MICROSTRUCTURE AND MECHANICAL PROPERTIES OF IN-SITU FORMATION FIBROUS POLYTYPE AlN COMPOSITE-MATERIAL

摘要

In-situ formation fibrous polytype AlN composite ceramic materials was prepared fromAlN-Y2O3-SiO2 system.In comparison with AlN ceramics,both bending strengthand fracture toughness of the composite materials are much bettered.Microstructuralobservation revealed that a lot of epitaxial growth fibrous AlN polytype occurred inmatrix.Y2O3 seems to act as a densifier for in-situ formation materials and as mediumfor growth of fibrous polytype.SiO2 is the growth promoter for fibrous polytype.Theoccurrnce of fibrous polytype may increase the strength and toughness of AlN ceramiccomposite mateirals.