Alumina reinforced eucryptite ceramics: Very low thermal expansion material with improved mechanical properties

Abstract

Composite materials formed by a LAS matrix reinforced with second phases are promising materials in many applications where better mechanical properties than those corresponding to conventional low thermal expansion coefficient materials are required. In this study we will show the capability of the design of a LAS–alumina submicron composite. The main scope of this work is to test the sinterability of the composites and to design a composition for a very low thermal expansion submicron composite. For this purpose, Taimei alumina (TM-DAR) powders and an ad hoc synthesized β-eucryptite phase were used to fabricate the composite. XRD phase compositions and microstructures are discussed together with data from dilatometries in a wide temperature range. The results obtained show the possibility of designing a submicron composite with a very low thermal expansion coefficient and improved mechanical properties that can be used in oxidizing conditions.