Self-reinforcement in Li-alpha-sialon ceramics

Self-reinforcement of Li-alpha -sialon ceramics by in situ growth of elonga ted alpha and beta -sialon grains has been explored and analysed. Propertie s of Li-alpha -sialon ceramics are mainly determined by the overall startin g composition and the crystalline modification of the starting Si3N4 powder which in turn determine the final microstructure of the materials. Both th e morphology and crystalline phase of the elongated sialon grains have stro ng effects on the toughening mechanism. The results indicate that alpha -si alons reinforced by elongated beta -sialon grains have advantages over simi lar materials reinforced by elongated alpha -sialon grains because of the t ype of crack deflection toughening mechanism involved. (C) 2001 Kluwer Acad emic Publishers.