FABRICATION AND MICROSTRUCTURE OF AL2O3 SIC YAG HYBRID COMPOSITES PREPARED BY PARTICULATE DISPERSION

Stable Al2O3-SiC-YAG hybrid composites were successfully fabricated by reaction of Al2O3 and Y2O3 and incorporation of SiC. The hot-pressed bodies consisted of uniformly dispersed grains of microsized YAG parti culates and nanosized SiC particulates in an Al2O3 matrix. Although th e grain size of monolithic Al2O3 increases markedly with increased tem perature, the grain size of the Al2O3-SiC-YAG hybrid composites was ef fectively restrained due to grain-boundary pinning by the particulates .