MICROSTRUCTURE AND MECHANICAL PROPERTIES OF IN-SITU FORMATION FIBROUS POLYTYPE AIN COMPOSITE MATERIAL
原位生长纤维状多型体AlN复合陶瓷材料的显微结构与力学性能

In-situ formation fibrous polytype AIN composite ceramic material was prepared from AlN-Y_2O_3-SiO_2 system. In comparison with AlN ceramics, both bending strength and fracture toughness of the composite material are much bettered. Microstructural observation revealed that a lot of epitaxial growth fibrous AlN polytype occurred in matrix. Y_2O_3 seems to act as a densifier for in-situ formation material and as medium for growth of fibrous polytype. SiO_2 is the growth promoter for fibrous polytype. The occurrence of fibrous polytype may increase the strength and toughness of AlN ceramic composite material.