Orientation and Grain Boundary Microstructure of Alumina in Al/Al2O3 Composites Produced by Reactive Metal Penetration
Abstract:The orientation and grain boundary microstructure of alumina in reactive metal penetration Al/Al2O3 composites are studied using orientation imaging microscopy and the results are compared with those of sintered polycrystalline Al2O3. The interconnected Al2O3 in the composite material is separated by Σ3 boundaries (twins) with a 60° rotation around the  direction. A high frequency (∼100%) of Σ3 coincidence boundaries in composite alumina is remarkable since only ∼12% of boundaries in a sintered polycrystalline Al2O3 are of special nature. The coincidence boundaries in the in situ alumina grow in a coherent and faceted manner.
Document Type: Research Article
Affiliations: Department of Machine Intelligence and Systems Engineering, Tohoku University, Sendai 980-8579, Japan
Publication date: October 1, 2005