Preparation and properties of aluminium titanate-alumina composites with a corrugated microstructure

Abstract

Repeated deformation processing was used to produce layered aluminium titanate (ATI)-alumina composites with a corrugated microstructure. Viscous nonpolar pastes of ATI and alumina powders were prepared using paraffin oil as the dispersing medium. These pastes were rolled into tapes 1 mm thick, which were then stacked together to form starting bi-material laminates in an A-B-A sequence. The laminates were then plastically deformed by repeated folding and rolling at room temperature. After a sufficiently large true plastic deformation, composites with corrugated microstructures were successfully produced. During sintering, part of the ATI decomposed; in the alumina layers large anisotropic grains were formed. The mechanical properties of the sintered composites improved with structural refinement, in spite of extensive microcracking observed during cooling from the sintering temperature. In addition, the thermal expansion coefficient along the rolling direction did not differ from that of the reference material.