Densification of in-situ Toughened SiC-YAG Composites
原位增韧SiC-YAG复相陶瓷的致密化

Densification, a phase transformation, elongated SiC grain growth and microstructure,and mechanical properties, especially toughness, of in--situ toughened SiC-YAG composites wereinvestigated in detail. By using packing powders with same compositions as packed samples, theevaporation of Al2O3 was inhibited and full densification (>99% of theoretical density) of in-situtoughened SiC-YAG was achieved. The phase transformation occurrs at 1950, however,remained SiC can be still found by XRD after post-heated at 2100 for 4h. The content ofliquid phase and a-SiC seeds has no effect on the phase transformation rate. Following phasetransformation and grain growth during post-heating, further densification of in-situ SiC-YAGcontinues and the network microstructure consisting of elongated SiC grains can be obtained.Finally, the SEPB fracture toughness achieved is near 7.0 MPa.m1/2.