of the composites with non-coated Hi-Nicalon hot-pressed at 1700 or 1750℃ showed slight ductility with short fiber pull-out, whereas the composites with BN-coated Hi-Nicalon showed completely brittle fracture. In the case of composites hot-pressed at 1650℃, the load-displacement curves showed ductile fracture regardless of with/without BN-coating on the fibers. Generally, BN has a low chemically-active nature, however, the sinterability of the composites increased with the presence of BN in the composites.